Database: MEDLINE <: biomedical, nursing & dental literature, 1966 - Nov 2000.> Search Strategy (You Saved Citations 1-208 From Set 64): ----------------------------------------------------------------------------- 1 exp Tooth demineralization/ 22684 2 demineralization.mp. 1629 3 caries.mp. 15334 4 caires.mp. 1 5 craies.mp. 0 6 careis.mp. 4 7 carise.mp. 0 8 (teeth adj3 cavit:).mp. 422 9 (tooth adj3 cavit:).mp. 217 10 (dental adj3 cavit:).mp. 276 11 (dentin adj3 cavit:).mp. 256 12 (enamel adj3 cavit:).mp. 183 13 (teeth adj3 decay:).mp. 379 14 (tooth adj3 decay:).mp. 325 15 (dental adj3 decay:).mp. 251 16 (dentin adj3 decay:).mp. 12 17 (enamel adj3 decay:).mp. 20 18 (active adj decay).mp. 9 19 (rampant adj3 decay:).mp. 14 20 (recurrent adj3 decay:).mp. 30 21 (white adj spot:).mp. 513 22 carious.mp. 2083 23 cariology.ti,ab. 56 24 (non-cavitated adj3 lesion:).mp. 15 25 (noncavitated adj3 lesion:).mp. 2 26 Tooth remineralization/ 479 27 (dental adj3 fissure:).mp. 99 28 (tooth adj3 fissure:).mp. 50 29 (teeth adj3 fissure:).mp. 98 30 caries-free.mp. 606 31 cariesfree.mp. 17 32 Cariogenic agents/ 729 33 precavit:.mp. 8 34 (filled adj3 teeth).mp. 513 35 (filled adj3 tooth).mp. 117 36 (oral adj fissure:).mp. 6 37 (tooth adj3 remineraliz:).mp. 28 38 (teeth adj3 remineraliz:).mp. 24 39 dft.mp. 415 40 dfs.mp. 1266 41 dmf:.mp. 6412 42 cariogeni:.mp. 1789 43 or/1-42 32343 44 Dental enamel proteins/ 707 45 amelogenin.mp. 390 46 enamelin.mp. 79 47 ameloblastin.mp. 21 48 tuftelin.mp. 22 49 (enamel adj matrix adj serine adj protease:).mp. 1 50 (dentin: adj phosphoprotein:).mp. 205 51 (dentin: adj matrix: adj protein:).mp. 36 52 (dentin: adj sialoprotein:).mp. 45 53 (dentin: adj sialophosphoprotein:).mp. 9 54 "DPP".mp. 1029 55 "DMP".mp. 486 56 "DSPP".mp. 11 57 "DSP".mp. 896 58 or/54-57 2400 59 dentin:.mp. 13431 60 58 and 59 59 61 Collagen/ 46914 62 or/44-53,60-61 47851 63 43 and 62 243 64 limit 63 to english language 208 65 from 64 keep 1-208 208 *************************** <1> UI - 20341505 AU - Acil Y AU - Terheyden H AU - Dunsche A AU - Fleiner B AU - Jepsen S IN - Department for Oral and Maxillofacial Surgery, Kiel University, Arnold-Heller-Strasse 16, 24105 Kiel, Germany. acil@mkg.uni-kiel.de TI - Three-dimensional cultivation of human osteoblast-like cells on highly porous natural bone mineral. SO - Journal of Biomedical Materials Research 2000 Sep 15;51(4):703-10 AB - In this study, we investigated the growth and extracellular matrix synthesis of human osteoblast-like cells on highly porous natural bone mineral. Human bone cells were isolated from trabecular bone during routine iliac crest biopsies. Under conventional culture conditions, trabecular bone cells were able to assume the organization of a three-dimensional structure on a porous natural bone mineral (Bio-Oss(R) Block). Scanning electron microscopy examination after 6 weeks revealed multiple cell layers on the trabecular block. Transmission electron microscopy examination after 6 weeks revealed the accumulation of mature collagen fibrils in the intracellular and extracellular spaces, and showed multilayered, rough endoplasmic reticulum as well as mitochondria-rich cells surrounded by dense extracellular matrix. These morphological observations suggest that the cell layer may resemble the natural three-dimensional structure. Biochemical analysis revealed that the hydroxylysylpyridinoline, lysylpyridinoline, and hydroxyproline content of the cell layer increased in a time-dependent manner, whereas in monolayer culture without natural bone mineral, no measurable amounts of hydroxylysylpyridinoline or lysylpyridinoline, and a barely measurable amount of hydroxyproline, were noted. Mature collagen extracted by ethylenediaminetetraacetic acid-demineralization from the cell layer on natural bone mineral showed an identical electrophoretic pattern to that observed in human bone, as evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The present study demonstrated an excellent biocompatibility of the highly porous natural bone mineral in a three-dimensional bone cell culture system, and thus its potential for tissue-engineered growth of human bone. <2> UI - 20265403 AU - Schwartz Z AU - Lohmann CH AU - Wieland M AU - Cochran DL AU - Dean DD AU - Textor M AU - Bonewald LF AU - Boyan BD IN - Department of Orthopedics, University of Texas Health Science Center, San Antonio 78229-3900, USA. TI - Osteoblast proliferation and differentiation on dentin slices are modulated by pretreatment of the surface with tetracycline or osteoclasts. SO - Journal of Periodontology 2000 Apr;71(4):586-97 AB - BACKGROUND: Implant surface roughness and chemical composition, as well as other factors, affect the ability of osteogenic cells to form bone adjacent to an implant. The same principles may also apply to the tooth root and some reports have shown that surface modification of the root may lead to improved restoration of the periodontal apparatus. The most common of these surface modification techniques involves demineralization with citric acid or treatment with tetracycline to expose collagen fibrils. In addition, during normal bone remodeling, osteoclasts demineralize the extracellular matrix, leaving resorption pits and exposed collagen fibrils. In this study, the effect of different dentin surface-preparation techniques on osteoblasts were compared. METHODS: Slices of sperm whale dentin were mechanically polished and surfaces were treated with tetracycline-HCl (TCN) or were cultured with mouse bone marrow cells to create a surface with osteoclast (OC) resorption pits or left untreated. Profilometry, x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to evaluate the 3 different dentin surfaces. MG63 osteoblast-like cells were cultured on the 3 different surfaces and the effect of dentin surface preparation technique on MG63 cell proliferation (cell number), differentiaton (alkaline phosphatase specific activity of isolated cells and cell layer lysates; osteocalcin production), and local factor production (transforming growth factor (TGF)-beta1 and prostaglandin E2 (PGE2) compared. RESULTS: Profilometry showed the polished and TCN surfaces were smooth with comparable Ra values, whereas the OC surfaces were slightly rougher due to resorption pits which covered 3.7% of the surface. XPS measurements showed that TCN treatment reduced the Ca and P content of the surface, indicating that it had dissolved the mineral. Osteoclast-resorption also reduced the Ca and P content, but to a lesser extent. MG63 cell proliferation on polished dentin and tissue culture polystyrene was equivalent. In contrast, cells grown on the TCN- and OC-treated surfaces exhibited increased proliferation. No effect of surface treatment on cell alkaline phosphatase activity was observed, but activity in the cell layer lysates was increased on the TCN- and OC-treated surfaces. Osteocalcin production was reduced on all dentin surfaces, but the greatest reduction was found on the TCN-treated surface. Production of both TGF-beta1 and PGE2 was increased on the treated surfaces. All effects were greatest in cultures grown on the TCN-treated dentin. CONCLUSIONS: These data indicate that demineralization of the dentin surface promotes proliferation of osteoblasts and early differentiation events like production of alkaline phosphatase and autocrine mediators such as PGE2 and TGF-beta1. However, later differentiation events like osteocalcin production are decreased. Osteoclast-mediated bone resorption elicits similar responses; less than 4% of the dentin surface resulted in approximately 75% of the response caused by TCN treatment. These observations suggest that greater attention should be paid to the effects of osteoclastic resorption in designing methods for enhancing bone and cementum formation adjacent to root surfaces. <3> UI - 20321765 AU - Eliades G AU - Vougiouklakis G AU - Palaghias G IN - Research Center for Biomaterials, Athens, Greece. ekevyl@hol.gr TI - Effect of dentin primers on the morphology, molecular composition and collagen conformation of acid-demineralized dentin in situ. SO - Dental Materials 1999 Sep;15(5):310-7 AB - OBJECTIVES: The purpose of this study was to assess the effect of two commercial primers and distilled water on the morphology, molecular composition and collagen conformation of acid-demineralized dentin in situ. METHODS: Dentin specimens etched with Scotchbond Etchant were imaged by tapping mode AFM and analyzed by MIR-FTIR spectroscopy. They were then primed with Scotchbond Multi-Purpose Plus Primer, Scotchbond 1 Adhesive or distilled water and imaged and analyzed again. The chemical modifications induced on the uppermost 2 microns of primed dentin were studied after water and original primer subtraction. The conformational changes of type I collagen at this region were evaluated by deconvoluting the amide I band components. The absorbance ratio An(1655/1627) was used to semiquantitatively assess, on a relative basis, the extent of collagen denaturation. RESULTS: All the priming treatments swelled the collapsed dentin collagen left after etching. No evidence of primary bonding was found after priming treatments, while approximately 50% of the conditioned dentin collagen appeared denatured. Treatment with distilled water did not change the status of denatured collagen, however, application of the commercial primers refolded the alpha-helix to approximately 95% of the extent found on the native reference dentin. SIGNIFICANCE: The dynamic response of dentin collagen to demineralization and priming treatments reveals the critical role of some primers in rapidly restoring the conformational status of acid-denatured collagen. Implementation of reactive adhesive groups in alpha-helix recovery may provide an associative means of modifying the mechanical properties of the demineralized collagen based on the extent of their intermolecular bonding. <4> UI - 20206382 AU - Kirkham J AU - Robinson C AU - Strafford SM AU - Shore RC AU - Bonass WA AU - Brookes SJ AU - Wright JT IN - Division of Oral Biology, Leeds Dental Institute, Clarendon Way, Leeds, UK. orl.6jen@oralbio.novell.leeds.ac.uk TI - The chemical composition of tooth enamel in junctional epidermolysis bullosa. SO - Archives of Oral Biology 2000 May;45(5):377-86 AB - The junctionalis form of epidermolysis bullosa (EBJ) is associated with a number of clinical problems involving tooth enamel, including increased susceptibility to caries. The aim here was to carry out a chemical characterization of the enamel of teeth from EBJ patients compared with that of unaffected controls. The results showed that while protein concentration, amino acid composition and carbonate content were similar in both groups, EBJ enamel contained a significantly reduced mineral per volume content, resulting in enamel hypoplasia. In addition, Western blotting revealed the presence of serum albumin (a known inhibitor of enamel crystal growth) in EBJ enamel. This was not detected in control enamel or in enamel of teeth from patients with the dystrophic form of the disease. It is concluded that EBJ enamel is developmentally compromised and that the enamel defects are commensurate with the reported genetic lesions. <5> UI - 20114181 AU - Milia E AU - Lallai MR AU - Garcia-Godoy F IN - Department of Restorative Dentistry, Universita degli Studi di Sassari, Italy. emilia@odontoiatria.medicina.uniss.it TI - In vivo effect of a self-etching primer on dentin. SO - American Journal of Dentistry 1999 Aug;12(4):167-71 AB - PURPOSE: To determine the ultrastructural aspects of the dentin collagen area in the cavity preparation floor produced in vivo after phosphoric acid acid-etching or after using Clearfil Liner Bond 2 self-etching primer (LB2 Primer). MATERIALS AND METHODS: Twenty-four non-carious third molars scheduled for extraction from young adult patients (16-30 years old) were used. Conventional Class I cavities (+/- 2 mm deep) were prepared on the occlusal surfaces of all teeth using a cylindrical diamond bur on a high-speed handpiece with copious water spray. To avoid dehydration of the dentin, the smear layer-covered dentin was briefly air-dried for 2 seconds. Cavities were assigned at random to the following groups: Group A: Dentin etched for 15 seconds with 34% phosphoric acid, rinsed for 20 seconds and then briefly air-dried for 2 seconds with oil-free compressed air leaving the surfaces slightly moist. Group B: LB2 Primer was applied to the cavity surfaces for 30 seconds and then briefly air-dried to remove the solvent. Group C: The untreated dentin smear layer was used as a control. In all three groups, the cavities were filled incrementally with a resin-based composite (APX), light curing every increment for 40 seconds. After 30 minutes, the teeth were extracted atraumatically and the samples immediately prepared for evaluation with the transmission electron microscope. RESULTS: The use of a self-etching primer did not produce significant morphological changes in the moist dentin substrate. Adverse morphological conditions where observed when there was an excess water on the dentin surface. Phosphoric acid altered the collagen more severely than the self-etching primer. <6> UI - 20043058 AU - Dung SZ IN - Division of Periodontology, National Yang-Ming University, Taipei, Taiwan, ROC. TI - Effects of mutans streptococci, Actinomyces species and Porphyromonas gingivalis on collagen degradation. SO - Chung Hua i Hsueh Tsa Chih - Chinese Medical Journal 1999 Nov;62(11):764-74 AB - BACKGROUND: While Streptococcus mutans and Actinomyces spp are considered to be major pathogenic microorganisms of root caries, their roles in the degradation of organic matrix components of human root dentin need clarification. METHODS: Ten laboratory strains and 11 clinical isolates of mutans streptococci and Actinomyces species, and positive bacterial or purified enzyme controls (Porphyromonas gingivalis whole cell lysates, trypsin or clostridial collagenase) were used to establish the degradation of azocollagen (AC), insoluble type I collagen (IC) or human dentin collagen (DC) from dentin powder in two types of experiments investigating collagenolytic activity either during or after bacterial growth. Ultraviolet-irradiated dentin powder and gamma-irradiated IC were used to assess the collagenolytic activity of test strains during bacterial growth. AC, IC and acid-treated dentin powder were used to determine the collagenolytic activity of