Spies Benedikt Christopher, Kohal Ralf-Joachim, Balmer Marc, Vach Kirstin, Jung Ronald E
Department of Prosthetic Dentistry, Center for Dental Medicine, Medical Center - University of Freiburg, Freiburg, Germany.
Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
Clin Oral Implants Res. 2017 May;28(5):613-619. doi: 10.1111/clr.12842. Epub 2016 Mar 29.
The aim of this uncontrolled prospective multicenter study was to determine the success and survival rate of posterior single crowns composed of zirconia frameworks hand-layered with a leucite-reinforced feldspathic ceramic supported by one-piece zirconia oral implants.
In two centers, sixty patients received 71 zirconia oral implants. To obtain a clear indication of posterior implant-supported single crowns (ISSCs), 14 patients (25 implants) were excluded from the analysis (11 bridges, three anterior crowns). The remaining patients were provided with single implants in posterior regions. As one patient lost his implant and another refused further participation after final prosthesis insertion, 44 ISSCs/patients (19 females, 25 males) were available for evaluation. Of these patients, all were seen at prosthetic delivery and the 6- and 12-month follow-up appointments. Evaluations were performed using modified United States Public Health Service (USPHS) criteria. Restorations within Alpha and Bravo ratings were regarded as success. This included minor chippings, a slight roughness, slightly soundable restoration margins and minimal contour deficiencies. In case of more distinct defects that could, however, be repaired to a clinically acceptable level, restorations were regarded as surviving. Kaplan-Meier plots and log-rank tests were used for the success/survival analyses and the calculation of potential group differences (gender, jaw and center).
After a mean observation period of 12.5 months (SD: 0.8 months), no ISSC had to be replaced, resulting in a Kaplan-Meier survival rate of 100%. The Kaplan-Meier success rate was 90.9% (one major chipping, one obvious roughness, one significant crevice and one pronounced over-contouring). Minor chippings and occlusal roughness were frequent complications. No significantly different survival/success rates could be observed between the mentioned groups.
The frequent incidence of minor chippings suggests a high technique sensitivity when providing zirconia implants with veneered zirconia-based crowns questioning its suitability for this indication.
本项非对照前瞻性多中心研究旨在确定由氧化锆框架手工分层涂覆白榴石增强长石质陶瓷制成、由一体式氧化锆口腔种植体支持的后牙单冠的成功率和存留率。
在两个中心，60例患者接受了71颗氧化锆口腔种植体。为了明确后牙种植体支持单冠（ISSCs）的情况，14例患者（25颗种植体）被排除在分析之外（11例桥体，3例前牙冠）。其余患者在后牙区域植入单颗种植体。由于1例患者种植体丢失，另1例患者在最终义齿植入后拒绝进一步参与，因此有44例ISSCs/患者（19例女性，25例男性）可供评估。所有这些患者均在义齿交付时以及6个月和12个月随访预约时接受检查。使用改良的美国公共卫生服务（USPHS）标准进行评估。评定为Alpha和Bravo级别的修复体视为成功。这包括轻微崩瓷、轻微粗糙、修复体边缘轻微可探及以及最小的外形缺陷。如果存在更明显的缺陷，但可以修复到临床可接受的水平，则修复体视为存留。采用Kaplan-Meier曲线和对数秩检验进行成功/存留分析，并计算潜在的组间差异（性别、颌骨和中心）。
平均观察期为12.5个月（标准差：0.8个月）后，无需更换任何ISSC，Kaplan-Meier存留率为100%。Kaplan-Meier成功率为90.9%（1例严重崩瓷、1例明显粗糙、1例明显缝隙和1例明显外形过大）。轻微崩瓷和咬合面粗糙是常见并发症。在上述组间未观察到显著不同的存留/成功率。
轻微崩瓷的频繁发生表明，为氧化锆种植体提供基于氧化锆的贴面冠时技术敏感性较高，这对其在此适应证中的适用性提出了质疑。
