Progress in Orthodontics最新文献

{"title":"Effectiveness of clear aligners for maxillary expansion in growing patients: a systematic review and meta-analysis.","authors":"Lucía Fonseca Planells, Carlos Bellot-Arcís, José María Montiel-Company, Vanessa Paredes-Gallardo, Natalia Zamora-Martínez","doi":"10.1186/s40510-026-00620-7","DOIUrl":"10.1186/s40510-026-00620-7","url":null,"abstract":"<p><strong>Background: </strong>Maxillary transverse deficiency is one of the most common issues encountered in orthodontic practice. Ideally, intervention should take place before the midpalatal suture has completely ossified, in order to take advantage of the patient's active growth. In recent years, treatment with clear aligners has emerged as an alternative to fixed appliances, offering a new way to achieve expansion in paediatric patients.</p><p><strong>Objectives: </strong>This systematic review aimed to analyse the predictability of movements induced by clear aligners in maxillary expansion, and to compare the effectiveness of the Invisalign First® system with conventional expansion appliances.</p><p><strong>Search methods: </strong>A systematic review was conducted by searching PubMed-Medline, Scopus, Embase, Web of Science and Cochrane databases.</p><p><strong>Eligibility criteria: </strong>Retrospective and prospective studies, as well as one randomised clinical trial, published between January 2021 and October 2025, which answered the PICO question, were included.</p><p><strong>Data extraction and synthesis: </strong>The quality of the included studies and the risk of bias were assessed using ROBINS-I (Risk of Bias in Non-randomised Studies) and ROB2 (Risk of Bias 2). For the quantitative analysis, heterogeneity among the included studies was quantified using the I² statistic, and the results were presented in a forest plot. The Trim and Fill method was used to assess publication bias.</p><p><strong>Results: </strong>Following a review of 267 publications, 15 studies were ultimately included in the review, and seven in the meta-analysis. Statistically significant differences were reported for the following variables: intermolar distance (6-6) ( - 1.77 mm; -2.57; - 0.97 95%CI; - 4.35 Z-test, p < 0.0001); total palatal volume ( - 460.63 mm³; - 738.32; - 182.94 95%CI; - 3.25 Z-test, p = 0.0011); and arch perimeter ( - 1.75 mm; - 2.71; - 0.80 95%CI; - 3.59 Z-test, p = 0.0003). These results indicate that aligners produce significantly less skeletal transverse expansion than conventional expanders.</p><p><strong>Conclusions: </strong>Clear aligners appear to be capable of producing maxillary expansion, mainly through dentoalveolar changes that are more evident in the anterior region and at the level of deciduous teeth. In patients presenting with more pronounced transverse deficiencies, conventional expanders seem to achieve greater skeletal and posterior transverse changes. However, given that most of the current evidence derives from retrospective studies with moderate risk of bias, these conclusions should be interpreted cautiously and confirmed by well-designed prospective research.</p><p><strong>Registration number: </strong>CRD420250608558.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13133309/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147790344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Factors contributing to the variability of anterior overbite opening after standardized posterior bite raiser placement: a prospective single-arm pre-post clinical study.","authors":"Raji Pescia, Gregory S Antonarakis, Stavros Kiliaridis","doi":"10.1186/s40510-026-00622-5","DOIUrl":"10.1186/s40510-026-00622-5","url":null,"abstract":"<p><strong>Background: </strong>Posterior bite raisers are frequently used in orthodontics, yet the magnitude of the resulting anterior overbite change shows substantial interindividual variability. This study aimed to identify dental and cephalometric characteristics that explain interindividual variability in anterior overbite opening following standardized posterior bite raiser placement.</p><p><strong>Methodology: </strong>Forty-seven subjects (7-56 years of age) with a recent lateral cephalogram were recruited. Digital intraoral impressions of the dentition were taken before and after temporary placement of a 2mm-diameter stainless-steel posterior bite raiser in the central fossae of both mandibular first permanent molars. Overbite changes and dental characteristics were recorded on digital dental casts, while skeletal parameters were measured on the corresponding lateral cephalogram. Regression analyses were performed to identify associations between anterior bite opening and individual dental or cephalometric characteristics.