In vitro Evaluation of the Enamel Micro-Hardness and Micro-Roughness Subjected to Three Amazonian Citrus Fruit Juices

In the Amazon rainforest the high consumption of citrus fruits is related to their benefits on the immune system. However, the pH of these fruits is lower than the critical pH of dental enamel, and their continuous consumption can damage dental surfaces and cause hypersensitivity, especially in young adults, who are more susceptible to these damages. Therefore, the objective of this study was to evaluate the hardness and roughness of bovine tooth enamel exposed to the juice of three Amazonian fruits: grapefruit, orange-lemon hybrid, and camu camu. To perform the erosive challenge, the pH of the three fruits was measured. Grapefruit juice had a pH of 2.33, orange-lemon hybrid a pH of 2.46, and the camu camu a pH of 2.58. Specimens were exposed to the fruit juice for five minutes, three times a day, for fourteen days. The initial and final micro- hardness and micro-roughness of the specimens were evaluated. To compare the values before and after exposure to the citrus fruits, Student’s t-test and Wilcoxon test were used. To compare the results of each variable, the Kruskal- Wallis test and Mann-Whitney U test were used. The fruits used in this research decreased the micro-hardness and increased the roughness of the bovine tooth enamel surface. No statistically significant differences were found when comparing the erosive effect among the three citrus fruits. However, statistically significant differences were found when comparing the initial and final micro-hardness and micro- roughness values of the enamel specimens.

KEY WORDS: hardness, roughness, citrus, erosion, pH.