Department of Restorative Dentistry, Dental Materials Area, Piracicaba School of Dentistry, Campinas State University, Piracicaba, São Paulo, Brazil.
Acta Odontol Scand. 2010 May;68(3):171-9. doi: 10.3109/00016351003636390. Epub 2010 Mar 3.
To assess the bond strength of Rely-X Unicem (RX), in comparison with Cement-Post (CP), to the cervical, middle and apical thirds of root canal dentin irradiated with a 980-nm diode laser.
Forty maxillary canines were separated into four equal groups according to the cement used and the laser surface treatment: RX/laser irradiation (LI) group; RX/no irradiation (NI) group; CP/LI group; and CP/NI group. Two slices (2-mm thick) of each root third were submitted to a push-out test to assess the bond strength of the cement to the root canal dentin. The data obtained were submitted to two-way ANOVA and fracture analysis was performed by scanning electron microscopy.
The type of cement as well as 980-nm LI at the different root canal thirds significantly affected the bond strength values (p < 0.05). LI promoted an increase in bond strength of RX in all root thirds (p < 0.05). For all groups, bond strength to the cervical third was highest, followed by the middle and apical thirds (p < 0.05). When the cements were compared, RX always presented the highest bond strength in comparison with CP, irrespective of the laser application (p < 0.05). Fracture analysis showed a predominance of mixed failures for RX and of adhesive failure between dentin and cement for CP, irrespective of the laser application.
The 980-nm LI promoted an increase in bond strength of the self-adhesive resinous cement to root dentin.
评估 Rely-X Unicem（RX）与 Cement-Post（CP）相比，在经 980nm 二极管激光照射后的根管牙本质的颈、中、根尖三分之一处的粘结强度。
40 颗上颌尖牙根据使用的水泥和激光表面处理分为四组：RX/激光照射（LI）组；RX/无照射（NI）组；CP/LI 组；CP/NI 组。每个根三分之一的两个切片（2mm 厚）进行推出试验，以评估水泥与根管牙本质的粘结强度。获得的数据进行双因素方差分析，并用扫描电子显微镜进行断裂分析。
水泥的类型以及在不同根管三分之一处的 980nm LI 显著影响粘结强度值（p<0.05）。LI 促进了 RX 在所有根管三分之一处粘结强度的增加（p<0.05）。对于所有组，颈三分之一的粘结强度最高，其次是中三分之一和根尖三分之一（p<0.05）。当比较水泥时，RX 始终表现出比 CP 更高的粘结强度，无论激光应用如何（p<0.05）。断裂分析显示，RX 主要表现为混合性失效，CP 主要表现为牙本质和水泥之间的黏附性失效，无论激光应用如何。
980nm LI 促进了自粘结树脂水泥对根管牙本质粘结强度的增加。
