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J W Stamm

Publications and source records attributed to J W Stamm.

At least 19 recordsLinked to original sources
PubMed1992

The University of North Carolina Caries Risk Assessment study: further developments in caries risk prediction.

Over 4000 first and fifth grade children from the areas surrounding Aiken, South Carolina, and Portland, Maine, participated in a 4-yr study to develop caries risk assessment models. The predictors used at baseline included detailed clinical examinations, salivary microbiological tests, and sociodemographic and dental behavior data. Mean 3-yr caries increments in South Carolina were twice those in Maine. For the four risk assessment models (two grade cohorts at two sites) specificity values averaged 0.83 and sensitivity values averaged 0.60. Clinical predictors such as prior DMFS, pit and fissure morphology, and predicted caries risk status were the major contributors to the models.

Child↗
PubMed1992

University of North Carolina Caries Risk Assessment Study: comparisons of high risk prediction, any risk prediction, and any risk etiologic models.

The purpose of this analysis is to compare three different statistical models for predicting children likely to be at risk of developing dental caries over a 3-yr period. Data are based on 4117 children who participated in the University of North Carolina Caries Risk Assessment Study, a longitudinal study conducted in the Aiken, South Carolina, and Portland, Maine areas. The three models differed with respect to either the types of variables included or the definition of disease outcome. The two "Prediction" models included both risk factor variables thought to cause dental caries and indicator variables that are associated with dental caries, but are not thought to be causal for the disease. The "Etiologic" model included only etiologic factors as variables. A dichotomous outcome measure--none or any 3-yr increment, was used in the "Any Risk Etiologic model" and the "Any Risk Prediction Model". Another outcome, based on a gradient measure of disease, was used in the "High Risk Prediction Model". The variables that are significant in these models vary across grades and sites, but are more consistent among the Etiologic model than the Predictor models. However, among the three sets of models, the Any Risk Prediction Models have the highest sensitivity and positive predictive values, whereas the High Risk Prediction Models have the highest specificity and negative predictive values. Considerations in determining model preference are discussed.

Child↗
PubMed1992

The University of North Carolina caries risk assessment study: caries increments of misclassified children.

The University of North Carolina caries risk assessment was conducted between 1986 and 1989 with 5000 children initially in grades 1 and 5 from low fluoride sites in South Carolina and Maine. Clinical, microbiologic, behavioral, and demographic factors served as independent variables used in logistic multiple regression models to determine the predicted caries risk classification of each child. The 3-yr DMFS increment of each child was the dependent variable, and the 20-25% of those in each cohort with the highest increment were considered the high risk group. Sensitivity and specificity values averaged 0.60 and 0.83 respectively, indicating the misclassification of substantial numbers of children. This paper reports analysis of the DMFS increments of the misclassified children. The majority of children had DMFS increments within one or two surfaces of the classification cut points. Many false negative children had increments composed entirely of filled surfaces, often of minimal extent and without evidence of previous decay. Many false positive children had increments composed of decayed surfaces and would have benefitted from being identified as high risk and assigned to a preventive program. Other false positive children had sealants placed after the baseline examination that undoubtedly reduced their true increment. It is concluded that the consequences of misclassification are not serious for most children in this study.

Child↗
PubMed1991

Dental fluorosis following downward adjustment of fluoride in drinking water.

The drinking water fluoride concentration in Hong Kong was reduced by about 0.2 ppm in June 1978. This study was undertaken to determine whether the prevailing level of dental fluorosis was affected by such a minor change. Cohorts of children (N = 1,062) aged seven to 12 years, who were born both before and after the fluoride reduction, were examined clinically using Dean's fluorosis index. Based on upper right central incisors, dental fluorosis prevalence decreased from 64 to 47 percent and the community fluorosis index decreased from 1.01 to 0.75 (P less than .01). Thus, dental fluorosis was reduced, although the reduction in water fluoride concentration was not sufficient to achieve the minimal fluorosis level that Dean associated with a fluoride concentration optimal for caries prevention. Variation in dental fluorosis has been reported previously to result from marked sudden changes, during tooth formative years, to drinking water fluoride concentration. This study confirms preliminary findings that variation in dental fluorosis arising from minor changes to the fluoride level in drinking water is also measurable.

