Assistant Professor, Department of Oral Rehabilitation, Dental College of Georgia at Augusta University, Augusta, Ga.
Associate Professor and Director, Graduate Prosthodontics, Department of Prosthodontics, Louisiana State University, School of Dentistry, New Orleans, La.
J Prosthet Dent. 2017 Aug;118(2):221-227. doi: 10.1016/j.prosdent.2016.11.016. Epub 2017 Feb 20.
Delamination of veneering ceramic is reported as one of the most frequent problems associated with veneered zirconia restorations.
The purpose of this in vitro study was to compare the shear bond strength of sintered lithium disilicate to that of pressed fluorapatite glass-ceramic on a zirconia substrate.
Thirty zirconia blocks (20×15×2.5-mm thick) were cut, sintered, and divided into 2 groups. A pressed group, a zirconia liner, was applied and sintered, and the lost-wax technique was used to fabricate fluorapatite glass-ceramic blocks (3×3×3 mm), which were pressed onto the sintered zirconia blocks. A sintered group, lithium disilicate blocks, were cut (3×3×3 mm) and sintered to the sintered zirconia blocks by using a low-fusing glass-ceramic. The thickness of the low-fusing glass-ceramic was standardized to approximately 80 μm prior to sintering. The shear bond strength levels of the specimens were tested using a universal testing machine at a crosshead speed of 1 mm/min until failure. Representative separated specimen surfaces were examined for fracture characteristics, using scanning electron microscopy at ×50 magnification. Debonding data were compared using a 2-tailed, unpaired Student t test (α=.05).
The sintered group demonstrated mean shear bond strength values (41.2 ±6.3 MPa), which were significantly higher (P<.001) than those of the pressed group (21.3 ±4.3 MPa).
Sintering of computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate ceramic achieved higher shear bond strength values than pressing fluorapatite glass-ceramic to zirconia substructure material.
层离是包埋陶瓷的最常见问题之一，与饰面氧化锆修复体有关。
本体外研究的目的是比较烧结二硅酸锂与压制成型氟磷灰石玻璃陶瓷在氧化锆基底上的剪切结合强度。
制备 30 个氧化锆块（20×15×2.5-mm 厚），烧结，分为 2 组。压组，应用和烧结氧化锆衬里，使用失蜡技术制作氟磷灰石玻璃陶瓷块（3×3×3mm），将其压接到烧结氧化锆块上。烧结组，切割二硅酸锂块（3×3×3mm）并通过低熔玻璃陶瓷烧结到烧结氧化锆块上。在烧结前，将低熔玻璃陶瓷的厚度标准化至约 80μm。使用万能试验机以 1mm/min 的十字头速度测试试样的剪切结合强度水平，直至破坏。使用扫描电子显微镜以×50 放大倍数检查代表性分离的试样表面的断裂特征。使用双侧、非配对学生 t 检验（α=.05）比较离解数据。
烧结组的平均剪切结合强度值（41.2±6.3MPa）明显高于压组（21.3±4.3MPa）（P<.001）。
计算机辅助设计和计算机辅助制造（CAD-CAM）烧结二硅酸锂陶瓷的结合强度值高于将氟磷灰石玻璃陶瓷压到氧化锆基层材料上。