</p><p><strong>Results: </strong>Placement of 2mm posterior bite raisers decreased anterior overbite by an average of 2.2mm, but with large interindividual variation (0.3-4.0mm). The magnitude of anterior opening was significantly associated with the molar relationships (p<.001), whereby patients with Class I molar relationships showed greater opening (2.5mm, range 0.6-4.0mm) than those with Class II molar relationships (1.7mm, range 0.2-3.8mm). Occlusal morphology also influenced the outcome, as deeper mandibular fossae were correlated with reduced anterior opening (p<.01). Skeletal cephalometric variables were not significantly associated with the quantity of bite opening.</p><p><strong>Conclusions: </strong>The anterior opening induced by posterior bite raisers is highly variable among individuals and primarily determined by local dental morphology and intercuspation rather than skeletal characteristics. Recognizing these dental predictors may help clinicians anticipate the vertical response to posterior bite disocclusion during orthodontic treatment.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13125319/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147790277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Baseline positional asymmetry and its association with planned tooth movements in clear aligner therapy.","authors":"Tugba Haliloglu Ozkan, Elif Nadide Akay Polat","doi":"10.1186/s40510-026-00621-6","DOIUrl":"10.1186/s40510-026-00621-6","url":null,"abstract":"<p><strong>Background: </strong>Digital treatment planning software in clear aligner (CA) therapy incorporates virtual simulations to generate planned tooth movements. While baseline tooth positions constitute one of the geometric inputs to digital setups, limited information is available regarding the association between pre-treatment positional asymmetry and the magnitude of planned movements, and how these associations vary by tooth and movement type.</p><p><strong>Methods: </strong>A retrospective analysis was conducted on 65 patients (390 anterior teeth) treated with Invisalign^®. Baseline malpositions of anterior teeth were measured using 3D digital models in ClinCheck^®, while planned movements-including rotation, angulation, extrusion, and intrusion-were extracted from the corresponding digital treatment plans. Baseline asymmetry between contralateral teeth was calculated to quantify movement complexity. General Linear Model (GLM) regression analyses were employed to assess the relationship between initial asymmetry and the magnitude of planned movements. Descriptive statistics and normality assessments were also performed.</p><p><strong>Results: </strong>In the 11-21 tooth pair, baseline asymmetry was significantly associated with planned extrusion (p = .002) and rotation (p < .001), but not intrusion (p = .190) or angulation (p = .270). For the 12-22 pair, significant associations were observed for intrusion (p = .008), angulation (p < .001), and rotation (p < .001), but not extrusion (p = .493). In the 13-23 pair, only extrusion was significantly associated with baseline differences (p < .001); no significant effects were observed for the other movement types.</p><p><strong>Conclusion: </strong>Baseline positional asymmetry was associated with variation in planned extrusion, intrusion, and rotation movements within digital CA setups. These findings should be interpreted as descriptive associations rather than evidence of software-imposed constraints or internal planning strategies, and underscore the relevance of baseline geometry when interpreting digitally planned tooth movements.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13083615/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147693786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive three-dimensional analysis of alveolar bone adaptation and root resorption following premolar extraction in Class II malocclusion: a cohort study.","authors":"Hasan M Sharhan, Hanan Al-Fakeh, Huda M Sharhan, Majedh Abdo Ali Al-Somairi, Enas Senan Alyafrusee, Gaobo Tao, Nassem Ali Al-Worafi, Chao He, Najah Alhashimi, Maged S Alhammadi, Bowen Zheng, Yi Liu","doi":"10.1186/s40510-026-00616-3","DOIUrl":"10.1186/s40510-026-00616-3","url":null,"abstract":"<p><strong>Aims: </strong>This study aimed to assess the three-dimensional effects of orthodontic premolar extraction in Class II division 1 malocclusion cases treated with fixed appliances on maxillary bony changes (alveolar bone thickness and height) and maxillary dental changes (root length and tooth volume).