正畸脱落托槽底面不同处理方法对再粘接抗剪切强度的影响

Effect of Different Treatment Methods for the lost Orthodontic Bracket Base on Shear Bond Strength inthe Second Bonding

目的观察4种方法处理脱落托槽底板后对再粘接抗剪切强度的影响。方法收集因正畸需要拔除的前磨牙75颗,随机数表法分为5组,每组15个样本,按照对脱落托槽底面的不同处理方式分为:A组(新托槽组)、B组(磨除组)、C组(磨除法+牙釉质粘合树脂液剂组)、D组(燃烧组)、E组(燃烧法+牙釉质粘合树脂液剂组)。各样本均采用CTM8020微机控制电子万能材料试验机测定抗剪切强度(SBS)。结果 A组、C组再次粘接时粘接强度较首次粘接强度高,差异具有统计学意义(P<0.05);D组、E组再次粘接强度低于首次粘接,差异有统计学意义(P<0.05);B组再次粘接强度低于首次粘接,差异无统计学意义(P=0.589)。结论磨除法处理后的托槽用于再次粘接时,在托槽底面涂布牙釉质粘合树脂液剂能获得较高的再粘接强度。

Objective To observe the effect of 4 different treatment methods for the lost orthodontic bracket base on shear bond strength （SBS） in the second bonding. Methods 75 extracted premolars for orthodontic purpose were selected and randomly divided into 5 groups ： group A, B, C, D and E, 15 teeth in each ; in group A, new brackets were used in the second bonding; in group B, residual adhesives were removed with diamond burs and then the brack- ets were re-used in the second bonding; in group C, residual adhesives were removed with diamond burs and the en- amel bonding resin primer was applied on the base of the brackets in the second bonding; in group D, the brackets were re-used after burned with an alcohol burner, in group E, the brackets were re-used after burned with an alcohol burner and the enamel bonding resin primer was applied on the base of the brackets in the second bonding; the SBS of each bracket was tested with CTM8020 computerized electronic universal material test machine. Results In group A and group C, the SBS was higher in the second bonding than in the first bonding, the difference was of statistical sig- nificance （P 〈 0. 05） ; in group D and group E, the SBS was lower in the second bonding than in the first bonding, the difference was of statistical significance （P 〈 0. 05 ） ; in group B, the SBS was lower in the second bonding than in the first bonding with no statistical difference （P = 0. 589）. Conclusions Higher re-bonding strength can be obtained in brackets first treated with diamond burs by applying enamel bonding resin primer on the base in the second bonding.