A 'sufficient cause' model for dental caries.

BACKGROUND: It is generally believed that dental caries is an infectious disease. The occurrence of dental caries is affected by a variety of determinants. In order to estimate the precise extent of the relation between specific determinants and the outcome phenomenon (i.e. the occurrence of dental caries), a coherent disease model is required. This model should also permit multivariate analysis to control for confounders and interactions. Only with such a disease model will it be possible to investigate the relation between the occurrence of a determinant and dental caries, and to estimate the extent of this relation. The known causal models for the explanation of dental caries do not fully meet these requirements. METHOD: Rothman's 'sufficient cause' model has been used as a starting point for the development of a new coherent disease model, to explain the occurrence of dental caries and allow multivariate analysis. RESULTS: The sufficient cause for dental caries comprises three component causes: sufficient microorganisms with cariogenic potential, easily fermentable carbohydrates and teeth. Whether dental caries actually occurs also depends on the influence of independent risk factors that interact with the component causes in a protective, as well as in a risk-increasing manner. These independent risk factors are saliva, fluoride, oral hygiene and diet. CONCLUSIONS: The 'sufficient cause' model for dental caries is a biological model in which distinction between protective and risk-increasing factors has been made, and interaction between factors has been described. With this model, it will now be possible to assess the extent of the relationship between a determinant and dental caries (the outcome phenomenon) using multivariate techniques.

Incidence of dental caries in the primary dentition in children with a cleft lip and/or palate.

The incidence of dental caries in the primary dentition was determined in Dutch cleft lip and/or palate children (n = 81) and in children without a congenital malformation (n = 77). In the oral cleft group the incidence of dental caries (0.037; 95% CI 0.031-0.046) was significantly higher than in the control group (0.004; 95% CI 0.002-0.007) with a crude incidence rate ratio of 9.3. Adjusted for oral hygiene, oral cleft yielded a rate ratio (relative risk) of approximately 3.5 (95% CI 1.35-9.28) in the multivariate analysis. Dental caries occurred in 25 children with an oral cleft (30.9%) and in 5 control children (6.5%). All types of teeth were affected in the oral cleft group while in the control group dental caries only occurred in maxillary incisors and second molars. The highest incidence of dental caries was found in the teeth beside the oral cleft and in the primary molars of the oral cleft group.

Increased caries prevalence in 2.5-year-old children with cleft lip and/or palate.

The prevalence of dental caries was determined clinically in 2.5-year-old Dutch cleft lip and/or palate children (n = 76) and in children without congenital malformation (n = 75). The parents were given a structured questionnaire regarding the child's dietary habits, oral hygiene, fluoride exposure and social economic background. The prevalence of dental caries was higher in children with oral cleft than in children without oral cleft. Initial caries (white spots) was diagnosed in 17.1% of the subjects with oral cleft compared with 4.0% of the control subjects. Manifest caries (cavities) was found in 26.3% of the children with oral cleft compared with 5.3% of the controls. The dft score (manifest caries) was significantly higher for the oral cleft group (0.59 +/- 1.35) than for the control group (0.11 +/- 0.54). 52% of the total number of initial and manifest lesions were localized to the maxillary incisors. A multivariate analysis yielded initial caries, oral hygiene and treatment with preoperative infant orthopaedics as the variables significantly associated with manifest caries.

Prevalence of Streptococcus mutans and lactobacilli in 18-month-old children with cleft lip and/or palate.

The prevalence of Streptococcus mutans and lactobacilli was determined in 62 18-month-old Dutch children with a cleft lip and/or palate. Plaque and saliva samples were collected, a dental examination was performed, and the parents were interviewed with a structured questionnaire regarding general health, dietary habits, fluoride exposure, and socioeconomic class. Appropriate dilutions of the plaque and saliva samples were cultured on selective media to count all viable bacteria, S. mutans and lactobacilli. S. mutans was detected in the saliva of 45% of the children, and lactobacilli was detected in 16%. Also, S. mutans was detected in 48% of the plaque samples and lactobacilli in 8%. Of all of the variables examined, consumption of more than three snacks and beverages between main meals was significantly associated with presence of S. mutans in saliva. Preoperative infant orthopedic treatment (i.e., wearing an acrylic plate from shortly after birth) was significantly associated with presence of lactobacilli in saliva. The presence of S. mutans in the plaque samples was also significantly associated with presence of lactobacilli in saliva. These results indicate that children with oral cleft are at an increased risk of being infected by S. mutans and lactobacilli at a very early age. Such early colonization indicates a high risk for caries in the primary dentition.