Comparison of Salivary Ion Activity Product for Hydroxyapatite (IPHA), Alkaline Phosphatase and Buffering Capacity of Adults According to Age and Caries Severity

Statement of Problem: Tooth caries is influenced by different biochemical characteristics of saliva. As hydroxyapatite is the main component of enamel, salivary ion activity product for hydroxyapatite (IPHA) as well as alkaline phosphatase may be attributed to dental caries. Purpose: The aim of the present study was to compare salivary buffering capacity, alkaline phosphatase and IPHA of adults according to the dental caries and age. Materials and Method: One hundred and twenty 19 to 44 years old male individuals were divided into four groups according to the dental caries rate and age: group 1: 19-35 years old low dental caries (DMFT <5); group 2: 19-35 years old high dental caries (DMFT 5<); group 3: 35-44 years old low dental caries (DMFT <11) and 35-44 years old high dental caries (DMFT 11<). Five millilitre of unstimulated saliva was collected, and then buffering capacity, the level of alkaline phosphatase activity and IPHA was determined for each sample. Data was analyzed by soft ware SPSS using two-way ANOVA, Friedman and Mann-Whitney tests.Results: Mean and standard deviation of buffering capacity of group 1 to 4 was 2.66±0.54, 2.64±0.56, 2.70±0.70 and 2.26±0.82, respectively. The difference was not significance (p= 0. 305). Mean and standard deviation of alkaline phosphatase activity of group 1 to 4 was 5.82±2.91, 5.30±1.52, 4.77±1.82 and 4.55±1.61, respectively. There was no significant difference (p= 0.692). Mean and standard deviation of IPHA of group 1 to 4 was 29.39±0.61, 29.51±0.76, 29.14±0.56 and 29.75±0.75, respectively. The difference was significant (p= 0.049).Conclusion: Based on the results of the present study, buffering capacity and the level of alkaline phosphatase couldn’t affect dental caries, independently. However, the higher value of IPHA may be attributed to the higher dental caries rate. Ageing decreases alkaline phosphatase activity.