Domenick T. Zero, D.D.S., M.S., Margherita Fontana, D.D.S., Ph.D., and Aine M. Lennon, B.Dent.Sc., Ph.D.:
Other papers at this conference have discussed individual risk indicators of caries. This review focuses on studies of the predictive validity of various combinations of risk indicators. Such indicators may be useful in the clinical management of dental caries by helping dental professionals determine if additional diagnostic procedures are required, identify patients who require caries control measures, assess the impact of caries control measures, make treatment planning decisions, and determine the timing of recall appointments. Although there is a high level of interest in identifying risk indicators, only a few studies have attempted to determine how the application of risk indicators affects dental health outcomes (Brambilla, Gagliani, Felloni, et al., 1999; Hausen, Karkkinena, Seppa, et al., 2000).
Multifactorial modeling has proved its value in longitudinal caries prediction studies by showing the interrelations and interactions of risk factors. Beck and colleagues (1988) indicated that one or more social, behavioral, microbiologic, environmental, and clinical variables should be included in such a model, given the many factors that influence dental caries. Modeling has usually been based on a dichotomized dependent variable, either as "no" versus "some" caries increment (Beck, Weintraub, Disney, et al., 1992) or with specified cut-off points in populations with high caries incidence (Abernathy, Graves, Bohannon, et al., 1987). The accuracy of models has rarely been 80 percent, which is considered to be the minimum level for screening purposes. "To be useful, a working model should produce a sensitivity of 0.75 or higher and specificity level of at least 0.85 or higher" (Stamm, Disney, Graves, et al., 1988). It has therefore been suggested that a risk model should have a combined sensitivity and specificity of at least 160 percent (Kingman, 1990).
References were systematically assessed for their validity. Since valid evidence is considered best obtained from randomized, controlled longitudinal (prospective) studies, those were given the highest scores in our review. Studies were graded as "good," "fair," or "poor," depending on the amount of information they provided to support the methodology used. The main variables assessed for this purpose (other than the inclusion criteria) were: (1) whether the study reported how samples were obtained, (2) whether the examiners were trained/calibrated, (3) whether examiner reliability was reported, and (4) whether examiners were blinded during the study. Tables 1, 2, and 3 include the longitudinal prospective studies considered to be good sources of evidence for predictions in primary teeth, permanent teeth in children and adolescents, and permanent teeth in adults. None of the root caries studies reviewed met these criteria.
Of all the models reviewed, none of those graded as "good" had a combined sensitivity and specificity in excess of 160 percent, although the model reported by Demers and colleagues (1992) comes very close (159 percent). These authors concluded that previous caries experience was the strongest predictor in their model, followed by parents¹ education. For primary teeth there was one "fair" study in which combined sensitivities and specificities totaled 170 percent (Holst, Martensson, Lavrin, et al., 1997). That study used infants 1 year old, for 2 years, and all categories of risk assessment factors. Visible plaque, deep fissures, and oral hygiene were the strongest predictors.