sonicated bacterial whole cells and cell-free culture supernatants recovered from test strains after growth. Hydroxyproline or spectrophotometric assays were used to analyze the level of degraded collagen. RESULTS: Data from this study showed that in contrast to the positive controls, none of the laboratory strains or clinical isolates elicited significant degradation of AC, IC or DC. CONCLUSIONS: Results indicated that mutans streptococci and Actinomyces species had no significant collagenolytic activity, but may be involved in the root caries process through other mechanisms. In addition, proteolytic enzymes from other oral bacteria such as Porphyromonas gingivalis or from host cells such as neutrophils may also participate in the pathogenesis of root caries. <7> UI - 99451701 AU - Dung TZ AU - Liu AH IN - Division of Periodontology, Yang-Ming University, Taipai, Taiwan. tony@mailsrv.ym.edu.tw TI - Molecular pathogenesis of root dentin caries. [Review] [96 refs] SO - Oral Diseases 1999 Apr;5(2):92-9 AB - Human dentin has a higher content of organic matrix and more non-ideal hydroxyapatite than human enamel. Ultrastructural studies indicate that root caries involves both mineral dissolution and breakdown of the organic matrix. Factors involved in the root caries process seem more complicated than those in enamel caries. Moreover, the distinct roles of acids and enzymes and the sequence of events in the root caries process are not well-understood. Although Streptococcus mutans and Actinomyces viscosus are considered to be major pathogenic micro-organisms of root caries, their roles in degradation of the organic matrix components of root dentin need clarification. The purpose of this paper is to review the basic composition of root dentin and the roles of acids and both endogenous and bacterial enzymes in the root caries process. [References: 96] <8> UI - 99381476 AU - Lan WC AU - Lan WH AU - Chan CP AU - Hsieh CC AU - Chang MC AU - Jeng JH IN - School of Dentistry, College of Medicine, National Taiwan University, Taipei. TI - The effects of extracellular citric acid acidosis on the viability, cellular adhesion capacity and protein synthesis of cultured human gingival fibroblasts. SO - Australian Dental Journal 1999 Jun;44(2):123-30 AB - Root surface demineralization is widely used as an adjunct to periodontal treatment. To clarify the influence of citric acid root conditioning on periodontal wound healing, the effects of citric acid and associated extracellular acidosis on the viability (MTT assay), attachment and protein synthesis ([3H]-proline incorporation into trichloroacetic acid-precipitated proteins) of human gingival fibroblasts (GF) were investigated. A concentration of 47.6 mmol/L of citric acid (pH 2.3) in water led to total cell death within three minutes of incubation. Media containing 23.8 mmol/L and 47.6 mmol/L of citric acid exerted strong cytotoxicity (47 to 90 per cent of cell death) and inhibited protein synthesis (IC50 = 0.28 per cent) of GF within three hours of incubation. Incubation of cells in a medium containing 11.9 mmol/L of citric acid also suppressed the attachment and spreading of fibroblasts on culture plates and Type I collagen, with 58 per cent and 22 per cent of inhibition, respectively. Culture medium supplemented with 11.9, 23.8 and 47.6 mmol/L of citric acid also led to extracellular acidosis by decreasing the pH value from 7.5 to 6.3, 5.2 and 3.8, respectively. In addition, it was confirmed that the toxic effect of media containing citric acid was due to their acidity rather than the citrate content. Most of the citric acid-induced cell death could be prevented by adjusting the pH value of the culture medium to pH 7.5. Sodium citrate, at a concentration of 47.6 mmol/L, also exerted little cytotoxicity. The results suggested that toxicity of citric acid in specific stages of the healing process must be considered prior to its clinical application. Careful management of citric acid in order to avoid contact with tissue or the development of other demineralizing agents is important in enhancing periodontal wound healing. <9> UI - 99308092 AU - Blomlof JP AU - Blomlof LB AU - Cederlund AL AU - Hultenby KR AU - Lindskog SF IN - Department of Basic Oral Sciences, Faculty of Odontology, Karolinska Institutet, Huddinge, Stockholm, Sweden. TI - A new concept for etching in restorative dentistry?. SO - International Journal of Periodontics & Restorative Dentistry 1999 Feb;19(1):30-5 AB - The purpose of the present study was to investigate the scanning electron microscopic texture of enamel and dentin cavity surfaces in extracted human teeth following different etching modalities, specifically combinations of etchants adapted to the tissue composition of the cavity walls. It was concluded that an etching technique that combined the action of 2 different etchants--ethylenediaminetetraacetic acid (EDTA) on dentin and phosphoric acid on enamel--optimized retention structures on each tissue surface of a dental cavity better than either 1 of the 2 etchants that were applied to both types of tissue in the cavity walls. <10> UI - 99173476 AU - Nakade O AU - Koyama H AU - Arai J AU - Ariji H AU - Takada J AU - Kaku T IN - Department of Oral Pathology, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Japan. o-nakade@hoku-iryo-u.ac.jp TI - Stimulation by low concentrations of fluoride of the proliferation and alkaline phosphatase activity of human dental pulp cells in vitro. SO - Archives of Oral Biology 1999 Jan;44(1):89-92 AB - Fluoride has been used for decades, either systemically or topically, to prevent dental caries. The purpose of this study was to clarify the effects of low concentrations of fluoride on proliferation, differentiation and extracellular-matrix synthesis in normal human dental pulp cells (DP-1 and DP-2) in vitro. The effects were compared with those on a human osteoblastic osteosarcoma cell line, TE-85. Fluoride at micromolar concentrations significantly and dose-dependently stimulated [3H]thymidine incorporation into DNA in DP-1, DP-2 and TE-85 cells, with optimal effects around 50 microM, by 127 +/- 7%, 124 +/- 0.6% and 152 +/- 13.4%, respectively. To assess the potential influence of fluoride on cell differentiation, the effects of mitogenic concentrations on alkaline phosphatase activity were measured. Fluoride significantly increased the enzyme's activity in DP-1 and TE-85 by 177 +/- 12% and 144 +/- 12.3%. To evaluate the effect on extracellular-matrix synthesis, the synthesis of type I collagen was indirectly determined by an assay of procollagen type I c-peptide production. Fluoride significantly increased that production by 150 +/- 8.7% in TE-85, but not in either DP-1 or DP-2. These observations suggest that fluoride, if used at low concentrations, could be a useful therapeutic agent where increased regeneration of dentine is desired, such as after pulp amputation, by stimulating the proliferation and differentiation of the dental pulp cells. <11> UI - 99212548 AU - Zhang Y AU - Agee K AU - Nor J AU - Carvalho R AU - Sachar B AU - Russell C AU - Pashley D IN - Department of Oral Biology, School of Dentistry, Medical College of Georgia, Augusta, USA. TI - Effects of acid-etching on the tensile properties of demineralized dentin matrix. SO - Dental Materials 1998 Jun;14(3):222-8 AB - OBJECTIVES: Little research has been done to evaluate the effects of acids commonly used in adhesive dentistry, on the tensile properties of the demineralized dentin matrix. The purpose of this study was to evaluate the effects of a number of acidic conditioners on the ultimate tensile strength (UTS) and modulus of elasticity (E) of human coronal dentin matrix. METHODS: Small hour-glass shaped (for UTS) or l-beam shaped (for determination of E) were prepared from mid-coronal dentin of extracted human third molars. After protecting the ends with varnish, the middle of the specimens was completely demineralized in 0.5 M EDTA (pH 7). UTS was determined by tensile stressing to failure. Modulus of elasticity was calculated from stress strain curves. The results were analyzed by ANOVA and Student-Neuman-Keuls test at the 95% confidence level. RESULTS: Brief (ca. 1-2 min) exposure of demineralized dentin matrix to acids had no measurable effects on its tensile properties. Ten-minute exposures to 2.5% and 17.5% nitric acid lowered (p < 0.05) the UTS compared to phosphate buffered saline (PBS)-exposed controls. Exposure of the decalcified dentin to 10% citric acid containing 3% ferric chloride, 10% citric acid, 37% phosphoric acid or 17.5% nitric acid containing 3% ferric chloride for 10 min had no effect on UTS. None of these acids consistently lowered stiffness. SIGNIFICANCE: The results indicate that relatively long exposures to acids are required to alter the tensile properties of demineralized dentin. It is unlikely that the brief exposures to acids that are used in adhesive dentistry would acutely weaken the physical properties of demineralized dentin. However, long-term studies should be done to determine if such treatment increases the susceptibility of the matrix to hydrolysis. <12> UI - 99000621 AU - Suzuki Y AU - Yamaguchi A AU - Ikeda T AU - Kawase T AU - Saito S AU - Mikuni-Takagaki Y IN - Department of Oral Biochemistry, Kanagawa Dental College, Yokosuka, Japan. TI - In situ phosphorylation of bone and dentin proteins by the casein kinase II-like enzyme. SO - Journal of Dental Research 1998 Oct;77(10):1799-806 AB - Our previous studies suggested the possibility of extracellular phosphorylation of matrix phosphoproteins into more phosphorylated forms by mature odontoblasts and osteocytes (Mikuni-Takagi et al., 1995; Satoyoshi et al., 1995). To elucidate such phosphorylation of bone and dentin proteins, we developed a histochemical method using frozen sections to determine the sites of enzymatic processing by the casein kinase II-like enzyme. It was observed that proteins in bone, dentin, and predentin are phosphorylated by the endogenous enzyme when the tissue slices were incubated with [gamma-32P] GTP, suggesting that there are both substrates and the enzyme in these matrices. In vivo, phosphate donors, ATP and GTP, may be supplied through dentinal canals and osteocyte canaliculi. Immunohistochemical analysis of frozen sections showed that the extremely intense staining of phosphoserine residues by anti-phosphoserine antibodies appeared in dentin only after demineralization of the tissue samples. It implies that these phosphoserine residues become bound to mineral as soon as the phosphorylation is completed, thereby being inaccessible to the antibodies without demineralization. The data support our notion that the extracellular phosphorylation of dentin/bone proteins, regulated by the developmental stages of bone and dentin cells, occurs prior to matrix mineralization. <13> UI - 98368984 AU - Clarkson BH AU - Chang SR AU - Holland GR IN - Department of Cariology, Restorative Sciences and Endodontics, University of Michigan, Ann Arbor, Mich., USA. bricla@umich.edu TI - Phosphoprotein analysis of sequential extracts of human dentin and the determination of the subsequent remineralization potential of these dentin matrices. SO - Caries Research 1998;32(5):357-64 AB - Phosphoprotein appears to play an important role in the mineralization of dentin during tooth development and remineralization after demineralization by dental caries. To better understand this role, we describe the extraction and characterization of phosphoprotein from immature, human root apex dentin during and after EDTA demineralization. The extraction procedure included dissociation of the demineralized dentin matrix by guanidine hydrochloride (Gdn.HCl) followed by subsequent digestion with cyanogen bromide (CNBr) and collagenase. Characterization of these extracts included 'Stains-All' staining of SDS polyacrylamide gels (SDS-PAGE) and amino acid, protein and phosphorus analyses. The ability of these matrices to remineralize was determined by TEM and measuring calcium levels in the remineralized tissue by atomic absorption spectroscopy. The staining of SDS-PAGE gels and amino acid analysis showed that an intact phosphophoryn was extracted from the dentin of the immature apices during EDTA demineralization and that it had an apparent Mr approximately 140,000. In the subsequent extracts and digests, the phosphoprotein has a range of molecular weights, some of which may have been degraded products of the intact phosphoprotein. A greater quantity of phosphoprotein was found in the EDTA-demineralized dentin matrices than in dentin after Gdn.HCl, CNBr and collagenase digests. These EDTA-demineralized matrices also remineralized to a greater extent than those dissociated with Gdn.HCl. The differences in both the quantity and the quality, as defined by the amino acid residue profile, of the phosphoprotein in the sequential extracts of the root apex dentin may be important in affecting the ability of this tissue to remineralize. <14> UI - 98375395 AU - Wiebe CB AU - Larjava HS IN - Department of Oral Biological and Medical Sciences, University of British Columbia, Vancouver, Canada. TI - Do mutations in the basement membrane zone affect the human periodontium? Review with special reference to epidermolysis bullosa. [Review] [83 refs] SO - Journal of the Western Society of Periodontology - Periodontal Abstracts 1998;46(1):5-18 AB - Epidermolysis bullosa (EB) is a group of diseases characterized by the development of blisters or erosions following minor trauma to the skin. Oral findings that have been associated with EB include keratin-filled cysts; blistering of the mucosa, tongue, and lips; perioral carcinomas; ankyloglossia; lingual papilla atrophy; caries; enamel hypoplasia; rapid attrition of the teeth; and obliteration of the oral vestibule. Defects at the basal cell/basement membrane/connective tissue levels correspond to the mutations in basal cell keratins, hemidesmosome components, and type VII collagen, respectively. In a number of types of EB, structural defects in the skin have been shown and genetic mutations determined. Although there are no publications documenting the prevalence of periodontal diseases in patients with epidermolysis bullosa, it is likely that some molecular defects in the basement membrane zone could increase the susceptibility of a patient to periodontal disease, as this has been noted in the related disorder of Weary-Kindler syndrome. Early-onset