American Journal of Orthodontics and Dentofacial Orthopedics最新文献

Introduction: This study aimed to compare the effect of artificial saliva (AS) aging on the trueness and precision of direct-printed aligners vs thermoformed aligners.

Methods: Four types of aligners were manufactured from the same reference standard tessellation language (STL) file: using Duran Plus (n = 12) for thermoformed ones, and TC-85DAC (n = 12), Clear A (n = 12), or OD Clear TF (OC, n = 12) resins for direct-printed ones. A printed model was used for thermoformed aligners, whereas digital design models were generated for direct-printed aligners from the reference STL file. The samples were sprayed and scanned (Trios 3; 3 Shape, Copenhagen, Denmark) before and after aging in AS at 37°C for 24 hours, 7 days, and 14 days. STL files were imported into CloudCompare software (CloudCompare, 2.13.2 version, Paris, France) and superimposed on the design or digital model (trueness) or to each other within each group (precision) using a 7 reference-point algorithm. Two-way analysis of variance was performed to evaluate the influence of saliva aging and material type.

Results: A significant effect of the material type was observed with a lower trueness and precision for Duran Plus aligners compared with the 3 groups of direct-printed aligners. A significant effect of AS aging, with a decrease of trueness and precision, was also noted for both thermoformed and printed aligners.

Conclusions: This in vitro study demonstrated that direct-printed aligners provided higher trueness and precision than thermoformed ones. Exposure to AS decreased the trueness and precision for both types. However, further studies are needed to validate the behaviors of direct-printed aligners clinically.

Introduction: Accurate assessment of skeletal maturity is essential for orthodontic treatment planning and growth modulation. This study aimed to develop a comprehensive machine learning (ML) model to predict skeletal maturation stages using cervical vertebral morphology, dental maturation stage (DMS), gender, and age.

Methods: A total of 860 patients with lateral cephalograms, panoramic, and hand-wrist radiographs were included. A baseline model using 6 cervical morphologic parameters was compared with enhanced models incorporating DMS, gender, and age. Six ML algorithms were evaluated, with CatBoost showing the highest performance. Feature importance was analyzed using 2 methods, and the final model was assessed using a confusion matrix, receiver operating characteristic curves, and calibration curves.

Results: Incorporating DMS, gender, and age significantly improved predictive performance. The CatBoost model achieved an area under the receiver operating characteristic curve of 0.924, an area under the precision-recall curve of 0.806, and an F1-score of 0.752. Feature importance analysis confirmed the strong predictive contribution of DMS, especially the mandibular second molar. The final model demonstrated high accuracy, strong discrimination, and good calibration across all skeletal maturity stages.

Conclusions: This study presents a novel and clinically practical ML model for skeletal maturity prediction, integrating routinely acquired orthodontic records. The results demonstrate that combining DMS with cervical morphology, age, and gender enhances prediction accuracy, offering a reliable alternative to traditional hand-wrist assessments.

Introduction: This study aimed to evaluate the associations between miniscrew length and long-term skeletal, dentoalveolar, and nasal airflow changes after miniscrew-assisted rapid palatal expansion (MARPE).

Methods: This retrospective study included 32 adult patients with successful midpalatal suture separation after MARPE with either long (n = 15) or short (n = 17) miniscrews. Cone-beam computed tomography scans were obtained at pretreatment (T0), postexpansion (T1), and follow-up (T2). Skeletal and dentoalveolar changes were assessed using 3-dimensional landmark analysis. Nasal airflow was evaluated using computational fluid dynamics (pressure-flow ratio and maximum airflow velocity). Between-group and within-group comparisons and correlation analyses were performed.

Results: A significant time × group interaction was observed for inter-processus zygomaticus width (P = 0.002), with the long miniscrew group showing greater skeletal expansion than the short miniscrew group (mean difference at T2-T0: 1.15 mm). No significant group differences in nasal airflow outcomes were observed at any time point. Significant long-term improvements (T2-T0) in pressure-flow ratio and maximum velocity were observed in both groups, exceeding the changes seen immediately after expansion (T1-T0). Correlation analysis revealed that the baseline nasal airflow parameters were stronger predictors of functional improvement than the magnitude of maxillary expansion.

Conclusions: Among successful cases, MARPE with long miniscrews was associated with greater long-term skeletal expansion at the maxillary basal bone level than with short miniscrews. Although nasal airflow improved after MARPE, the magnitude of improvement did not differ by miniscrew length and appeared more related to baseline nasal functional status.