Inhibition of dentine demineralization by zinc oxide: In vitro and in situ studies

Objective The objective of this study was to evaluate the inhibitory effect of zinc oxide on dentine demineralization in vitro and in situ. Methods In the in vitro study, dentine specimens treated with a zinc oxide suspension were demineralized in a pH 5 solution. In the in situ study, subjects wore dentine specimens on their teeth and instructed to rinse with zinc-containing toothpaste slurry three times a day for 14 days. The design of study was a crossover one. Results Microradiography employed in the in vitro study revealed the dentine surfaces treated with distilled water had a lower mineral content than those treated by zinc. Toothpaste with zinc had a statistically significant, 49% greater inhibitory efficacy on dentine demineralization over the control. In the in situ study, zinc-containing toothpaste was also confirmed to have an inhibitory effect on dentine demineralization when compared to the zinc-free toothpaste. These in vitro and in situ studies revealed that zinc oxide can have a significant effect on the inhibition of dentine demineralization, even when the zinc oxide is blended into toothpaste. Significance This suggests that zinc oxide may be effective in the prevention of root caries.