periodontal disease can be expected to develop in some types of EB patients, even in the absence of common periodontal pathogens, because of a reduced resistance at the junctional epithelial complex. [References: 83] <15> UI - 98383518 AU - Tjaderhane L AU - Larjava H AU - Sorsa T AU - Uitto VJ AU - Larmas M AU - Salo T IN - Faculty of Dentistry, University of British Columbia, Vancouver, Canada. TI - The activation and function of host matrix metalloproteinases in dentin matrix breakdown in caries lesions. SO - Journal of Dental Research 1998 Aug;77(8):1622-9 AB - Matrix metalloproteinases (MMPs) are a family of enzymes which, in concert, are capable of degrading collagen. We investigated whether human MMPs could participate in the degradation of dentin organic matrix after demineralization. We performed Western blot analyses using MMP-specific antibodies to identify MMPs in human dental caries lesions. Enzymography and functional activity assays, with 125I-labeled gelatin as substrate or quantitating the degradation of type I collagen, were used to determine the activity of purified and salivary gelatinolytic (MMP-2 and MMP-9) and collagenolytic (MMP-8) enzymes with and without acid-activation in pHs relevant to caries. Respective analyses were done with caries-related bacteria. We performed electron microscope analyses to assess the degradative activity of sterilized salivary host MMPs on demineralized human dentin. Human MMP-2, MMP-8, and MMP-9 were identified in demineralized dentinal lesions. The latent purified forms of these enzymes were activated at low pH (4.5), followed by neutralization, mimicking the conditions during caries progression. Incubation of human saliva at low pH followed by neutralization resulted in a four-fold increase in the gelatinolytic activity. No gelatinolytic or collagenolytic activity was observed in bacterial samples. The activated enzymes in saliva degraded demineralized dentin organic matrix in vitro. These results demonstrate the pH-dependent activation mechanism of MMPs, which may have a distinct role in different physiological and pathological conditions. They further demonstrate that host MMPs, activated by bacterial acids, have a crucial role in the destruction of dentin by caries. <16> UI - 98327597 AU - Bergenholtz A AU - Babay N IN - Department of Preventive Dental Sciences, College of Dentistry, King Saud University College of Dentistry, Riyadh, Kingdom of Saudi Arabia. TI - Scanning electron microscopy of the root surface texture of extracted periodontally diseased teeth following various etching and chelating regimens. SO - International Journal of Periodontics & Restorative Dentistry 1998 Apr;18(2):171-9 AB - Scanning electron microscopy of root surfaces that had been ultrasonically scaled and subjected to various conditioning regimens revealed the presence of two distinct types of cracks: extensive cracks, presumed to have been caused by drying before and during sputter-coating procedures; and smaller cracks that reflected the pattern of the irregular underlying dentin. Both etching and chelating agents appear to cause demineralization of the interfacial layer between cementum and dentin, causing a "peeling off" of cementum and exposure of the underlying dentin. The results suggest that burnishing the scaled root surface with either saline or any of the etching or chelating agents for at least 10 seconds, followed by soaking the cementum in 8% ethylenediaminetetraacetic acid for about 40 seconds, achieved a root surface that might be regarded as optimal for regeneration of periodontal tissues. <17> UI - 98154908 AU - Saito T AU - Yamauchi M AU - Crenshaw MA IN - Dental Research Center, University of North Carolina at Chapel Hill, 27599-7455, USA. TI - Apatite induction by insoluble dentin collagen. SO - Journal of Bone & Mineral Research 1998 Feb;13(2):265-70 AB - Phosphoproteins are thought to play a role in mineral formation in dentin. A portion of this phosphoprotein is bound to collagen. We have investigated the requirement for bound phosphate in mineral induction by isolated dentin collagen. Insoluble bovine dentin collagen obtained by ethylene-diamino-tetra-acetic acid (EDTA) demineralization had 19.5 mol of P/mol of collagen that could not be extracted with 0.5 M EDTA in 4 M guanidine HCl. When this collagen was incubated in supersaturated solutions that did not spontaneously precipitate, apatite was induced. With progressive enzymatic dephosphorylation, induction times for mineral formation became progressively longer. The dentin did not induce mineral formation when 90% of the ester phosphate was removed. Insoluble bone collagen, which had even less phosphate, also did not induce mineral formation. Mineral induction times by dentin collagen increased with decreasing solution saturations. Using these data, the interfacial tension for mineral induction was determined to be 90 ergs/cm2. This value approximated that of phosphatidic acid liposomes and of phosvitin cross-linked to agarose beads, and it might reflect the energetics of heterogeneous nucleation on a highly phosphorylated surface. Sequestering of calcium-phosphate clusters on the phosphoprotein probably accounts for the observed calcium binding by dentin collagen in excess of that required to neutralize the phosphate esters of the collagen. Because the phosphoprotein is immobilized at a low density on the collagen, it cannot self-associate in calcium-phosphate solutions as it does when it is free in solution. This immobilized phosphoprotein allows the mineral clusters formed on its surface to grow into a crystalline order. <18> UI - 98231493 AU - Ovchinnikov IV AU - Ovtchinnikova OI AU - Druzina EB AU - Buzhilova AP AU - Makarov NA IN - Genetic Identification Center, Moscow, Russia. TI - Molecular genetic sex determination of Medieval human remains from north Russia: comparison with archaeological and anthropological criteria. SO - Anthropologischer Anzeiger 1998 Mar;56(1):7-15 AB - Sex determination presents a difficult problem in archaeology and anthropology in cases of fragmentary or juvenile remains, and where grave goods are absent. Here, a molecular genetic analysis of the sex of human remain from the Early Medieval cemetery at Nefedievo, North Russia, was carried out and the results were compared with archaeological and anthropological data. Teeth without cavities (15 samples) and bones (9 samples) were used as the ancient DNA source. The repetitive sequences in DYZ1, DYZ3, DXZ3 loci, and a unique sequence in the first intron of the X-Y homologous gene amelogenin, were amplified. Sex was determined in 87.5% of the samples by archaeological criteria, in 95.8% of the samples by anthropological methods, and in 79.2% of the samples by DNA analysis. PCR allowed the sex of infant's remains to be identified in individual where the sex could not be determined by anthropological methods and in three remains where sex could not be inferred from archaeological data. Uneven preservation of nuclear DNA loci was evident. <19> UI - 98156636 AU - Kleter GA AU - Damen JJ AU - Buijs MJ AU - Ten Cate JM IN - Department of Cariology-Endodontology-Pedodontology, Academic Center for Dentistry Amsterdam (ACTA), The Netherlands. TI - Modification of amino acid residues in carious dentin matrix. SO - Journal of Dental Research 1998 Mar;77(3):488-95 AB - The Maillard reaction between sugar and protein has been postulated as the cause for the browning and arrestment of caries lesions. This reaction has been implicated as the cause for decreased degradability of collagen in vivo. The aim of the present study was to verify the occurrence of the reaction in vivo. Carious and sound dentin samples were taken from extracted human teeth and analyzed for the fluorescence characteristic of the Maillard reaction and oxidation and, by HPLC, for Maillard products. In addition, physiological cross-links were analyzed by HPLC. Oxidation- and Maillard reaction-related fluorescence increased in collagenase digests from carious dentin. Advanced Maillard products (carboxymethyllysine and pentosidine) increased, whereas furosine, a marker for the initial reaction, was not observed consistently. This implies no direct addition of sugars to protein, but rather the addi-tion of smaller metabolites and glycoxidation products. In addition, the physiological cross-links hydroxylysinonorleucine and dihydroxylysinonorleucine decreased in carious dentin. Also for hydroxylysylpyridinoline, a decrease was observed, but not consistently. In conclusion, the caries process modifies amino acids in dentin collagen, which can lead to increased resistance against proteolysis and ultimately to caries arrestment. <20> UI - 98267935 AU - Marshall GW Jr AU - Marshall SJ AU - Kinney JH AU - Balooch M IN - Department of Restorative Dentistry, University of California, San Francisco 94143-0758, USA. TI - The dentin substrate: structure and properties related to bonding. [Review] [138 refs] SO - Journal of Dentistry 1997 Nov;25(6):441-58 AB - OBJECTIVES: Dentin is a vital, hydrated composite material with structural components and properties that vary with location. These variations are reviewed along with alterations by physiological and pathological changes that allow classification into various forms of dentin. Structural characteristics and mechanical properties are reviewed and the limitations of our understanding of structure-property relationships for normal and modified forms of dentin are discussed with respect to their impact on dentin bonding. Recent progress in methods available to study dentin and its demineralization are emphasized with their promise to increase our understanding of dentin properties and structure. DATA SOURCES: Recent microstructural studies, focusing on scanning electron microscopy, atomic force microscopy and X-ray tomographic microscopy are included. A review of fundamental studies with emphasis on microstructurally sensitive methods, and prior reviews of basic mechanical properties are included with discussion of their correlation to composition and structure. STUDY SELECTION AND CONCLUSIONS: Emphasis in this work was placed on the major structural components of the tissue, including the collagen based organic matrix and its mineral reinforcement, the distribution of these components and their microstructural organization as related to mechanical properties and response to demineralization. Little information is included on biochemical and developmental studies or on non-collagenous proteins and other organic components for which limited understanding is available with respect to their role in structure-property relations and influence on bonding. In spite of the fact that the complexity of dentin precluded a comprehensive review, it is clear that local structural variations influence properties and impact nearly all preventive and restorative dental treatments. Much more work is needed in order to understand differences between vital and non-vital dentin, and dentin from extracted teeth. Although our knowledge is rudimentary in certain areas, increasingly sophisticated methods of studying dentin should provide the necessary information to model structure-property relations, optimize dentin bonding, and improve many aspects of preventive and restorative dentistry. [References: 138] <21> UI - 98248855 AU - Iwanowski TJ AU - Torneck CD IN - Department of Endodontics, University of Toronto, Ontario. TI - 3H proline uptake in the tubular compartment of dentin in the rat molar. SO - Journal of Endodontics 1997 Nov;23(11):659-62 AB - With the use of conventional autoradiographic techniques, it was demonstrated that dentin captures 3H proline in significantly greater amounts (p < 0.0002) than sclerotic dentin or alveolar bone. Histological observation and the absence of capture by sclerosed dentin indicated that this capture occurs within the tubular compartment of dentin. It is suggested that this capture reflects the deposition of collagen in this compartment. An increase in 3H proline capture occurs in dentin affected by cavity preparation (p < 0.0001). This increase in capture, on the basis of electron microscopic observation, could not be linked to an increase of collagen deposition in affected tubules. <22> UI - 98231302 AU - Ozcan G AU - Kurtis B AU - Balos K IN - Gazi University, Faculty of Dentistry, Department of Periodontology, Ankara, Turkiye. TI - Combined use of root conditioning, fibrin-fibronectin system and a collagen membrane to treat a localized gingival recession: a 10-case report. SO - Journal of Marmara University Dental Faculty 1997 Sep;2(4):588-98 AB - The purpose of this research was to evaluate the effectiveness of combined root surface conditioning with tetracycline HCI, fibrin sealing system, guided tissue regeneration procedure and coronal sliding flap application in the treatment of localized gingival recessions. The present study was conducted on 10 patients with localized facial recessions of at least 3mm. A trapezium-shaped flap was elevated apically to the margin of the bone dehiscence and the root surface was thoroughly scaled by hand instruments and burs. Tetracycline HCI (pH 1.9) solution was then topically applied for 5 minutes and the root surface thoroughly rinsed with sterile saline. A collagen membrane was trimmed and shaped to cover the entire root surface and later removed and a fibrin sealing system injected onto the root surface. Immediately membrane was placed again on the root surface without applying any pressure. The flap was sutured in the coronal position to completely cover the root surface and membrane. Control group patients were treated with only coronal sliding flap operation. Sutures were removed 10 days after surgery. Patients were clinically reevaluated 6 months postoperatively. The mean amount of root surface coverage obtained was similar in the test and control groups (test = 71.7%; control = 68.55%) but the clinical attachment gain (test = 4.21mm; control = 2.86mm) and pocket depth variations (test = 1.14mm reduction; control = 0.07mm reduction) differed significantly (P < 0.001). This study found promising healing of localized gingival recessions to result from a combined use of tetracycline HCI root demineralization, fibrin sealing system application, guided tissue regeneration procedure and coronal sliding flap operation. <23> UI - 98131284 AU - Hall RC AU - Embery G IN - Department of Basic Dental Science, University