Effects of implant angulation and impression coping type on the dimensional accuracy of impressions

Purpose: To analyze the accuracy of impressions in relation to implant angulation and type of impression coping. Materials and Methods: Three metal master models with 2 implants of 3 different angulations (parallel, mesiodistal, and buccolingual) were fabricated. Nine groups of experimental models were fabricated to duplicate the 3 master models using 3 types of impression copings: transfer, pick-up, and hybrid. The distance between the analogs for each model was measured using a video measuring system. The influence of angulation and type of impression coping was analyzed by a two-way ANOVA (P <0.05). Results: There were significant differences in error rates in relation to implant angulation and type of impression coping (P <0.05). Impressions of buccolingually divergent implants with transfer copings showed statistically higher error rates than other groups (P <0.05). Conclusions: Buccolingual divergence can be a variable that influences the impression accuracy of transfer copings compared with pick-up and hybrid copings. Hybrid copings demonstrate reasonable reproducibility similar to that of pick-up copings.