Table 1. Primary teeth-prospective studies (good level of evidence)
|
Researcher |
N |
Age at onset |
Study Design |
Variables: |
Variables: Microflora |
Variables: |
Variables: |
Outcome = |
Sensitivity |
Specificity |
| [Isokangas et al., 1993] |
297 (3-4 year olds) |
3-4 |
Prospective |
Caries, Predicted caries |
Not used |
Not used |
Sociodemographic |
< 1 dentinal caries lesion in need of restoration(actual data NR) |
45% |
92% |
| [Demers et al., 1992] |
302 |
5 year olds |
Prospective (1 year) |
Caries experience: |
SM, LB (Bactotest) |
Buffer capacity |
Age, sex, parents education, family structure, fluoride consumption, oral hygiene (debris index) |
> 1 ds(mean dfs increment: 2.1 + 3.6) |
81.8% |
77.4% |
|
|
||||||||||
Table 1. Primary teeth-prospective studies (good level of evidence) (continued)
|
Researcher |
Baseline Scores |
True High Risk Criteria Used |
Method of modeling |
Country |
Sampling method |
Training of examiners reported |
Reliability of examiners |
Blinding of examiners |
Blinding of patients |
Subject Attrition |
Authors conclusion |
|
[Isokangas et al., 1993] |
NR |
High risk: Any caries increment |
Not used |
Finland (Ylivieska) |
All 3-16 year olds in public dental care were included |
15 clinicians participated. No training reported. |
NR (dentists examined different children) |
Not possible for ethical reasons |
NR |
NR |
Clinicians can predict risk using only caries and socio-demographic variables available at annual examinations |
|
[Demers et al., 1992] |
NR |
At least one new carious lesion in primary teeth: high risk |
(LRA; 9 variables studied) |
Canada (Montreal) Non-fluoridated community |
Random selection of schools |
Calibrated (2 examiners) |
For caries: |
NR |
NR |
126 |
Previous caries experience was the best predictor, followed by parents education. |
Table 2. Permanent teeth-children and adolescents; prospective studies (good level of evidence)
|
Researcher |
N |
Age at onset |
Study Design |
Variables: Past Caries or Disease Experience |
Variables: Microflora |
Variables: |
Variables: Other |
Outcome=Validation criteria=true disease |
Sensitivity |
Specificity |
|
[Disney et al., 1992b]| North Carolina Study "High Risk Prediction Model" |
4158: |
6 years |
Prospective |
DMFS (Radike, no radiographs), dmfs, predicted caries; fluorosis, white spot lesions |
SM (Cariescreen), LB (Bactotest), mean plaque score |
Pit and Fissure Morphology |
Sociodemographic (higher in Portland-exclusively white); examiner, age, brushing frequency, between meals snacks |
> 4 DMFS> 2 DMFS (At 3 years-DMFS increment: Aiken: 1.9 (grade 1), 3.1 (grade 5) Portland: 0.8 (grade 1), 1.5 (grade 5) |
59% (grade 1); 62% |
83% (grade 1); 81% (grade 5) |
| [Isokangas et al., 1993] |
1464 (516 year olds)
|
316 |
Prospective |
Caries, Predicted caries |
Not used |
Not used |
Socio-demographic |
< 1 dentinal caries lesion in need of restoration(actual data NR) |
5-16 year olds; 58% |
5-16 year olds:84%; |
Table 2. Permanent teeth-children and adolescents; prospective studies (good level of evidence) (continued)
|
Researcher |
Baseline Scores (Mean + SD) |
True High Risk Criteria Used |
Method of modeling |
Country |
Sampling method |
Training of examiners reported |
Reliability of examiners |
Blinding of examiners |
Blinding of patients |
Subject Attrition |
Authors conclusion |
|
[Disney et al., 1992b] North Carolina Study "High Risk Prediction Model" |
Aiken: DMFS:0.3 (grade 1), 3.0 (grade 5)
|
High risk:25% of the total sample size. |
(LRA, stepwise, 3843 variables studied) |
USA |
NR |
Trained |
Examiner reliability; intraclass correlations above 90% for 10/12 comparisons. Reliability for noncaries data showed fair agreement among examiners. |
Yes |
NR |
Lost approx. 20% from baseline (more than N) |
Models had high specificity for children at low risk. Clinical predictors were the most important ones, while the other factors contributed little to the prediction. |
| [Isokangas et al., 1993] |
NR |
High risk: Any caries increment |
Not used |
Finland (Ylivieska) |
All 3-16 year olds in public dental care were included |
15 clinicians participate. No training reported. |
NR (dentists examined different children) |
Not possible for ethical reasons |
NR |
NR |
