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Background Few prospective investigations have compared direct and indirect techniques through comprehensive and detailed clinical evaluations, considering the impact of all factors. Objectives This study aimed to compare and evaluate direct and indirect bonding methods at a single institution and to clarify the selection criteria for the bonding method. Materials and methods This single-centre, quasi-randomized controlled clinical trial included 153 patients who required fixed orthodontic treatment. They were randomly divided into indirect and direct binding groups by the project lead (K.K.), who was blinded to all clinical data, and performed the allocation using medical record numbers. The chair time for bracket bonding, discomfort during bracket bonding, oral hygiene after bonding, number of bracket failures, number of intentional bracket reattachments, post-treatment occlusal index, and total treatment time were assessed. Outcomes were compared using a two-sample t -test or Mann–Whitney U test (P  < .05). Results Fifty-eight patients were included in the indirect bonding group (20 male, 38 female; mean age: 20.63 ± 5.69 years) and 66 (14 male, 52 female; mean age: 23.17 ± 8.83 years) in the direct bonding group. Compared to the direct bonding group, the indirect bonding group had shorter chair time (P  < .001), a shorter total treatment period (P  < .01), and a better final occlusal relationship (P  < .001). The number of bracket detachments was higher (P  < .001) in the indirect bonding group, but the number of intentional reattachments was lower (P  < .001). Conclusion Indirect bonding may improve the efficiency of orthodontic treatment. Harms No harm was observed during the study. Trial registration number This trial was approved by the Ethics Review Committee of Okayama University (approval number: d10001), UMIN registration number 000022182. [ABSTRACT FROM AUTHOR]

Objective: The objective of the study was to elucidate the association between cranial base (Bjork‐Jarabak analysis), midsagittal cross‐sectional area of the airway in the pharyngeal region (MCSA‐PR) data and pharyngeal‐airway volume (PAV) and develop a model that could help clinicians predict PAV using two‐dimensional (2D) data (Bjork polygon and MCSA‐PR). Materials and Methods: Pre‐treatment lateral cephalometric radiographs and magnetic resonance imaging (MRI) scans of 82 women were categorized into three anteroposterior skeletal groups based on ANB angle: Class I (n = 29), 1.5° ≤ ANB≤5.1°; Class II (n = 26), ANB >5.1°; Class III (n = 27), ANB <1.5°. The Bjork polygon, MCSA‐PR data from cephalograms and PAV data from MRI scans were examined. Intergroup comparisons were performed using the Kruskal–Wallis test and one‐way analysis of variance (ANOVA), with pairwise comparisons conducted using the Bonferroni‐corrected Mann–Whitney U‐test for the Kruskal–Wallis test and Bonferroni‐corrected multiple comparison test for one‐way ANOVA. Forward multiple linear regression was used to create model equations for predicting PAV. Results: MCSA‐PR and anterior (N‐S) and posterior (S‐Ar) cranial‐base lengths were positively correlated with the PAV. We developed four models; three operated at the group level, and one encompassed the entire sample. Notably, all models could effectively explain the variance in the PAV data. The model for the Class I group was the strongest (adjusted R2 = 0.77). Conclusion: Our findings indicate the remarkable potential of the MCSA‐PR, N‐S and Bjork sum angles (BSA) as predictors of the PAV and the relevance of 2D cephalometric and cranial‐base parameters in predicting the three‐dimensional (3D) pharyngeal‐airway size. [ABSTRACT FROM AUTHOR]

Background: Masticatory activity affects the morphology of the maxillo-mandibular complex, however, its influence on the cranial base remains to be elucidated. The recent integration of quantitative morphometric analysis with 3D imaging enabled a comprehensive and high-resolution morphological characterization of the craniofacial complex. We aimed to investigate the influence of masticatory activity on the morphology of the growing cranial base by three-dimensional (3D) geometric morphometric approach using micro-CT., Methods: The micro-CT data was reanalyzed to illustrate the 3D shape of the cranial base, and wireframe models were generated by connecting landmarks on the images. In the original study, mice were fed a soft diet (SD) of powdered pellets or a conventional hard diet (HD) for 6 weeks from 3 to 9 weeks of age, immediately after weaning. A principal component (PC) analysis analyzed shape variations and assessed their significance, while canonical variate (CV) analysis facilitated the comparison and differentiation of groups based on shape, unveiling meaningful shape distinctions., Results: Three PCs were extracted that significantly separated the SD and HD groups among those explaining variations in shape. These PCs were related to the length of the sphenoid bone, the width of the anterior part of the sphenoid bone, and the length of the cranial base. Furthermore, one CV effectively distinguished SD from HD, and CV analysis showed that the sphenoid was shortened in the length and narrowed at the border of the temporal bone in SD mice., Conclusions: Masticatory loading affects the skeletal development of the cranial base. The morphology of the sphenoid bone was affected in both the sagittal and transverse axes., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)