喷砂处理对不同底面设计陶瓷托槽再粘接影响的实验研究

目的：探讨喷砂处理对不同底面设计的陶瓷托槽再粘接抗剪切强度的影响。方法：选取90颗因正畸拔除的健康前磨牙，随机抽取30颗用于制备脱落陶瓷托槽，其余60颗用于粘接实验。将60颗牙根据不同底面设计分成3大组：微隐窝底面组（A组）、微晶体底面组（B组）、树脂底面组（C组），每大组分成2小组：新托槽组（n）、喷砂组（sb），每组10颗牙。陶瓷托槽粘接于未经酸蚀处理的微湿的离体牙上，然后用去托槽钳小心取下，形成脱落托槽，对托槽底面进行喷砂处理，并在底面常规涂硅烷偶联剂。离体牙经常规牙面处理后，分别粘接新托槽及处理后的托槽，测定并比较各组抗剪切强度。结果：三组托槽初次粘接及再次粘接抗剪切强度分别为（12．4733±3．4326）Mpa和（9．1612±1．3261） Mpa；（12．7374±3．8999）Mpa和（6．7152±3．1876）Mpa；（9．5022±1．8801）Mpa和（6．6281±2．1187）Mpa，其中A组的抗剪切强度大于B组和C组的抗剪切强度，差别有统计学意义（P＜0．05）；B组和C组两者的抗剪切强度有差别，但无统计学意义（P＞0．05）。结论：三组陶瓷托槽再粘接抗剪切强度明显下降，但高于正畸临床所需的最低抗剪切强度值。其中微隐窝底面与微晶底面和聚合体网底相比，抗剪切强度下降最少，更适合喷砂处理。

Effects of sandblasting on the bond strength of rebonded ceramic brackets with different base designs

Objective：The purposes of this study was to evalute the effects of sandblasting on shear bond strength （SBS）of rebonded ceramic brackets with different base designs. Method：90 human premolars extracted for orthodontic purpose were collected and divided randomly into two parts：one part （60 teeth）for the bond strength test;the other part（30 teeth） for getting debonded ceramic bracksts. For experimental part：60 human premolars were divided randomly into three groups according to different base designs：（A） round pits base,（B） microcrystalline lock base,（C）polymer mesh base. Then each test group was divided into two groups：new brackets as controls（N）, sandblasting（SB）.30 teeth were selected respectively from three different base designs of ceramic brackets and were bonded to unetched and slightly wet tooth sur-faces,then separated from the tooth surface easily with a tweezer with light pressure.Then different base designs of debonded brackets were sandblasted,then a silane coupling agent was applied to of bases.The teeth in each group were treated by con-ventional treatment,then were bonded with new brackets and sandblasted brackets. Shear force test was performed and then the shear bond strength was measured. Result：The SBS of 3 group which was bonded and rebounded were （12.4733 ± 3.4326）Mpa and （9.1612 ±1.3261）Mpa;（12.7374 ±3.8999）Mpa and （6.7152 ±3.1876）Mpa;（9.5022 ±1.8801）Mpa and （6.6281 ±2.1187）Mpa.The SBS of round pits base were significantly higher than microcrystalline lock base and polymer mesh base（P〈0.05）. There were no statistically significant difference between microcrystalline lock base and polymer mesh base （P 〉0.05）. Conclution：After sandblasting,the shear bond strength of rebonded ceramic brackets with different base designs decreased,but was higer than the minimum bond strength required.In three cersmic brackets with different base de-signs,round pits base and microcrystalline lock base were more suitable for sandblasting treatment.