Impact of scan body splinting on the accuracy of complete-arch digital implant impressions.

Background/purpose: The accuracy of intraoral scanners in capturing complete-arch implant impressions remains a subject of ongoing investigation. This study aimed to evaluate the influence of different scanning strategies and the effect of splinting scan bodies on the accuracy of complete digital scans of the mandible. Materials and methods: A master model of an edentulous mandible with four dental implants was used. The implants were positioned bilaterally in the regions of the mandibular lateral incisors and second premolars. A laboratory scanner was utilized to digitize the reference model. Three experimental groups were used to evaluate the effects of different scanning strategies and auxiliary reference methods on scan accuracy: Group A (single-stage scan), Group B (two-stage scan without additional references), and Group C (two-stage scan with additional reference points). Results: A total of 45 digital scans were analyzed. To evaluate scan accuracy, linear deviations were measured at the four implant sites and compared against the digital reference model. Group A consistently demonstrated the highest accuracy, with the lowest overall mean linear deviation of 39.57 ± 8.69 μm across all implant positions. Group B recorded a marginally higher mean deviation of 42.80 ± 24.24 μm. Group C showed the greatest linear deviation (70.60 ± 17.69 μm), and the differences were statistically significant when compared with both Groups A and B (P < 0.05). Conclusion: The findings of this study indicate that single-stage scanning yields superior accuracy, whereas the incorporation of poorly designed or improperly positioned reference markers may inadvertently compromise scan precision.