Monaco Carlo, Bortolotto Tissiana, Arena Antonio, Krejci Ivo
J Adhes Dent. 2015 Dec;17(6):567-74. doi: 10.3290/j.jad.a35251.
To evaluate the marginal adaptation and fracture load of composite resin onlays reinforced with different substructures.
Thirty-two extracted, caries-free premolars were selected for this study and endodontically treated. Group 1 was used as the control group, and the teeth were restored only with as-manufactured composite resin overlays. Group 2 teeth were restored with composite resin overlays with 3 fiber-reinforced composite (FRC) layers placed horizontally on the bottom of the restoration. Group 3 teeth were restored with composite resin overlays with 6 fiber-reinforced composite (FRC) layers placed as in group 2. Group 4 teeth were restored with composite resin overlays and FRC placed with an anatomical design. All specimens underwent SEM evaluation of their marginal adaptation before and after thermocycling and cyclic mechanical loading. All specimens were then subjected to a fracture test, recording the value for the initial (IF) and final (FF) failure. Differences in the means were compared using matched-pairs t-tests and one-way ANOVA. The level of significance was set at α = 0.05.
No statistically significant difference between the four groups in terms of marginal adaptation was observed at the tooth/luting composite and luting composite/overlay interfaces before and after loading. The fracture loads of IF and FF, from most to least resistant were: group 4 (1431.8 ± 294.3 N/1710.1 ± 326.6 N), group 3 (1428.1 ± 251.4 N/1467.9 ± 242.4 N), group 2 (852.6 ± 413.5 N/1058.1 ± 251.5 N) and group 1 (899.8 ± 352.7 N/923.5 ± 318.8 N). Significant differences (p = 0.026) were observed comparing group 1 to groups 2 and 3, and group 1 to 4. Three irreparable fractures were found in group 3, four in group 2, and five in groups 1 and 4.
The presence or absence of reinforcement and the different configuration of the reinforcement fibers affect fracture strength but only partially the failure modality. The presence or absence of reinforcement does not alter marginal adaptation.
评估不同子结构增强的复合树脂高嵌体的边缘适合性和断裂载荷。
本研究选取32颗拔除的无龋前磨牙并进行根管治疗。第1组作为对照组，牙齿仅用成品复合树脂高嵌体修复。第2组牙齿用复合树脂高嵌体修复，在修复体底部水平放置3层纤维增强复合材料（FRC）。第3组牙齿用复合树脂高嵌体修复，按第2组的方式放置6层纤维增强复合材料（FRC）。第4组牙齿用复合树脂高嵌体修复，并按解剖学设计放置FRC。所有标本在热循环和循环机械加载前后均进行边缘适合性的扫描电子显微镜（SEM）评估。然后对所有标本进行断裂试验，记录初始（IF）和最终（FF）失效值。使用配对t检验和单因素方差分析比较均值差异。显著性水平设定为α = 0.05。
在加载前后，四组在牙体/粘结性复合树脂和粘结性复合树脂/高嵌体界面的边缘适合性方面均未观察到统计学上的显著差异。IF和FF的断裂载荷，从最抗断裂到最不抗断裂依次为：第4组（1431.8±294.3 N/1710.1±326.6 N）、第3组（1428.1±251.4 N/1467.9±242.4 N）、第2组（852.6±413.5 N/1058.1±251.5 N）和第1组（899.8±352.7 N/923.5±318.8 N）。比较第1组与第2组和第3组以及第1组与第4组时观察到显著差异（p = 0.026）。第3组发现3例不可修复的骨折，第2组4例，第1组和第4组各5例。
增强结构的有无以及增强纤维的不同构型会影响断裂强度，但仅部分影响失效方式。增强结构的有无不会改变边缘适合性。