Child↗
PubMed1991

University of North Carolina caries risk assessment study. III. Multiple factors in caries prevalence.

The baseline caries experienced of approximately 5,000 children in South Carolina and Maine was used as the dependent variable in caries risk assessment analyses. Clinical, microbiologic, and demographic factors served as independent variables in a multivariate relationship to caries through regression and discriminant function analyses. Four factors--number of dental visits by the child in the past year, presence of white spot lesions, and both the urgency of need for restorative care and the future caries increment predicted by the examiner--associated significantly and consistently with caries prevalence in primary and permanent teeth of first and fifth graders at both study sites. Several factors associated significantly with caries prevalence at only one site or grade within a site, suggesting that wide applicability of a specific caries risk assessment model may be limited. In these analyses, sensitivity ranged from .60 to .72 and specificity varied from .86 to .91 in the four grade-site groups. The ultimate goal of this longitudinal study is to identify highly caries-prone children in time to prevent the occurrence of a future caries increment. Although the lack of consistent association of many variables, including microbiologic factors, with baseline caries prevalence was unexpected, it is expected that some of these variables will contribute predictive power in the prospective study.

Child↗
PubMed1991

An epidemiologic estimate of the critical period during which human maxillary central incisors are most susceptible to fluorosis.

The temporal relation between a declining fluorosis gradient and an abrupt downward shift in community drinking water fluoride concentration was evaluated through multiple correlation analysis to determine the critical time frame during which developing maxillary central incisors are most susceptible to fluoride challenge. Fluorosis data were scrutinized through a time-related series of epidemiologic "windows" or time frames of varying lengths. The placement of these time frames was in turn related to the presumed start of enamel mineralization (at birth), and ranged from zero to 60 months later. In this way, the susceptibility of developing enamel to changes in water fluoride concentration was localized. The greatest risk was associated with a four-month critical period commencing at 22 months following birth. The risk of fluorosis from exposures to a fluoride challenge acting during shorter periods was better localized than risk associated with longer exposures. We concluded (1) that human maxillary central incisors are most susceptible to fluorosis during a critical period of as little as four months' duration, commencing at 22 months of age; and (2) that for these incisors, fluoride exposure during the months prior to this period carries less risk than continued exposure for up to 36 months beyond this critical time.

Aging↗
PubMed1991

Classification tree prediction models for dental caries from clinical, microbiological, and interview data.

Caries prediction by Classification And Regression Tree (CART) analysis is an appropriate and powerful alternative or complement to the commonly used classification methods of logistic regression and discriminant analysis, both parametric and nonparametric. The binary classification tree method discussed in this article is designed for complex data and does not require assumptions about the predictor variables or about the presence or absence of interactions among the predictor variables. Furthermore, the results give insight into the structures and interactions in the data and are easy to interpret and apply. In preliminary applications of the CART algorithms to data from The University of North Carolina Caries Risk Assessment Study, the method produced prediction rules having sensitivities and specificities that were similar to or slightly better than those associated with logistic and discriminant analyses. The classification trees constructed tended to involve far fewer predictor variables than required for adequate logistic and discriminant models. For example, for first-grade children in Aiken, South Carolina, nine variables were used to define a prediction rule having 64% sensitivity and 86% specificity. Ten-fold cross-validation estimates for future data were 58% and 79%, respectively. For first-grade children in Portland, Maine, two variables were used to define a prediction rule having 62% sensitivity and 77% specificity. The cross-validation estimates for future data were 58% and 78%, respectively. A brief, and previously unavailable, explanation of the CART method is given for the special case of a dichotomous outcome variable.

