固化光源光照方向和角度对微渗漏影响的研究

目的：研究固化光源光照方向及角度对复合树脂固化后微渗漏的影响。方法：选择63颗离体前磨牙,在颊面牙颈部以釉牙骨质界为中心制备圆形V类洞,常规酸蚀粘结,充填复合树脂,将所有实验牙以光源不同朝向随机分为A组：光源方向朝向龈壁;B组：光源方向朝向牙合壁;C组：光源方向朝向近中壁。再将A、B、C每组按固化光源与充填材料表面所成的角度不同随机分1组：成30°光照;2组：成60°光照;3组：成90°光照。所有实验牙均光照40s。分别浸泡于0.1%罗丹明B荧光染色剂中24h。然后经修复体中央,沿牙体长轴沿颊舌向纵向剖成两半,在激光扫描共聚焦显微镜（Laser Scanning Confocal Microscopy,LSCM）下分别观察检测微渗漏大小。结果：龈壁处的微渗漏情况：在光源的不同朝向下,不同的光照角度对龈壁处微渗漏的影响均具有统计学意义,光照角度均为90°时微渗漏值最小（P〈0.05）;牙合壁处的微渗漏情况：当光源朝向牙合壁及近中壁照射时,牙合壁处3组之间微渗漏有明显差异（P〈0.05）,光照角度90°时微渗漏最小;当光源朝向龈壁时,牙合壁处微渗漏之间没有明显的差异。结论：固化光源的光照方朝向及光照角度对微渗漏有影响。

Effects of Curing Light Direction and Angle on the Microleakage of Tooth and Composite Resin.

Objective.. To compare the effects of different light--emitting diode （LED） curing light direction and angle on the microleakage between tooth and the composite resin at gingival and occlusal wall. Methods： Sixty- three non-carious premolars were selected and Class V cavity was prepared at the cemento--enamel junction on the bucca of each tooth. The diameter of each cavity is 2ram, and the depth is 1.5mm. After etched and bonded, the cavities were filled with the composite resin, and randomly divided into three groups A, B and C. Then every group was subdivided equably into three groups again as group 1, 2 and 3. The light angles projected on the dental material surface were 30°,60°,90°. All apical foramens of the teeth were sealed by resin. After the samples were kept in 0.1 % Rhodamine-B solution at （37±1）℃ in attemperator for 24 hours, all teeth were sectioned through the midline of the restoration and examined with laser scanning confocal microscope （LSCM）. Results： Three different angles of the light-emitting diode （LED） curing light source affected obviously the microleakage of gingival wall in three directions. The smallest microleakage value was found in the group of 90° （P〈0.05）. Three different angles of curing light source affected obviously the microleakage of the occlusal wall. The smallest microleakage value Was found in the group of 90°（P〈0.05）. When the source faces to the gingival wall, there is no difference among three angles on the occlusal wall. Conclusion： The direction and angle of LED curing light source affected significancely the microleakage of tooth and composite resin at gingival and occlusal wall.