Salivary pH and DMFT Index in Smokers and Non-smokers: A Comparative Study Based on the Quantitative Rate of Smoking

Background: The effect of cigarette smoking duration on salivary pH and its relation to the rate of dental caries is unknown. Our aim was to comparatively investigate the salivary pH and DMFT index in cigarette smokers and non-smokers based on the quantitative rate of smoking. Methods: This case-control study was conducted using simple random sampling. Three ml samples of not stimulated whole saliva were collected from 92 smokers and 37 nonsmokers. DMFT indices were recorded. The rate of smoking was calculated by pack-year index. Salivary pH was measured by pH meter (744 Metrohm). The data were analyzed by analysis of variance (ANOVA) and Pearson correlation coefficient was used to compare the status of pH and DMFT between smokers and non-smokers. The correlation of pH level and DMFT index with the amount of smoking was also investigated in smokers. Results: The mean salivary pH level in smokers and non-smokers was 6.57±0.06 and 7.04±0.06, respectively. The mean DMFT in smokers and nonsmokers was 7.60±0.5 and 4.80±0.5, respectively. Salivary pH decreased significantly with the increase of pack-year index (P = 0.01). The relationship between DMFT and the amount of smoking was not significant. DMFT index was significantly higher in smokers with over 300 pack-years than in other smokers (P = 0.01). Conclusions: Cigarette smoking was associated with lower salivary pH and higher DMFT index. The increased number of smoked cigarettes was associated with increased number of decayed teeth.