Trueness of digital implant impressions based on implant angulation and scan body materials

Effects of implant angulation on digital implant impression accuracy remain controversial. Therefore, this in vitro study aimed to compare the digital implant impression trueness among models with different implant angulations and scan body materials. Six partially edentulous mandibular models with dental implants on the right second premolar and second molar areas were categorized according to the implant angulation of the distal implant (parallel, or 15° mesially or lingually tilted compared to the mesial implant) and scan body materials (polyetheretherketone or titanium). After scanning each model with intraoral scanners, the root mean square and within-tolerance values were calculated with respect to the reference, and nonparametric statistical tests were performed (α =.05). Scan data from models with the mesially tilted distal implant showed better trueness than the corresponding parallel and lingually tilted groups in terms of root mean square values (p <.017). The root mean square value in the titanium scan body group was lower than that in the polyetheretherketone scan body group (p <.001). However, the percentage within a tolerance of ±.1 mm was higher in the polyetheretherketone scan body group than in the titanium scan body group (p =.001). Intraoral scan data of models where the terminal implant was mesially tilted showed better trueness.