of Wales College of Medicine, Cardiff, UK. TI - The use of immunohistochemistry in understanding the structure and function of the extracellular matrix of dental tissues. [Review] [64 refs] SO - Advances in Dental Research 1997 Nov;11(4):478-86 AB - The availability of monoclonal and polyclonal antibodies directed toward the recognition of epitopes in a variety of extracellular matrix components of the dentition represents a powerful tool in the investigation of the structure and biology of dental tissues in health and disease. The immunolocalization of both whole molecule structures and specific regions of molecules has the potential to yield information on tooth development, the effects of aging, changes in tooth structure during the initiation and progression of the caries process, together with the response of the tooth to restorative treatment. This review reports on current research to elucidate the role of extracellular matrices of enamel, dentin, cementum, and bone. Attention is directed at the use of antibodies toward the small leucine-rich proteoglycans such as decorin and biglycan, in addition to their glycosaminoglycan chains. Antibodies are also being developed toward dental tissue-specific macromolecules such as phosphophoryn and amelogenin; the use of these antibodies will increase our understanding of the role of these macromolecules in mineralized tissues. [References: 64] <24> UI - 98145150 AU - Vargas MA AU - Cobb DS AU - Armstrong SR IN - University of Iowa, College of Dentistry, Department of Operative Dentistry, Iowa City 52242, USA. TI - Resin-dentin shear bond strength and interfacial ultrastructure with and without a hybrid layer. SO - Operative Dentistry 1997 Jul-Aug;22(4):159-66 AB - The purpose of this study was (1) to evaluate the effect of a 2-minute exposure of 5% NaOCl following acid conditioning of the dentin on the shear bond strength for two adhesive systems and (2) to examine the ultrastructure of the resindentin interface under SEM. The mesial and distal surfaces of 28 extracted human third molars were ground to expose dentin, then polished with 600-grit SiC. Teeth were randomly assigned to four test groups (n = 14) and received the following treatments: Scotchbond Multi-Purpose (SBMP)--Samples were conditioned with 37% phosphoric acid, rinsed and left moist, SBMP primer and adhesive were applied according to the manufacturer's directions, and Restorative Z-100 composite resin was bonded to the dentin surface. SBMP/NaOCl--The same procedures were followed as for SBMP except the surfaces were treated with 5% NaOCl for 2 minutes, after acid conditioning. All-Bond 2 (AB2)--The same technique was followed as for SBMP, using AB2 according to the manufacturer's recommendations. AB2/NaOCl--The same procedure was followed as for SBMP/NaOCl, using AB2. Specimens were thermocycled in a water bath 300 times between 5 degrees-55 degrees C, then sheared in a Zwick Universal Testing Machine. A one-way ANOVA and Duncan's Multiple Range Test were used for statistical analysis of the data. A 2-minute exposure of dentin to 5% NaOCl following acid conditioning of the dentin had no significant effect on the dentin shear bond strength for Scotchbond Multi-Purpose, but significantly increased the bond strength of All-Bond 2 specimens. The interfacial structure of the dentin to resin bond for two dentin treatments and two adhesive systems was studied morphologically under the scanning electron microscope. Argon ion beam etching and acid demineralization clearly revealed the hybrid layer for the conventional treatment with phosphoric acid and indicated an absence of this resin-impregnated collagen network in those specimens treated with both phosphoric acid and NaOCl. <25> UI - 98128426 AU - Eliades G AU - Palaghias G AU - Vougiouklakis G IN - Research Center for Biomaterials, Athens, Greece. eliades@athena.compulink.forthnet.gr TI - Effect of acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ. SO - Dental Materials 1997 Jan;13(1):24-33 AB - OBJECTIVE: The aim of the study was to evaluate the effect of some acidic conditioners on dentin morphology, molecular composition and collagen conformation in situ. METHODS: Smear layer-covered dentin specimens prepared from third molars immediately after extraction were imaged by tapping made AFM and analyzed by MIR-FTIR spectroscopy. The same specimens were subjected to conditioning treatments with CA Agent (Kuraray), Scotchbond Etchant (3M Dental Products) and Scotchbond MP Etchant (3M Dental Products) gels and then imaged and analyzed again. The extent of dentin decalcification at the uppermost 2 microns region was calculated from the percentage reduction in the-PO4/amide I peak area ratio of conditioned specimens relative to their individual smear layer-covered references. These results were compared by ANOVA and Scheffe statistical analyses. The conformational changes of dentin type I collagen at the region were studied qualitatively by deconvoluting the amide I bands of MIR-FTIR spectra and assigning the band components to carbonyl hydrogen bonding states related to the alpha-helix structure. RESULTS: All the conditioners removed the smear layer, funneled the tubules, increased the intertubular roughness and contaminated the dentin surfaces with residues from irreversibly adsorbed thickening agents. Conditioned dentin surfaces showed a reduction in orthophosphates and carbonates and an increase in amide I, II and III groups. CA Agent manifested a significantly lower extent of dentin decalcification than Scotchbond etchants (p < 0.05). Collagen conformational changes involved a decrease in intermolecular hydrogen bonded amide I carbonyls associated with the alpha-helix structure and enhancement of imide carbonyls hydrogen bonded to water, which suggest collagen denaturation. SIGNIFICANCE: Apart from dentin decalcification, the acidic conditioners induced considerable changes on dentin collagen conformation mostly associated with denaturation processes. In addition, irreversibly adsorbed residual thickeners substantially modified the morphology and composition of dentin surfaces. These findings show the complex interaction pathways between conditioners and dentin surfaces and the great potential of modern in situ imaging and analysis techniques in probing these interactions. <26> UI - 98055482 AU - Hansen EK AU - Asmussen E IN - Department of Dental Materials, School of Dentistry, University of Copenhagen, Denmark. ERIK.ASMUSSEN@odont.ku.dk TI - Improved efficacy of dentin-bonding agents. SO - European Journal of Oral Sciences 1997 Oct;105(5 Pt 1):434-9 AB - Dentin cavities, prepared in extracted human teeth, were treated with various proprietary dentin-bonding agents and then filled with a light-cured restorative resin for posterior use. All bonding agents were either treated in accordance with the manufacturers' instructions or combined with Gluma, which is an aqueous solution of glutaraldehyde and HEMA, a hydrophilic monomer. 10 min after polymerization, the width and the extent of the marginal contraction gap was measured approximately 0.1 mm below the free surface of the filling, using a light microscope. With nearly all dentin-bonding agents, the marginal contraction gap could be significantly reduced if Gluma was used after conditioning of the dentin. The reason for this improvement may be that glutaraldehyde cross-links the collagen fibers and thereby strengthens the organic part of the hybrid layer, however, other mechanisms might also play a role in the improvement found. <27> UI - 98014998 AU - Heilman JR AU - Jordan TH AU - Warwick R AU - Wefel JS IN - Dows Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City 52242-1010, USA. TI - Remineralization of root surfaces demineralized in solutions of differing fluoride levels. SO - Caries Research 1997;31(6):423-8 AB - The beneficial effects of fluoride on enamel have been well documented. However, limited data are available concerning the amount of fluoride required for beneficial effects on tooth root. Although studies have shown that fluoride inhibits root demineralization, the aim of this study was to investigate the location, extent and amount of remineralization on root dentin substrates after demineralization has occurred. The root surfaces of extracted human teeth were demineralized in a pure chemical buffer containing varying concentrations of sodium fluoride. After this lesion initiation, the same root sections were then placed into a remineralizing solution. The root sections were characterized after demineralization, and again after remineralization, by polarized light microscopy (PLM) and microradiography (MRG). Lesion depths after the demineralization phase were found to be inversely proportional to the fluoride concentration. When fluoride was present, bands or lines within the body of the lesion were observed with PLM and MRG. Using quantitative MRG, variations in mineral content and distribution were recorded. Examination of the root sections after the remineralization phase showed remineralization to have occurred on the remaining mineral and not on organic matrix devoid of mineral. The amount and location of mineral deposition may be of great significance in the arrestment and treatment of in vivo root surface caries. <28> UI - 97456914 AU - Hammarstrom L IN - Center for Oral Biology, Karolinska Institutet, Stockholm, Sweden. TI - Enamel matrix, cementum development and regeneration. [Review] [50 refs] SO - Journal of Clinical Periodontology 1997 Sep;24(9 Pt 2):658-68 AB - Studies during the last 20 years have indicated that enamel-related proteins are involved in the formation of cementum. In the present article, this relation is further explored. Attention is called to the fact that coronal acellular extrinsic fiber cementum is formed on the enamel surface in a number of species. The composition of the enamel matrix proteins and the expression of these proteins during root formation are briefly reviewed. The dominating constituent of the enamel matrix, amelogenin, is shown by means of immunohistochemistry to be expressed in human teeth during root formation. Amelogenin was also found to be present in Tomes' granular layer of human teeth. When mesenchymal cells of the dental follicle were exposed to the enamel matrix a non-cellular hard tissue matrix was formed at the enamel surface. Application of porcine enamel matrix in experimental cavities in the roots of incisors of monkeys induced formation of acellular cementum that was well attached to the dentin. In control cavities without enamel matrix, a cellular, poorly attached hard tissue was formed. The present studies provide additional support to the idea that enamel matrix proteins are involved in the formation of acellular cementum and also that they have the potential to induce regeneration of the same type of cementum. [References: 50] <29> UI - 98021121 AU - Isik G AU - Ince S AU - Saglam F AU - Onan U IN - University of Istanbul, Faculty of Dentistry, Department of Periodontology, Turkey. TI - Comparative SEM study on the effect of different demineralization methods with tetracycline HCl on healthy root surfaces. SO - Journal of Clinical Periodontology 1997 Sep;24(9 Pt 1):589-94 AB - Periodontal regeneration through the use of root demineralization received a lot of interest in periodontology. Topical application of acid to dentin surfaces produced a zone of demineralization, exposing dentin collagen fibrils and opening dentin tubules. In this study, the in vitro effects of different tetracycline HCl application techniques were investigated. According to the results of this SEM study, it may be desirable to apply tetracycline HCl using burnishing technique to expose maximum intertubular fibrils and for the tubular openings. However, this technique should be studied when placed in an in vivo system. <30> UI - 97357200 AU - Agematsu H AU - Sawada T AU - Watanabe H AU - Yanagisawa T AU - Ide Y IN - Department of Anatomy, Tokyo Dental College, Masago Mihamaku Chiba, Japan. TI - Immuno-scanning electron microscope characterization of large tubules in human deciduous dentin. SO - Anatomical Record 1997 Jul;248(3):339-45 AB - BACKGROUND: This study was undertaken to elucidate the type and origin of collagen fibrils which construct the large tubules in deciduous coronal dentin by scanning electron microscope and anti-types I and III collagen antibody procedures. METHODS: The studies were performed on human deciduous teeth. The teeth were fixed in 4% paraformaldehyde solution and then fractured either mesio-distally parallel to the long axis of the tooth or transversely perpendicular to the long axis of the tooth crown. The specimens were three-dimensionally observed employing the scanning electron microscope to distinguish the content of large tubules. Polyclonal antibodies of anti-type I and anti-type III collagen with 20 nm colloidal gold, and secondary electron imaging and backscatter electron imaging of high-resolution field emission scanning electron microscopy were used to examine the types of collagen fibrils. RESULTS: The large tubules extended from the vicinity of the incisal edge of the dentino-enamel junction to the pulp cavity. Inside the large tubules, fibers in compact bundles run parallel to the longitudinal axis of the tubules. The fiber bundles consisted of collagen fibrils which were 50-150 nm in diameter with typical cross striation. Immuno-scanning electron microscopy showed type I collagen-labelling gold particles and type III collagen-labelling gold particles to be abundant on the fibrils. Types I and III collagen-labelling gold particles were present on the banded collagen fibrils regardless of their diameter. CONCLUSIONS: It was found that type III collagen is present together with type I collagen on the fibrils constructing the large tubules of the human deciduous dentin. This immunohistochemical study suggested that the fibrils constructing the large tubules were derived from the von Korff fibers, and types I and III collagens formed copolymers. <31> UI - 97432637 AU - van Strijp AJ AU - van Steenbergen TJ AU - ten Cate JM IN - Department of Cariology and Endodontology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. TI - Bacterial colonization of mineralized and completely demineralized dentine in situ. SO - Caries Research 1997;31(5):349-55 AB - The changing environment in a developing root lesion may result in a succession of the microbial