Clinicians can predict risk using only caries and sociodemographic variables available at annual examinations |
Table 3. Permanent teeth adults-prospective studies (good level of evidence)
|
Researcher |
N (dentate) |
Age (t outset |
Study Design |
Variables: Past Caries or Disease Experience |
Variables: Microflora |
Variables: |
Variables: Other |
Outcome= |
Sensitivity % |
Specificity % |
|
[Hawkins et al., 1997;van Houte, 1993] |
699 |
50+ |
Prospective 3 years |
No calculus removed no radiographs |
Not Used |
Not Used |
Educational level Total household income Dental visiting pattern Born in Canada Major life event in past 6 months Wearing partial denture |
One or more net coronal DFS increments |
80.2 |
46.2 |
Table 3. Permanent teeth adults-prospective studies (good level of evidence) (continued)
|
Researcher |
Baseline Scores |
True High Risk Criteria Used |
Method of modeling |
Country |
Sampling method |
Training of examiners reported |
Reliability of examiners |
Blinding of examiners |
Blinding of patients |
Subject Attrition |
Authors conclusion |
|
[Hawkins et al., 1997;van Houte, 1993] |
Caries incidence 57% |
NR |
LRA |
Canada, Ontario |
Random |
Calibration reported |
94%kappa 0.76 coefficient of reproducibility 0.97 (p<0.001) |
NR |
NR |
206 |
Non-clinical factors, which showed significant effects were education and marital status, both of these factors may influence attitudes towards oral health. |
Another recommendation follows from the consistent finding that past caries experience is a strong predictor of future disease. Most studies have used the DMFS (decayed, missing, filled surfaces) index to determine past caries experience. This approach does not necessarily separate out the D component from the F component. Furthermore, this approach does not establish whether decayed lesions are active (progressing) or inactive (arrested). The presence of caries activity should be a much stronger predictor of future carious lesions (frank cavitations) than the DMFS index. The development of technology to detect early caries lesions and to directly assess caries lesion status may prove to be the best way to identify patients who need aggressive preventive intervention.
Beck JD, Weintraub JA, Disney JA, Graves RC, Stamm JW, Kaste LM, et al., University of North Carolina Caries Risk Assessment Study: comparisons of high risk prediction, any risk prediction, and any risk etiologic models. Comm Dent Oral Epidemiol 1992;20:31321.
Brambilla E, Gagliani M, Felloni A, García-Godoy F, Strohmenger L. Caries-preventive effect of topical amine fluoride in children with high and low salivary levels of mutans streptococci. Caries Res 1999;33:4237.
Demers M, Brodeur JM, Mouton C, Simard PL, Trahan L, Veilleux G. A multivariate model to predict caries increment in Montreal children aged 5 years. Comm Dental Health 1992;9:27381.
Disney JA, Graves RS, Stamm JW, Bohannan HM, Abernathy JR, Zack DD. The University of North Carolina Caries Risk Assessment study: further developments in caries risk prediction. Comm Dent Oral Epidemiol 1992;20:6475.
Hausen H, Karkkainen S, Seppa L. Application of the high-risk strategy to control dental caries. Comm Dent Oral Epidemiol 2000;28:2634.
Hawkins RJ, Jutai DK, Brothwell DJ, Locker D: Three-year coronal caries incidence in older Canadian adults. Caries Res 1997;31:40510.
Holst A, Martensson I, Laurin M. Identification of caries risk children and prevention of caries in pre-school children. Swed Dent J 1997;21:18591.
Isokangas P, Alanen P, Tiekso J. The clinician¹s ability to identify caries risk subjects without saliva tests‹a pilot study. Comm Dent Oral Epidemiol 1993;21:810.
Kingman A, Little W, Gomez I, Heifetz SB, Driscoll WS, Sheats R, et al., Salivary levels of Streptococcus mutans and lactobacilli and dental caries experiences in a US adolescent population. Comm Dent Oral Epidemiol 1988;16:98103.
Moss ME, Zero DT. An overview of caries risk assessment and its potential utility. J Dent Educ 1995;59:93240.
Stamm JW, Disney JA, Graves RC, Bohannan H, Abernathy JR. The University of North Carolina Caries Risk Assessment Study. I: Rationale and content. J Public Health Dent 1988;48:22532.
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