다양한 도재 수리시스템에 따른 지르코니아 상부도재와 복합레진의 전단결합강도 비교

Abstract

Zirconia all ceramic restoration has recently been introduced as a promising metal-free core structure for fixed prostheses. With the demand of esthetic treatment and development of the CAD/CAM technology in dentistry, the usage of full zirconia crown is gradually increased. But still, full zirconia crown for the anterior restorations are limited by color sensitivity. To overcome this shade mismatching problem, porcelain layering technique on the zirconia core is widely used. While this layering technique is esthetic than full zirconia, in some cases, it is failing by ceramic veneer-chipping without exposing the zirconia core. In this situation, ideally, remake of the restoration is desirable, but it is not always feasible. Therefore depending on the size of the fracture in the veneering porcelain, intraoral repair methods using surface treatment and composite resins may be indicated. The aim of this study is to compare the shear bond strength of various porcelain repair systems to zirconia veneering porcelain. 40 porcelain disk specimens were fabricated and trimmed with fine diamond bur to remove glazed and contaminated surface. All of specimens were divided into 4 groups (n=10) according to the following porcelain repair systems : Group 1-CoJetTM Intraoral Adhesive Repair System (3M ESPE, Seefeld, Germany) ; Group 2- Ceramic repair system(Ivoclar Vivadent, Liechtenstein) ; Group 3- Porcelain Repair Kit (Ultradent, South Jordan, USA); Group 4- Signum Ceramic Bond(Heraus, Germany). As a composite resin, Z350 (3M-ESPE ,USA) were condensed and polymerized to the surface treated specimen. Bonded specimens were stored in 37°C distilled water for 24 hours. The shear bond strength were tested using a universal testing machine at a crosshead speed of 5mm/min. All results were statistically analyzed by one-way ANOVA and Tamhane post hoc test. After surface treatments, surface morphologies and wettability were examined with optical microscope, field-emission scanning electron microscope(FE-SEM), AFM and water contact angle goniometer to examine the surface treatment effects. As a results, surface irregularities were increased after silica coating in Group I , 37% phosphoric acid in Group II and 9%HF in Group III. The surface of the zirconia specimens treated with Ceramic bond was more smoother than diamond bur treated surface. The highest wettability values were obtained with silica coating in Group I, and other surface treatment methods also were shown better surface wettability than polished or diamond bur treated surface. There were not significant differences in the shear bond strengths between 4 groups(P<.05). The bond strength between zirconia veneering porcelain and a resin composite was affected by mechanical and chemical surface treatment. Therefore, The commercial porcelain repair system can be used for the repair of the zirconia veneering porcelain fracture.