flora in the dentine. As demineralization proceeds, the collagenous matrix is exposed, which could be conducive to the growth of specific microorganisms. In this study both sound and completely demineralized dentine were placed together in the partial prothesis of 8 individuals to test whether the type of substrate influenced the composition of the bacterial flora. After 6 weeks the degradation of the collagenous matrix, the demineralization of the dentine and the microbial composition were assessed. The collagen loss varied between 0 and 69 wt%. Mineral loss from the originally sound dentine specimens ranged from virtually none to complete demineralization. Percentages of total streptococci, mutans streptococci, Actinomyces and lactobacilli isolated from both dentinal substrates did not differ significantly. The percentage of lactobacilli in the dentine specimens was positively correlated to the lesion depth. The percentage of Actinomyces species was significantly higher in both the dentine specimens that had been demineralized in vitro and those that were found to be completely demineralized in situ compared to the partially demineralized dentine specimens. In vitro, no collagenolytic activity of the predominant flora isolated from both dentinal substrates could be shown. <32> UI - 97390292 AU - Kleter GA AU - Damen JJ AU - Buijs MJ AU - Ten Cate JM IN - Department of Cariology Endodontology Pedodontology, Academic Center for Dentistry Amsterdam (ACTA), The Netherlands. TI - The Maillard reaction in demineralized dentin in vitro. SO - European Journal of Oral Sciences 1997 Jun;105(3):278-84 AB - The Maillard reaction between carbohydrate and protein has been proposed as a cause of the browning of carious lesions. The aim of the present investigation was to determine the occurrence of this reaction in bovine dentin collagen in vitro and to establish the effect of the reaction on the proteolytic degradation of bovine dentin collagen in vitro. Slices of demineralized bovine dentin were incubated with 0.2 M glucose or buffer for 10 weeks at 37 degrees C. The formation of initial (furosine) and advanced (pentosidine) products of the Maillard reaction in dentin exposed to glucose was confirmed by HPLC. After reduction with NaBH4 to prevent intermediate Maillard products from further reaction, slices were either degraded with collagenase for fluorescence measurement or incubated with trypsin or pepsin to assess enzymatic degradation. Fluorescence characteristic for the Maillard reaction increased in glucose-exposed slices. Degradation of collagen by pepsin, but not by trypsin, was greatly depressed following glucose pretreatment. This may indicate an altered sensitivity to proteolytic degradation; the Maillard reaction thus has a potential role in caries arrestment. <33> UI - 97233552 AU - Baroncelli GI AU - De Luca F AU - Magazzu G AU - Arrigo T AU - Sferlazzas C AU - Catena C AU - Bertelloni S AU - Saggese G IN - Department of Pediatrics, University of Pisa, Italy. TI - Bone demineralization in cystic fibrosis: evidence of imbalance between bone formation and degradation. SO - Pediatric Research 1997 Mar;41(3):397-403 AB - Bone turnover, collagen metabolism, and bone mineral status were investigated in 59 patients with cystic fibrosis and in 72 sex and age-matched control subjects. In all patients and control subjects serum concentrations of osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP), amino-terminal propeptide of type III procollagen (PIIINP), and cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), and urinary values of cross-linked N-telopeptides of type I collagen (NTX), as well as total body bone mineral content (TBBM) were measured. Higher ICTP (microgram/L) and NTX (bone collagen equivalent/urinary creatinine (nmol/mmol) values were found in pre-pubertal, pubertal, and young adult patients than in control subjects (ICTP: 15.4 +/- 2.1 and 13.2 +/- 1.8, p < 0.001; 23.3 +/- 5.3 and 20.1 +/- 4.1, p < 0.02; 4.8 +/- 1.1 and 4.0 +/- 1.0, p < 0.05. respectively; NTX: 1047.5 +/- 528.6 and 227.8 +/- 71.8, p < 0.01; 997.8 +/- 391.7 and 376.3 +/- 91.0, p < 0.01; 993.2 +/- 398.0 and 73.9 +/- 28.5, p < 0.01, respectively). Lower OC and PICP levels (microgram/L) were showed in pubertal patients in comparison with control subjects (OC: 20.2 +/- 12.3 and 39.0 +/- 15.1, p < 0.01; PICP: 305.8 +/- 130.4 and 436.2 +/- 110.1, p < 0.02, respectively). Lower OC and higher PIIINP levels (microgram/L) were found in young adult patients than in control subjects (OC: 4.4 +/- 3.0 and 7.0 +/- 3.1, p < 0.05; PIIINP: 4.8 +/- 1.1 and 3.1 +/- 1.0, p < 0.001, respectively). TBBM (z score) was reduced in prepubertal, pubertal, and young adult patients (-0.8 +/- 0.4, -1.0 +/- 0.4, -1.1 +/- 0.5, respectively). Patients with cystic fibrosis have bone demineralization and imbalance between bone formation and degradation. <34> UI - 97309674 AU - Aoba T IN - Nippon Dental University, Department of Pathology, Tokyo, Japan. TI - The effect of fluoride on apatite structure and growth. [Review] [148 refs] SO - Critical Reviews in Oral Biology & Medicine 1997;8(2):136-53 AB - Fluoride participates in many aspects of calcium phosphate formation in vivo and has enormous effects on the process and on the nature and properties of formed mineral. The most well-documented effect of fluoride is that this ion substitutes for a column hydroxyl in the apatite structure, giving rise to a reduction of crystal volume and a concomitant increase in structural stability. In the process of enamel mineralization during amelogenesis (a unique model for the cell-mediated formation of well-crystallized carbonatoapatite), free fluoride ions in the fluid phase are supposed to accelerate the hydrolysis of acidic precursor(s) and increase the driving force for the growth of apatitic mineral. Once fluoride is incorporated into the enamel mineral, the ion likely affects the subsequent mineralization process by reducing the solubility of the mineral and thereby modulating the ionic composition in the fluid surrounding the mineral, and enhancing the matrix protein-mineral interaction. But excess fluoride leads to anomalous enamel formation by retarding tissue maturation. It is worth noting that enameloid/enamel minerals found in vertebrate teeth have a wide range of CO3 and fluoride substitutions. In the evolutionary process from elasmobranch through enameloid to mammalian enamel, the biosystems appear to develop regulatory functions for limiting the fluoridation of the formed mineral, but this development is accompanied by an increase of carbonate substitution or defects in the mineral. In research on the cariostatic effect of fluoride, considerable emphasis is placed on the roles of free fluoride ions (i.e., preventing the dissolution and accelerating the kinetics of remineralization) in the oral fluid bathing tooth mineral. Fluoride also has been used for the treatment of osteoporosis, but much still remains to be learned about maximizing the benefit and minimizing the risk of fluoride when used as a public health measure. [References: 148] <35> UI - 97239364 AU - van Strijp AJ AU - van Steenbergen TJ AU - ten Cate JM IN - Department of Cariology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. A.van.strijp@acta.nl TI - Effects of chlorhexidine on the bacterial colonization and degradation of dentin and completely demineralized dentin in situ. SO - European Journal of Oral Sciences 1997 Feb;105(1):27-35 AB - The effects of 0.2% chlorhexidine on selected plaque microorganisms were studied in an intraoral dentin caries model. In 8 individuals wearing partial dentures, sound and completely demineralized dentin specimens were placed consecutively in 2 periods of 4 weeks, respectively. Throughout the experimental period, the specimens were treated 2 x daily with 0.2% chlorhexidine; control specimens were treated with water. Plaque accumulation on the specimens was left undisturbed. No protection against demineralization of the dentin or degradation of the dentin collagen by the chlorhexidine treatment was observed. The chlorhexidine treatment did not result in a reduction of the total cultivable flora when compared with the control specimens. A significant reduction of mutans streptococci and total streptococci recovered from completely demineralized dentin treated with chlorhexidine was observed, but the proportions of Actinomyces and lactobacilli were not affected significantly. It is speculated that areas of exposed roots, which are difficult to reach by oral hygiene measurements, such as approximal surfaces, will not be protected by a 0.2% chlorhexidine mouthrinse against the caries process. <36> UI - 97094335 AU - Jackson RJ AU - Lim DV AU - Dao ML IN - Department of Biology, University of South Florida, Tampa, FL 33620-5150, USA. TI - Identification and analysis of a collagenolytic activity in Streptococcus mutans. SO - Current Microbiology 1997 Jan;34(1):49-54 AB - Streptococcus mutans is an important pathogen in coronal caries and is implicated in dental root decay by its ability to bind collagen from various sources. In the present study, electron microscopic analysis demonstrated the ability of S. mutans to bind and to disrupt collagen fibrils of the amniotic membrane. The synthetic peptide FALGPA, which is similar in structure to collagen, was degraded by S. mutans, with a lower level of FALGPA hydrolytic activity observed in sucrose-grown cells compared with cells grown in the absence of sucrose. Inhibition studies of FALGPA hydrolytic activity showed a pattern characteristic of collagenase activity, with inhibition by 1,10-phenanthroline and EDTA, but not by phenylmethylsulfonyl fluoride (PMSF). Additionally, immunological cross-reactivity was observed between proteins from disrupted cells of S. mutans and antiserum to collagenase from Clostridium histolyticum. Gelatinolytic activity was demonstrated by gelatin zymogram analysis. These findings suggest that collagenolytic activity by S. mutans may be an important virulence factor in dental root decay. <37> UI - 97350629 AU - Smith CE AU - Issid M AU - Margolis HC AU - Moreno EC IN - Department of Anatomy & Cell Biology, Faculty of Dentistry, McGill University, Montreal, Quebec, Canada. TI - Developmental changes in the pH of enamel fluid and its effects on matrix-resident proteinases. SO - Advances in Dental Research 1996 Nov;10(2):159-69 AB - The objectives of this study were to measure pH in developing enamel at progressively older (more mature) stages of amelogenesis in vivo, and then to formulate synthetic enamel fluid mixtures that approximated these pH values for in vitro studies. The ultimate goal was to characterize the molecular weights of proteinases visualized by enzymograms incubated in synthetic enamel fluid using gelatin and casein as substrates. For most experiments, the proteinases were extracted en masse from small freeze-dried enamel strips directly into a non-reducing sample preparation buffer. In some experiments, we pre-treated the enamel strips with acetic acid to determine if this common method for demineralization and protein extraction caused any changes in the activity levels of the enamel proteinases. In other experiments, we first soaked enamel strips in synthetic enamel fluid to determine solubility of the proteinases within an aqueous phase. The results indicated that the pH of developing enamel remained fairly constant near pH 7.23 across the secretory stage, but it was generally more acidic (6.93) and fluctuated in focal areas between mildly acidic (6.2-6.8) and near-neutral (7.2) conditions across the maturation stage. The pH then slowly rose to near 7.35 when the enamel was almost mature (hard). The acidic conditions were generally inhibitory to most enamel proteinases, but there were some caseinase activities in mid-maturation-stage enamel near 23-30 kDa which appeared to be activated by weakly acidic conditions (pH 6.28). Pre-treatment of enamel samples with 0.5 M acetic acid markedly altered the overall profile of enamel proteinases, causing activation of some latent proteinase activities and permanent inhibition of other activities. Most proteinases in whole homogenates were insoluble in synthetic enamel fluid. This suggests that they may be tightly bound, directly or indirectly, to matrix proteins or mineral components in situ. <38> UI - 97296093 AU - Saeki Y AU - Kato T AU - Okuda K IN - Department of Bio-Technology, Lotte Central Laboratory Co., Ltd., Saitama, Japan. TI - Inhibitory effects of funoran on the adherence and colonization of oral bacteria. SO - Bulletin of Tokyo Dental College 1996 May;37(2):77-92 AB - Funoran, a sulfated polysaccharide extracted from the seaweed Gloiopeltis furcata, strongly inhibited the adsorption of mutans streptococci to saliva-coated hydroxyapatite (S-HA) used as an experimental pellicle and strongly desorbed cariogenic mutans streptococci pre-adsorbed to S-HA. Colonization inhibition and anticariogenic effects of funoran were also investigated in experimental rats. The colonization of Streptococcus cricetus E49 inoculated on the molar teeth of experimental rats administered funoran was less frequent than that in a funoran-free group. The mean buccal and lingual, sulcal, and total caries scores of rat groups administered funoran were significantly lower than those of the funoran-free group. The inhibitory effect of funoran on periodontopathic bacterial attachment was studied in vitro. Funoran strongly inhibited the adsorption of Porphyromonas gingivalis, Fusobacterium nucleatum, and actinomyces species to S-HA and collagen-coated hydroxyapatite (Co-HA) and apparently inhibited their attachment to the human gingival fibroblast Gin-1 cell line. The present study indicates that funoran inhibits colonization by cariogenic and periodontopathic bacteria and excludes them from human oral cavity. <39> UI - 97156397 AU - Gwinnett AJ AU - Tay FR AU - Pang KM AU - Wei SH IN - Department of Oral Biology and Pathology, School of Dental Medicine, SUNY at Stony Brook 11794-8702, USA. TI - Quantitative contribution of the collagen network in dentin hybridization. SO - American Journal of Dentistry 1996 Aug;9(4):140-4 AB - PURPOSE: To determine the quantitative contribution of dentin hybridization to bonded assembly strength and demonstrate the micromorphology of the interface with and without collagen present. MATERIALS AND METHODS: Four groups of 10 molar teeth were finished to a 320 grit dentin