Abstract：
OBJECTIVE: This study evaluated the fracture resistance of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate crown, onlay, and non-anatomical occlusal veneer (A-OV) with and without margin fabricated.
METHODS: Sixty-four CAD-CAM lithium disilicate restorations were designed as (1) complete coverage crown (CCC); (2) A-OV with margin; (3) non-A-OV with margin (NA-OV-M); and (4) non-A-OV without margin (NA-OV-NM), 16 of each. Restorations were crystallized and adhesively luted to resin dies using resin cement. Specimens were then subjected to 400,000 cycles of chewing in a mastication simulator. A universal testing machine was used to apply a compressive load at a crosshead speed of 1 mm/min to the long axis of the tooth with a stainless-steel sphere until fracture occurred. One-way ANOVA followed by post hoc tests were used to assess the impact of preparation design on the fracture load of CAD-CAM lithium disilicate restorations.
RESULTS: The highest fracture load was recorded for CAD-CAM lithium disilicate indirect restorations for non-A-OVs preparation with margin (2549 ± 428 N) and onlay (2549 ± 293 N) and the lowest fracture load was recorded for CCCs (2389 ± 428 N); however, there was no significant (p = 0.640) between groups.
CONCLUSIONS: CAD-CAM lithium disilicate restorations fabricated for anatomical and non-A-OV preparation display a fracture resistance similar to CCCs. Conservative partial coverage restorations may be considered an acceptable approach for posterior teeth.
METHODS: Sixty-four CAD-CAM lithium disilicate restorations were designed as (1) complete coverage crown (CCC); (2) A-OV with margin; (3) non-A-OV with margin (NA-OV-M); and (4) non-A-OV without margin (NA-OV-NM), 16 of each. Restorations were crystallized and adhesively luted to resin dies using resin cement. Specimens were then subjected to 400,000 cycles of chewing in a mastication simulator. A universal testing machine was used to apply a compressive load at a crosshead speed of 1 mm/min to the long axis of the tooth with a stainless-steel sphere until fracture occurred. One-way ANOVA followed by post hoc tests were used to assess the impact of preparation design on the fracture load of CAD-CAM lithium disilicate restorations.
RESULTS: The highest fracture load was recorded for CAD-CAM lithium disilicate indirect restorations for non-A-OVs preparation with margin (2549 ± 428 N) and onlay (2549 ± 293 N) and the lowest fracture load was recorded for CCCs (2389 ± 428 N); however, there was no significant (p = 0.640) between groups.
CONCLUSIONS: CAD-CAM lithium disilicate restorations fabricated for anatomical and non-A-OV preparation display a fracture resistance similar to CCCs. Conservative partial coverage restorations may be considered an acceptable approach for posterior teeth.
摘要：
目的：这项研究评估了椅边计算机辅助设计和计算机辅助制造（CAD-CAM）焦硅酸锂冠的抗断裂性，onlay,以及带有和不带有边缘的非解剖学咬合贴面（A-OV）。
方法：将64个CAD-CAM焦硅酸锂修复体设计为（1）完全覆盖冠（CCC）；（2）有余量的A-OV；（3）有余量的非A-OV（NA-OV-M）；（4）无余量的非A-OV（NA-OV-NM），每个16将修复物结晶并使用树脂水泥粘合到树脂模具上。然后将样品在咀嚼模拟器中进行400,000次咀嚼循环。使用万能试验机以1毫米/分钟的十字头速度向具有不锈钢球的牙齿的长轴施加压缩载荷，直到发生断裂。使用单向方差分析和事后测试来评估制备设计对CAD-CAM焦硅酸锂修复体的断裂载荷的影响。
结果：对于边缘（2549±428N）和高嵌体（2549±293N）的非A-OVs制备的CAD-CAM二硅酸锂间接修复体，记录到最高断裂载荷，对于CC（2389±428N）；然而，组间无显著性差异(p=0.640).
结论：用于解剖和非A-OV制备的CAD-CAM二硅酸锂修复体显示出与CC相似的抗断裂性。保守的部分覆盖修复可能被认为是后牙的可接受方法。
方法：将64个CAD-CAM焦硅酸锂修复体设计为（1）完全覆盖冠（CCC）；（2）有余量的A-OV；（3）有余量的非A-OV（NA-OV-M）；（4）无余量的非A-OV（NA-OV-NM），每个16将修复物结晶并使用树脂水泥粘合到树脂模具上。然后将样品在咀嚼模拟器中进行400,000次咀嚼循环。使用万能试验机以1毫米/分钟的十字头速度向具有不锈钢球的牙齿的长轴施加压缩载荷，直到发生断裂。使用单向方差分析和事后测试来评估制备设计对CAD-CAM焦硅酸锂修复体的断裂载荷的影响。
结果：对于边缘（2549±428N）和高嵌体（2549±293N）的非A-OVs制备的CAD-CAM二硅酸锂间接修复体，记录到最高断裂载荷，对于CC（2389±428N）；然而，组间无显著性差异(p=0.640).
结论：用于解剖和非A-OV制备的CAD-CAM二硅酸锂修复体显示出与CC相似的抗断裂性。保守的部分覆盖修复可能被认为是后牙的可接受方法。
