Department of Periodontology, College of Dentistry, University of Florida, Gainesville, FL 32608, USA.
J Periodontol. 2011 Apr;82(4):613-8. doi: 10.1902/jop.2010.100415. Epub 2010 Nov 2.
Previously, we demonstrated that the geometry of the fixture-abutment interface influences the risk of bacterial invasion into the internal part of the implant, although the contribution of loading on this invasion was not evaluated. The aim of the present study is to use an in vitro dynamic-loading model to assess the potential risk for invasion of oral microorganisms into the fixture-abutment interface microgap of dental implants with different fixture-abutment connection characteristics.
Twenty-eight implants were divided into two groups (n = 14 per group) based on their microgap dynamics. Group 1 was comprised of fixtures with internal Morse-taper connection that connected to standard abutments. Group 2 was comprised of implants with a four-groove conical internal connection that connected to multibase abutments. The specimens were immersed in a bacterial solution of Escherichia coli and loaded with 500,000 cycles of 15 N in a wear simulator. After disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated, and cultured under appropriate conditions. The difference between loosening and tightening torque value was also measured.
One of the 14 samples in Group 1 and 12 of the 14 of samples in Group 2 developed multiple colony forming units for E. coli. Implants in Group 1 exhibited an increase in torque value in contrast to implants in Group 2, which exhibited a decrease.
This study indicates that differences in implant design may affect the potential risk for invasion of oral microorganisms into the fixture-abutment interface microgap under dynamic-loading conditions.
此前，我们已经证明了连接体-基台界面的几何形状会影响细菌侵入种植体内部的风险，尽管尚未评估加载对这种侵入的影响。本研究旨在使用体外动态加载模型评估在动态加载条件下不同连接体-基台连接特征的种植体连接体-基台界面微间隙中口腔微生物侵入的潜在风险。
根据微间隙动力学，将 28 个种植体分为两组（每组 14 个）。第 1 组由与标准基台连接的内莫氏锥度连接的固位体组成。第 2 组由与多基台连接的四槽锥形内连接的种植体组成。将标本浸入大肠杆菌的细菌溶液中，在磨损模拟器中进行 500,000 次 15 N 循环加载。在拆卸固位体和基台后，从基台的螺纹部分取出微生物样本，进行平板培养，并在适当的条件下进行培养。还测量了松动和拧紧扭矩值之间的差异。
第 1 组的 14 个样本中有 1 个，第 2 组的 14 个样本中有 12 个产生了大量的大肠杆菌菌落形成单位。与第 2 组相比，第 1 组的种植体显示出扭矩值的增加，而第 2 组则显示出扭矩值的降低。
本研究表明，种植体设计的差异可能会影响动态加载条件下口腔微生物侵入连接体-基台界面微间隙的潜在风险。
