Ng Yuan-Ling, Reddington Liam P, Berman Antony, Knowles Jonathan C, Nazhat Showan N, Gulabivala Kishor
Unit of Endodontology, Division of Restorative Dental Science, UCL Eastman Dental Institute, University College London, London, UK.
Division of Biomaterials & Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK.
Aust Endod J. 2020 Aug;46(2):234-243. doi: 10.1111/aej.12397. Epub 2020 Feb 11.
This study aims to evaluate the viscoelastic and chemical properties of dentine after different durations of exposure to 5.25% NaOCl, 17% EDTA and Ca(OH) solutions, and NaOCl in alternating combination with EDTA. Standard dentine bars were randomly assigned to: (i) formal-saline control-1; (ii) NaOCl; (iii) EDTA; (iv) NaOCl/EDTA; (v) formal-saline control-2; (vi) Ca(OH) pH 12.6; and (vii) Ca(OH) pH 9.8. Groups 1--4 underwent 10 min cycles of soaking and dynamic mechanical analysis up to 120 min. Groups 5-7 underwent similar tests at days 7, 14, 28 and 84. FTIR spectra of dentine discs exposed to the same regimens assessed surface chemistry. NaOCl or Ca(OH) (pH 12.6) solutions reduced the organic (N-H[1], N-H[3], C=0) peak components of dentine. This study demonstrated that accumulative damage of dentine could be facilitated by alternated exposure to NaOCl and EDTA. Exposure of dentine to Ca(OH) (pH12.6) for 7 days reduced viscous behaviour, inferring increased potential for fatigue failure.
本研究旨在评估牙本质在暴露于5.25%次氯酸钠（NaOCl）、17%乙二胺四乙酸（EDTA）和氢氧化钙（Ca(OH)）溶液以及NaOCl与EDTA交替组合不同时长后的粘弹性和化学性质。标准牙本质条被随机分为：（i）甲醛 - 生理盐水对照 - 1；（ii）NaOCl；（iii）EDTA；（iv）NaOCl/EDTA；（v）甲醛 - 生理盐水对照 - 2；（vi）pH值为12.6的Ca(OH)；以及（vii）pH值为9.8的Ca(OH)。第1 - 4组进行长达120分钟的10分钟浸泡和动态力学分析循环。第5 - 7组在第7、14、28和84天进行类似测试。暴露于相同方案的牙本质圆盘的傅里叶变换红外光谱（FTIR）评估表面化学。NaOCl或Ca(OH)（pH 12.6）溶液降低了牙本质的有机（N - H[1]、N - H[3]、C = O）峰成分。本研究表明，交替暴露于NaOCl和EDTA会促进牙本质的累积损伤。牙本质暴露于pH值为12.6的Ca(OH) 7天会降低粘性行为，这意味着疲劳失效的可能性增加。
