Practical uses of caries risk assessments using saliva buffer capacity

Objectives: To evaluate salivary buffering capacity using a handy-type pH meter and to establish a practical use of this caries risk assessment for caries risk control. Materials and method: The study population consisted of 118 patients who attended for treatment in Tokyo Medical and Dental University. After reading the pH value of 0.5 ml of the stimulated whole saliva, the 10ml of 0.1N HCl was titrated into each sample up to 160ml titration in total, and the pH value was read each time using a handy pH meter (Twin pH B-212, Horiba Ltd. Japan). The buffer strip (CRT® buffer, IVOCLARVIVADENT) was evaluated as a control. The differences in ranking results (high, medium, low) between acid buffer capacity and CRT® buffer were statistically analyzed by Mann-Whitney U test (p<0.05). For each acid buffering capacity, the differences in DMFT was also statistically analyzed by one-way ANOVA and scheffe's test (p<0.05). Results: The individual saliva buffer capacity beneath titrated 50ml of HCl was ranked into the following three groups; high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). There were no significant differences between acid buffer capacity and CRT® buffer (p>0.05). On the other hand, the DMFT of the high buffer capacity group was significantly lower than that of the medium or low groups (p<0.05). Conclusion: Because this quantitative saliva buffer capacity test can be carried out at the chair-side, it could add important information for clinical caries risk assessment. To avoid over caries treatments, an appropriate caries risk assessment for each patient is important. It would not necessarily restore the arrested caries or initial caries in patients with low caries risk. On the other hand, for patients with a high caries risk, professional advice and self-oral care might be appropriate before caries treatments.