Dental Caries

Etiology

The development of dental caries depends on interrelationships among the tooth surface, dietary carbohydrates, and specific oral bacteria. Organic acids produced by bacterial fermentation of dietary carbohydrates reduce the pH of dental plaque adjacent to the tooth to a point where demineralization occurs. The initial demineralization appears as an opaque white spot lesion on the enamel, and with progressive loss of tooth mineral, cavitation of the tooth occurs ( Fig. 338.1 ).

The group of microorganisms, mutans streptococci, is associated with the development of dental caries. These bacteria have the ability to adhere to enamel, produce abundant acid, and survive at low pH. Once the enamel surface cavitates, other oral bacteria (lactobacilli) can colonize the tooth, produce acid, and foster further tooth demineralization. Demineralization from bacterial acid production is determined by the frequency of carbohydrate consumption and by the type of carbohydrate. Sucrose is the most cariogenic sugar because one of its by-products during bacterial metabolism is glucan, a polymer that enables bacteria to adhere more readily to tooth structures. Dietary behaviors, such as consuming sweetened beverages in a nursing bottle or frequently consuming sticky candies, increase the cariogenic potential of foods because of the long retention of sugar in the mouth.

Epidemiology

As per the 2011–2012 National Health and Nutrition Examination Survey (NHANES), approximately 15% of children ranging from 2 to 8 yr of age had one or more primary teeth affected by dental caries ( Fig. 338.2 ). In the permanent dentition, over 10% of children aged 12-15 yr had dental caries and one-fourth of children were affected by age 16-19 yr ( Fig. 338.3 ).

Clinical Manifestations

Dental caries of the primary dentition usually begins in the pits and fissures. Small lesions may be difficult to diagnose by visual inspection, but larger lesions are evident as darkened or cavitated lesions on the tooth surfaces ( Fig. 338.4 ). Rampant dental caries in infants and toddlers, referred to as early childhood caries , is the result of early colonization of the child with cariogenic bacteria and the frequent ingestion of sugar, either in the bottle or in solid foods. The carious process in this situation is initiated earlier and consequently can affect the maxillary incisors first and then progress to the molars as they erupt.

The prevalence of untreated caries was significantly higher in children between 3 and 9 yr of age living at or below 100% of federal poverty level compared with those above the poverty level. Besides high frequency of sugar consumption and colonization with cariogenic bacteria, other enabling factors include low socioeconomic status of the family, other family member with carious teeth, recent immigrant status of the child, and the visual presence of dental plaque on the child's teeth. Children who develop caries at a young age are known to be at high risk for developing further caries as they get older. Therefore the appropriate prevention of early childhood caries can result in the elimination of major dental problems in toddlers and less decay in later childhood.

Among adolescents, the prevalence of dental caries experience was higher in age group 16-19 yr (67%) compared with age group 12-15 yr (50%). Overall, the caries experience did not significantly differ by race, Hispanic origin, and poverty levels.