As discussed earlier, a normal salivary pH (normal: 6 to 7, range: 5.3 to 7.8) is imperative to maintain a healthy oral environment. Consequently, measuring resting and stimulated salivary pH is an important element of caries risk assessment. Measuring salivary pH can also be used to determine the time it takes to return to normal pH after an acid challenge (Figure 2). This information then provides an opportunity to correlate the buffering capacity of the patient’s saliva and information obtained from the patient’s social history, i.e., their pattern of consumption of beverages with a pH < 5 such as most soft drinks, citrus juices, coffee, wine, energy drinks, and sports drinks.
Figure 2. Saliva-check Buffer System.
Bicarbonate (HCO3-) ions play a major role in the salivary buffering system. Since mastication is a powerful stimulus of the secretion of sodium bicarbonate into parotid saliva, patients with residual salivary gland function may benefit from chewing sugar-free gum (e.g., Biotène Dry Mouth Gum, Trident with Xylitol Gum, or Trident XtraCare with Recaldent).32 Patients without residual salivary gland function can increase their salivary pH and their salivary buffering capacity by frequently rinsing with a sodium bicarbonate solution. In particular, patients should rinse vigorously after the intake of acidic foods and drinks.