Predictors of Dental Caries Increment in Schoolchildren: A Longitudinal Study of Salivary and Behavioral Risk Factors

Background: This study analyzed the association between caries increment and clinical, salivary, bacteriological, and behavioral risk markers in a two-year follow-up study of schoolchildren in Mexico City. Methods: A two-year follow-up study was conducted in elementary schoolchildren, where 118 schoolchildren aged 7–10 years at baseline (50% boys) participated in the follow-up. Toothbrushing frequency, sugar consumption, and dental caries indices were recorded according to WHO criteria. Salivary secretion rates, buffering capacity (Dentobuff®), and cariogenic bacterial counts (Dentocult SM and LB®) were also measured. Logistic regression was applied to analyze associations between caries increment and risk markers. Results: The mean baseline caries indices were dmft 4.8 (SD 4.0) and DMFT 0.6 (SD 0.9). Children were classified into three caries experience groups: caries-free, filled-teeth, and caries-active. After two years, baseline caries-free children had a lower caries increment in permanent teeth (0.2, SD 0.7) than other groups (p < 0.0001). However, the caries increment was similar between groups (p = 0.0827). Logistic regression revealed associations with toothbrushing frequency [OR = 2.77, p = 0.026], S. mutans counts [OR = 3.38, p = 0.050], and Lactobacillus counts [OR = 2.91, p = 0.029]. Conclusions: Children with low toothbrushing frequency and high cariogenic bacterial counts developed more caries lesions than those with better oral hygiene and lower bacterial levels. Greater emphasis should be placed on promoting oral hygiene and reducing bacterial load in the oral cavity.