smear layer. Two groups served as controls and two experimental groups were subjected to collagenase digestion of the collagen exposed by acid conditioning. All-Bond 2 and Amalgambond were used to bond Bisfil and Epic resin composite, respectively. Stored in water at 37 degrees C for 24 hours the assemblies were tested in a shear mode at a crosshead speed of 5 mm/minute. Means and standard deviations were subjected to analysis for statistical significance. Twenty four teeth in four groups were examined by scanning (SEM) and transmission electron microscopy (TEM) for the relationship between resin and conditioned dentin with and without the collagen network. RESULTS: All-Bond 2 and Amalgambond controls were 28.41 +/- 3.9 and 19.04 +/- 5.96 MPa, collagenase-treated groups scored 26.43 +/- 2.90 and 19.70 +/- 4.25 MPa respectively. No significant difference existed between the control and experimental groups. SEM showed an intertubular collagen network with patent tubules and a pronounced porous, irregular dentin topography following collagen digestion. A distinct hybrid zone and tubular penetration was observed but the collagenase-treated specimens showed only resin in the tubules and their lateral extensions. TEM confirmed the absence of a distinct hybrid zone in the collagenase groups with a tight, gap-free junction between the resin and the undemineralized dentin. An electron dense zone (< 50 nm) at the leading edge of conditioning was observed for All-Bond 2 and Amalgambond groups. It was concluded that the resin-reinforced or hybridized, collagenous network does not detract from, nor contribute any significant quantitative value per se to dentin bonding with the systems tested. <40> UI - 97049246 AU - Flaitz CM AU - Hicks MJ IN - Department of Stomatology, University of Texas-Houston Health Science Center, USA. TI - Effects of carbamide peroxide whitening agents on enamel surfaces and caries-like lesion formation: an SEM and polarized light microscopic in vitro study. SO - ASDC Journal of Dentistry for Children 1996 Jul-Aug;63(4):249-56 AB - Whitening enamel with carbamide peroxide (CP) to remove cosmetically displeasing stains has become common-place in dental practice. This in vitro study evaluated CP treatment effects on enamel surface morphology and caries-like lesion susceptibility. Tooth quarters were prepared from 10 caries-free human molars following a fluoride-free prophylaxis. The tooth quarters were assigned to the following treatment groups: 1) Distobuccal-10 percent NW gel (Nite White, Discus Dental); 2) Distolingual-10 percent PL paste (Platinum, Colgate); 3) Mesiobuccal-16 percent NW gel; and 4) Mesiolingual-Control. Following the manufacturers' recommended treatment, each quarter was sectioned with one portion prepared for SEM and the other portion for caries-like lesion formation. Intact enamel surfaces were present with all treatments. Enamel prism markings with exaggerated prism peripheries and mild to moderate prism core loss were seen with both 10 percent NW and 16 percent NW gels, but was more prominent with 16 percent NW gel. Amorphous surface layers with occasional exposure of indistinct prism markings occurred with 10 percent PL paste. Body of lesion mean depths were 135 microns control, 159 microns 16 percent NW, 144 microns 10 percent NW, and 122 microns 10 percent PL. Lesion depths were significantly different (p < 0.05 DMR paired design) between 10 percent PL and 16 percent NW, and between control and 16 percent NW. Whitening enamel surfaces in vitro with 10 percent carbamide peroxide paste containing dicalcium phosphate dihydrate (Colgate-Platinum) produced an amorphous surface layer and reduced caries susceptibility when compared with 16 percent carbamide peroxide gel (Nite White). <41> UI - 97142528 AU - Nomura Y AU - Sakai H AU - Ishii Y AU - Shirai K IN - Scleroprotein and Leather Research Institute, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Japan. TI - Preparation and some properties of type I collagen from fish scales. SO - Bioscience, Biotechnology & Biochemistry 1996 Dec;60(12):2092-4 AB - Soluble collagen from fish (sardine) scales was yielded at about 5% with 0.5 M acetic acid after demineralization with EDTA, while a great portion of the collagen remained insoluble. The solubility of this insoluble collagen was about 20% at 45 degrees C (denaturation temperature of soluble collagen) for 24 h. The remaining 80% of the insoluble collagen was denatured in the form of insoluble gelatin, and that may be an interesting food material. <42> UI - 97110459 AU - Kirkham J AU - Robinson C AU - Strafford SM AU - Shore RC AU - Bonass WA AU - Brookes SJ AU - Wright JT IN - Division of Oral Biology, Leeds Dental Institute, UK. TI - The chemical composition of tooth enamel in recessive dystrophic epidermolysis bullosa: significance with respect to dental caries. SO - Journal of Dental Research 1996 Sep;75(9):1672-8 AB - Previous reports have linked the prevalence of tooth abnormalities with high caries experience in the different types of epidermolysis bullosa (EB). However, it is not known to what extent the apparent susceptibility to enamel caries is due to disease-related altered enamel chemistry in these cases. The aim of this study was to characterize the enamel of teeth from patients suffering from recessive epidermolysis bullosa dystrophica (rEBD) in terms of its mineral content, carbonate content, protein content, and amino acid composition. The results showed that dental enamel from these patients was essentially normal in terms of its chemistry. It is therefore concluded that the high caries experience in recessive dystrophic epidermolysis bullosa patients is probably related to other factors, such as compromised oral hygiene and prolonged oral clearance due to extensive oral soft tissue damage and a cariogenic diet. <43> UI - 97050203 AU - Bowman SM AU - Zeind J AU - Gibson LJ AU - Hayes WC AU - McMahon TA IN - Department of Orthopaedic Surgery, Charles A. Dana Research Institute, Harvard-Thorndike Laboratory, Boston, MA, USA. TI - The tensile behavior of demineralized bovine cortical bone. SO - Journal of Biomechanics 1996 Nov;29(11):1497-501 AB - Bone is frequently modeled as a two-phase composite of hydroxyapatite mineral crystals dispersed throughout an organic collagen matrix. However, because of the numerous limitations (e.g. small sample size, poor strain measuring techniques, rapid demineralization with acids) of previous mechanical tests of bone with its hydroxyapatite chemically removed, we have determined new, accurate data on the material properties of the demineralized bone matrix for use in these composite models. We performed tensile tests on waisted specimens of demineralized bovine cortical bone from six humeral diaphyses. Specimens were demineralized over 14 days with a 0.5 M disodium EDTA solution that was replaced daily. Atomic absorption spectrophotometry was used to track the demineralization process and to determine the effectiveness of our demineralization protocol. Mechanical tests were performed at room temperature under displacement control at an approximate strain rate of 0.5% per s. We imposed nine preconditioning cycles before a final ramp to failure, and measured gauge length displacements using a non-invasive optical technique. The resulting stress-strain curves were similar to the tensile behavior observed in mechanical tests of other collagenous tissues, exhibiting an initial non-linear 'toe' region, followed by a linear region and subsequent failure without evidence of yielding. We found an average modulus, ultimate stress, and ultimate strain of 613 MPa (S.D. = 113 MPa), 61.5 MPa (S.D. = 13.1 MPa), and 12.3% (S.D. = 0.5%), respectively. Our average modulus is approximately half the value frequently used in current composite bone analyses. These data should also have clinical relevance because the early strength of healing fractured bone depends largely on the material properties of the collagen matrix. <44> UI - 96263089 AU - Sasaki T IN - Second Department of Oral Anatomy,School of Dentistry, Showa University, Tokyo, Japan. TI - Recent advances in the ultrastructural assessment of osteoclastic resorptive functions. SO - Microscopy Research & Technique 1996 Feb 1;33(2):182-91 AB - Ultrastructural enzyme and immunocytochemical studies have made great contributions to clarifying intriguing questions as to the actual role of osteoclastic ruffled borders in bone resorption. In the present study, vacuolar-type H(+)-ATPase and cysteine-proteinase (cathepsin) were localized in osteoclasts by means of light and electron microscopic immunocytochemistry. The specific immunoreactivity of vacuolar-type H(+)-ATPase was detected along the ruffled border membranes, associated pale vacuoles, and cisterns of the rough-surfaced endoplasmic reticulum of osteoclasts. Anti-cathepsin B immunoreaction occurred in Golgi vesicles, lysosomes, pale vesicles and vacuoles, and the extracellular canals of ruffled borders of osteoclasts. The resorbing bone surfaces were also immunoreactive for anti-cathepsin B. In a coculture system of osteoclasts with devitalized dentine slices, a specific H(+)-ATPase inhibitor (bafilomycin A1) markedly reduced both demineralized areas and resorption lacuna formation on the dentine slices. On the other hand, the cathepsin inhibitor, E-64, inhibited only resorption lacuna formation but had no effect on demineralization of the dentine slices. These results suggest that H(+)-ATPase and cathepsins in osteoclasts are involved, respectively, in the extracellular solubilization of apatite crystals and subsequent degradation of bone matrix and that the ruffled border-clear zone complex of osteoclasts is the main site of cell-matrix interactions during bone resorption processes. <45> UI - 96267822 AU - Uno S AU - Finger WJ IN - Department of Operative Dentistry, Hokkaido University, School of Dentistry, Sapporo, Japan. TI - Effects of acidic conditioners on dentine demineralization and dimension of hybrid layers. SO - Journal of Dentistry 1996 May;24(3):211-6 AB - OBJECTIVES: This study was aimed at investigating the relationships between dentine conditioning for different durations with different acids and (1) the resulting depth of dentinal demineralization and (2) the rebounding capacity of collapsed collagen due to primer and adhesive resin penetration. METHODS: Two commercial and four experimental acids were tested directly by light microscopic evaluation of the depth of decalcification of dentine, and indirectly by determination of the hybrid layer thickness and the total depth of demineralization effects on perpendicular sections through Gluma bonded composite resin specimens. RESULTS: Depths of demineralization increased by both acid concentrations and conditioning times following a logarithmic relationship. There was good agreement between the results of the direct and the indirect procedures. Thirty seconds' conditioning with 20% phosphoric-acid gel resulted in 10-microns hybrid layer thickness. This 20% compound was considered a suitable compromise as a uni-etch conditioner since 30-s etch duration also generated an effective enamel retentive pattern and at the same time a frosted enamel appearance for visual control of extent and efficacy of enamel conditioning. <46> UI - 96159405 AU - Dung SZ AU - Gregory RL AU - Li Y AU - Stookey GK IN - Department of Periodontics, Indiana University School of Dentistry, Indianapolis 46202, USA. TI - Effect of lactic acid and proteolytic enzymes on the release of organic matrix components from human root dentin. SO - Caries Research 1995;29(6):483-9 AB - The mechanisms of organic matrix breakdown in the root caries process are not well understood. Therefore, the combined and separate effects of lactic acid and proteolytic enzymes on the degradation of human dentin collagen, glycoproteins, proteoglycans and phosphoproteins were investigated in the present study. Dentin powder was pretreated with lactic acid (pH 4.0), distilled and deionized (dd) water (pH 7.0) and EDTA/guanidine HCl (pH 7.4) for 24 h. Pellets of acid- or dd water-pretreated dentin powder were washed, dried, and then treated with trypsin, bacterial or mammalian tissue collagenase, or control buffer for 3 h. The released dentin proteins were analyzed by reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting to identify degraded type I collagen, proteoglycans, glycoproteins and phosphoproteins. All water and acid pretreatment and enzyme treatment groups demonstrated two collagen fragment bands with molecular weights at approximately 79 kD. Further studies showed that the 79 kD proteins from acid-pretreated dentin collagen were degraded by tissue collagenase, suggesting that endogenous collagenase may be involved in the degradation of root dentin collagen. Dentin proteoglycans were detectable in all the treatment groups by protein slot blotting. Relatively few distinct glycoproteins and proteoglycans, and no phosphoproteins were detected by immunoblotting. Results from this study suggest that both acids and proteolytic enzymes from either host or microbial origin are important in the degradation of human dentin matrix and the mechanisms involved in the release of various noncollagenous proteins may be different. <47> UI - 96116598 AU - Yamamoto T AU - Yokoyama A AU - Katayama I AU - Nishioka K IN - Department of Dermatology, Tokyo Medical and Dental University School of Medicine, Japan. TI - Dermatofibroma with myxoid changes in a patient with psoriasis. SO - Journal of Dermatology 1995 Oct;22(10):780-3 AB - A 38-year-old female with psoriatic arthritis developed a dermatofibroma (DF) on her upper arm. Its position was not exactly on a psoriatic plaque; however, psoriatic lesions were present diffusely around the DF lesion. Histological examination revealed the typical features of DF with myxoid changes in the portion between the tumor nest and the overlying epidermis. The mast cell number was significantly increased over that of solitary DFs without myxomatous lesions. It was suggested that mast cells may play a role in induction of the myxoid changes in the DF lesion in this case. <48> UI - 96122693 AU - Higashi T AU - Okamoto H IN - Department of Endodontology and Periodontology, Hiroshima University School of Dentistry, Japan. TI - The effect of ultrasonic irrigation before and after citric acid treatment on collagen fibril exposure: an in vitro SEM study. SO - Journal