American Journal of Orthodontics and Dentofacial Orthopedics最新文献

{"title":"Biomechanical effects of attachment designs on maxillary molar expansion with clear aligners: A 3-dimensional finite elements analysis using a single patient model.","authors":"Irem Sensoy, Banu Kilic, Gokmen Kurt","doi":"10.1016/j.ajodo.2026.02.015","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.02.015","url":null,"abstract":"<p><strong>Introduction: </strong>The aim of this study is to determine, using finite element analysis (FEA), attachment configurations that minimize adverse biomechanical effects on the molars during posterior expansion with clear aligners and support biomechanical interpretation for treatment planning. Using FEA, the Invisalign G8 protocol (Align Technology, San Jose, Calif) and conventional attachment designs were compared.</p><p><strong>Methods: </strong>Seven FEA models with attachments placed on the maxillary posterior teeth were created: (1) group 0: control group; (2) group 1: buccal horizontal rectangular attachment; (3) group 2: buccal gingivally-beveled rectangular attachment; (4) group 3: buccal-optimized expansion support attachment; (5) group 4: optimized attachment combined with an occlusally-beveled palatal attachment; (6) group 5: optimized attachment combined with a palatal horizontal rectangular attachment; and (7) group 6: palatal horizontal rectangular attachment without a buccal attachment. In the loading method, the deformation occurring in the clear aligner geometry and the contact forces resulting from the deformation were applied in the opposite direction.</p><p><strong>Results: </strong>In all groups, expansion was observed to occur in the form of buccal displacement of the crown and palatal displacement of the root. Optimized attachment configurations were associated with greater buccal crown displacement relative to palatal root displacement. In group 4, the highest expansion values and the lowest palatal root displacement were identified.</p><p><strong>Conclusions: </strong>Simulation results indicated that parallel tooth displacement was not achieved with maxillary molar expansion using clear aligners, and buccal tipping predominated. Optimized attachments demonstrated a biomechanical tendency toward greater expansion efficiency. The combined use of optimized and palatal attachments showed increased buccal crown displacement with reduced palatal root displacement.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147678357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interleukin-33 and superoxide dismutase 3 mediates co-achieved tooth movement acceleration and root protection.","authors":"Xiaomeng Dong, Yujie Zhu, Bin Li, Fan Yang, Wanxi Chen, Hui Xu","doi":"10.1016/j.ajodo.2026.01.024","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.01.024","url":null,"abstract":"<p><strong>Background: </strong>Achieving co-occurrence of tooth movement acceleration and root protection has been a fascinating challenge. This study investigated how interleukin-33 (IL-33)-superoxide dismutase 3 (SOD3) crosstalk affects the alveolar bone and cementum during orthodontic treatment.</p><p><strong>Methods: </strong>The effects of IL-33-SOD3 signaling on the immortalized murine cementoblast cell line 30 cells, bone marrow stromal cells, and RAW 264.7 cells were evaluated. In vivo, the distance of orthodontic tooth movement and the volume of root resorption were quantified in mice treated with soluble suppression of tumorigenicity 2 (sST2, a decoy receptor for IL-33) and adenovirus-mediated sod3.</p><p><strong>Results: </strong>Endogenous SOD3 was found to enhance the osteogenic differentiation and mineralization of cementoblast-like cells, whereas IL-33-inhibited SOD3 expression and the SOD3-mediated promineralization effect on these cells. In bone marrow stromal cells, endogenous SOD3 promoted osteoblast differentiation and mineralization, although to a lesser extent than in the immortalized murine cementoblast cell line 30 cells, with a lack of effect of IL-33 on SOD3 expression. SOD3 attenuated osteoclastic activity in RAW 264.7 cells, to a lesser extent, compared with the IL-33-mediated suppression of osteoclastogenesis. Combined administration of sST2 and adenovirus-mediated sod3 gene transfer resulted in accelerated tooth movement while providing protection to the roots.</p><p><strong>Conclusions: </strong>The SOD3 signaling cross-talked with IL-33 and differentially regulated cementoblast-like cells, osteoblast progenitors, and osteoclast precursor cells. Combined treatment of sST2 and sod3 gene transfer reorchestrated the IL-33-SOD3 signaling and led to accelerated bone remodeling coupled with reinforced root repair, achieving the co-occurrence of tooth movement acceleration and root protection in mice.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147647434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Orthognathic surgery need following BAMP therapy in unilateral complete cleft lip and palate with moderate to severe maxillary deficiency: a prospective study.","authors":"Julia Petruccelli, Vanessa Couto, Renato Faco, Renata T R M Bastos, David Normando, Hugo de Clerck, Daniela Garib","doi":"10.1016/j.ajodo.2026.02.008","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.02.008","url":null,"abstract":"<p><strong>Background: </strong>The objective of this study was to assess the long-term stability of bone-anchored maxillary protraction (BAMP) in patients with unilateral complete cleft lip and palate (UCLP) and sagittal midface deficiency.