Methods: Three beverages were selected and tested for their pH value using a pH electrode (pHM240, MeterLab, France) every 15 minutes for one hour. Enamel specimens were immersed in artificial saliva (as described by ten Cate) for 24 hours prior to reatment. One half the enamel surface was covered with wax while the exposed half was pre-treated with MI Paste™ or Clinpro 5000™ slurry. The untreated side served as control. After removing wax, specimens were immersed in Coca-Cola™, Gatorade™, and Poland Spring™ water for a 30 minute acidic challenge. The Vickers microhardness was determined on both the toothpaste exposed and protected control sides. Mean microhardness (+s.d.) were calculated and significance determined utilizing a student’s t-test.
Results:
Mean pH readings for Poland Spring water was 6.88, 2.83 for Gatorade™, and 2.29 for Coca-Cola™. In Gatorade™ and Coca-Cola™, there was a significant increase in microhardness of enamel of the MI Paste treated side compared to the untreated side (14.2% p<0.002 and 18.6% p<0.01). There was a non-significant decrease in microhardness of enamel of the MI Paste treated side in Poland Spring water (2.6%). There was an increase in microhardness of enamel of the Clinpro 5000 treated side compared to the untreated side in all three beverages (7.4% in water non-significant, 12.3% in Gatorade (p<0.043) and 20.2% in Coca-Cola p<0.007)).
Conclusions:
Specimens incubated in Poland Spring water served as the baseline in the experiment, and no significant difference were found between the pre-treated side and untreated side for both toothpaste. Acidic beverages caused erosive damage on enamel. Brushing with MI Paste™ and Clinpro 5000™ offered an effective protection of enamel surface from an acidic challenge.