牙科激光焊钛固定桥适合性的研究

The fitness of cast titanium fixed partial dentures joined by laser welding

目的:比较整体铸造钛固定桥与分部铸造后激光焊接钛固定桥的适合性。方法:机械加工2个标准金属全冠模型,用硅橡胶制取阴模并灌注13个超硬石膏模型。浸蜡压塑成形法完成统一规格的蜡型,桥体用同一规格的塑料棒代替。共分为3组,即单冠铸钛组、分部铸钛焊接组、整体铸钛组。铸件完成后分别置于各自的石膏代型上,用环氧树脂包埋、片切,在HitachiS-2700扫描电子显微镜下观察颈缘特定位置铸件与代型之间的间隙。结果:整体铸钛组颈缘间隙明显大于分部铸钛焊接组和单冠铸钛组(P<0.05),分部铸钛焊接组和单冠铸钛组的颈缘间隙无明显区别。结论:分部铸钛焊接组的适合性优于整体铸钛组。3单位整体铸钛组的颈缘间隙小于100μm,也符合临床要求。

Objective： To study the fitness of three-unit titanium fixed partial dentures joined by laser welding. Methods ： Two standard models for three-unit cast titanium fixed partial denture were fabricated and for each model 13 stone dies were duplicated. 13 complete crown wax patterns of the dies were pressure molded and divided into 3 groups,a plastic rod was used as a pontic. 2-full-crown dentures were cast in the first group;individually cast full crown dentures were prepared and the 2 single full-crown dentures were joined by laser welding in the second group; whole cast full-crown dentures were made in the third group. Castings were seated on their respective dies, embedded in epoxy resin and sectioned. Gap distance between the casting and the die was measured at specified marginal sites under S-2700 Hitachi SEM. Results：The fitness of laser-welded fixed partial dentures was significantly better than that of one-piece castings. The gap openings measured in all castings were within the range of clinical acceptability. Conclusion： Laser welding might be beneficial to the fitness of cast titanium fixed partial dentures.