PENGARUH KONSENTRASI BAHAN IN-OFFICE BLEACHING TERHADAP KEKERASAN EMAIL

Hydrogen peroxide as the bleaching material which is applied to the teeth has raised questions as to possible adversed effect on tooth structure. This study evaluated the effects of 30%, 35% and 38% hydrogen peroxide on enamel hardness. A total of 32 extracted human incisors were randomly divided into 4 groups of 8. An in-office bleaching was conducted where the groups I , II and III were treated with 30%, 35%, and 38% hydrogen peroxide respectively. Thirty minutes bleaching sessions were conducted which were irradiated with halogen lamp with a distance of 30 cm. Group IV was not exposed to any bleaching system and served as the control group. After bleaching the subjects were washed and sectioned at cervical level. The crowns were imbedded in acrylic resin with facial surfaces facing up. Enamel microhardness measurements were carried out using Vickers Hardness Tester on 3 points of labial surface of each tooth which were incisal, middle and apical one-third. Data was analyzed using one-way ANOVA and t-test at a 0.05 significance level. The mean enamel hardness in the control group 490.9988 ± 57, 33 511 VHN, in group I (H2O2 30%) 351, 8338 ± 37, 61 337 VHN, in group II (35% H2O2) 233, 7925 ± 38, 83 932 VHN, on group III (38% H2O2) 194, 7075 ± 24, 77 265 VHN Results with one way ANOVA showed significant differences between groups of hydrogen peroxide 30%, 35%, and 38% (p <0.05). The results with ttest shows the differences between the treatment group (p