Objective: This study investigated how the number of images collected for digital measurements in dentistry affects accuracy compared with traditional methods. Methods: A Frasaco maxillary model was scanned using a SHINING 3D AutoScan-DS-MIX dental 3D scanner to create an STL file. The maxilla was molded 10 times using polyvinyl siloxane (Zhermack Elite HD+) to produce plaster models, which were scanned with the same reference scanner to generate 10 STL files. The Frasaco model was scanned 10 times, capturing images in intervals of 800–1000, 1000–1200, and 1200–1500 using a 3Shape TRIOS 3 intraoral scanner, creating additional STL files. These were analyzed with reverse engineering software. Results: The most accurate measurements were obtained using 1200–1500 images. Conventional impression techniques performed significantly worse. There was a significant difference between the groups Digital 1200–1500 and Plaster (p < 0.001) and between Digital 800–1000 and Plaster (p = 0.007). No significant difference was found when the digital groups were compared among themselves. There was also no significant difference between the Plaster and Digital 1000–1200 groups. To compare precision values that were normally distributed across three or more methods, a one-way ANOVA was used. Trueness values that were not normally distributed with three or more methods were compared employing the Kruskal–Wallis test. Conclusions: Different image counts affect digital measurement accuracy. The most accurate measurements were obtained when collecting 1200–1500 images. Conventional impression techniques were shown to perform significantly worse than digital impression.

Ateşalp İleri S, et al. J Adv Prosthodont. 2025 Aug;17(4):197-209. https://doi.org/10.4047/jap.2025.17.4.197

The durability of bonding between the denture base and reline materials plays a critical role in the long-term success of removable prostheses. This study aimed to compare the bond strength of denture base resins fabricated by heat-polymerization, CAD-CAM milling, and 3D printing techniques after thermocycling and different surface treatments. A total of 216 specimens (10 × 10 × 20 mm) were prepared from three base materials and subjected to surface treatment via no treatment (control), alumina air abrasion, or an Er/YAG laser. Two reline materials (hard and soft) were applied according to manufacturers’ instructions. All samples underwent 5000 thermal cycles and were tested using a tensile bond strength test. SEM analysis was performed to evaluate failure modes. The highest bond strength was observed in the milled resin group combined with alumina air abrasion and the hard reline material, reaching up to 12.41 MPa. Statistically significant effects were found for the material type, surface treatment, and reline material (p < 0.001). The results indicate that material properties, surface preparation, and reline type critically influence bond performance. Milled PMMA bases and hard relining agents, particularly when combined with air abrasion, offer superior bonding outcomes.

The influence of rescanning protocols, the locking function, and scan modes on the trueness of intraoral scanners (IOS) remains unclear. This study aimed to evaluate how standard and high-definition (HD) scan modes, in combination with the locking function, affect trueness within a cut-and-rescan protocol. A maxillary model simulating a three-unit fixed dental prosthesis was scanned using the 3Shape TRIOS 3 IOS under five conditions: full scan (STD), rescan with standard mode (STD-NL), rescan with HD mode (HD-NL), rescan with standard mode and locking (STD-L), and rescan with HD mode and locking (HD-L). Sixty scans were obtained and compared with a reference model. Trueness was evaluated using root mean square (RMS) values. Data were analyzed using ANOVA and Tukey HSD tests. The HD-L group (46.3 ± 1.69) demonstrated significantly improved trueness compared with the STD (51.7 ± 4.20) and STD-NL (51.2 ± 3.93) groups (p < 0.05), most notably in the anterior segment. In conclusion, the combined use of HD mode and the locking function significantly improves rescanning trueness. Therefore, the HD-L protocol is recommended for achieving optimal trueness, especially in anatomically complex regions.