Shear bond strength of the three different kinds of resin cement on CAD/CAM ceramic inlay / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the bond strengths between the latest CAD/CAM ceramic inlay and various resin cements which are used primarily for esthetic restoration. MATERIALS AND METHODS: Cylindrical ceramic blocks(Height: 5 mm, diameter: 3 mm) were fabricated by using Cerec3 and bonded on the dentin of the ninety extracted caries-free molars using three different kinds of resin cement(Unicem(R), Biscem(R), and Variolink II(R)) according to the manufacturer's instructions. Ninety specimens were divided into 3 groups according to three different kinds of resin cement. Half of each group were conducted thermocycling under the conditions of the 5 - 55degrees C, 5,000 cycle but the other half of them weren't. All specimens were kept in normal saline 37degrees C, for 24 hours before measuring the bond strength. The shear bond strength was measured by Universal testing machine with a cross head speed of 0.5 mm/min. The results were analyzed statistically by t-test and one-way ANOVA. RESULTS: Unicem(R) group showed the highest shear bond strength despite a slight decline by thermocycling. The shear bond strength of Unicem(R) group and ValiolinkII(R) group were significantly influenced by thermocycling, whereas Biscem(R) group was not influenced (P<.05). There were no significant differences in the bond strength between the three groups without thermocycling, but there was significant differences between Unicem(R) group and Valiolink II(R) group with thermocycling(P<.05). CONCLUSION: It has been shown to be clinically effective when the self-adhesive resin cements Unicem(R) and Biscem(R) were used instead of the etch-and-rinse resin cement Valiolink II(R) during the bonding of CAD/CAM ceramic inlay restorations with teeth.

Influence of three different preparation designs on the marginal and internal gaps of CEREC3 CAD/CAM inlays / 대한치과보존학회지

The aim of this study was to evaluate the marginal and internal gaps in CEREC3 CAD/CAM inlays of three different preparation designs. CEREC3 Inlays of three different preparation designs (n = 10) were fabricated according to Group I-conventional functional cusp capping/shoulder preparation, Group II-horizontal reduction of cusps and Group III-complete reduction of cusps/shoulder preparation. After cementation of inlays, the bucco-lingual cross section was performed through the center of tooth. Cross section images of 20 magnifications were obtained through the stereomicroscope. The gaps were measured using the Leica application suite software at each reference point. Statistical analysis was performed using one-way ANOVA and Tukey's test (alpha<0.05). The marginal gaps ranged from 80.0 to 97.8 microm for Group I, 42.0 to 194.8 microm for Group II, 51.0 to 80.2 microm for Group III. The internal gaps ranged from 90.5 to 304.1 microm for Group I, 80.0 to 274.8 microm for Group II, 79.7 to 296.7 microm for Group III. The gaps of each group were the smallest on the margin and the largest on the horizontal wall. For the CEREC3 CAD/CAM inlays, the simplified designs (groups II and III) did not demonstrate superior results compared to the traditional cusp capping design (group I).