</p><p><strong>Methods: </strong>This retrospective cohort study was conducted with 50 adult patients (aged 18-35 years) who underwent orthodontic treatment with fixed appliances and extraction of four first premolars. Pre and post treatment cone beam computed tomography scans were analyzed to obtain quantitative measurements of alveolar bone height and thickness, as well as root length and tooth volume.</p><p><strong>Results: </strong>There were significant post-treatment reductions in alveolar bone height in almost all teeth, as well as the cervical alveolar bone thickness, particularly on the palatal side of the anterior teeth. Root resorption was evident across all teeth, and central incisors showed the most significant reduction in root length. Tooth volume decreased significantly across all dentitions.</p><p><strong>Conclusions: </strong>Premolar extraction in orthodontic treatment is associated with significant changes in alveolar bone height, thickness, root resorption, and tooth volume, particularly in the anterior maxillary region.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13065861/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147640797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the impact of attachment designs on canine derotation in clear aligner therapy: a finite element analysis.","authors":"Preeti Kulkarni, Puneet Batra, Nikhillesh Vaiid","doi":"10.1186/s40510-026-00619-0","DOIUrl":"10.1186/s40510-026-00619-0","url":null,"abstract":"<p><strong>Background: </strong>Successful canine derotation in Clear Aligner Therapy (CAT) relies on strategic attachment design, influencing force direction and root control. This study employs Finite Element Analysis (FEA) to compare the biomechanical efficacy of three attachment designs, aiming to optimize treatment strategies for canine derotation.</p><p><strong>Methodology: </strong>A three-dimensional finite element model of the maxillary arch was developed to simulate the rotational movement of maxillary canine in CAT. Three attachment groups used for evaluation were- VL: Vertical-angulated labial attachments only, VLP: Vertical-angulated labial and palatal attachments, VLPPP: Vertical-angulated labial attachments with palatal pressure points. Incremental rotational force of 10, 20, 30, 40 degrees was applied across all three groups. Tooth displacement, attachment deformation, periodontal ligament (PDL) stress and alveolar bone stress were analyzed and compared using ANSYS simulation software.</p><p><strong>Results: </strong>VLPPP showed the highest tooth displacement pattern of 0.017 mm with incremental rotational force application but also exhibited highest stress concentration at PDL and alveolar bone level of 516.10 Mpa. VL showed the least tooth movement of 0.012 mm and lowest stress levels of 374.33 Mpa.</p><p><strong>Conclusion: </strong>VLPPP generated the highest force output, but also induced the greatest biological stress. In contrast, VLP with dual surface attachments effectively facilitated tooth movement while minimizing biological stress. Multi-surface force application enhances biomechanical control in clear aligner canine derotation.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13057179/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147629347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting transversal dental arch expansion outcomes with Invisalign aligners in permanent dentition: a systematic review and meta-analysis.","authors":"Marco Serafin, Elisa Boccalari, Marta Calò, Piero Antonio Zecca, Alberto Caprioglio","doi":"10.1186/s40510-026-00618-1","DOIUrl":"10.1186/s40510-026-00618-1","url":null,"abstract":"<p><strong>Objective: </strong>To evaluate the predictability of Invisalign in producing transverse dental arch expansion in permanent dentition and to identify clinical and methodological factors influencing expansion accuracy.</p><p><strong>Methods: </strong>A systematic search of PubMed, Embase, Scopus, and WOS (up to November 2025) identified clinical studies reporting planned and achieved expansion. Predictability was defined as the achieved-to-planned expansion ratio and synthesized as logit-transformed proportions in random-effects meta-analyses. Tooth-group-specific pooled estimates were calculated for each arch. Meta-regressions, non-parametric correlations, linear and multivariable regressions, and hierarchical clustering explored the influence of publication year, age, arch, tooth type, material, aligner-change interval, and planned/achieved expansion. Risk of bias was assessed with ROBINS-I and certainty of evidence with GRADE.