Objective: To analyze the marginal roughness and marginal fitness of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) laminate veneers with different materials and thicknesses, and to provide a reference for the clinical application of laminate veneers.
Methods: The butt-to-butt type laminate veneers were prepared on resin typodonts, the preparations were scanned, and the laminate veneers were manufactured by chairside CAD/CAM equipment. The laminate veneers were divided into four groups (n=9) according to the materials (glass-matrix ceramics and resin-matrix ceramics) and thickness (0.3 mm and 0.5 mm) of the veneers, with a total of 36. The marginal topo-graphies of each laminate veneer were digitally recorded by stereomicroscope, and the marginal rough-nesses of the laminate veneers were determined by ImageJ software. The marginal fitness of the laminate veneers was measured by a fit checker and digital scanning and measuring method. At the same time, the mechanical properties of glass-matrix ceramic and resin-matrix ceramic bars (n=20) were tested by a universal testing device.
Results: The marginal roughness of 0.3 mm and 0.5 mm glass-matrix ceramic laminate veneers was (24.48±5.55) μm and (19.06±5.75) μm, respectively, with a statistically significant difference (P < 0.001). The marginal roughness of 0.3 mm and 0.5 mm resin-matrix ceramic laminate veneers was (6.13±1.27) μm and (6.84±2.19) μm, respectively, without a statistically significant difference (P>0.05). The marginal roughness of the glass-matrix ceramic laminate veneers was higher than that of the resin-matrix ceramic laminate veneers with a statistically significant difference (P < 0.001). The marginal fitness of 0.3 mm and 0.5 mm glass-matrix ceramic laminate veneers were (66.30±26.71) μm and (85.48±30.44) μm, respectively. The marginal fitness of 0.3 mm and 0.5 mm resin-matrix ceramic laminate veneers were (56.42±19.27) μm and (58.36±8.33) μm, respectively. There was no statistically significant difference among the 4 groups (P>0.05). For glass-matrix ceramics, the flexural strength was (327.40±54.25) MPa, the flexural modulus was (44.40±4.39) GPa, and the modulus of resilience was (1.24±0.37) MPa. For resin-matrix ceramics, the flexural strength was (173.71±16.61) MPa, the flexural modulus was (11.88±0.51) GPa, and the modulus of resilience was (1.29±0.27) MPa. The flexural strength and modulus of glass-matrix ceramics were significantly higher than those of resin-matrix ceramics (P < 0.001), but there was no statistically significant difference in the modulus of resilience between the two materials (P>0.05).
Conclusion: The marginal roughness of CAD/CAM glass-matrix ceramic laminate veneers is greater than that of resin-matrix ceramic laminate veneers, but there was no statistically significant difference in marginal fitness among them. Increasing the thickness can reduce the marginal roughness of glass-matrix ceramic laminate veneers, but has no effect on the marginal roughness of resin-matrix ceramic laminate veneers.
目的: 评价不同材料及厚度椅旁计算机辅助设计和计算机辅助制作(computer-aided design and computer-aided manufacturing，CAD/CAM)瓷贴面的边缘粗糙度和边缘密合度，旨在为瓷贴面的临床应用提供参考。
方法: 在树脂人工牙上进行对接型瓷贴面牙体预备，利用扫描仪扫描预备体，利用椅旁切削设备CAD/CAM瓷贴面。根据陶瓷材料类型(玻璃基陶瓷和树脂基陶瓷)及贴面厚度(0.3 mm和0.5 mm)将贴面分为4组(n=9)，共36个。利用体式显微镜拍摄瓷贴面边缘形貌的数码照片，在软件内测量边缘粗糙度；利用间隙检查剂和数字化扫描与测量方法评价瓷贴面的边缘密合度；同时利用万能力学试验机测试玻璃基陶瓷和树脂基陶瓷条形试件(n=20)的力学性能。
结果: 厚度为0.3 mm和0.5 mm玻璃基陶瓷贴面的边缘粗糙度分别为(24.48±5.55) μm和(19.06±5.75) μm，差异有统计学意义(P < 0.001)；厚度为0.3 mm和0.5 mm树脂基陶瓷贴面的边缘粗糙度分别为(6.13±1.27) μm和(6.84±2.19) μm，差异无统计学意义(P>0.05)；玻璃基陶瓷贴面的边缘粗糙度大于树脂基陶瓷，差异有统计学意义(P < 0.001)。厚度为0.3 mm和0.5 mm玻璃基陶瓷贴面的边缘密合度分别为(66.30±26.71) μm和(85.48±30.44) μm，厚度为0.3 mm和0.5 mm树脂基陶瓷贴面的边缘密合度分别为(56.42±19.27) μm和(58.36±8.33) μm，4组间差异均无统计学意义(P>0.05)。玻璃基陶瓷的弯曲强度为(327.40±54.25) MPa，弯曲模量为(44.40±4.39) GPa，回弹模量为(1.24±0.37) MPa；树脂基陶瓷的弯曲强度为(173.71±16.61) MPa，弯曲模量为(11.88±0.51) GPa，回弹模量为(1.29±0.27) MPa；玻璃基陶瓷的弯曲强度和弯曲模量大于树脂基陶瓷，差异有统计学意义(P < 0.001)，但两种材料的回弹模量差异无统计学意义(P>0.05)。
结论: 椅旁CAD/CAM玻璃基陶瓷贴面的边缘粗糙度大于树脂基陶瓷贴面，但二者的边缘密合度无显著差异。增加贴面厚度可降低玻璃基陶瓷贴面的边缘粗糙度，但对树脂基陶瓷贴面的边缘粗糙度无影响。
Keywords: Ceramics; Computer-aided design; Dental marginal adaptation; Dental veneers; Materials testing.