May K B, Edge M J, Lang B R, Wang R F
Department of Prosthodontics, School of Dentistry, University of Michigan. Ann Arbor 48109-1078, USA.
J Prosthodont. 1996 Sep;5(3):206-13. doi: 10.1111/j.1532-849x.1996.tb00298.x.
In this study, the Periotest instrument was used to measure the precision of fit between cast high noble-metal frameworks and the supporting implants in a patient-simulation model. Three framework conditions and three implant-location variables were used to evaluate the rigidity of the assembly as measured by the Periotest method. The framework variables were (1) one-piece castings (OPC); (2) sectioned-soldered inaccurate castings (SSIC); and (3) sectioned-soldered accurate castings (SSAC). The implant-location variables were right anterior (RA), center (C), and left anterior (LA).
The patient simulation model used consisted of three self-tapping Branemark implants in a reasonable arch curvature in bovine bone. Three working casts were fabricated from the patient-simulation model using polyvinyl siloxane and tapered impression copings. From the working casts, three sets of three frameworks were fabricated as OPCs, SSICs, and SSACs using type 3 high noble alloy. The SSICs were fabricated with a quantitative misfit of 101.6 microns at the facial surface, between the abutment-to-gold cylinder interface at the C implant location. Periotest value (PTV) measurements were made at the midfacial surface of the frameworks directly above each abutment-to-gold cylinder interface. Three measurements were made for each test condition. The data were analyzed to compare framework condition(s) and implant location(s) using ANOVA and Fisher's Protected Least Significant Difference Comparison Test.
The ANOVA showed that significant differences exist between the mean PTV data for framework condition and for implant location (p < .01). Significant differences were shown between the mean PTV data for the SSAC assemblies and the OPC and SSIC assemblies. The SSICs displayed a more positive (+) mean PTV than the OPCs. The OPC assemblies had a more positive mean PTV than the SSAC assemblies. The mean PTV data for the SSAC assemblies had a significantly different PTV (p < .01) than the other two framework condition assemblies. The OPC and the SSIC assemblies had PTVs that were not significantly different. The C implant location was significantly different from the RA and the LA implant locations (p < .01). The RA and the LA implant locations were not significantly different from each other. The C implant location always demonstrated the most positive mean PTV regardless of the framework condition being tested.
The Periotest instrument quantified differences in the precision of fit between three framework conditions. The SSAC assemblies were significantly more rigid than the OPC and SSIC assemblies. The OPC and SSIC assemblies' mean PTVs were not significantly different. The mean PTVs for the C implant location and the RA and LA implant locations were significantly different (p < .01). The mean PTVs of the RA and LA implant locations were not significantly different. The implant-location PTVs followed the same rank order for all three framework conditions. The procedures used to fabricate a more precise fit between the framework and the supporting implants is influenced by the skill of the clinician and technician.
在本研究中，使用Periotest仪器在患者模拟模型中测量铸造高贵金属支架与支撑种植体之间的适配精度。采用三种支架条件和三个种植体位置变量，通过Periotest方法评估组件的刚性。支架变量为：（1）整体铸造（OPC）；（2）分段焊接的不准确铸件（SSIC）；（3）分段焊接的准确铸件（SSAC）。种植体位置变量为右前（RA）、中央（C）和左前（LA）。
所使用的患者模拟模型由置于牛骨中具有合理牙弓曲度的三个自攻型Branemark种植体组成。使用聚乙烯基硅氧烷和锥形印模帽从患者模拟模型制作三个工作模型。从工作模型出发，使用3型高贵金属合金制作三组各三个支架，分别为OPC、SSIC和SSAC。SSIC在C种植体位置的基台与金柱界面处的唇面定量失配为101.6微米。在每个基台与金柱界面正上方的支架唇面中部进行Periotest值（PTV）测量。每种测试条件进行三次测量。使用方差分析（ANOVA）和Fisher保护最小显著差异比较检验对数据进行分析，以比较支架条件和种植体位置。
方差分析表明，支架条件和种植体位置的平均PTV数据之间存在显著差异（p <.01）。SSAC组件的平均PTV数据与OPC和SSIC组件之间存在显著差异。SSIC的平均PTV比OPC更正（+）。OPC组件的平均PTV比SSAC组件更正。SSAC组件的平均PTV数据与其他两种支架条件组件的PTV有显著差异（p <.01）。OPC和SSIC组件的PTV没有显著差异。C种植体位置与RA和LA种植体位置有显著差异（p <.01）。RA和LA种植体位置彼此之间没有显著差异。无论测试的支架条件如何，C种植体位置始终显示出最正的平均PTV。
Periotest仪器量化了三种支架条件之间适配精度的差异。SSAC组件比OPC和SSIC组件显著更具刚性。OPC和SSIC组件的平均PTV没有显著差异。C种植体位置与RA和LA种植体位置的平均PTV有显著差异（p <.01）。RA和LA种植体位置的平均PTV没有显著差异。对于所有三种支架条件，种植体位置的PTV遵循相同的排序。在支架与支撑种植体之间制作更精确适配的程序受临床医生和技术人员技能的影响。
