Methods: Data on saliva characteristics at baseline and dental caries incidence were collected in an ongoing longitudinal study with a systematic random sample of patients visiting Northwest PRECEDENT general dental practices in the Northwest United States. Risk Ratios (RR) were estimated for adults (18-64 years old) using GEE binomial regressions to relate salivary characteristics to dentin caries (yes/no), adjusting for demographic and lifestyle characteristics.
Results: Of 414 adults with one or more follow-up visits and enrolled into the study for at least 9 months, the dental caries incidence was 36.5% (Results for children/adolescents and seniors will be reported later). Compared to adults with salivary flow <60 seconds, the adjusted risk ratios of new dental caries for those with resting salivary flow >60-<90 seconds and >90 seconds were 1.5 [95% Confidence Interval (CI)=1.0-2.1] and 1.1 (95%CI=0.8-1.4), respectively. Adults with a stimulated salivary flow rate >0.6-<1.0 ml/min and <0.6 ml/min had a 50% (RR=1.5; 95%CI=1.2-2.1) and 30% (RR=1.3; 95%CI=0.8-2.2) higher caries risk than those with stimulated flow rate >1.0 ml/min. Associations of salivary consistency, resting and stimulated salivary pH and buffering capacity with dental caries were not statistically significant.
Conclusion: Results should be interpreted with caution because follow-up of the participants is ongoing. In this general practice patient population returning for follow-up visits, moderate resting and stimulated salivary flow were associated with new dental caries, but not low resting and stimulated salivary flows. The initial results indicate that salivary flow rate may be useful for caries risk assessment, but other salivary characteristics (consistency, pH and buffering capacity) may not.
Submitted on behalf of Northwest PRECEDENT; NIDCR grants DE016750/DE016752.
Keywords: Dental caries, Epidemiology and Saliva