Influence of colonization with mutans streptococci on caries risk in Japanese preschool children: 24 month survival analysis.

Purpose: This study evaluates how various microbial- and salivary-related risk factors influenced the hazard for caries development in preschool children.

Methods: The study population consisted of 131 subjects (age: 0.5 to 6.0 yrs). Oral examination, including two bacterial tests and buffering capacity test, was conducted at six month intervals over 24 months. A survival analysis was used to describe caries hazard over a 24-month follow-up period. A Cox proportional hazards regression analysis was performed to test the influence of salivary mutans streptococci (MS), aciduric bacteria, buffering capacity and age on caries development.

Results: Of the total subjects, 60 children (46%) were found to be caries-free at baseline. Caries hazard correlated significantly with salivary MS levels at baseline (relative risk, 1.7; P = 0.003), but not with aciduric bacteria and buffering capacity. This analysis showed that all of children with high colonization of MS at baseline had dental caries 15 months later.

Conclusion: The results suggest that salivary MS level at baseline influenced caries hazard in preschool children.