of Periodontology 1995 Oct;66(10):887-91 AB - The surface characteristics of periodontally diseased human teeth after two treatments were compared both before and after partial demineralization with citric acid. Thirteen teeth were obtained from patients with advanced periodontal disease. Three teeth were selected for control groups and 10 were used for experimental groups. All diseased root surfaces were identified and outlined. The roots were cut longitudinally into two sections. They were then scaled and root planed and the paired sections were separately classified into two control or two experimental groups. Three sections in control group 1 were rinsed by syringe with saline solution. The three sections in control group 2 were treated with ultrasonic irrigation. The 10 sections in experimental group 1 were rinsed by syringe with saline solution before and after citric acid application; the 10 sections in experimental group 2 were irrigated ultrasonically before and after citric acid application. The concentration of the citric acid was 25% (pH 1.62) and the immersion time was 3 minutes. The root samples were examined by scanning electron microscope. A significant amount of grinding debris covered on all the root surfaces in control group 1, whereas smear was removed in control group 2. The features of root surfaces of the two experimental groups differed considerably. All specimens in experimental group 2 exhibited collagen fibrils exposed as a consequence of citric acid etching. On the other hand, the smear layer was not thoroughly removed from the root surface in experimental group 1, which meant that few collagen fibrils were exposed after partial demineralization. From these results, ultrasonic irrigation before and after citric acid application improves exposure of collagen fibrils, which may be desirable for clinical success in periodontal regenerative therapy. <49> UI - 96102452 AU - Titley KC AU - Smith DC AU - Chernecky R AU - Maric B AU - Chan A IN - Department of Pediatric Dentistry, Faculty of Dentistry, University of Toronto. TI - An SEM examination of etched dentin and the structure of the hybrid layer. SO - Journal / Canadian Dental Association. Journal de l Association Dentaire Canadienne 1995 Oct;61(10):887-94 AB - The clinical requirements of dentin bonds are that they should be non-permeable to oral fluids, seal dentinal tubules, protect the pulp, and be long lasting and durable. Dentin bonding systems that use acidic agents to remove the smear layer are currently being used. Acid conditioning not only removes the smear layer, but also demineralizes the surface of the intertubular dentin and produces intratubular demineralization and funnelling. A dentin bond is produced when hydrophillic resin monomers infiltrate the dentinal tubules and collagen of the demineralized intertubular zone, producing a hybrid layer. The use of a critical point drying technique and SEM allows a clear visualization of the structure of the hybrid layer. This study showed that currently used hydrophillic resin monomers are unable to completely infiltrate the demineralized zone, and it is speculated that this failure could contribute to microleakage and influence the long-term durability of the bond. It is also apparent that these bonds depend on the mechanical investment of collagen by the infiltrating monomer. Since none of the unfilled resins tested seem capable of completely infiltrating the demineralized collagenous zone, the degree of demineralization produced by the commercial acid concentrations in current use is questioned. More dilute acids than those available commercially are shown to reduce both the degree and depth of demineralization, and we suggest that the resultant thinner layer may lend itself to more complete resin infiltration of the collagen. <50> UI - 95376559 AU - Debari K AU - Sasaki T AU - Udagawa N AU - Rifkin BR IN - Department of Anatomy, School of Medicine, Showa University, Tokyo, Japan. TI - An ultrastructural evaluation of the effects of cysteine-proteinase inhibitors on osteoclastic resorptive functions. SO - Calcified Tissue International 1995 Jun;56(6):566-70 AB - This study was designed to evaluate the effects of specific and potent cathepsin inhibitors on osteoclastic resorptive functions in vitro by means of a novel ultrastructural assay system. Mouse bone marrow cell-derived osteoclasts were suspended on dentine slices and cultured for 48 hours in the presence of either E-64 (a generalized cysteine proteinase inhibitor) or Z-Phe-Phe-CHN2 (a selective cathepsin L inhibitor). After the removal of cultured osteoclasts, co-cultured dentine slices were examined using electron microscopy: backscattered (BSEM), scanning (SEM), and atomic force (AFM). In morphometric analyses of BSEM images, there were no significant differences in the areas of demineralized dentine surfaces between control and inhibitor-treated groups, suggesting that cathepsin inhibitors had no effect on dentine demineralization by cultured osteoclasts. However, in SEM and AFM observations, both inhibitors remarkably reduced to the same extent, the formation of deep resorption lacunae on dentine slices that had resulted from degradation of matrix collagen. In addition, Z-Phe-Phe-CHN2 treatment produced deeper, ring-like grooves with little collagen exposure in shallow resorption lacunae. These results strongly suggest that (1) cathepsins released by osteoclasts are involved in the formation of deep resorption lacunae, and (2) cathepsin L plays a key role in bone resorption. <51> UI - 95346971 AU - Burns T AU - Wilson M AU - Pearson GJ IN - Department of Microbiology, Eastman Dental Institute for Oral and Dental Health Care Sciences, London, UK. TI - Effect of dentine and collagen on the lethal photosensitization of Streptococcus mutans. SO - Caries Research 1995;29(3):192-7 AB - Suspensions of the cariogenic bacterium, Streptococcus mutans were treated with either toluidine blue O or aluminium disulphonated phthalocyanine and then exposed to light from a helium-neon or gallium-aluminium-arsenide laser, respectively, after passing through demineralized dentine slices. Bacteria were also embedded in a collagen matrix prior to sensitization and exposure to the laser light. When dentine slices were interposed between the laser light and the bacterial suspension, substantial kills (10(7) CFU) were achieved at energy doses of 876, 1,752, and 3,504 mJ with the helium-neon laser and of 1,188, 2,376, and 4,752 mJ with the gallium-aluminium-arsenide laser. There was no apparent relationship between the extent of killing and the degree of demineralization of the dentine. Prolonging the exposure of the sensitized bacteria to the laser light increased the kill achieved. Substantial numbers (10(8) to 10(10) CFU) of S. mutans were also killed when embedded in a collagen matrix and exposed to 438 and 1,314 mJ of helium-neon laser light and 594 and 1,782 mJ of light from the gallium-aluminium-arsenide laser. These results imply that lethal photosensitization may be effective at killing S. mutans in a carious lesion, even when the organism is embedded in demineralized dentine. <52> UI - 95355646 AU - Prati C AU - Ferrieri P AU - Galloni C AU - Mongiorgi R AU - Davidson CL IN - School of Dentistry, University of Bologna, Italy. TI - Dentine permeability and bond quality as affected by new bonding systems. SO - Journal of Dentistry 1995 Aug;23(4):217-26 AB - OBJECTIVES AND METHODS: The relationship between dentine bonding and the condition of dentine for four dentine bonding systems (All Bond 2, Clearfil Liner Bond, Scotchbond MP and XR Bond) has been examined. Different dentine conditions were evaluated and correlated with adhesion values. Dentine permeability was calculated using a hydraulic pressure apparatus working under physiological pulpal pressure (6.9 kPa), while remaining dentine thickness (RDT) was measured using pincer calipers. Scanning electron microscopic (SEM) examinations were effected to analyse dentine morphology. These evaluations were considered as an index of the condition of dentine. Shear bond strength tests were used to evaluate adhesion. Dentine samples after the bonding systems application were stored for 24 h under pulpal pressure before bond strength was tested. RESULTS: Scanning electron microscopy examinations indicated that the application of bonding system conditioners caused the removal of smear layer, the demineralization of dentine and the formation of a layer of collapsed collagen fibrils in the intertubular and peritubular dentine. Primers were able to infiltrate the collagen fibrils. A layer of resin infiltrated/reinforced dentine (the so-called 'hybrid layer') was observed for All Bond 2, Clearfil Linear Bond and Schotchbond MP. CONCLUSIONS: Significant correlations were observed only for XR Bond, which proved very sensitive to RDT and dentine permeability despite the presence of smear layer. The other three materials did not show any correlation with dentine conditions. By contrast they showed the highest bond values. <53> UI - 95316265 AU - Wu TM AU - Rodriguez JP AU - Fink DJ AU - Carrino DA AU - Blackwell J AU - Caplan AI AU - Heuer AH IN - Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio, USA. TI - Crystallization studies on avian eggshell membranes: implications for the molecular factors controlling eggshell formation. SO - Matrix Biology 1995 Feb;14(6):507-13 AB - The avian eggshell is a natural biopolymer and mineral composite. It is a very useful model for biomimetic mineralization, since it is among the fastest forming hard tissues known. Isolated eggshell membranes, which were demineralized in vitro, were used to investigate the in vitro modulation of CaCO3 crystal deposition by organic matrix materials. Crystallization on the demineralized eggshell membrane occurred almost exclusively at the peripheries of residual calcium reserve assemblies, which contain a high concentration of sulfur. Similar structures are observed for eggshell membranes after natural demineralization. The characteristic rhombohedral crystal morphologies of the calcite crystals grown in this in vitro system are much less regular when grown in the presence of organic matrix or partially purified dermatan sulfate proteoglycans obtained from the eggshell. The effect of these macromolecules on the morphology and size of CaCO3 crystals is concentration-dependent. These studies indicate the complexity of the molecular and ionic interactions involved in the initiation and formation of the eggshell, with the focus on the role of the organic matrix. <54> UI - 95302262 AU - Higashi T AU - Onzuka T AU - Satoh G AU - Yoshino H AU - Okamoto H IN - Department of Endodontology and Periodontology, Hiroshim School of Dentistry, Japan. TI - Collagen formation at the tooth-cell interface: comparative ultrastructural study on the effect of partial demineralization of cementum with dentin. SO - Journal of Periodontology 1995 Apr;66(4):267-73 AB - In order to compare the effect of partial demineralization with root planing and partial demineralization of cementum with that of dentin on healing, the ultrastructural morphology of the interface between the layer of human periodontal ligament-derived, fibroblast-like cells (HPF) and the treated root surface was studied in an in vitro culture system. Sixty (60) pairs made from transversally-cut root slices, 500 microns thick, were obtained from extracted human periodontally diseased teeth. Thirty (30) pairs of the root slices were preliminarily root planed (RP). The remaining half were root planed and then partially demineralized in a solution of citric acid (RP+CA). The opposite surface of paired slices was made uniform by using either cementum or dentin. Consequently, all root slices were classified into four experimental groups: RP-cementum and RP-cementum pairs (group 1), RP-dentin and RP-dentin pairs (group 2), RP+CA-cementum and RP+CA-cementum pairs (group 3), and RP+CA-dentin and RP+CA-dentin pairs (group 4). Each pair of root slices was placed on the floor of a 35-mm culture dish. HPF were seeded at a concentration of 4 x 10(5) cells/dish. Co-cultures of HPF and the root slices were examined using phase contrast and electron microscope after 4, 6, and 10 weeks. Electron-dense material covered non-demineralized root surfaces and the lining cells in accumulating cell layers were oriented parallel to the root surface and attached to the material in groups 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS) <55> UI - 95310603 AU - Kinney JH AU - Balooch M AU - Haupt DL Jr AU - Marshall SJ AU - Marshall GW Jr IN - Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, California 94551, USA. TI - Mineral distribution and dimensional changes in human dentin during demineralization. SO - Journal of Dental Research 1995 May;74(5):1179-84 AB - Many bonding agents require the dentin surface to be acid-etched prior to being bonded. Understanding the stability and morphology of the etched dentin surface is important for improving bond strength and reliability in these systems. In this study, the atomic force microscope was used to quantify dimensional changes that occur to fully hydrated dentin during demineralization with a pH 4.0 lactic acid gel. A high-resolution microtomography instrument, the x-ray tomographic microscope, was also used to quantify the mineral density distribution in the dentin as a function of etching time. The intertubular dentin surface shrank by less than 0.5 microns during etching, while the peritubular dentin receded at an initially rapid linear rate. The dentin surface retained its initial morphology, although it was more porous with the removal of the peritubular dentin. Beneath the etched surface, there were three major zones characterized by mineral density differences. The first zone was a fully demineralized collagen layer, subjacent to which was a partially demineralized zone of roughly constant mineral density. Immediately following the partially mineralized layer was normal dentin. The presence of the partially mineralized layer could be explained in terms of different transport rates in the peritubular and intertubular dentin. <56> UI - 95289658 AU - Uno Y AU - Saito R IN - Department of Otolaryngology, Okayama Saiseikai General Hospital, Japan. TI - Bone resorption in human cholesteatoma: morphological study with scanning electron microscopy. SO - Annals of Otology, Rhinology & Laryngology 1995 