</p><p><strong>Methods: </strong>The sample comprised 30 patients with UCLP (20 males and 10 females), with a mean age of 11.8 years (standard deviation = 0.79 years). All patients presented with moderate to severe maxillary deficiencies and were prospectively treated with BAMP for 18 months. Cone-beam computed tomography was obtained before (T1) and after BAMP therapy (T2), whereas conventional lateral cephalograms were acquired at least 5 years after BAMP therapy (T3: mean age = 20.15 years, standard deviation = 2.38 years). Moreover, 3 patients were lost during the follow-up, and 1 was excluded because of missing T2 records. Interphase comparisons were performed using analysis of variance and Tukey honest significant difference test (P <0.05). Discriminant analysis was used to identify pre and posttreatment predictive variables associated with surgical or nonsurgical outcomes.</p><p><strong>Results: </strong>Among the 26 patients included in the final sample, 46.2% (n = 12) received nonsurgical treatment in phase 2, whereas 53.8% (n = 14) required orthognathic surgery. In the nonsurgical subgroup, the outcomes achieved with BAMP therapy remained stable from T2 to T3. In the surgical subgroup, treatment changes were negligible, and an impairment of facial convexity was observed during the posttreatment follow-up. Discriminant analysis revealed that pretreatment indicators predictive of nonsurgical outcomes included a less negative overjet, a smaller mandibular plane angle, and a reduced gonial angle. Greater improvements in the ANB angle and overjet during treatment were associated with a higher likelihood of a nonsurgical outcome.</p><p><strong>Conclusions: </strong>Patients with UCLP who achieved a positive overjet during BAMP therapy remained stable in the long-term, and orthognathic surgery was avoided. Hyperdivergent growth pattern with obtuse gonial angle and more severe negative overjet were initial predictors of the need for orthognathic surgery. Greater correction of the skeletal maxillomandibular relationship and overjet during BAMP therapy was associated with nonsurgical outcomes.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147639817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical settling elastics for resolving posterior open bite during the fine-tuning staging for clear aligner therapy: A prospective clinical study.","authors":"Linlin Xiao, Shangyou Wen, Xuechun Yuan, Xian He, Xiaoyue Han, Xiaoyan Guan, Wenli Lai, Hu Long","doi":"10.1016/j.ajodo.2026.01.028","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.01.028","url":null,"abstract":"<p><strong>Background: </strong>Posterior open bite (POB) is a common and challenging complication during clear aligner therapy, primarily because of the biomechanical susceptibility of posterior teeth to intrusion, occlusal block effect, and excessive expansion. Although posterior vertical elastic traction has been proposed as a potential intervention, its clinical efficacy and the factors influencing treatment outcomes remain poorly understood. This prospective study aimed to evaluate the effectiveness of posterior settling elastics in correcting POB and identify key predictors of treatment success.</p><p><strong>Methods: </strong>Fifty-two patients treated with Invisalign (Align Technology, Santa Clara, Calif) who exhibited POB, defined as a vertical distance >0 mm for mesiobuccal (MB), distobuccal (DB), or palatal (PL) cusps of maxillary and mandibular molars in centric occlusion after the refinement of the aligner, were enrolled. A total of 172 molar sites were assessed, of which 95 received elastic traction (vertical or triangular), and 77 were treated with aligners alone. Digital models at pretreatment (T0), predicted (T1), and posttreatment (T2) stages were acquired via iTero Element scanning (Align Technology, San Jose, Calif) and registered to a standardized coordinate system using Geomagic Studio 2014 (3D Systems, Rock Hill, SC). Actual cusp extrusion distances relative to the reference xy-plane were measured, and occlusal contact areas were quantified using Boolean superposition. Univariate and mixed-effects multivariate linear regression analyses were conducted to identify predictors of cusp extrusion.</p><p><strong>Results: </strong>Multivariate analysis revealed that MB cusp extrusion was positively associated with elastic traction (P <0.001), baseline MB cusp distance (P <0.001), predicted extrusion (P <0.001), and female sex (P <0.001) and was negatively associated with pretreatment anterior overjet and overbite. Similar patterns were observed for the DB cusp extrusion. PL cusp extrusion was primarily predicted by its baseline distance (P <0.05) and predicted extrusion (P <0.05), and was negatively influenced by the pretreatment DB cusp distance.