固化光源对牙本质粘结强度的影响

Effect of Light Source on the Microtensile Bond Strength of Dentin

目的:研究两种固化光源对牙本质粘结的微拉伸强度的影响。方法:选取因正畸需要拔除的前磨牙20颗,随机分成4组。去除面釉质,暴露平的牙本质表面,分别使用卤素光固化灯和发光二极管光固化灯固化粘结剂和复合树脂,形成3mm高的树脂冠:A组:卤素光固化灯固化粘结剂20s,卤素光固化灯固化树脂40s;B组:卤素光固化灯固化粘结剂20s,发光二极管光固化灯固化树脂30s;C组:发光二极管光固化灯固化粘结剂20s,发光二极管光固化灯固化树脂30s;D组:发光二极管光固化灯固化粘结剂20s,卤素光固化灯固化树脂40s。所有实验牙置于(37±1)℃的生理盐水中24h后,用硬组织切片机将其切成粘结面积约1.0mm×1.0mm的条形试件,用以测试牙本质微拉伸粘结强度。在扫描电镜下观察样本的断裂界面。结果:固化粘结剂的光源对牙本质微拉伸粘结强度的影响有显著的统计学意义(P<0.05)。4组中微拉伸粘结强度最大值为(29.55±4.39)MPa,出现在C组。扫描电镜下观察测试样本的断裂多数为粘结界面破坏。结论:固化光源对牙本质粘结的微拉伸强度存在影响,牙本质的粘结强度主要与固化粘结剂的光源有关。本实验显示使用发光二极管光固化灯固化粘结剂20s,发光二极管光固化灯固化树脂30s时牙本质的粘结强度最好。

Objective： To compare the effect of halogen dental curing light and light - emitting diode（LED） curing light on the microtensile bond strength of dentin. Methods： Twenty extracted human premolars were randomly divided into four groups o Resin crowns with 3ram high were built up on flat superficial dentin surface exposed after removing the occlusal enamel. The orthodontic adhesive and composite resin were polymerized using halogen dental curing light （QTH） and light - emitting diode（LED） curing light respectively： Group A, QTH curing for 20s for adhesive and 40s for the composite res- in; Group B, the adhesive cured with QTH for 20s, the composite resin cured with LED for 30s ; GroupC, LED curing for 20s for adhesive and 30s for the composite resin, Group D, the adhesive cured with LED for 20s ,the composite resin cured with QTH for 40s. After 24 hours＇storage in water,all teeth were sectioned to obtain bar- shaped specimens with bonded surface area about 1.0mm × 1. 0mm. Dentin mierotensile bond strengths were measured~ All the fractured surfaces were observed under scanning electron microscope （SEM）. Results： The results showed that the light source curing for adhesive affected significantly on microtensile bond strength of dentin（P 〈0.05）. The highest bond strength value was （29.55± 4. 39 ） MPa, which was found in group C. SEM observations of failure patterns presented that most of them exhibited interra- cial cohesive failure. Conclusion： Different light sources influence microtensile bond strength of dentin. Bond strength is more dependent on the light source used for adhesive than for curing resin. The mierotensile bond strength of dentin is the best when the adhesive is exposed to light -emitting diode（LED） for 20 seconds and the resin exposed to LED for 30 seconds.