Jun;104(6):463-8 AB - The detailed mechanism of bone resorption in cholesteatoma was investigated by means of eroded ossicles obtained during middle ear surgery for cholesteatoma. In the light microscopic study, multinucleate osteoclasts with ruffled borders were found in contact with the eroded bone, which appeared to be osteoclastic lacunae. Scanning electron microscopy revealed the lacunae to be many absorption bays, 30 to 100 microns in diameter, clustered on the surface of eroded areas. Numerous cone-shaped stubs of digested collagen fiber bundles, consisting of scores of collagen fibrils and degenerated extracellular organic substances, were visible at higher magnification on the bottom of the absorption bay. The pattern of fusion and twining of the disarranged collagen fibrils at the top of the partly digested fiber bundles was clearly rendered by the alkali-water maceration method for scanning electron microscopy. We infer from the morphological evidence that osteoclastic resorption may be one of the major mechanisms of bone destruction in cholesteatoma, and that demineralization and degeneration of extracellular organic substances precede disruption of collagen fibrils at the front of bone resorption. <57> UI - 95301794 AU - Sano H AU - Takatsu T AU - Ciucchi B AU - Russell CM AU - Pashley DH IN - Department of Operative Dentistry, Tokyo Medical and Dental University, Japan. TI - Tensile properties of resin-infiltrated demineralized human dentin. SO - Journal of Dental Research 1995 Apr;74(4):1093-102 AB - The ability of adhesive resins to restore the physical properties of demineralized dentin has not been well-documented. The unfilled resins that are used for adhesion have relatively low moduli of elasticity and limited ability to increase dentin stiffness, although they may increase the ultimate tensile strength of dentin. This study tested the hypothesis that resin infiltration of demineralized dentin can restore its tensile properties to those of mineralized dentin. Small (ca. 0.5 mm thick x 0.5 mm wide) specimens of demineralized human dentin were infiltrated with one of five different dentin bonding resins over many hours, to determine how these resins altered the tensile properties of dentin. Tensile stress and strain were measured in these and control (mineralized and demineralized) specimens until their ultimate failure. The results indicate that some adhesive resins, after infiltrating demineralized dentin, can restore and even exceed the ultimate tensile strength of mineralized dentin. These resins increased the modulus of elasticity of resin-infiltrated dentin to values equal to or greater than those of the resins but far below those of mineralized dentin. Although the conditions in this experiment were far removed from the manufacturer's recommendations or clinical practice, the results support the potential of resin infiltration for reinforcing dentin. <58> UI - 95238681 AU - D'Souza RN AU - Bachman T AU - Baumgardner KR AU - Butler WT AU - Litz M IN - Department of Basic Sciences, University of Texas, Houston Health Science Center 77030, USA. TI - Characterization of cellular responses involved in reparative dentinogenesis in rat molars. SO - Journal of Dental Research 1995 Feb;74(2):702-9 AB - During primary dentin formation, differentiating primary odontoblasts secrete an organic matrix, consisting principally of type I collagen and non-collagenous proteins, that is capable of mineralizing at its distal front. In contrast to ameloblasts that form enamel and undergo programmed cell death, primary odontoblasts remain metabolically active in a functional tooth. When dentin is exposed to caries or by operative procedures, and when exposed dentinal tubules are treated with therapeutic dental materials, the original population of odontoblasts is often injured and destroyed. The characteristics of the replacement pool of cells that form reparative dentin and the biologic mechanisms that modulate the formation of this matrix are poorly understood. Based on the hypothesis that events governing primary dentinogenesis are reiterated during dentin repair, the present study was designed to test whether cells that form reparative dentin are odontoblast-like. Cervical cavities were prepared in rat first molars to generate reparative dentin, and animals were killed at various time intervals. In situ hybridization with gene-specific riboprobes for collagen types I and III was used to study de novo synthesis by cells at the injured dentin-pulp interface. Polyclonal antibodies raised against dentin sialoprotein (DSP), a dentin-specific protein that marks the odontoblast phenotype, were used in immunohistochemical experiments. Data from our temporal and spatial analyses indicated that cells forming reparative dentin synthesize type I but not type III collagen and are immunopositive for DSP. Our results suggest that cells that form reparative dentin are odontoblast-like. <59> UI - 95238673 AU - McGrady JA AU - Butcher WG AU - Beighton D AU - Switalski LM IN - Department of Periodontics, School of Dental Medicine, University of Pittsburgh, Pennsylvania 15261, USA. TI - Specific and charge interactions mediate collagen recognition by oral lactobacilli. SO - Journal of Dental Research 1995 Feb;74(2):649-57 AB - The mechanisms by which oral lactobacilli, one of the three major genera of cariogenic bacteria, attach to tooth surfaces are unknown. We hypothesize that recognition of collagen, the major component of dentin, may be a mechanism which localizes these bacteria to exposed root surfaces as well as to carious lesions which have penetrated the dentin. We found that the majority of oral Lactobacillus spp. strains recognize and bind collagen type I. Binding of 125I-labeled collagen type I to two strains of L. casei rhamnosus has been characterized in some detail. These strains were previously characterized with respect to their attachment to dentin (Switalski and Butcher, 1994). The process of 125I-collagen binding was mediated via specific as well as charge interactions. The putative adhesin-mediated (specific) interaction involved a limited number of bacterial surface components (2 x 10(3)/cell). Under conditions conducive for non-specific interactions (low ionic strength), the binding was higher by an order of magnitude. Collagen binding strains were found to adhere to collagen-coated surfaces, while strains unable to bind collagen adhered to a much lesser extent. Adherence of bacteria to collagen-coated surfaces could be competitively inhibited with collagen. These interactions may target collagen-binding strains of lactobacilli to dentin collagen in the oral cavity and thus play a role in the pathogenesis of root surface and/or coronal caries. Interference with this collagen-mediated attachment of lactobacilli may provide effective means of caries control, particularly in view of the fact that other oral acidogenic microbiota also interact with collagen. <60> UI - 97260287 AU - Titley K AU - Chernecky R AU - Maric B AU - Valiquette N AU - Smith D IN - Department of Pediatric Dentistry, Faculty of Dentistry, University of Toronto, Ontario, Canada. TI - The morphology of the demineralized layer in primed dentin [published erratum appears in Am J Dent 1994 Jun;7(3):following table of contents]. SO - American Journal of Dentistry 1994 Feb;7(1):22-6 AB - This study critically examined the surface and subsurface effects of selected dentin priming agents. Various dentin priming agents were used and specimens were prepared for SEM examination by conventional air drying or by a freeze fracture and critical point drying technique. The results showed that in specimens prepared by freeze fracture and critical point drying technique the demineralization of the dentin surface and subsurface by priming agents leaves a visible network of collagen fibrils. This technique allows better evaluation of the adaptation of bonding resins to the collagen network of the demineralized layer. <61> UI - 96073164 AU - Loo CY AU - Willcox MD AU - Knox KW IN - Institute of Dental Research, Surry Hills, Australia. TI - Surface-associated properties of Actinomyces strains and their potential relation to pathogenesis. SO - Oral Microbiology & Immunology 1994 Feb;9(1):12-8 AB - Twenty-nine strains from the Actinomyces species were tested for a range of surface properties. Results show considerable heterogeneity both between different species and within some of the species, especially Actinomyces naeslundii. Two commonly used A. naeslundii strains, T14V and ATCC 12104, fell within the low (salivary aggregation and collagen binding by T14V), moderate (surface charge and haemagglutination) or high range of values (hydrophobicity, saliva-coated hydroxyapatite adhesion, polystyrene binding by T14V, fibrinogen binding by T14V and collagen binding by A. naeslundii ATCC 12104). Both strains adhered well to saliva-coated hydroxyapatite; T14V bound the highest amount of fibrinogen, ATCC 12104 had the highest number of cells bound to collagen and T14V was not bound at all. The heterogeneity of these characteristics highlights the need to include a range of strains of Actinomyces in studies on their pathogenicity. Statistical correlations were found between a number of properties, for example saliva-coated hydroxyapatite adhesion and hydrophobicity, and between haemagglutination and hydrophobicity. <62> UI - 95217662 AU - Harty DW AU - Oakey HJ AU - Patrikakis M AU - Hume EB AU - Knox KW IN - Institute of Dental Research, Surry Hills, N.S.W., Australia. TI - Pathogenic potential of lactobacilli. SO - International Journal of Food Microbiology 1994 Dec;24(1-2):179-89 AB - Lactobacilli are often considered to be commensal or beneficial participants in human microbial ecology and considerable research is being carried out into the effects of the use of lactobacilli as additives in both human and animal diets. However, lactobacilli also cause some human diseases (e.g. dental caries, rheumatic vascular disease, septicaemia and infective endocarditis (IE)), and have recently been identified as potential emerging pathogens in elderly and immunocompromised patients, particularly those receiving broad spectrum antibiotic therapy. The identification of potential pathogenic traits amongst lactobacilli will therefore facilitate the use of the organisms for probiotic purposes. The ability to aggregate human platelets is considered to be a possible pathogenic trait in the progression of IE. A comparison of bacterial cell surface properties amongst L. rhamnosus strains showed that platelets were aggregated by 5/5 IE strains and 8/16 laboratory strains. For the L. paracasei subsp. paracasei strains the respective numbers were 2/5 and 2/9. However two strains, morphological mutants of a non-aggregating strain, which had been re-isolated after passaging through rats were found to aggregate platelets. No loss of aggregating function occurred on extensive subculturing of IE strains. Aggregation also occurred with 11/14 strains for five other species, namely, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus oris, Lactobacillus plantarum and Lactobacillus salvivarius, with each species being represented indicating that the property is not uncommon in the genus. A comparison of IE and oral isolates of L. rhamnosus and L. paracasei subsp. paracasei and seven other Lactobacillus species, has shown that the binding of both fibronectin and fibrinogen by lactobacilli is greatly increased, up to 50 fold, when the pH is reduced from 7.0 to 5.0. Re-exposing the lactobacilli to a neutral pH environment releases most of the bound proteins, but the amount still remaining bound to the cell is several times more than is bound at neutral pH. Lactobacilli will also bind to the proteins that make up the extracellular matrix of endothelial cells. Lactobacilli bound significantly better to collagen types I and V than to types III and IV (p < 0.01). Further, strains isolated from IE cases, particularly L. rhamnosus strains, bound significantly better to types I and V than did 'normal' strains (p < 0.02). Type V collagen has been demonstrated at the sites of endothelial damage. Thus the binding of lactobacilli, particularly L. rhamnosus to these collagen types may be of importance in the early stages of colonization of the damaged heart valve.(ABSTRACT TRUNCATED AT 400 WORDS) <63> UI - 95233947 AU - Nakashima M IN - Department of Conservative Dentistry, Faculty of Dentistry, Kyushu University 61, Fukuoka, Japan. TI - Induction of dentine in amputated pulp of dogs by recombinant human bone morphogenetic proteins-2 and -4 with collagen matrix. SO - Archives of Oral Biology 1994 Dec;39(12):1085-9 AB - Recombinant human bone morphogenetic protein (BMP)-2, BMP-4 and transforming growth factor (TGF)-beta 1 combined with collagen matrix as a carrier were examined for their effects on pulp regeneration and dentine formation. Seventy days after implantation of 2 micrograms of BMP-2, mineralized osteodentine-like tissue containing embedded osteodentinocytes was seen in the cavity. Unmineralized fibrous tissue and pulp-like loose connective tissue were also found in the same cavity. In teeth implanted with 660 ng of BMP-2 only unmineralized fibrous and pulp tissues were seen. In teeth with 220 ng of BMP-2 or collagen alone, pulp tissue was seen. It is therefore likely that the cavity fills with pulp tissue and that spindle-shaped cells elaborate extracellular matrix that mineralizes to be osteodentine in a dose-dependent manner. Similar osteodentine was seen in teeth implanted with 4 micrograms of BMP-4 and collagen. No distinct tubular dentine was formed, unlike an earlier experiment in which BMP-2 or -4 was implanted with enriched, inactivated dentine matrix. These findings suggest that both BMP-2 and -4 induce osteodentine formation if combined with collagen matrix; some other matrix component present in inactivated dentine matrix might be essential for further differentiation into odontoblasts. In teeth implanted with TGF-beta 1, the carrier collagen remained in the cavity and little pulp tissue proliferation was seen, suggesting a possible inhibitory effect of TGF-beta 1 in pulp regeneration. It is likely that the response to growth and differentiation factors is dependent on the state of differentiation of pulp cells. <64> UI - 95202601 AU - Fukae M AU - Tanabe T AU - Yamada M IN - Department of Biochemistry, School of Dental Medicine, Tsurumi Unive