UNASSIGNED: A total of 99 extracted human premolars were selected for the analysis. The surface roughness was first assessed (roughness control). One specimen from each subgroup was examined using a scanning electron microscope to illustrate the surface topography. Eighty-eight teeth were prepared using total- or self-etchants and bonded to precoated or flash-free adhesive metal or ceramic brackets. The remaining 11 specimens were not bonded to brackets (microhardness controls). The brackets were debonded after immersion in distilled water for 24 h. The specimens were again scanned for surface roughness and topography imaging. Finally, the microhardness was assessed using a micro-Vickers hardness test at a force of 200 g for 10 s.
UNASSIGNED: An overall statistically significant increase in surface roughness and reduced surface microhardness were observed in all experimental groups when compared with those in the control groups. The etchant type was the only variable found to contribute to the measured surface properties, with increased roughness and reduced microhardness introduced by total-etching compared to those by self-etching.
UNASSIGNED: Orthodontic brackets introduced a significant increase in enamel surface roughness and reduce microhardness compared with untreated enamel, regardless of the bracket material, etchant type, and adhesive system. The etchant type was the only variable contributing to these changes, with total etching having a more pronounced effect.
■总共选择99个提取的人前磨牙用于分析。首先评估表面粗糙度(粗糙度控制)。使用扫描电子显微镜检查来自每个子组的一个样本以说明表面形貌。使用总计或自蚀刻剂制备了88颗牙齿,并将其粘合到预涂层或无闪光的粘合剂金属或陶瓷托槽上。剩余的11个试样没有粘结到支架上(显微硬度控制)。在蒸馏水中浸泡24小时后将托槽脱粘。再次扫描样品的表面粗糙度和形貌成像。最后,显微硬度使用显微维氏硬度测试在200g的力持续10s进行评估。
■与对照组相比,在所有实验组中均观察到表面粗糙度的总体统计学显着增加和表面显微硬度的降低。蚀刻剂类型是唯一发现有助于测量表面性质的变量,与自蚀刻相比,通过全蚀刻引入的粗糙度增加和显微硬度降低。
■与未经处理的牙釉质相比,正畸托槽引入了牙釉质表面粗糙度的显着增加,并降低了显微硬度,无论支架材料如何,蚀刻剂类型,和粘合剂系统。蚀刻剂类型是导致这些变化的唯一变量,总蚀刻具有更显著的效果。