Comparison of the erosive potential of gastric juice and a carbonated drink in vitro.

The aim of this study was to compare the erosive effect of gastric juice and a carbonated drink on enamel and dentine by measuring release of calcium from 30 hemisectioned teeth in vitro. In addition, the titrable acidity (mL of 0.05 M sodium hydroxide required to neutralize) and pH of the fluids was estimated. The mean pH of the seven gastric acid samples was 2.92 (range 1.2-6.78) and mean titratable acidity 0.68 mL (range 0.03-1.64). Both the pH and the titratable acidity of the gastric juice varied between patients all of whom suffered from symptoms of reflux disease. The carbonated drink had a pH of 2.45 and a titratable acidity of 0.29 mL. The median amount of calcium released by the gastric acids from enamel was 69.6 microg L-1 (interquartile range 5.4-144) and 62.4 microg L-1 (2.2-125.3) from dentine. The carbonated drink released 18.7 microg L-1 (13.4-23.4) and 18.6 microg L-1 (11.9-35.3), respectively. The differences in calcium release by gastric juice and the carbonated drink were statistically significant for both enamel (P < 0.005) and dentine (P < 0.01). It is concluded that gastric juice has a greater potential, per unit time, for erosion than a carbonated drink.