Influence of Implant Angulation and Implant Site on the Accuracy of Intraoral Digital Impressions: An in Vitro Study.

Background The objective of this in vitro study was to evaluate the effects of implant angulation and site on the accuracy of intraoral digital impressions by assessing linear, angular, and rotational deviations. Methods Two 3D-printed maxillary models with four implants (14, 16, 23, and 26) were created and categorized into parallel (P) and non-parallel (NP) implant groups. Both bounded edentulous areas with adjacent teeth (AT) and free-end edentulous areas (FR) were included. Reference scans were obtained using a laboratory scanner, while 10 digital impressions per model were captured with an intraoral scanner. Linear, angular, and rotational deviations were analyzed using Geomagic Control X software. Results Angular deviation showed a statistically significant difference across combinations of implant angulation and site (P=0.044). The NP–AT group showed the lowest angular deviation (0.29 ± 0.18°), whereas the P–AT group exhibited the highest values (0.88 ± 0.82°). A significant difference was found only between NP–AT and P–AT groups (P = 0.041). However, no statistically significant differences in linear deviation were found among the study groups (P = 0.125). Although the lowest mean value was observed in the NP–AT group (26.69 ± 11.12 μm) and the highest in the P–AT group (70.55 ± 54.75 μm). For rotational deviation, significant differences were observed among implant sites within the parallel group (P < 0.001), and a significant difference between parallel and non-parallel implants was identified only at implant site 14 (P < 0.05). Conclusion Within the limitations of this in vitro study, implant angulation and implant site influenced angular and rotational deviations in a site-dependent manner, while linear deviation was not significantly affected.