Brandt William Cunha, de Moraes Rafael Ratto, Correr-Sobrinho Lourenço, Sinhoreti Mário Alexandre Coelho, Consani Simonides
Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas, UNICAMP, Av. Limeira 901, 13414-903, Piracicaba-SP, Brazil.
Dent Mater. 2008 Jun;24(6):846-50. doi: 10.1016/j.dental.2007.09.012. Epub 2007 Nov 28.
To evaluate push out force, hardness and cross-link density (CLD) of composite restorations photo-activated by different methods.
Z250 (3M ESPE) and XL2500 halogen unit (3M ESPE) were used. For push out force and hardness tests, conical restorations were made in bovine incisors. For CLD evaluation, cylindrical specimens were prepared. Different activation methods were tested: high-intensity continuous (HIC), low-intensity continuous (LIC), soft-start (SS) or pulse-delay (PD), with constant radiant exposure. Knoop readings were performed on bottom and top surfaces. Data were submitted to two-way ANOVA and Tukey's test (alpha=0.05). Push out force data were submitted to ANOVA and Tukey's test (alpha=0.05). Failure modes were classified under magnification (40x). CLD was estimated by hardness readings before and after storage in ethanol. Data were submitted to RM-ANOVA and Tukey's test (alpha=0.05).
No significant differences in top hardness (KHN, N/mm2) were observed for HIC (598), LIC (564), SS (585) and PD (573). LIC presented significantly lower bottom hardness (520) than HIC (574), SS (562) and PD (572). Push out force (N) for SS (246) and PD (238) were similar, but significantly higher compared to LIC (198) and HIC (193). For HIC and LIC, only adhesive and mixed failures were observed. For SS and PD, cohesive failures also occurred. After storage, HIC and LIC presented significantly lower softening than PD. HIC also presented lower softening than SS, and similar results were observed for SS and PD.
Different activation methods can interfere with push out force, hardness and CLD of composite restorations.
评估通过不同方法光激活的复合树脂修复体的推出力、硬度和交联密度（CLD）。
使用Z250（3M ESPE）和XL2500卤素灯装置（3M ESPE）。对于推出力和硬度测试，在牛切牙中制作锥形修复体。对于CLD评估，制备圆柱形标本。测试了不同的激活方法：高强度连续（HIC）、低强度连续（LIC）、软启动（SS）或脉冲延迟（PD），辐射暴露恒定。在底部和顶部表面进行努氏读数。数据进行双向方差分析和Tukey检验（α = 0.05）。推出力数据进行方差分析和Tukey检验（α = 0.05）。在40倍放大倍数下对失败模式进行分类。通过在乙醇中储存前后的硬度读数估计CLD。数据进行重复测量方差分析和Tukey检验（α = 0.05）。
HIC（598）、LIC（564）、SS（585）和PD（573）在顶部硬度（KHN，N/mm²）方面未观察到显著差异。LIC的底部硬度（520）显著低于HIC（574）、SS（562）和PD（572）。SS（246）和PD（238）的推出力（N）相似，但与LIC（198）和HIC（193）相比显著更高。对于HIC和LIC，仅观察到粘结性和混合性失败。对于SS和PD，也发生了内聚性失败。储存后，HIC和LIC的软化程度显著低于PD。HIC的软化程度也低于SS，SS和PD观察到类似结果。
不同的激活方法会干扰复合树脂修复体的推出力、硬度和CLD。
