Division of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC.
Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA.
J Prosthodont. 2021 Jan;30(1):76-82. doi: 10.1111/jopr.13287. Epub 2020 Dec 2.
To evaluate the survival rate (fatigue resistance), bonding efficiency and marginal integrity of monolithic zirconia partial and full coverage single restorations adhesively bonded to the tooth structure using air-particle abrasion, a primer with 10-methacryloyloxydecyl dihydrogen phosphate and a composite-resin cement (APC) protocol.
Extracted human premolars (N = 32) were randomly divided into four groups of eight specimens each. Premolars were prepared for the following restorations: full crown (group 1, control), mesial-occlusal-distal-facial onlay (MODF, group 2) preserving 2 mm facio-lingual functional cusp width, mesial-occlusal-distal-lingual onlay (MODL, group 3) preserving 2 mm facio-lingual nonfunctional cusp width, mesial-occlusal-distal-buccal-lingual onlay (MODBL, group 4), overlay preparation. All restorations were milled from monolithic 3 mol% yttria (3Y) zirconia blocks (ZirCad, A1 LT, Ivoclar Vivadent) with CAD/CAM software presets at minimum occlusal and axial thicknesses of 1 mm. The intaglio surface of the restorations was air-particle abraded (50 µm Al O , 2-Bar pressure, 15 s, 10 mm distance) and primed. An adhesive cement system was used to bond the restorations. Each group was subjected to thermomechanical loading for 1.2 million cycles (force = 70 N, 1.4 Hz) with simultaneous thermocycling (5-55°C, 30 s dwell time) using a mastication simulator. All specimens were examined under scanning electron microscope (SEM) analysis (30, 100, and 150×) to evaluate cracks and marginal defects. Fracture of restoration and/or fracture within tooth structure, and debonding were considered modes of failure.
One specimen from group 2 debonded at 632,000 cycles. None of the specimens failed due to fracture. SEM analysis at 30× indicated marginal integrity issue of the remaining seven intact specimens of group 2 in the area of antagonist contact. No specimens from group 1, 3, and 4 demonstrated marginal integrity issue at 30×. None of the specimens demonstrated any microcrack at 100× and150×.
Due to its fatigue resistance, 3Y-zirconia is a viable option for partial and full coverage single restorations. Following a strict bonding protocol, zirconia demonstrated durable adhesion to the tooth structure. Occlusal contact on restoration margins should be avoided.
评估使用空气颗粒喷砂、含 10-甲丙烯酰氧基癸基二氢磷酸酯的底漆和复合树脂粘结剂（APC）方案粘结到牙体结构的整体氧化锆局部和全冠单修复体的存活率（疲劳抗性）、粘结效率和边缘完整性。
从 32 个人类前磨牙中随机分为四组，每组 8 个样本。以下列方式制备前磨牙修复体：全冠（组 1，对照组）、近中-颊-远中-舌面嵌体（MODF，组 2）保留 2 毫米颊舌向功能尖宽度、近中-颊-远中-舌面嵌体（MODL，组 3）保留 2 毫米颊舌向非功能尖宽度、近中-颊-远中-颊舌面嵌体（MODBL，组 4），嵌体预备。所有修复体均由整体式 3 摩尔氧化钇（3Y）氧化锆块（ZirCad，A1 LT，Ivoclar Vivadent）使用 CAD/CAM 软件按最小牙合面和轴向厚度 1 毫米铣削而成。修复体的内表面采用空气颗粒喷砂（50 µm Al O ，2-Bar 压力，15 s，10 mm 距离）和底漆处理。使用粘结剂系统将修复体粘结。每组在咀嚼模拟器上进行 120 万次热机械循环（力=70 N，1.4 Hz），同时进行热循环（5-55°C，30 s 停留时间）。所有样本均在扫描电子显微镜（SEM）下进行分析（30、100 和 150×），以评估裂纹和边缘缺陷。修复体断裂和/或牙体结构内的断裂以及脱粘被认为是失效模式。
组 2 的一个样本在 632,000 次循环时脱粘。没有一个样本因断裂而失效。在 30×时，对组 2 其余 7 个完整样本在对颌接触区域的边缘完整性问题进行了 SEM 分析。组 1、3 和 4 的样本在 30×时均未显示出边缘完整性问题。在 100×和 150×时，没有样本显示任何微裂纹。
由于其抗疲劳性，3Y 氧化锆是局部和全冠单修复体的可行选择。采用严格的粘结方案，氧化锆与牙体结构具有持久的粘结力。应避免修复体边缘的牙合接触。
