Karl Matthias, Scherg Stefan, Grobecker-Karl Tanja
Int J Oral Maxillofac Implants. 2017 Sep/Oct;32(5):971-975. doi: 10.11607/jomi.5592.
Achievement of high insertion torque values indicating good primary stability is a goal during dental implant placement. The objective of this study was to evaluate whether or not two-piece implants made from zirconia ceramic may be damaged as a result of torque application.
A total of 10 two-piece zirconia implants were repeatedly inserted into polyurethane foam material with increasing density and decreasing osteotomy size. The insertion torque applied was measured, and implants were checked for fractures by applying the fluorescent penetrant method. Weibull probability of failure was calculated based on the recorded insertion torque values.
Catastrophic failures could be seen in five of the implants from two different batches at insertion torques ranging from 46.0 to 70.5 Ncm, while the remaining implants (all belonging to one batch) survived. Weibull probability of failure seems to be low at the manufacturer-recommended maximum insertion torque of 35 Ncm. Chipping fractures at the thread tips as well as tool marks were the only otherwise observed irregularities.
While high insertion torques may be desirable for immediate loading protocols, zirconia implants may fracture when manufacturer-recommended insertion torques are exceeded. Evaluating bone quality prior to implant insertion may be useful.
在牙种植体植入过程中，实现高植入扭矩值以表明良好的初期稳定性是一个目标。本研究的目的是评估由氧化锆陶瓷制成的两件式种植体是否会因施加扭矩而受损。
总共10个两件式氧化锆种植体被反复插入密度增加且截骨尺寸减小的聚氨酯泡沫材料中。测量施加的植入扭矩，并通过荧光渗透法检查种植体是否骨折。根据记录的植入扭矩值计算威布尔失效概率。
在来自两个不同批次的5个种植体中，在46.0至70.5 Ncm的植入扭矩范围内出现了灾难性失效，而其余种植体（均属于一个批次）存活下来。在制造商推荐的35 Ncm最大植入扭矩下，威布尔失效概率似乎较低。螺纹尖端的碎裂骨折以及工具痕迹是唯一观察到的其他不规则情况。
虽然对于即刻加载方案可能需要高植入扭矩，但当超过制造商推荐的植入扭矩时，氧化锆种植体可能会骨折。在植入种植体之前评估骨质可能是有用的。
