Dimensional accuracy of 3D-printed implant models is essential for precise implant-supported restorations. The objective of this study was to evaluate the influence of printing orientation and model base design on the accuracy of implant position transfer. A standardized maxillary model with four implants was scanned using an intraoral scanner. Solid and hollow models were designed and printed using digital light processing (DLP) technology at orientations of 0°, 45°, and 90° (n = 10 per group). All models were digitized with a high-precision industrial scanner, and implant position deviations were determined by comparing corresponding reference points with the master model. Data were analyzed using two-way analysis of variance and post hoc tests (α = 0.05). Printing orientation significantly affected accuracy (p < 0.001). Models printed at 45° showed the highest deviations, whereas those printed at 0° and 90° exhibited comparable and superior accuracy. Model design (solid vs. hollow) had no significant influence at 0° and 90°, but hollow models were more accurate at 45° (p < 0.001). Mean deviations ranged from 131 μm to 382 μm. Printing at 0° or 90° is recommended, while 45° orientations should be avoided. Model design showed minimal effect on accuracy.

Utilizing dental CAD/CAM systems, chairside treatments allow patients to be treated within one day without the need for an intermediate dental laboratory. With this procedure, it is also essential to ensure a sufficient marginal fit of the restoration. Therefore, this study investigates the influence of the milling strategy on the marginal fit of CAD/CAM-fabricated lithium disilicate crowns. For this purpose, 10 crowns were fabricated from each of the materials IPS e.max CAD and Celtra Duo using the fastest and finest available milling strategy. The accuracy of the marginal fit of the 40 crowns was examined using the industrial scanner ATOS Triple Scan and the associated software using the triple scan protocol. In a comparison of the milling processes, the restorations fabricated using the finest process always exhibited a better marginal fit, with mean deviations of 87 μm and 146 μm for IPS e.max CAD and 111 μm and 118 μm for Celtra Duo. The difference was only statistically significant for the crowns made of IPS e.max CAD (p = 0.008). All mean deviations determined were below the clinically acceptable marginal gap values (150 μm). Both materials can be used for chairside-fabricated crowns; however, choosing the faster milling strategy leads to higher marginal discrepancies.

The objective was to evaluate the trueness of interocclusal registration obtained with three intraoral scanning systems versus a conventional impression and bite registration in fully dentate patients. Twenty adults with complete dentitions and Angle Class I occlusion were enrolled. Complete-arch scans were obtained with Primescan, iTero Element, and TRIOS 4, followed by bilateral virtual interocclusal registration. Conventional impressions and polyvinyl siloxane records were used to fabricate stone casts, digitized with a laboratory scanner with the record and after manual articulation in maximum intercuspation. Industrial scanner datasets served as participant-specific references. Three-dimensional deviations were analyzed by repeated-measures ANOVA and Holm-adjusted paired t-tests (α = 0.05). The conventional workflow with an interocclusal record showed the greatest deviation (797 ± 308 μm; p < 0.001). Manual articulation (331 ± 167 μm) did not differ significantly from Primescan (262 ± 120 μm), iTero Element (256 ± 101 μm), or TRIOS 4 (325 ± 168 μm) (p ≥ 0.223); no differences were found among scanners under the conditions of this study (p ≥ 0.468). Virtual interocclusal registration showed greater trueness than the conventional workflow with a physical record, whereas manual articulation performed comparably to digital workflows. These conclusions apply only to fully dentate patients with stable occlusal support and maximum intercuspation.

Accurate transfer of implant position to the virtual model is essential for digital implant prosthodontic workflows. Although scan body geometry and CAD software may affect this process, evidence regarding their combined effect remains limited. This in vitro study evaluated the effects of two scan body systems and three CAD software programs on implant-position transfer accuracy and assessed their interaction. An edentulous maxillary titanium model with three implants was digitized ten times for each of two scan body systems. Each data set was processed with exocad, 3shape, and DWOS. Implant-position transfer was assessed as the three-dimensional Euclidean deviation of standardized scan body reference points. Data were analyzed using a two-way mixed repeated-measures ANOVA and Holm-adjusted pairwise comparisons (α = 0.05). Scan body system, CAD software, and their interaction significantly affected transfer accuracy (p < 0.001). Medentika showed lower mean deviations than NT-Trading with all software programs, although the difference was not significant with 3shape. For NT-Trading, 3shape produced significantly lower deviations than exocad and DWOS, whereas for Medentika, exocad produced significantly lower deviations than DWOS, with no significant differences between 3shape and either exocad or DWOS. Implant-position transfer accuracy depended on the specific combination of scan body system and CAD software. These findings suggest that scan body system and CAD software should be considered jointly when evaluating implant-position transfer accuracy.