Khoroushi Maryam, Feiz Atieh, Ebadi Maysam
Associate Professor, Department of Operative Dentistry and Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
Dent Res J (Isfahan). 2009 Spring;6(1):17-22.
Failure of composite restorations in terms of microleakage after intracoronal bleaching has been reported. The purpose of this study was to assess in vitro effect of sodium ascorbate and calcium hydroxide as intermediary filling materials to repair the microleakage associated with adhe-sive restoration following intracoronal bleaching.
Sixty endodontically-treated incisors with access cavities extended to the cementoenamel junction in gingival margin were randomly divided into five equal groups. In group 1, cavities were restored by applying Single Bond and Z100 composite resin. In groups 2-5, 35% hydrogen peroxide gel was placed into the pulp chamber and sealed for 5 days. In group 2, teeth were then restored as in group 1. In groups 3 and 4, 10% sodium ascorbate gel and calcium hydroxide paste were applied in the pulp chamber for 40 hours, removed, rinsed and then, restored. In group 5, the cavities were incu-bated for 7 days and then, restored. Samples were thermocycled, immersed in basic fuschin, and sec-tioned. Dye penetration was scored using a stereomicroscope. Data were analyzed using Kruskal- Wallis and Mann-Whitney U tests (α = 0.05).
There was no significant difference in enamel margins (P = 0.163). In dentinal margins (P = 0.003), groups 1, 3 and 5 exhibited similar leakage patterns, each one of groups 1, 3 and 5 had sig-nificant differences with each one of groups 2 and 4.
Intracoronal bleaching using 35% H2O2 gel increases the microleakage in dentinal margins. Application of the antioxidant agent or a seven-day delay following bleaching may improve the marginal integrity. Applying calcium hydroxide might jeopardize dentinal sealing.
已有报道称，冠内漂白后复合树脂修复体出现微渗漏失败的情况。本研究的目的是评估抗坏血酸钠和氢氧化钙作为中间充填材料在体外修复冠内漂白后与粘结修复相关的微渗漏的效果。
60颗经牙髓治疗的切牙，其进入腔延伸至牙龈边缘的牙骨质釉质界，随机分为五组，每组12颗。第1组，应用单键粘结剂和Z100复合树脂修复窝洞。第2 - 5组，将35%过氧化氢凝胶置于髓腔并密封5天。第2组，然后按第1组方法修复牙齿。第3组和第4组，在髓腔中应用10%抗坏血酸钠凝胶和氢氧化钙糊剂40小时，去除、冲洗后再进行修复。第5组，窝洞孵育7天，然后进行修复。样本进行热循环处理，浸入碱性品红中，然后切片。使用体视显微镜对染料渗透情况进行评分。数据采用Kruskal - Wallis检验和Mann - Whitney U检验进行分析（α = 0.05）。
釉质边缘无显著差异（P = 0.163）。在牙本质边缘（P = 0.003），第1组、第3组和第5组表现出相似的渗漏模式，第1组、第3组和第5组中的每一组与第2组和第4组中的每一组均存在显著差异。
使用35%过氧化氢凝胶进行冠内漂白会增加牙本质边缘的微渗漏。应用抗氧化剂或漂白后延迟7天可能会改善边缘完整性。应用氢氧化钙可能会损害牙本质封闭。