Child↗
PubMed1991

Risk assessment for oral diseases.

This paper seeks to achieve four goals, each of which forms the basis for a section in the presentation. First, the rationale of risk assessment is fully described. In this section, some of the necessary conditions are identified that make disease prediction worth pursuing. The second section discusses some essential background to the understanding of risk assessment in dentistry. In this segment, attention is focused on population-based and individual-based perspectives, alternative approaches to expressing health risk, and methods for comparing the predictive accuracy of alternative risk assessment models. The third section of the paper develops a conceptual framework for risk assessment in dentistry. Particular emphasis is devoted to the identification of risk factors and their incorporation into alternative statistical models. In the fourth section, empirical data are offered by which certain comparisons of the alternative risk models can be drawn. The paper concludes with a discussion that emphasizes data and technical limitations, speculates on future applications, and suggests new avenues for research.

DMF Index↗
PubMed1991

Clinical evaluation of seven anticalculus dentifrice formulations.

One hundred ninety-two subjects completed a clinical trial to determine the effects of seven dentifrice formulations on calculus inhibition. The double-blind study involved a ten-day control phase and a ten-day experimental phase. For the control phase, subjects were evaluated for calculus present, received a prophylaxis and had pre-weighed mylar strips attached to the lingual surfaces of the mandibular incisors to harvest mineral deposits. Subjects were then assigned the placebo dentifrice for unsupervised twice-daily use and were required to report once a day for a supervised mouthrinse using a 1:3 dilution of the dentrifice. The experimental phase was identical except that subjects were allocated the experimental dentifices using a stratified random assignment based on age, gender and the initial presence of calculus. Simple linear regression analyses of the dry and ash log weights obtained from the strips were performed. The results showed no statistically significant differences among the test products; however, two formulations containing zinc citrate showed some calculus inhibition-potential suggesting that further research and development of such products may be warranted.

Adult↗
PubMed1990

The University of North Carolina Caries Risk Assessment Study. II. Baseline caries prevalence.

Baseline clinical dental examinations were conducted on 5,233 children in grades 1 or 5 from the areas surrounding Aiken, SC, and Portland, ME, as part of a longitudinal study being conducted to predict children at high risk to dental caries. Mean caries levels in the Aiken area were nearly twice those of the Portland area. Black children experienced slightly more disease than whites. In addition to lower levels of caries experience, Portland children also had more treatment needs met, as indicated by higher filled ratio scores.

Black or African American↗
PubMed1990

Relationship of total fluoride intake to beneficial effects and enamel fluorosis.

Recent studies indicate that the prevalence of very mild to moderate dental fluorosis, as classified by Dean, has increased relative to that found in earlier investigations. To date, fluoridated water, fluoride supplements, the diet, fluoride dentifrices, and other topical fluoride applications have been identified as sources of systemic fluoride. Recent evidence suggests that there is a strong association between mild to moderate enamel fluorosis and the use of fluoride supplements during early childhood, and that the presently recommended supplementation schedule for U.S. children above the age of 2 years may be too high. Evidence also suggests that there is a strong association between fluoride dentifrice use during early childhood and enamel fluorosis in fluoridated populations. These findings support the need for a careful review of existing supplementation schedules and early oral hygiene practices. There is a pressing need for additional analytical epidemiological studies to confirm existing findings and to determine whether other fluoride sources may be associated with enamel fluorosis. Further, since exposure to combinations of individual risk factors has been shown to carry more than merely an additive increase in the risk of fluorosis, these studies must be multifactorial in design. There is also a need for more fluorosis prevalence and severity data to be gathered, so that the development of enamel fluorosis as a public health problem can be assessed, and so that the success of measures implemented to maximize efficacy while minimizing unwanted side-effects can be monitored.

Dental Enamel↗
PubMed1990

Adult root caries survey of two similar communities with contrasting natural water fluoride levels.

