Salivary characteristics and dental caries: evidence from general dental practices.

Background: Saliva is one of the intraoral host factors that influence caries development. The authors conducted a study to investigate whether salivary characteristics are associated with recent dental caries experience.
Methods: Dentist-investigators and dental staff members collected data pertaining to a two-year cumulative incidence of dental caries (previous 24 months) and salivary characteristics during baseline assessment in an ongoing longitudinal study. The systematic random sample consisted of patients (n = 1,763) visiting general dental practices (n = 63) within the Northwest Practice-based REsearch Collaborative in Evidence-based DENTistry (PRECEDENT). The authors estimated adjusted rate ratios (RRs) by using generalized estimating equations log-linear regression to relate salivary characteristics to coronal carious lesions into dentin.
Results: Low resting pH (≤ 6.0) in the overall sample and low stimulated salivary flow rate (≤ 0.6 milliliter/minute) in older adults (≥ 65 years old) were associated with increased dental caries (RR, 1.6; 95 percent confidence interval [CI], 1.1-2.2; RR, 2.4; 95 percent CI, 1.5-3.8, respectively). Low buffering capacity was associated with decreased dental caries in children and adolescents (RR, 0.3; 95 percent CI, 0.1-1.0; RR, 0.2; 95 percent CI, 0.1-0.7, respectively). A thick, sticky or frothy salivary consistency also was associated with decreased dental caries in adults (RR, 0.6; 95 percent CI, 0.4-1.0). Associations between other salivary characteristics and dental caries for the overall sample and within each age group were not statistically significant.
Conclusions: Salivary characteristics were associated weakly with previous dental caries experience, but the authors did not find consistent trends among the three age groups. Different salivary characteristics were associated with an increased caries experience in older adults and a lowered caries experience in children and adolescents and adults. Practical Implications. Further investigations are needed in this population setting to understand the study's conflicting results. The study findings cannot support the use of salivary tests to determine caries risk in actual clinical settings.