The Vectra M3 3-dimensional digital stereophotogrammetry system: A reliable technique for detecting chin asymmetry

The influence of structured light scanning probe configuration on the 3D scanning accuracy of the maxillofacial region in a smiling state: An in vitro study

Currently, single-unit, dual-unit, and triple-unit structured light 3D scanning technologies have become the predominant facial scanning methods. However, the impact of different unit strategies on facial scanning accuracy remains unclear. A standardized 3D facial model in a smiling state was established. Key point reference coordinates and 3D data were obtained using a coordinate measurement instrument and an industrial-grade laser 3D scanner. Three structured light scanning techniques (single-, dual-, triple-unit) were utilized to capture the 3D information of the model. Linear distance deviations and 3D surface deviations (trueness and precision) of the three scanning strategies were compared. The triple-unit scanning strategy exhibited the lowest deviation among 20 trueness indicators and 22 precision indicators for linear distance measurements (P < 0.05). Furthermore, the accuracy of the triple-unit strategy (trueness: 0.1607 ± 0.0201 mm, precision: 0.0161 ± 0.0112 mm) for overall facial scanning was significantly lower than that of the single-unit and dual-unit strategies, particularly in critical regions for oral and maxillofacial aesthetic analysis, such as the orbital, nasal, and perioral regions. The triple-unit structured light scanning strategy significantly enhances the accuracy of facial 3D scanning, particularly when acquiring 3D facial information from the midline and perioral regions. This in vitro study demonstrates that the triple-unit structured light 3D scanning strategy effectively improves the accuracy of facial scanning, especially in the oral-maxillofacial aesthetic regions. This approach provides a foundation and support for both preoperative planning and postoperative evaluation of aesthetic restoration.

Lip Lifting Efficacy of Hyaluronic Acid Filler Injections: A Quantitative Assessment Using 3-Dimensional Photography

The study aimed to compare the volume enhancement and the lifting capacity of two different hyaluronic acid gels for lip injection. Thirty-six Korean female patients were randomized into two groups according to the cross-linking degree of the hyaluronic acid filler injected. Using a fixed injection protocol, patients were injected with 1 mL of hyaluronic acid filler in the lips and followed up at four and 12 weeks after injection. Lip volume, lip projection, and columella–labial angle were measured using a 3-dimensional imaging system at each time point. Follow-up values were compared with baseline. Compared with pre-treatment values, there was a statistically significant increase in mean lip volume and lip projection at four and 12 weeks after injection, with no significant differences between the two groups. Lips injected with hyaluronic acid filler of intermediate cross-link density resulted in more acute angles than lips injected with lightly cross-linked hyaluronic acid. The difference was statistically significant at each follow-up time point. No serious complications were observed throughout the study period. Our results imply that in patients who want a prominent upper lip lift, lip injections using hyaluronic acid fillers with intermediate cross-linking density can be a good option due to their lift capacity. The degree of cross-linking may not be a significant determinant of simple lip volume augmentation when other variables are constant.