Comparison of internal fit ond load bearing capacity of 3 different full molar crowns that digital and conventional impressions method are prepared

Purpose: The aim of this study was to compare internal fit and load bearing capacity of 3 different full molar crowns that digital and conventional impressions method was prepared. Material and method: Acrylic maxillary first molar tooth was prepared 1.5 mm chamfer on step and 2.0 mm occlusal reduction in order to imitate the natural tooth then zirconium model was obtained. 3 different materials with digital and conventional measuring technique is obtained using this model. Materials were designated as zirconium, hybrid ceramic and high resistance polymer. 10 crowns in each group will be preferred conventional impression method, other 10 crowns remained in group will be preferred digital impression method. 20 molar crowns are made for each group. Thus, 60 molar full crowns are produced with the CAD-CAM system. Experimental groups were; GP Highly resistant polymer produced by the conventional impression method GZ Zirconium produced by the conventional impression method GC Hybrid ceramic produced by the conventional impression method DP Highly resistant polymer produced by the digital impression method DZ Zirconium produced by the digital impression method DC Hybrid ceramic produced by the digital impression method In order to ensure standardization, cement space has been identified as 30μm during the production stage. Silicone replica technique used for calculation of internal gaps of the all crowns. Replicas that obtained were digitized under a 40X light microscopy. Then hammer tip diameter of 5mm to be parallel to the long axis of the restoration in a universal testing machine and 0.5 mm/min until the resulting deformation was made to loading. Values were recorded in Newton and statistical analysis was used. Results and conclusion: As a result of impressions, mean values for internal gap were GP: 92.03 μm, GZ: 102.22 μm, GC: 93.62 μm , DP: 93.67 μm , DZ: 98.65 μm, DC: 81.74 μm. mean values for load bearing capacity were GP: 2193.73 N, GZ: 3203.45 N, GC: 2261.25 N , DP: 2214.23 N , DZ: 3292.82 N, DC: 2325.02 N . The internal fit from crowns produced by conventional and digital impressions method showed no significantly statistically difference. Load bearing capacity of zirconium groups showed statistically highest values then the other groups. The findings of this study need to be confirmed with in vitro and in vivo studies.