Rojas-Rueda S, Hernandez A I, Abuhammoud S, Jurado C A, Fu C-C, Lawson N C
Silvia Rojas-Rueda, DDS, Master of Science in Dental Biomaterials resident, University of Alabama at Birmingham School of Dentistry, Birmingham, AL, USA.
Alfredo I. Hernandez, DDS, MS, associate professor, Division of Prosthodontics, ATSU Arizona School of Dentistry & Oral Health, Mesa, AZ, USA.
Oper Dent. 2025 Jan 1;50(1):59-66. doi: 10.2341/24-073-L.
This study aimed to assess the fracture resistance of chairside computer assisted design and computer assisted manufacturing (CAD-CAM) lithium disilicate partial and full-coverage crowns and veneers for maxillary canines.
Forty-eight restorations for maxillary right canines (12 per group) were designed as follows: (1) partial crown with finish line in the upper middle third; (2) partial crown with finish line in the lower middle third; (3) traditional labial veneer; and (4) traditional full-coverage crown. Restorations were fabricated out of lithium disilicate (Amber Mill, Hassbio) using a chairside CAD-CAM system (Cerec Dentsply Sirona). Partial and full crowns and veneers were treated with a primer system (Monobond Plus, Ivoclar Vivadent) and cemented using dual-cure resin cement (Variolink Esthetic, Ivoclar Vivadent) and cemented to printed resin dies. Subsequently, the restorations were subjected to 10,000 thermocycles between 5°C and 55°C with a dwell time of 30 seconds. The restorations were then loaded axially on the incisal edge in compression to fracture with a flat indenter.
Full-coverage crowns displayed the highest fracture resistance (809±28.57 N) followed by partial crowns with finish line in lower third (649±21.74 N) and crowns with finish line in upper third (421±17.46 N). Veneers displayed the lowest fracture resistance values (259±15.69 N).
The fracture resistance of partial and full-coverage crowns and veneers was significantly influenced by the design. Full coverage crowns displayed the highest fracture resistance and partial crowns showed higher fracture resistance than traditional veneers.
本研究旨在评估椅旁计算机辅助设计与计算机辅助制造（CAD-CAM）的二硅酸锂部分覆盖和全冠修复体以及上颌尖牙贴面的抗折性能。
为上颌右侧尖牙设计了48个修复体（每组12个），如下所示：（1）边缘位于中上三分之一的部分冠；（2）边缘位于中下三分之一的部分冠；（3）传统唇面贴面；（4）传统全冠。使用椅旁CAD-CAM系统（Cerec，登士柏西诺德）由二硅酸锂（Amber Mill，哈斯生物）制作修复体。部分冠、全冠和贴面用底漆系统（Monobond Plus，义获嘉伟瓦登特）处理，并用双固化树脂水门汀（Variolink Esthetic，义获嘉伟瓦登特）粘固到打印的树脂代型上。随后，修复体在5°C至55°C之间进行10000次热循环，保压时间为30秒。然后，使用扁平压头在切缘轴向加载修复体直至其断裂。
全冠显示出最高的抗折性能（809±28.57 N），其次是边缘位于下三分之一的部分冠（649±21.74 N）和边缘位于上三分之一的部分冠（421±17.46 N）。贴面显示出最低的抗折性能值（259±15.69 N）。
部分覆盖和全冠修复体以及贴面的抗折性能受设计的显著影响。全冠显示出最高的抗折性能，部分冠的抗折性能高于传统贴面。
