de Paula Andréia Bolzan, Duque Cristiane, Correr-Sobrinho Lourenço, Puppin-Rontani Regina M
Department of Dental Materials, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil.
Oper Dent. 2008 Jul-Aug;33(4):434-40. doi: 10.2341/07-114.
This study evaluated the compressive strength and marginal adaptation of composite onlays using indirect and direct techniques after thermal and mechanical cycling. Onlay standardized cavities were prepared in 50 permanent molars and restored with Z-250 resin composite using indirect (IRT) or direct (DRT) restorative techniques. The restorations were either submitted or not submitted to thermal (500 cycles, 5 degrees to 55 degrees C) and mechanical cycling (50,000 cycles, 50N). The teeth were distributed to five groups (n=10): G1-IRT/cycling; G2-IRT/no cycling; G3-DRT/cycling; G4-DRT/no cycling and G5 (control group)-sound teeth. All prepared teeth were stored in 100% relative humidity at 37 degrees C for 24 hours, followed by finishing with Sof-Lex discs. A caries detector solution was applied on the tooth-restoration interface of all teeth for five seconds, followed by washing and drying. Four digital photographs were taken of each tooth surface. The extent of gaps was measured using standard software (Image Tool 3.0). All groups were submitted to compression testing in a universal testing machine (INSTRON) at a crosshead speed of 1 mm/minute until failure. The compressive strength (CS) and marginal adaptation data were submitted to ANOVA and Tukey test (p<0.05). For both evaluation criteria (compressive strength and marginal adaptation), there were no statistically significant differences among the restorative techniques. Deterioration over time was observed for both types of restorations. However, the prevalence of catastrophic fractures increased among direct restorations. The application of thermal/mechanical cycling only influenced marginal adaptation.
本研究评估了热循环和机械循环后使用间接和直接技术的复合高嵌体的抗压强度和边缘适合性。在50颗恒牙上制备高嵌体标准化窝洞，并用Z - 250树脂复合材料采用间接修复技术（IRT）或直接修复技术（DRT）进行修复。修复体要么进行热循环（500次循环，5摄氏度至55摄氏度）和机械循环（50,000次循环，50N），要么不进行。牙齿被分为五组（n = 10）：G1 - IRT/循环；G2 - IRT/无循环；G3 - DRT/循环；G4 - DRT/无循环和G5（对照组）-完好牙齿。所有制备好的牙齿在37摄氏度、相对湿度100%的环境中储存24小时，然后用Sof - Lex盘进行修整。在所有牙齿的牙体修复界面上涂抹龋病检测液5秒钟，然后冲洗并干燥。每颗牙齿表面拍摄四张数码照片。使用标准软件（Image Tool 3.0）测量间隙程度。所有组在万能测试机（INSTRON）上以1毫米/分钟的十字头速度进行压缩测试直至破坏。抗压强度（CS）和边缘适合性数据进行方差分析和Tukey检验（p < 0.05）。对于两种评估标准（抗压强度和边缘适合性），修复技术之间没有统计学上的显著差异。两种类型的修复体均观察到随时间的恶化。然而，直接修复体中灾难性骨折的发生率增加。热/机械循环的应用仅影响边缘适合性。