</p><p><strong>Results: </strong>Twenty-three studies (1391 patients) were included; 21 entered the meta-analyses. Average predictability was 75.5% in the maxilla and 80.6% in the mandible. Mandibular second premolars showed the highest pooled predictability (88%), whereas lower second molars were least reliable (73%). In subsets reporting both levels, gingival-margin predictability was consistently lower than cusp-level values. Prediction intervals were very wide in both arches. Meta-regressions showed small but significant reductions in predictability in more recent publications (p = 0.01) and with increasing patient age (p = 0.016); greater achieved expansion showed only a modest positive association with predictability. Multivariable regression identified younger age (p = 0.001), SmartTrack material (p < 0.001), and mandibular segments (p = 0.001) as independent predictors of higher predictability. Publication bias was evident, and overall certainty of evidence was rated very low.</p><p><strong>Conclusions: </strong>Invisalign aligners provide moderate-to-high predictability for dentoalveolar transverse expansion in permanent dentition, particularly in premolar regions and in the mandibular arch. Expansion is mainly expressed as buccal crown tipping. Age, aligner material, and arch location modestly influence outcomes, underscoring the need for biologically realistic planning, selective overcorrections, and careful case selection.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13035959/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147576681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of facial shape on perceived attractiveness.","authors":"Nikolaos Gkantidis, Sven Stucki, Mohammed Ghamri, Demetrios Halazonetis, Georgios Kanavakis","doi":"10.1186/s40510-026-00617-2","DOIUrl":"10.1186/s40510-026-00617-2","url":null,"abstract":"<p><strong>Background/objectives: </strong>Facial attractiveness is often regarded as subjective, yet perceptions are strongly influenced by cultural, social, and biological factors. This study aimed to investigate whether and to what extent three-dimensional facial shape is associated with attractiveness ratings assigned by external evaluators, and whether these associations differ between males and females.</p><p><strong>Methods: </strong>A total of 601 young adults (393 females; 208 males), aged 21-35 years, were assessed using three-dimensional facial photography. Facial shape was quantified using 29 anatomical curves and 1,021 landmarks analyzed through geometric morphometric methods. Six external examiners (three males, three females), matched in age to the study population, independently rated attractiveness using Visual Analogue Scales (VAS). Multivariate regression models were applied to examine associations between facial shape and attractiveness scores. Analyses were conducted separately for males and females to account for biological differences in facial morphology.</p><p><strong>Results: </strong>Facial shape was significantly associated with attractiveness ratings in females (η² = 0.075; P < 0.001). Higher attractiveness scores were linked to well-balanced vertical facial proportions and a more angular facial appearance, with sharper contours, reduced facial fullness, and mild profile convexity. A fuller and more projected upper lip was also characteristic of higher-rated faces. In males, effect size was comparable (η² = 0.070), but the association did not reach statistical significance (P = 0.106). Attractive male faces tended to exhibit an angular and well-defined facial structure, decreased lateral fullness, slightly increased lower facial height, central facial projection, and a straight profile.</p><p><strong>Conclusions: </strong>Facial shape is associated with externally perceived facial attractiveness, with statistically significant effects observed in females. The findings align with previous research on self-perceived attractiveness and underscore the influence of facial morphology on societal perceptions of attractiveness.