Clelland N L, Carr A B, Gilat A
Department of Restorative Dentistry, Prosthodontics, and Endodontics, College of Dentistry, Ohio State University, Columbus 43210-1211, USA.
J Prosthodont. 1996 Sep;5(3):193-200. doi: 10.1111/j.1532-849x.1996.tb00296.x.
To measure and compare the strains transferred by screw-fastening one-piece full-arch prostheses as cast and after sectioning and soldering.
Photoelastic resin was applied directly to five 3.75 x 13-mm Brånemark implants, situated 7 mm apart, in a silicone mold of an edentulous mandible. Four strain gauge rosettes were also incorporated in the resin to allow strain measurements at four locations. Three frameworks were made from a single master cast produced from an impression of the five-implant model with 4-mm abutments. These frameworks were sequentially secured to the master model with five gold slot screws tightened to 10 N cm. Strain indicator readings were recorded at a standardized time following the initial fastening of each prosthesis. The test was repeated three times. Each of the three castings were subsequently sectioned and soldered in two locations, mesial to the two terminal fixtures. After soldering, the three superstructures were returned to the master model for measurement of postsolder strains three times each. A one-way repeated-measures ANOVA was performed to determine differences between mean principal strains between the as-cast and postsoldered groups.
A statistically significant difference was found in the principal strains between the as-cast and soldered frameworks. Overall, there was a decrease in the magnitude of strain for the soldered frameworks.
Sectioning and soldering improved the as-cast accuracy as far as the amount of strain transferred to the bone simulant.
测量并比较整体式全牙弓修复体在铸造状态下以及切割和焊接后的螺钉固定所传递的应变。
将光弹性树脂直接应用于无牙下颌骨硅橡胶模型中5颗间距为7 mm的3.75×13 mm的Brånemark种植体上。树脂中还嵌入了4个应变片，以便在4个位置进行应变测量。用4 mm基台从5种植体模型的印模制作单个主模型，制作3个框架。这些框架依次用5颗金槽螺钉固定到主模型上，拧紧至10 N·cm。在每次修复体初始固定后的标准化时间记录应变指示器读数。该测试重复3次。随后将3个铸件中的每一个在两个终端固定装置近中的两个位置进行切割和焊接。焊接后，将3个上部结构放回主模型，每次测量3次焊接后的应变。进行单向重复测量方差分析以确定铸造组和焊接后组之间平均主应变的差异。
铸造框架和焊接框架之间的主应变存在统计学显著差异。总体而言，焊接框架的应变大小有所降低。
就传递到骨模拟物上的应变而言，切割和焊接提高了铸造精度。
