Comparison of intracoronal bleaching methods on teeth discolored by different antibiotic pastes

To compare the bleaching efficacy of sodium perborate with different activation methods on crowns discolored by two different antibiotic pastes.

Eighty-five extracted human incisors were prepared to size #30 using ProTaper rotary instruments. After chemomechanical preparation and irrigation procedures, the specimens received triple antibiotic paste (TAP, n = 40), minocycline paste (MP, n = 40), or calcium hydroxide (n = 5, control group) and coronally sealed with temporary filling material. Spectrophotometric readings were obtained on day 0-week 4. Data were analyzed with the Mann-Whitney U-test and Wilcoxon sign test (P < 0.05). Sodium perborate was then inserted into the pulp chambers of discolored teeth (four subgroups, n = 10) and activated by heat or ultrasonically using two different frequencies and times. Spectrophotometric readings were obtained on days 3-7. Data were analyzed by the Mann-Whitney U-test and Kruskal-Wallis test (P > 0.05).

Both groups showed statistically significant coronal discoloration at each time interval (P < 0.01), but their final shades did not significantly differ between the groups (P > 0.05). Although the MP subgroups exhibited more bleaching than the TAP subgroups on days 3 and 7, the difference was not significant (P > 0.05). The bleaching results for the sodium perborate activation techniques did not significantly differ among groups (P > 0.05).

Both antibiotic pastes induced crown discoloration that was reversible using all sodium perborate bleaching techniques.