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13018507/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147516948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dimensional behaviors of direct-printed versus thermoformed clear retainers in relation to changes of inter-piece occlusal contact distribution measured by T-scan after intraoral aging: a prospective clinical study.","authors":"Hwarang Jeong, Min-Ji Jeon, Kun-Woo Park, Tamara Mahmalji, Jin-Young Choi, Su-Jung Kim","doi":"10.1186/s40510-026-00611-8","DOIUrl":"10.1186/s40510-026-00611-8","url":null,"abstract":"<p><strong>Background: </strong>This study compared site-specific dimensional changes after intraoral aging between direct-printed retainers (DPRs) and thermoformed retainers (TFRs), focusing on changes in occlusal contact areas (OCAs) and occlusal force distribution (OFD) across different intra-arch tooth locations and surfaces, reflecting the patient's dentoskeletal pattern.</p><p><strong>Methodology: </strong>Of 26 participants, 22 (12 males, 10 females; mean age 22.5 ± 4.2 years) were included and assessed for cephalometric skeletal patterns. DPRs (maxillary and mandibular) were fabricated from oral scans obtained on the day of debonding. TFR pairs were fabricated on printed master models using the same scan data. Before delivery (T0), maxillary DPRs and TFRs (n = 22 each) fitted on the master model were scanned using micro-computed tomography (micro-CT), and relative occlusal force distribution was quantitatively measured using a T-Scan device by dividing the dentition into five regions during occlusion with retainers in place. After two weeks of full-time intraoral use following the experimental protocol (T1), maxillary DPRs and TFRs were retrieved for the second assessment. Micro-CT gap widths were measured at five surface points around eight teeth for a total of 88 samples and analyzed for inter-retainer comparison and correlation with occlusal and skeletal variables using statistical analysis.</p><p><strong>Result: </strong>Unused DPRs revealed greater gap widths than TFRs at incisal edges and cusp tips of all tested teeth (P<.001). The retrieved TFRs showed an overall gap increase, especially in the gingival areas, along with an increase in the OCA (P<.05), in relation to the patient's mandibular plane angle (MPA) (P<.05). The retrieved DPRs exhibited gap decreases in the posterior teeth (P<.001) and gap increases in the anterior teeth, especially in the linguogingival area (P<.05), compared to the initial OCA value (P<.01), with no correlation with the patient's skeletal pattern. The OFD revealed no relationship with gap changes, regardless of the tooth location and surface.</p><p><strong>Conclusion: </strong>Within clinically acceptable ranges of gap discrepancy, the DPRs exhibited site-specific dimensional behavior after intraoral use representing enhanced retainer fit in the posterior teeth and worsened fit in the anterior teeth, in relation to the initial OCA, in contrast with the TFRs showing overall gap increases with higher susceptibility to patient's occlusal and skeletal patterns.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12996577/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147476113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alveolar bone remodeling following orthodontic closure of missing mandibular first molar spaces: a CBCT-based morphometric study.","authors":"Xinmeng Shi, Shuo Wang, Liyuan Chen, Tianhao Wu, He Zhang, Hangbo Liu, Shiying Zhang, Chang Li, Yuxin Liu, Zeyu Wang, Yongping Ma, Danqing He, Yan Liu","doi":"10.1186/s40510-026-00615-4","DOIUrl":"10.1186/s40510-026-00615-4","url":null,"abstract":"<p><strong>Background: </strong>Loss of the mandibular first molar is a common and detrimental clinical issue that often leads to alveolar bone resorption in the edentulous area, complicating future prosthetic or orthodontic interventions. This study aimed to evaluate the efficacy of orthodontic closure of missing mandibular first molar spaces and its impact on alveolar bone remodeling.</p><p><strong>Methods: </strong>Fifteen patients (17 sites) who underwent orthodontic closure of mandibular first molar spaces were retrospectively analyzed using cone-beam computed tomography (CBCT). The mesiodistal and buccolingual angulations of the mandibular second molars were measured in sagittal and coronal planes, respectively. The alveolar bone height was reflected by the distance from the cemento-enamel junction to the alveolar bone margin (CEJ-BM) at six sites on both the second premolars and second molars. Moreover, CBCT before and after orthodontic treatment were superimposed, and changes of alveolar bone width were obtained at three levels (3 mm, 6 mm and 9 mm below the cemento-enamel junction plane) and at three sections (mesial, middle and distal) within the edentulous region. Changes in alveolar bone volume within the extraction site were also calculated. Statistical analysis was performed by paired t-test.