RESUMEN
OBJECTIVES: The objective of this study was to systematically compare the transfer accuracy of conventional and digital implant impressions in patients using a new reference key-based method. MATERIAL AND METHODS: Thirty-nine cases were included in the study (upper jaw 22 edentulous, 8 partially edentulous, average distance between implants 30.15 ± 11.18 mm; lower jaw 6 cases edentulous, 3 cases partially edentulous, average distance between implants 33.19 ± 14.85 mm). Individual reference keys were manufactured and reversibly fixed on implants. A conventional (CVI) and a digital (DI) implant impression was made. The implant positions (center points) of conventional and digital models were measured (coordinate-measuring machine/three-dimensional analysis software) and superimposed with the positions of the reference keys to compare the deviations of the conventional and digital models. For statistical analysis, ANOVA with MIXED procedure was applied (p < .05). RESULTS: Mean deviation ranged from 0.040±0.029 mm (DI/upper jaw) to 0.079 ± 0.050 mm (DI/lower jaw). There were significant differences between the CVI and DI impressions in the lower jaw (p < .05). No significant differences in transfer accuracy were found between partially and completely edentulous patients for the impression methods. CONCLUSIONS: Within the limits of the present study, it can be concluded that full-arch digital implant impressions of the upper jaw in partially or completely edentulous patients showed comparable results to conventional implant impressions. However, with regard to the implant position transfer accuracy, there are still limitations for digital impression in the lower jaw.