Hanes Brenda, Feitosa Sabrina, Phasuk Kamolphob, Levon John A, Morton Dean, Lin Wei-Shao
Department of Prosthodontics, Indiana University School of Dentistry, Indianapolis, IN.
Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN.
J Prosthodont. 2022 Jun;31(5):441-446. doi: 10.1111/jopr.13440. Epub 2021 Oct 30.
To evaluate the fracture resistance behaviors of titanium-zirconium, one-piece zirconia, and two-piece zirconia implants restored by zirconia crowns and different combinations of abutment materials (zirconia and titanium) and retention modes (cement-retained and screw-retained zirconia crowns).
Three research groups (n=12) were evaluated according to combinations of abutment material, retention mode, and implant type. In the control group (TTC), titanium-zirconium implants (∅ 4.1 mm RN, 12 mm, Roxolid; Straumann USA, Andover, MA) and prefabricated titanium abutments (RN synOcta Cementable Abutment, H 5.5 mm; Straumann USA) were used to support cement-retained zirconia crowns. In the second group (ZZC), one-piece zirconia implants (PURE Ceramic Implant Monotype, ∅ 4.1 mm RD, 12 mm, AH 5.5 mm; Straumann USA) were used to support cement-retained zirconia crowns. In the third group (ZTS), two-piece zirconia implants (PURE Ceramic Implant, ∅ 4.1 mm RD, 12 mm) and prefabricated titanium abutments (CI RD PUREbase Abutment, H 5.5 mm) were used to support screw-retained zirconia crowns. All zirconia crowns were manufactured in the same anatomic contour with a 5-axis dental mill and blended 3 and 5 mol% yttria-stabilized zirconia (LayZir A2). Implants were inserted into specimen holders made of epoxy resin-glass fiber composite. All specimens were then subject to artificial aging in an incubator at 37°C for 90 days. Fracture resistance of specimen assemblies was tested under static compression load using the universal testing machine based on ISO14801 specification. The peak fracture loads were recorded. All specimens were examined at the end of the test microscopically at 5× and 10× magnification to detect any catastrophic failures. Comparisons between groups for differences in peak fracture load were made using Wilcoxon Rank Sum tests and Weibull and Kaplan-Meier survival analyses (α = 0.05).
The TTC group (942 ± 241 N) showed significantly higher peak fracture loads than the ZZC (645 ± 165 N) and ZTS (650 ± 124 N) groups (p < 0.001), while there was no significant difference between ZZC and ZTS groups (p = 0.940). The survival probability based on the Weibull and Kaplan-Meier models demonstrated different failure molds between titanium-zirconium and zirconia implants, in which the TTC group remained in the plastic strain zone for a longer period before fracture when compared to ZZC and ZTS groups. Catastrophic failures, with implant fractures at the embedding level or slightly below, were only observed in the ZZC and ZTS groups.
Cement-retained zirconia crowns supported by titanium-zirconium implants and prefabricated titanium abutments showed superior peak fracture loads and better survival probability behavior. One-piece zirconia implants with cement-retained zirconia crowns and two-piece zirconia implants with screw-retained zirconia crowns on prefabricated titanium abutment showed similar peak fracture loads and survival probability behavior. Titanium-zirconium and zirconia implants could withstand average intraoral mastication loads in the incisor region. This study was conducted under static load, room temperature (21.7°C), and dry condition, and full impacts of intraoral hydrothermal aging and dynamic loading conditions on the zirconia implants should be considered and studied further.
评估由氧化锆全冠修复的钛锆合金、一体式氧化锆和分体式氧化锆种植体，以及不同基台材料组合（氧化锆和钛）和固位方式（粘结固位和螺丝固位氧化锆全冠）的抗折性能。
根据基台材料、固位方式和种植体类型的组合评估三个研究组（n = 12）。在对照组（TTC）中，使用钛锆合金种植体（直径4.1 mm RN，长度12 mm，Roxolid；美国士卓曼公司，马萨诸塞州安多弗）和预制钛基台（RN synOcta可粘结基台，高度5.5 mm；美国士卓曼公司）来支持粘结固位氧化锆全冠。在第二组（ZZC）中，使用一体式氧化锆种植体（PURE陶瓷种植体单型，直径4.1 mm RD，长度12 mm，高度5.5 mm；美国士卓曼公司）来支持粘结固位氧化锆全冠。在第三组（ZTS）中，使用分体式氧化锆种植体（PURE陶瓷种植体，直径4.1 mm RD，长度12 mm）和预制钛基台（CI RD PUREbase基台，高度5.5 mm）来支持螺丝固位氧化锆全冠。所有氧化锆全冠均使用五轴牙科铣床制作成相同的解剖外形，并采用3 mol%和5 mol%氧化钇稳定氧化锆（LayZir A2）进行混合。将种植体植入由环氧树脂 - 玻璃纤维复合材料制成的标本固定器中。然后将所有标本在37°C的培养箱中进行人工老化90天。根据ISO14801标准，使用万能试验机在静态压缩载荷下测试标本组件的抗折性能。记录峰值抗折载荷。在试验结束时，对所有标本进行5倍和10倍放大倍数的显微镜检查，以检测任何灾难性破坏。使用Wilcoxon秩和检验、Weibull分析和Kaplan - Meier生存分析（α = 0.05）对组间峰值抗折载荷的差异进行比较。
TTC组（942 ± 241 N）的峰值抗折载荷显著高于ZZC组（645 ± 165 N）和ZTS组（650 ± 124 N）（p < 0.001），而ZZC组和ZTS组之间无显著差异（p = 0.940）。基于Weibull模型和Kaplan - Meier模型的生存概率表明，钛锆合金和氧化锆种植体之间存在不同的失效模式，与ZZC组和ZTS组相比，TTC组在断裂前在塑性应变区停留的时间更长。仅在ZZC组和ZTS组中观察到灾难性破坏，即在植入水平或略低于植入水平处种植体骨折。
由钛锆合金种植体和预制钛基台支持的粘结固位氧化锆全冠显示出更高的峰值抗折载荷和更好的生存概率表现。一体式氧化锆种植体搭配粘结固位氧化锆全冠以及分体式氧化锆种植体搭配预制钛基台上的螺丝固位氧化锆全冠显示出相似的峰值抗折载荷和生存概率表现。钛锆合金和氧化锆种植体能够承受切牙区域的平均口腔内咀嚼载荷。本研究是在静态载荷、室温（21.7°C）和干燥条件下进行的，应进一步考虑和研究口腔内热湿老化和动态载荷条件对氧化锆种植体的全面影响。