</p><p><strong>Results: </strong>Orthodontic space closure significantly improved second molar angulations in both the mesiodistal (p < 0.001) and buccolingual (p < 0.01) angulations. In 57.35% of measured sites, alveolar bone height increased, with significant elevations at the distobuccal, distolingual, and mesiobuccal sites of the second molar (p < 0.05). Alveolar bone width significantly increased at 3 mm and 6 mm below the CEJ plane after orthodontic closure (p < 0.05), accompanied by a notable increase in bone volume (before treatment: 2922.0 ± 479.0 mm³, after treatment: 3003.8 ± 489.6 mm³, p < 0.05).</p><p><strong>Conclusions: </strong>Orthodontic closure of mandibular first molar spaces promotes alveolar bone remodeling, including improvements in angulation, bone height, width, and volume. This approach offers a biologically advantageous alternative for managing molar loss, enhancing both function and long-term periodontal support.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12992760/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147470189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional dynamic evaluation of facial soft tissue changes following anterior traction in growing Angle Class III malocclusion patients.","authors":"Jinyao Han, Qiang Li, Liying Wang, Jin Zhang, Boting Liu, Haoqiang Zhan, Jia Liu, Kun Qi","doi":"10.1186/s40510-026-00612-7","DOIUrl":"10.1186/s40510-026-00612-7","url":null,"abstract":"<p><strong>Background: </strong>The aesthetic improvement of the midface is a critical goal in treating growing children with Angle Class III malocclusion. While the skeletal effects of maxillary anterior traction are well-established, predicting the final aesthetic outcome requires a precise understanding of the accompanying three-dimensional (3D) soft tissue response. Current literature lacks detailed, dynamic quantification of these adaptive changes using high-precision methodology. This study aims to address this gap by employing dynamic stereophotogrammetry to sequentially analyze the 3D soft tissue kinematics associated with maxillary advancement.</p><p><strong>Methods: </strong>In this study, the three-dimensional dynamic facial imaging system (3dMD) was employed to evaluate the effects of maxillary anterior traction treatment in 28 adolescents and children with Angle Class III malocclusion. Quantitative changes in facial root mean square (RMS) values and landmark displacements were compared across different treatment stages. Key measurements included RMS values at the initial (Ta), middle (Tb), and final (Tc) frames of four facial expression sequences (smile lips closed, smile lips open, lip purse, and cheek puff) along with the corresponding changes in anatomical landmark positions.</p><p><strong>Results: </strong>Analysis revealed that the RMS values for each sequence frame of facial dynamic expressions increased from baseline (pre-treatment) levels at both the 3-month follow-up (T1-T0) and the end of treatment (T2-T0). RMS values exhibited differential evolution across distinct phases of each facial expression. For the smile lips closed expression, the overall change did not reach statistical significance (p = 0.064). In contrast, the smile lips open expression exhibited statistically significant increases over the full treatment course (p = 0.015). More pronounced changes were observed in the lip purse and cheek puff expressions, both of which exhibited highly significant increases in RMS amplitude across the entire treatment period (p = 0.002 and p < 0.001, respectively). With regards to landmark displacements, statistically significant anterior movements were observed for landmarks b, c, d, e, f and h, while landmark a exhibited a significant posterior displacement. In contrast, no significant positional changes were detected for landmarks i and j.</p><p><strong>Conclusion: </strong>Anterior traction effectively improved the class III facial profile while dynamic 3D assessment revealed a non-linear adaptation pattern with enhanced midfacial convexity. These objective data are crucial for predicting outcomes in early-phase patient management.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12979718/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147437957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}