Effect of a Nano-hydroxyapatite Toothpaste on Enamel Erosive Lesions of Third Molars Induced by Exposure to Orange Juice.

Objectives: This study aimed to assess the effect of a nano-hydroxyapatite (nano-HA) toothpaste on erosive enamel lesions of third molars induced by exposure to orange juice.

Materials and methods: In this in vitro, experimental study, the microhardness of 24 sound-extracted third molars was measured by a Vickers tester. The teeth were then randomly assigned to three groups (n = 8) of nano-HA toothpaste (Pharmed), 1.23% sodium fluoride gel, and artificial saliva. The teeth were exposed to orange juice for 5 min daily for 7 days and were then exposed to nano-HA toothpaste, fluoride gel, or artificial saliva (depending on their group allocation) for 10 min a day. The microhardness of the teeth was measured again after 7 days. Data were analyzed using paired t-test, analysis of variance, and Bonferroni test (alpha = 0.05).

Results: Within-group comparisons showed a significant reduction in microhardness of the teeth after the intervention in artificial saliva (P = 0.000), and fluoride gel (P = 0.002) groups. However, no significant reduction occurred in the microhardness of the nano-HA group, compared with the baseline (P = 0.132). Between-group comparisons revealed no significant difference in the microhardness of the three groups at baseline (P > 0.05). However, after the intervention, the microhardness of the nano-HA group was significantly higher than that of other groups (P < 0.05). However, the difference in secondary microhardness between fluoride gel and artificial saliva groups was not significant (P = 1.00).

Conclusion: Pharmed toothpaste containing nano-HA has optimal efficacy for remineralization of enamel erosive lesions induced by exposure to orange juice.