AIM To evaluate the effect of simulated intraoral hydraulic, thermal, and mechanical stresses on the debonding characteristics of orthodontic brackets under different adhesive regimes. MATERIALS AND METHODS Groups of pre-coated (G1) and non-coated (G2) orthodontic metal brackets were bonded onto the buccal surfaces of 96 premolars using etch-and-rinse (SG1, n = 24) and self-etch (SG2, n = 24) primers. Twelve specimens (C1) from each subgroup were subjected to early debonding resistance tests, while the other twelve (C2) were used to test delayed debonding resistance after exposure to conditions simulating intraoral hydraulic, thermal, and mechanical stresses. The debonding resistance of the brackets was evaluated using a universal testing machine and the debonding patterns were micro-visualized to determine the adhesive remnant indexes of subgroups of specimens. RESULTS Within each group, the etch-and-rinse primer (SG1) resulted in higher debonding resistance than self-etch primers (SG2) (p < 0.05), while there was no difference between non-stressed and stressed specimens (p > 0.05). Within each category of test specimens, there was no difference between pre-coated (G1) and non-coated (G2) brackets (p > 0.05). The tested specimens in all categories showed comparable adhesive remnant indexes. However, higher percentages of favorable scores (0 and 1) were obtained for all stressed specimens. CONCLUSIONS Short-term cumulative intraoral stresses have no adverse effect on the debonding values of either pre-coated or non-coated brackets when either etch-and-rinse or self-etch primer is used for bonding. Exposure of the bonded brackets to different types of stress reflects favorable debonding patterns.

中文翻译：

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不同粘接方式下正畸托槽在口腔内应力下的脱粘特性：一项体外研究

目的 评估模拟口腔内水力、热力和机械应力对不同粘接方式下正畸托槽剥离特性的影响。材料和方法 使用蚀刻和冲洗 (SG1, n = 24) 和自蚀刻 (SG2, n = 24) 引物。每个子组中的 12 个样本 (C1) 进行了早期抗剥离性测试，而其他 12 个 (C2) 用于在暴露于模拟口腔内液压、热和机械应力的条件后测试延迟剥离性。使用万能试验机评估托槽的抗剥离性，并对剥离图案进行显微可视化，以确定样本子组的粘合剂残留指数。结果 在每组中，蚀刻和冲洗底漆 (SG1) 比自蚀刻底漆 (SG2) 具有更高的抗剥离性 (p < 0.05)，而无应力试样和应力试样之间没有差异 (p > 0.05) ）。在每一类试样中，预涂层 (G1) 和非涂层 (G2) 托槽之间没有差异 (p > 0.05)。所有类别的测试样本都显示出相当的粘合剂残留指数。然而，所有受压试样都获得了较高百分比的有利分数（0 和 1）。结论 当使用蚀刻和冲洗或自蚀刻底漆进行粘合时，短期累积口腔内应力对预涂层或未涂层托槽的剥离值没有不利影响。粘合托槽暴露于不同类型的应力反映了有利的剥离模式。