光照角度对牙体与充填材料间微渗漏影响的研究

目的：通过改变发光二极管（light emitting diode,LED）固化光源与充填材料表面所成角度,研究光照角度对牙体与充填材料间微渗漏的影响。方法：选取21颗完整的离体前磨牙,随机分成3组,以颊面牙颈部釉牙骨质界为中心制备直径2mm,洞深1.5mm的圆形V类洞,酸蚀粘结后,复合树脂充填,以3种不同的角度光照,3组光源均朝向根方,A组：固化光源与充填体表面成30°角光照;B组：成60°角光照;C组：成90°角光照。将3组实验牙置于（37±1）℃恒温箱,0.1%罗丹明B荧光染色剂浸泡24h后,经充填体中央,沿牙体长轴颊舌向纵剖成两半,激光扫描共聚焦显微镜（Laser Scanning Confocal Microscopy,LSCM）下观测龈壁及壁处的微渗漏。结果：改变固化光源与充填材料表面所成角度,对龈壁处微渗漏的影响具有统计学意义（P〈0.01）,龈壁处光照角度为90°时微渗漏最小;壁处3组之间微渗漏无明显差异。结论：固化光源光照角度的改变对牙体与充填材料间的微渗漏有影响。本实验光照角度为90°时牙体与充填材料间微渗漏最小。

Effects of Curing Light Angle on the Microleakage of Tooth and Dental Filling Material Surface

Objective：To compare the effects of different curing light angles on the microleakage between tooth and dental filling material at gingival and occlusal surface.Methods：Twenty-one non-carious premolars were selected and randomly divided into three groups.Class Ⅴ cavities were prepared at the cemento-enamel junction on 21 freshly extracted premolars on the buccal.The diameter was 2mm,and the depth was 1.5mm.After etching and bonding,the cavities were filled with composite.The light angles projected on the dental material surface were 30°,60°,90°using LED curing light.The source faced to the direction of root.The samples were kept in 0.1% Rhodamine-B solution at（37±1）℃ for 24 hours.Then all the teeth were sectioned through the midline of the restoration.Laser scanning confocal microscope（LSCM） was used to visualize the widths of dye penetrated pathways and quantitate the microleakage width.Results：The results showed that the angle of curing light source affected obviously the microleakage of gingival surface（P0.05）,but not occlusal surface.The smallest microleakage value of curing light angles was found in the group of 90°.Conclusion：The direction of curing light source affected significancely the microleakage of tooth and dental filling material surface.