Purpose: To assess and compare the accuracies of intraoral scanners (IOS) and stereophotogrammetry (SPG) devices for complete-arch digital implant impressions.Methods: A 4-analog model was digitized using a desk scanner to obtain a reference file. Thirty test scans were conducted using the investigated IOS device, while an additional 30 scans were performed using the SPG device. Using the best-fit algorithm, the resulting 60 test files were aligned with the reference file. Linear (ΔX, ΔY, and ΔZ-axis) and angular deviations (ΔANGLE) were evaluated. Three-dimensional (3D) deviation was calculated based on the Euclidean distance (ΔEUC). The analysis was stratified according to the scanning device and implant position. Fisher’s F and t-tests were used to compare the variances and expected values of the two scanning systems.Results: IOS expressed a higher 3D (ΔEUC) mean deviation than SPG (52.8 µm vs. 33.4 µm, P < 0.0001), with extreme measurements up to 181.9 µm. A significantly higher standard deviation (SD) was associated with IOS (37.1 µm vs. 17.7 µm, P < 0.0001). Considering angular deviations, the IOS showed slightly higher angular mean deviations (ΔANGLE) than the SPG (0.28° vs. 0.24°, P = 0.0022), with extreme measurements of up to 0.73°. The SPG SD values were significantly lower than the IOS SD values (0.14° vs. 0.04°, P < 0.0001).Conclusions: The SPG showed significantly higher 3D and angular accuracies for complete arch implant impressions, with consistent repeatability. IOS scanning revealed significantly higher extreme deviations exceeding the acceptable threshold value. Despite study limitations, SPG appears more feasible than IOS for complete-arch digital implant impressions.

The aim of this study was to evaluate the influence of implant scanbody (ISB) wear on the accuracy of digital impression for complete-arch. A polymethylmethacrylate (PMMA) edentulous mandibular model with four internal hexagonal interlocking conical connections was scanned with an extraoral optical scanner to achieve a reference file. Four cylindrical polyetheretherketone (PEEK) ISBs were scanned 30 times with IOS, and the test files were aligned to the reference file with a best-fit algorithm. For each analog linear (ΔX, ΔY and ΔZ-axis) and angular deviations (ΔANGLE) were assessed. Euclidean distance (ΔEUC) was calculated from the linear deviation, reporting a mean of 82 µm (SD 61) ranging from 8 to 347 µm. ΔANGLE error mean was 0.33° (SD 0.20), ranging from 0.02 to 0.92°. From a multivariate analysis, when ΔEUC was considered as a response variable, a significant influence of ISB wear by scan number in interaction to position for implant 3.6 was identified (p < 0.0001); when ΔANGLE was considered as a response variable, a significant effect of position 3.6 was recorded ((p < 0.0001). The obtained results showed that the ISB wear negatively influenced the accuracy of IOS, suggesting that ISB base wear could be detrimental for the seating of ISBs on angulated implants.

This paper is the first article in a new series on digital dental photography. Part 1 defines the aims and objectives of dental photography for examination, diagnosis and treatment planning, legal and forensic documentation, publishing, education, marketing and communication with patients, dental team members, colleagues and dental laboratory.