Evaluates the pH of saliva to determine the level of acidity in the mouth. Acid is produced by oral bacteria and carbohydrates. There are several factors that may influence acid production, including diet, eating habits, dehydration, smoking, poor oral hygiene, and excessive plaque build-up. If the mouth is continuously exposed to acid production, demineralization occurs. This process may lead to the erosion of tooth enamel, dental caries, or eventually periodontal disease (a chronic bacterial infection).