Drew Alexander, Randi Anthony, DiPede Louis, Luke Allyn
Int J Periodontics Restorative Dent. 2020 Mar/Apr;40(2):245-252. doi: 10.11607/prd.3952.
To correct for angulation discrepancies in the maxilla, implant companies have designed angulated screw channel (ASC) abutments. The design of these abutments allows for the restorative screw channel to be placed up to 25 degrees off the center axis of the implant. Minimal independent research has been published to evaluate the fatigue resistance of this implant-abutment connection. This study evaluated the fracture strength of a newly designed zirconia crown with a 25-degree angulated screw channel (n = 5) vs a straight channel (n = 5). Each specimen was subjected to an off-axis compression load from an MTS cyclic loading machine with a custom-designed indenter simulating a natural dentition. All the 25-degree angulated screw channel specimens failed, with four of the five (80%) catastrophically failing. Four of the five straight-channel specimens failed, with two of the five (40%) catastrophically failing. Results revealed the potential abutment fracture from internal stresses at the screw-zirconia and metallic-zirconia interfaces. Further research is needed to test the use of all-ceramic crowns with the use of the angulated screw channel.
为了矫正上颌骨的角度差异，种植体公司设计了带角度的螺钉通道（ASC）基台。这些基台的设计允许修复螺钉通道与种植体的中心轴偏离达25度。关于评估这种种植体 - 基台连接疲劳抗性的独立研究发表得很少。本研究评估了一种新设计的带有25度角螺钉通道的氧化锆冠（n = 5）与直通道氧化锆冠（n = 5）的断裂强度。每个样本都通过MTS循环加载机，使用定制设计的压头施加离轴压缩载荷，模拟天然牙列。所有25度角螺钉通道样本均失败，五个样本中有四个（80%）发生灾难性失败。五个直通道样本中有四个失败，五个样本中有两个（40%）发生灾难性失败。结果显示在螺钉 - 氧化锆和金属 - 氧化锆界面处存在因内应力导致基台骨折的可能性。需要进一步研究来测试使用带角度螺钉通道的全瓷冠的情况。
