Maringá, Paraná, Brazil, School of Dentistry, State University of Maringá, Maringá, Paraná, Brazil.
J Prosthet Dent. 2012 Dec;108(6):377-85. doi: 10.1016/S0022-3913(12)60196-6.
The influence of different joining techniques on passive fit at the interface structure/abutment of cobalt-chromium (Co-Cr) superstructures has not yet been clearly established.
The purpose of this study was to compare 3 different techniques of joining Co-Cr superstructures by measuring the resulting marginal misfit in a simulated prosthetic assembly.
A specially designed metal model was used for casting, sectioning, joining, and measuring marginal misfit. Forty-five cast bar-type superstructures were fabricated in a Co-Cr alloy and randomly assigned by drawing lots to 3 groups (n=15) according to the joining method used: conventional gas-torch brazing (G-TB), laser welding (LW), and tungsten inert gas welding (TIG). Joined specimens were assembled onto abutment analogs in the metal model with the 1-screw method. The resulting marginal misfit was measured with scanning electron microscopy (SEM) at 3 different points: distal (D), central (C), and mesial (M) along the buccal aspect of both abutments: A (tightened) and B (without screw). The Levene test was used to evaluate variance homogeneity and then the Welsch ANOVA for heteroscedastic data (α=.05).
Significant differences were found on abutment A between groups G-TB and LW (P=.013) measured mesially and between groups G-TB and TIG (P=.037) measured centrally. On abutment B, significant differences were found between groups G-TB and LW (P<.001) and groups LW and TIG (P<.001) measured mesially; groups G-TB and TIG (P=.007) measured distally; and groups G-TB and TIG (P=.001) and LW and TIG (P=.007) measured centrally.
The method used for joining Co-Cr prosthetic structures had an influence on the level of resulting passive fit. Structures joined by the tungsten inert gas method produced better mean results than did the brazing or laser method.
不同的连接技术对钴铬（Co-Cr）修复体界面结构/基台之间的被动拟合的影响尚未明确。
本研究旨在通过模拟修复体装配来测量边缘不匹配，比较 3 种不同的 Co-Cr 修复体连接技术。
使用特殊设计的金属模型进行铸造、切割、连接和测量边缘不匹配。在 Co-Cr 合金中制备了 45 个铸造棒型修复体，并通过抽签随机分为 3 组（n=15），根据使用的连接方法进行分组：传统气体炬钎焊（G-TB）、激光焊接（LW）和钨极惰性气体焊接（TIG）。将连接的试件用 1 颗螺丝方法装配到金属模型中的基台模拟体上。用扫描电子显微镜（SEM）在 3 个不同点（A 基台拧紧螺丝的近远中颊侧点、B 基台未拧螺丝的近远中颊侧点）测量边缘不匹配：D、C、M。使用 Levene 检验评估方差齐性，然后使用 Welsch 方差分析（异方差）（α=.05）。
在 A 基台，G-TB 组和 LW 组（P=.013）近中测量点以及 G-TB 组和 TIG 组（P=.037）中心测量点之间存在显著差异。在 B 基台，G-TB 组和 LW 组（P<.001）、LW 组和 TIG 组（P<.001）近中测量点之间存在显著差异；G-TB 组和 TIG 组（P=.007）远中测量点以及 G-TB 组和 TIG 组（P=.001）和 LW 组和 TIG 组（P=.007）中心测量点之间存在显著差异。
用于连接 Co-Cr 修复体结构的方法对结果的被动拟合水平有影响。使用钨极惰性气体方法连接的结构比钎焊或激光方法产生的平均结果更好。
