Research Unit in Innovative Dental Materials and Interfaces, EA4462, Faculty of Dental Surgery, Paris Descartes University, 1 rue Maurice Arnoux, 92120 Montrouge, France; Bretonneau Hospital, 23 rue Joseph de Maistre, 75018 Paris, France.
Université Paris Est, ICMPE (UMR 7182), CNRS, UPEC, 2 rue Henri Dunant, 94320 Thiais, France.
Dent Mater. 2018 Feb;34(2):341-354. doi: 10.1016/j.dental.2017.11.018. Epub 2017 Nov 26.
First, to analyse the in vitro release of BPA and Bis-GMA from an orthodontic resin composite (Transbond XT, 3M Unitek), stored in various conditions, by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS); then to extrapolate the data to the clinical situation. Secondly, to explore the thermal stability of Bis-GMA.
Cylinders of resin composite were prepared and stored according to 3 different protocols: (1) they were light-cured 20s, then placed in artificial saliva; (2) they were light-cured 2s, then placed in acetonitrile; (3) they were light-cured 2s, then placed in methanol. For each group, BPA and Bis-GMA release were determined with GC/MS and/or LC/MS at least after one week. Besides, 120 brackets (10 of each type) were bonded over metal teeth, then debonded, and the weight and the surface of resin composite residues were measured. BPA and Bis-GMA release of adhesive residues were extrapolated from the data obtained with the cylinders. Besides, BPA release from a heated Bis-GMA solution was measured.
With GC/MC, BPA was detected in all samples. With LC/MS, BPA was detected only from samples immersed in MeOH; Bis-GMA was detected, in varying amount according to the extraction media and the light-curing time. BPA was found after heating of the Bis-GMA solution.
Contamination risk and the heat applied in GC/MS may overestimate the BPA release from resin composite. Based on the LC/MS results, the risk of BPA release after orthodontic bonding would be more than 42000 times lower than the TDI for a 30-kg child.
首先，通过气相色谱/质谱（GC/MS）和液相色谱/质谱（LC/MS）分析储存在不同条件下的正畸树脂复合材料（Transbond XT，3M Unitek）中 BPA 和 Bis-GMA 的体外释放情况；然后将数据外推至临床情况。其次，探索 Bis-GMA 的热稳定性。
根据 3 种不同的方案制备和储存树脂复合材料圆柱体：（1）光固化 20 秒，然后放入人工唾液中；（2）光固化 2 秒，然后放入乙腈中；（3）光固化 2 秒，然后放入甲醇中。对于每组，用 GC/MS 和/或 LC/MS 至少在一周后测定 BPA 和 Bis-GMA 的释放情况。此外，将 120 个（每种类型 10 个）托槽粘结在金属牙上，然后脱粘，测量树脂复合材料残留物的重量和表面。从圆柱体获得的数据推断出粘结残留的 BPA 和 Bis-GMA 释放情况。此外，还测量了加热的 Bis-GMA 溶液中 BPA 的释放情况。
用 GC/MC，在所有样品中均检测到 BPA。用 LC/MS，仅从浸泡在 MeOH 的样品中检测到 BPA；根据提取介质和光固化时间，Bis-GMA 的含量不同。Bis-GMA 溶液加热后可检测到 BPA。
GC/MS 中的污染风险和热量可能会高估树脂复合材料中 BPA 的释放情况。根据 LC/MS 的结果，正畸粘结后 BPA 释放的风险将比 TDI 对 30 公斤儿童的风险低 42000 多倍。