For a comparative study of root caries, 502 adult lifelong residents of a naturally fluoridated community (1.6 ppm F) and 465 such residents of a nearby, comparable nonfluoridated community (0.2 ppm F) were examined. Substantially fewer carious lesions were found among adults in the fluoridated community relative to the nonfluoridated community. This was observed in virtually all age- and gender-specific groups. Given a cross-sectional design and considering only exposed root surfaces, root caries was related to age. In addition, the data from this study show that the number of root caries lesions is underestimated but that root caries prevalence is overestimated by the standard Root Caries Index (RCI). A less restrictive form of the RCI may lead to more valid estimation of root caries prevalence.

Adolescent↗
PubMed1989

Comparative effects of a 4-year fluoride mouthrinse program on high and low caries forming grade 1 children.

This paper presents the comparative effectiveness of fluoride mouthrinse (FMR) on high and low caries forming children after a 4-yr exposure to weekly rinse beginning in the first grade. Over 1200 grade 1 children drawn from both fluoride deficient and fluoridated sites were divided into treatment and concurrent, longitudinal control groups. After 4 yr these children were stratified according to caries increment; those above the 75th percentile were considered high caries formers, all others were designated low caries formers. After adjustment of the mean increments for differences in SES, age, race, and sex in rinse and control groups, high caries formers (approximately 25% of the children) in the rinse and control groups in fluoride deficient areas showed increments of 7.00 and 7.79 surfaces, respectively, indicating a savings of 0.79 surfaces. Low caries formers (approximately 75% of the children) demonstrated increments of 1.11 DMFS in the rinse group and 1.40 in the control group (savings 0.29 DMFS). The pattern was quite similar for children in fluoridated areas except that the increments, as well as the savings realized, were lower. The results raise questions as to the practical effectiveness of school based FMR programs even for high caries forming children.

Child↗
PubMed1989

Comparative effectiveness of flossing and brushing in reducing interproximal bleeding.

This study assesses the comparative effectiveness of three types of dental floss and toothbrushing in reducing interproximal bleeding sites, measured by stimulation with wooden interdental cleaners using the interdental bleeding index assessment method. The 119 adult subjects with gingival inflammation were randomly assigned to one of four groups at the beginning of a supervised 2 week clinical trial. The toothbrushing only group achieved a 35% reduction in bleeding sites and the three flossing groups all demonstrated dramatic reductions of about 67%. The three varieties of dental flosses were about equally effective in reducing interproximal bleeding and doubly effective as toothbrushing alone. Compared to probing, the interdental bleeding index method is considered a simplified method of assessing interproximal gingival inflammation.

Adult↗
PubMed1985

Effect of secular decline in caries on the evaluation of preventive dentistry demonstrations.

Studies of dental preventive interventions often do not incorporate a concurrent, longitudinal control group in their study design. The existence of a secular decline in dental caries during the conduct of these studies may result in an overstatement of the effectiveness of the preventive intervention. Results of a recent large caries preventive study are analyzed using both a concurrent, longitudinal control group and an historical comparison group to demonstrate this effect. Differences in effectiveness of preventive procedures determined using the two types of control groups are sufficient to suggest a probable misinterpretation of results of studies using only historical comparisons.

Adolescent↗
PubMed1979

Bone fluoride concentrations associated with fluoridated drinking water.

Recently published bone fluoride values from Iowa are very high compared to earlier reports, suggesting an increase in fluoride intake. Reanalysis of the Iowa specimens shows levels one-fourth those reported by the Iowa laboratory indicating an error in the original report. Seventeen bone specimens, collected from long-term residents of Rochester, New York, drinking 1 ppm F- water, had a mean value of 2085 +/- 270 ppm F- on an ashed-weight basis. This value is not significantly different from that predicted by the data of Zipkin et al. in 1958. These data, therefore, do not support the contention that there has been an increase in fluoride intake.

Bone and Bones↗