다른 중합방식으로 중합된 이원중합형 복합레진 코어재의 중합에 대한 평가

Abstract

Core build-up materials are used in a tooth broken down by trauma and extensive dental caries to restore the coronal portion of the tooth and should provide a satisfactory retention and resistance of the subsequent restoration. Lately composite core materials, in combination with improved bonding agents, are convenient to use than amalgam, when mechanical retention is difficult to achieve. Dual-cured core buildup composites have been designed to allow the clinician to build extended core restorations quickly, in bulk, as the chemical mode of the polymerization process can initiate resin polymerization in deep resin layers. This study was performed to evaluate the polymerization in dual cured core build-up resin composites using different activation modes. Two dual-cured composites core materials, MultiCore HB (Ivoclar Vivadent AG, Schaan, Liechtenstein) and BIS-CORE (Bisco, Schumburg, USA), were used for this study and two different groups for each materials were prepared, corresponding to two different activation mode: light curing for 40 sec (L) and self curing (S). Thus four groups were tested: ML (MultiCore HB with light curing), MS (MultiCore HB with self curing), BL (BIS-CORE with light curing), BS (BIS-CORE with self curing). Twenty-four core spaces, 4 mm wide and 10 mm deep, were prepared in acrylic resin blocks. The core spaces were divided into four groups. Each group was filled with the dual-cured core materials. After storage of the specimens for 24h in 37℃ water, each specimens were sectioned longitudinally with a low speed diamond saw. Vickers hardness was measured at the top, bottom surfaces and at the depths of 2, 4, 6, 8 mm. The data were divided into three regions, coronal, middle and apical. The data were statistically compared using two-way ANOVA and Tukey HSD test. The results from this study were as follows: 1. The ML group showed the highest Vickers hardness (84.06 ± 14.71 kg/㎟) and the BS group showed the lowest Vickers hardness (60.62 ± 5.05 kg/㎟). 2. In comparison among groups using same materials, Vickers hardness of the ML group was higher than that of the MS group (p ＜ 0.01). The BL group showed higher Vickers hardness than the BS group (p＜0.01). 3. In each experimental group, Ranking of Vickers hardness was as follows: coronal ＞ middle > apical (p ＜ 0.01) 4. In comparison among groups using same activation modes, Vickers hardness of the group using MultiCore HB was higher than that of the group using BIS-CORE (p ＜ 0.01). According to the results of present study, light curing show better polymerization than self curing of dual-cured composite core materials used in this study. Degree of polymerization decrease with increased cavity depth.