Kocaağaoğlu Hasan, Kılınç Halil Ibrahim, Albayrak Haydar
Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Pamukkale University, Denizli, Turkey.
Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey.
J Prosthet Dent. 2017 Jan;117(1):102-108. doi: 10.1016/j.prosdent.2016.06.004. Epub 2016 Sep 9.
Proper marginal, axial, and occlusal adaptation of dental restorations is essential for their long-term success. Production protocols including digital impression systems have been developed, but little information is available on the adaptation of zirconia restorations produced via them.
The purpose of this in vitro study was to compare the effects of digital impression protocols on the marginal, axial, and occlusal adaptation of zirconia copings.
Thirty extracted human maxillary premolar teeth without caries or defects were used. The teeth were prepared for zirconia crowns and randomly divided into 3 groups. Zirconia copings were designed at a thickness of 0.5 mm with 30 μm of simulated die spacer starting 1 mm from the margin of preparations. They were produced using computer-aided design-computer-aided manufacture (CAD-CAM) protocol with a conventional impression (group Cn) and 2 different production protocols with digital impressions (group C) and group Tr. The marginal, axial, and occlusal discrepancies of these copings were measured using the silicone replica technique with stereomicroscopy at ×50 magnification, and the data were analyzed with 1-way ANOVAs (α=.05).
The mean marginal discrepancy values were 85.6 μm for group Cn, 58.7 μm for group C, and 47.7 μm for the Tr group. Significant differences were found among the production protocols in marginal, axial, and occlusal discrepancies (P<.05). Copings fabricated with the aid of digital impressions had significantly fewer marginal discrepancies than those of group Cn (P<.05). Group Tr exhibited the lowest marginal discrepancy, whereas groups Cn and C demonstrated similar axial adaptations (P>.05), and group Tr revealed the lowest axial discrepancy (P<.05). With regard to the occlusal discrepancy evaluation, group Tr had the lowest discrepancy. However, no significant differences was found between groups C and Cn (P>.05).
The copings produced with the aid of digital impression systems exhibited better marginal and occlusal adaptation than those of the copings produced with the aid of conventional impression.
牙修复体边缘、轴面及咬合面的良好贴合对于其长期成功使用至关重要。已开发出包括数字印模系统在内的制作方案，但关于通过这些系统制作的氧化锆修复体贴合情况的信息却很少。
本体外研究的目的是比较数字印模方案对氧化锆基底冠边缘、轴面及咬合面贴合情况的影响。
使用30颗无龋坏或缺损的拔除人类上颌前磨牙。将这些牙齿预备为氧化锆全冠，并随机分为3组。氧化锆基底冠设计厚度为0.5mm，从预备体边缘起1mm处有30μm的模拟代型间隙。它们采用计算机辅助设计-计算机辅助制造（CAD-CAM）方案制作，一组使用传统印模（Cn组），两组使用数字印模（C组和Tr组）。使用硅橡胶复制技术，在×50放大倍数下通过体视显微镜测量这些基底冠的边缘、轴面及咬合面差异，并采用单因素方差分析（α = 0.05）对数据进行分析。
Cn组的平均边缘差异值为85.6μm，C组为58.7μm，Tr组为47.7μm。在边缘、轴面及咬合面差异方面，制作方案之间存在显著差异（P < 0.05）。借助数字印模制作的基底冠边缘差异明显少于Cn组（P < 0.05）。Tr组边缘差异最低，而Cn组和C组轴面贴合情况相似（P > 0.05），Tr组轴面差异最低（P < 0.05）。在咬合面差异评估方面，Tr组差异最低。然而，C组和Cn组之间未发现显著差异（P > 0.05）。
借助数字印模系统制作的基底冠比借助传统印模制作的基底冠表现出更好的边缘及咬合面贴合情况。
