Oral Clearance of an Acidic Drink in Patients with Erosive Tooth Wear Compared with that in Control Subjects

Purpose: The aim of this study was to compare the clearance of an acidic drink in patients with tooth wear caused by regurgitation erosion to that in patients without tooth wear. Materials and Methods: Oral clearance was measured using antimony electrodes at 4 soft tissue sites around the mouth in the patients with erosion caused by regurgitation and compared to a matched control group. The data were analyzed for pH at the resting state, the time below 5.5, and the lowest recorded pH. In addition, the resting hydration levels and viscosity of fluid from the minor salivary glands, the pH of resting saliva, and the flow rate and buffering capacity of stimulated saliva were compared between the 2 groups of patients. Results: The pH recorded at the tip of the tongue reached a lower level in the controls than in those in the erosive tooth wear group (P .05) and the time that the pH remained below 5.5 was longer in the controls than those with tooth wear (P .05). The flow rate from the minor salivary glands (P .05) and the viscosity of resting saliva appeared to differ between the two groups (P .001). Conclusion: Oral clearance at the tip of the tongue, measured as a function of the lowest pH reached and the time below 5.5, was quicker in those with erosive tooth wear than the controls. It is suggested that this may be a result of a feedback mechanism from constant exposure of the oral environment to low pH.