pH and Buffering Capacity of Whole Saliva from Individuals with Dental Erosion

Objectives: Dental erosion is an increasing problem in dentistry and might be related to salivary pH and buffering capacity. Methods: we collected unstimulated (UWS), parafilm-chewing stimulated (CH-SWS) and citric acid-stimulated (CI-SWS) whole saliva from 31 consecutive patients, referred to the saliva consulting-hour at the Academic Centre for Dentistry in Amsterdam. Fourteen individuals were referred for dental erosion (DE) with unknown etiology, 17 for other reasons (NDE: non dental erosion): xerostomia 11, altered taste 3, hypersalivation 2, mucosal alterations 1. Salivary secretion rates were determined gravimetrically and pH was measured with a Sentron 1001 system. Next, 0.5 ml 5 mM HCl was added 10 times to 1 ml CH-SWS, to assess the buffering capacity. Buffering capacity was expressed as the pH after addition of a total volume of 2.5 ml HCl (pH-ac) and the calculated volume of HCl to obtain a pH of 5.5 (ml-HCl). Results: The mean age of DE-patients (25.4±3.9 yr) was significantly lower than that of NDE-patients (54.4±10.3 yr, p < 0.001). The secretion rates of UWS did not differ between DE- and NDE-patients, but the CI-SWS flow rate was significantly higher in DE-patients (2.57±1.50 ml/min versus 1.50±0.78 for NDE, p=0.022). CH-SWS showed no significant differences between DE, NDE and 12 age-matched controls (C: 25.4±2.6 yr) with regard to secretion rate (DE 1.10±0.55 ml/min; NDE 0.99±0.55; C 1.19±0.45), pH (DE 6.98±0.26; NDE 6.96±0.26; C 7.06±0.25), pH-ac (DE 4.31±0.87; NDE 4.84±1.14; C 4.27±0.91) and pH-ml (DE 1.81±0.50 ml; NDE 2.22±1.07; C 1.84±0.67). Conclusions: Our data do not provide evidence for a relation between salivary buffering capacity and DE, suggesting that other factors like use of beverages or citric fruit consumption may be more important than salivary buffering capacity in developing DE.