*3.2.5 Alkaline phosphatase*

Alkaline phosphatase has been evaluated in saliva as a possible biomarker for the detection of periodontitis. Dabra and Singh [16] first study 20 healthy subjects with gingivitis, and 20 with chronic periodontitis were included. This investigation showed a statistically significant increase in alkaline phosphatase activities in the saliva of patients with periodontal disease compared to the control group. A recent study of Patel et al. [69] included 150 healthy subjects, 50 patients with chronic generalized gingivitis, and 50 with periodontitis. In this study it was shown that alkaline phosphatase can be considered for the diagnosis of diseased and healthy periodontal tissues; since as the severity of periodontal disease increases, it also increases alkaline phosphatase levels.

### *3.2.6 pH*

The pH of the saliva has been evaluated, and it has been found that there is a significant change in the pH depending on the severity of the periodontal condition, so the pH can be useful as a rapid diagnostic biomarker in the consultation. The study suggests that the pH becomes alkaline when patients have chronic gingivitis, but it becomes acidic when there is periodontitis [71].
