Effect of implant location and operator on the accuracy of implant scans using a combined healing abutment-scan body system

Objectives: To investigate the effect of implant location and operator on the accuracy of implant scans conducted with a combined healing abutment-scan body (CHA-SB) system. Material and Methods: A CHA-SB system was fixed on implants at left central incisor, first premolar, and first molar sites in a dentate maxillary model. An industrial optical scanner (ATOS Core 80) was utilized to scan and generate a reference model (RM). The model was scanned by three operators (n = 8) using an intraoral scanner (TRIOS 3). A software (GOM Inspect) was used to superimpose IOS test scans over RM and calculations (distance and angular deviations) were carried out to evaluate the accuracy of the scans. Data were compared with a 2-way ANOVA and Tukey HSD tests were employed to resolve significant interactions for trueness and precision (alpha = .05). Results: Implant location affected the trueness (P < .001) and the precision (P < .020) (distance and angular deviations). The scans of the implant at the central incisor site had the highest trueness (distance and angular deviations) (P < .016). The scans of the implant at molar site had the lowest precision (distance deviation data) (P < .012). The scans of the implant at premolar site had lower precision (angular deviation data) than the scans of the implant at central incisor site (P = .016). Operators' effect on the accuracy of scans was not significant (P >= .051). Conclusion: Implant location affected the scan accuracy of the combined healing abutment-scan body system. The scans of the implant at central incisor site had high trueness. The posterior the implant location, the lower was the precision of the scans. The accuracy of scans of different operators was similar. Clinical Significance: Higher deviations found in scans of posterior maxilla compared with those in the anterior region may require increased chairside adjustments when crowns are to be fabricated using the scans of the tested healing abutment-scan body system. However, clinical studies are necessary to corroborate the findings.