Department of Prosthodontics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea.
J Adv Prosthodont. 2013 Aug;5(3):312-8. doi: 10.4047/jap.2013.5.3.312. Epub 2013 Aug 31.
The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges.
A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of α=.05.
The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 µm/m at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups.
Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.
本研究旨在通过在带有应变片的内部锥形连接种植体周围评估应变发展来比较种植体上部结构的被动性。
一个嵌入了两个种植体的聚氨酯树脂块被用作测量模型。两组种植体修复体采用粘结固位设计，第一组的内表面进行调整，直到修复体与基台之间完全消除早期接触。在第二组中，仅去除肉眼可见的结节。第三组采用螺丝固位设计，通过计算机辅助设计/计算机辅助制造系统生成标本（n=10）。四个应变片固定在测量模型上种植体的近中和远中位置。在固定标本时记录每个应变片产生的应变。为了比较组间的差异，采用重复测量两因素分析，显著性水平为α=0.05。
分析应变大小的绝对应变值。不同应变片位置的平均绝对应变值范围为 29.53 至 412.94 µm/m。根据整体比较的结果，粘结固位修复体组显示出显著差异。铣削螺丝固位修复体组与粘结固位修复体组之间无显著差异。
在研究的限制范围内，可以得出结论，粘结固位设计并不总是比螺丝固位设计产生的应力水平低。粘结固位种植体修复体的内部调整对于实现被动贴合至关重要。
