PURPOSE: . This study aimed to evaluate the influence of implant placement depth on the accuracy of five full-arch digital impression techniques: 2 photogrammetry systems (Imetric [PGI] and Oxo Core [PGO]) and 3 intraoral scanning (IOS) routes (standard IOS, IOS with crown-shaped [IOS+C], and IOS with laterally-extending [IOS+LE] scanning aids). MATERIALS AND METHODS: . Three master models including 5 implants with 2-, 4-, and 6-mm subgingival implant depths were fabricated. Implant positions were recorded using each of the 5 techniques (n = 15). The resultant scans were compared to reference data generated by a laboratory scanner. Deviations were 3-dimensionally assessed using root mean square values to quantify both trueness and precision. Angular deviations (AD) were calculated to provide a detailed assessment of spatial inconsistencies. Data were statistically analyzed (α = 0.05). RESULTS: . Implant depth and impression technique, as well as their interaction, significantly affected trueness, precision, and angular deviation values (P < .001). PGI demonstrated the highest accuracy, with the lowest mean AD values across all implant positions (0.24 – 0.32°) and the highest trueness (26.57 μm) and precision (7.72 μm). IOS exhibited the largest distortions, with AD values up to 1.77° and trueness values of 74.84 μm. Precision of both photogrammetry systems were not influenced by implant depth. CONCLUSION . Implant depth significantly impacts the accuracy metrics of full-arch digital impressions. The Imetric system outperformed the other groups. Since laterally-extending scanning aids effectively improved accuracy, it may be recommended as a clinically viable alternative to standard IOS.

PURPOSE: The study aimed to determine the influence of implant angulation on the trueness of multi-unit implant impressions taken through different techniques and strategies. MATERIALS AND METHODS: As reference models, three partially edentulous mandibular models (Model 1: No angulation; Model 2: No angulation for #33, 15-degree distal angulation for #35 and #37; Model 3: No angulation for #33, 25-degree distal angulation for #35 and #37) were created by modifying the angulations of implant analogues. Using a lab scanner, these reference models were scanned. The obtained data were preserved and utilized as virtual references. Three intraoral scanning (IOS) strategies: IOS-Omnicam, ISO-Quadrant, and IOS-Consecutive, as well as two traaditional techniques: splinted open tray (OT) and closed tray (CT), were used to create impressions from each reference model. The best-fit alignment approach was used to sequentially superimpose the reference and test scan data. Computations and statistical analysis of angular (AD), linear (LD), and 3D deviations (RMS) were performed. RESULTS: Model type, impression technique, as well as interaction factor, all demonstrated a significant influence on AD and LD values for all implant locations (P < .05). The Model 1 and SOT techniques displayed the lowest mean AD and LD values across all implant locations. When considering interaction factors, CT-Model 3 and SOT-Model 1 exhibited the highest and lowest mean AD and LD values, respectively. Model type, impression technique, and interaction factor all revealed significant effects on RMS values (P ≤ .001). CT-Model 3 and SOT-Model 1 presented the highest and lowest mean RMS values, respectively. CONCLUSION Splinted-OT and IOS-Omnicam are recommended for multi-unit implant impressions to enhance trueness, potentially benefiting subsequent manufacturing stages.