University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Fixed and Removable Prosthodontics, Groningen, The Netherlands.
University of Zurich, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, Zurich, Switzerland.
Dent Mater. 2017 Dec;33(12):1392-1401. doi: 10.1016/j.dental.2017.09.010. Epub 2017 Nov 1.
The aim of this study was to investigate the influence of the luting agent on the application of laminate veneers (LVs) in an accelerated fatigue and load-to-failure test after thermo-cyclic aging.
Sound maxillary central incisors (N=40) were randomly divided into four groups to receive LVs (LiSiO) that were adhesively bonded: Group CEMF: Adhesive cement (Variolink Esthetic LC), fatigue test; Group CEMLF: Adhesive cement, load-to-failure test; Group COMF: Resin composite (Enamel HFO), fatigue test; Group COMLF: Resin composite, load-to-failure test. The specimens were thermo-mechanically aged (1.2×10 cycles at 1.7Hz/50N, 8000 cycles 5-55°C) and then subjected to either accelerated fatigue (5Hz, 25N increasing after each 500 cycles) or load to failure (1mm/min). Failure types were classified and data analyzed using chi-square, Kaplan Meier survival, Log Rank (Mantel-Cox) and independent-samples t-test.
After thermo-mechanical aging, fracture resistance (p<0.000) was higher in the composite groups. Kaplan Meier survival rates showed significant difference (p<0.001) between the composite (mean load: 1165N; mean cycles: 22.595) and the cement groups (mean load: 762.5N; mean cycles: 14.569). The same differences were observed in the load to failure test (cement M=629.4N, SD±212.82 and composite M=927.59N, SD±261.06); t (18)=-2.80, p=0.01. Failure types were observed as fractures and chipping in group CEMF, all other groups were predominantly adhesive failures between the luting agent and the laminate veneer.
The delivery of laminate veneers using a direct restorative composite rather than a resin cement resulted in significantly less chipping and fractures, higher fracture strength in both accelerated fatigue and load-to-failure.
本研究旨在探讨在热循环老化后，黏结剂对复合树脂直接贴面（LV）加速疲劳和负载至失效测试的应用影响。
随机将 40 颗上颌中切牙分为四组，使用黏结剂进行 LV 黏接：CEMF 组：黏结剂（Variolink Esthetic LC），进行疲劳测试；CEMLF 组：黏结剂，进行负载至失效测试；COMF 组：复合树脂（Enamel HFO），进行疲劳测试；COMLF 组：复合树脂，进行负载至失效测试。样本进行热机械老化（1.2×10 次，1.7Hz/50N，8000 次 5-55°C），然后进行加速疲劳（5Hz，每次增加 500 次后增加 25N）或负载至失效（1mm/min）。使用卡方检验、Kaplan-Meier 生存分析、Log Rank（Mantel-Cox）和独立样本 t 检验对失效类型进行分类和数据分析。
热机械老化后，复合材料组的断裂阻力（p<0.000）更高。Kaplan-Meier 生存率显示复合材料组与水泥组之间存在显著差异（p<0.001）（平均载荷：1165N；平均循环：22.595）。在负载至失效测试中也观察到相同的差异（水泥 M=629.4N，SD±212.82 和复合材料 M=927.59N，SD±261.06）；t（18）=-2.80，p=0.01。CEMF 组的失效类型为断裂和碎裂，其他组均为黏结剂与复合树脂之间的黏附性失效。
使用直接修复复合材料而非树脂黏结剂进行复合树脂贴面修复，可显著减少碎裂和断裂，在加速疲劳和负载至失效测试中均具有更高的断裂强度。
