Effect of impression coping splintingon impression accuracy

Alem K. A. (2018). Effect of impression coping splinting on impression accuracy. Ye-ditepe University, Institute of Health Science, Department of prosthodontics, MSc thesis, İstanbul. This study aimed to evaluate the effect of splinting of impression copingand different impression materials on the accuracy of multi implant impression accuraccy. A master model with four internal connection implants was prepared. Two implants placed in the canine region with 0° and 2 implants placed in thesecond molar region with 0°. Twenty five impression were performed on the master model using open tray technique (direct technique), and two different material (polyvinyl siloxane-PVS and polyether-PE). Models were divided into five groups (n=5). Two of the groups were non splinted andPVS and PE impressiom material were used in these groups. Three of the groups were splinted and PVS impressiom material were used in these groups.Models where scanned with 3D shape scanner. STL file where anaylzed and measurements where performed using 3D design program (Rhinoceros 0.5), to measure the discrepancies between the master model and the produced model. analysis of variance (ANOVA) according to Kruskal–Wallis was used. The Mann–Whitney U-test was applied for paired group comparisons (P=0.05). The results revealed that a significant difference between the splinted non-sectioned PVS and splinted sectioned PVS groups related to X axis discrepancies (P=0.030), with higher discrepancy related to splinted non-sectioned PVS technique (x̅=46±30) μm. Also there was a signifi-cant difference between the splinted non-sectioned PVS and non-splinted PVS groups re-lated to X axis discrepancies (P=0.014), with higher discrepancy related to splinted non-sectioned technique with polyvinyl siloxane (x̅=46±30) μm. The best results was in 3D was with splinted sectioned PVS group with polyvinyl siloxane (x̅=27±18) μm. The highest discrepancy among all measures recorded with splinted non-sectioned group in Z axes with (x̅=70±70) μm. We concluded that splinting of impression copingfor a parallely placed implants doesn't affected the impression accuracy, and a better result could be reached with Splinted Sectioned Auto-polymerizing Acrylic Resin Splint Group. Key words: Impression coping splint, impression accuracy, polyvinyl siloxane, polyether, impression technique.