ผลของการกำจัดชั้นสเมียร์ก่อนการฟอกสีฟันภายในตัวฟันต่อประสิทธิภาพการฟอกสีฟันและความแข็งผิวเนื้อฟัน

Abstract

Introduction: Removal of smear layer has been suggested prior to placement of bleaching agent in order to improve the effectiveness of intracoronal bleaching. However, there is no evidence available on the benefit of smear layer removal on the effectiveness of intracoronal bleaching. Objectives: To evaluate the effects of smear layer removal, using 37% phosphoric acid or 17% EDTA prior to intracoronal bleaching on shade improvement and dentin hardness Materials and methods: Ninety extracted premolars were artificially stained with human blood and divided into 3 groups according to smear layer removal protocol. Group I: distilled water 10 ml, Group II: 37% phosphoric acid gel for 15s and Group III: 17% EDTA 5 ml, for 60s followed by rinsing with distilled water. Subsequently, sodium perborate mixed with distilled water was placed and changed at day 7, 14 and 21. Shade measurement and dentin hardness testing were performed at 7, 14 and 21 days. Data were analysed by ANOVA and post-hoc test (Tukey Honestly Significant Difference (HSD)) (p<0.05). Results: In all groups, significant shade improvements were observed at all time points (DW p = 0.001, H,PO, p = 0.001, EDTA p = 0.000). However, there were no significant differences among groups on shade improvement (7 days p=0.746, 14 days p=0.272, 21 days p=0.897) and dentin hardness at 7, 14 and 21 days (7 days p = 0.492, 14 days p=0.706, 21 days p = 0.897). Conclusion: Within the limitations of this study, smear layer removal with either 37% phosphoric acid or 17 % EDTA did not increase the effectiveness of intracoronal bleaching on shade improvement and did not affect hardness of the dentin.