</p><p><strong>Conclusions: </strong>Posterior vertical settling elastics are effective in correcting clear aligner-induced POB, particularly by improving maxillary buccal cusp occlusal contacts. Optimal correction requires substantial overcorrection in the planned posterior extrusion and careful evaluation of baseline POB severity, anterior overjet and overbite, and patient sex to maximize treatment predictability.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147634906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficacy of Class II correction with clear aligner therapy and intermaxillary elastics in adolescent patients: A retrospective study.","authors":"Maurice J Meade, Bariah Rana, Tony Weir","doi":"10.1016/j.ajodo.2026.02.014","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.02.014","url":null,"abstract":"<p><strong>Introduction: </strong>The aim was to assess the changes in overjet and the intermaxillary sagittal first permanent molar (FPM) relationship in adolescent patients after treatment with an initial series of Invisalign (Align Technology, San Jose, Calif) aligners and Class II elastics.</p><p><strong>Methods: </strong>Patients satisfying the inclusion and/or exclusion criteria were selected from a database of patients treated by 18 orthodontists. Data were extracted from Align Technology's software facility related to demographic information and pretreatment, planned, and posttreatment overjet values. Metrology software was used to determine changes in the intermaxillary sagittal FPM relationships.</p><p><strong>Results: </strong>The mean (standard deviation) age of the 199 patients who satisfied selection criteria was 13.7 (2.1) years. Most were female (132 [66.3%]), and the mean overjet reduction was 33.95% of the planned reduction. The overjet of 62 (31.2%) patients was greater at the end of the prescribed aligner and Class II elastic wear, despite a planned reduction. The pretreatment sagittal FPM relationship reduced from a mean (standard deviation) of 2.53 (1.72) mm to 1.18 (1.97) mm, which corresponded to 45.91% of the planned change. The achieved outcome was in the opposite direction relative to that planned in 24 (12.06%) left FPMs and 24 (12.06%) right FPMs. Distalization appeared to be more efficacious (P <0.05) than the jump and en masse methods for sagittal correction of the FPM relationship.</p><p><strong>Conclusions: </strong>Approximately one-third of the planned overjet reduction and just less than half of the planned intermaxillary sagittal FPM changes were achieved with an initial series of Invisalign aligners and Class II elastics in a sample of adolescent patients.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147618448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical and surface properties of 3-dimensional-printed zirconia orthodontic brackets: An evaluation of ink-jet printing combined with vibratory polishing.","authors":"Biyao Li, Wanqing Wu, Chenyan Xie, Jie Xu, Yu Xu, Shun Yang, Jianying Feng","doi":"10.1016/j.ajodo.2026.01.029","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.01.029","url":null,"abstract":"<p><strong>Background: </strong>This study aims to evaluate the fundamental material properties of ink-jet-printed zirconia (IPZ) after vibratory polishing and analyze the frictional behavior and dimensional accuracy of the resulting orthodontic brackets.</p><p><strong>Methods: </strong>IPZ was used to fabricate customized brackets, followed by a 3-phase vibratory polishing. Vickers hardness, fracture toughness, surface roughness, scanning electron microscopy morphology, and linear reduction rate were measured on IPZ cubic samples (n = 20). IPZ brackets (n = 80) of 0.022 × 0.028-in slot were assessed for frictional resistance, scanning electron microscopy morphology, and slot dimensions. Control groups comprised stainless steel brackets, ceramic brackets, and stainless steel self-ligating brackets.</p><p><strong>Results: </strong>Hardness and fracture toughness of IPZ were 1374.34 ± 34.12 Vickers hardness and 9.01 ± 0.68 MPa·m^1/2, respectively. The average surface roughness value of our final polished cubic samples was <0.2 μm. Frictional resistance of polished IPZ brackets (eg, phase 3: 0.507 ± 0.153 N) was comparable to steel self-ligating brackets (0.573 ± 0.153 N; P >0.05) from phase 1 onward, with no further significant reduction in phases 2 and 3. The slot depth and height conformed to the German DIN 13996 standard. Substantial reduction of stair-stepped deposition layer lines was observed on the surface of polished cubic samples, whereas the morphologic changes were conspicuous in the slot base and the labial third of slot walls.</p><p><strong>Conclusions: </strong>IPZ demonstrated promising in vitro mechanical and surface properties, with the vibratory polishing manifesting its efficacy in reducing the stair-step effect, though the clinical performance of IPZ brackets requires subsequent validation. Further optimization of 3-dimensional printing techniques and slot-specific polishing methods is warranted.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147596070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of premolar extractions on occlusal contacts and chewing efficiency: A case-control study.","authors":"Meric Arslan, Berza Yilmaz, Mustafa Sarp Kaya","doi":"10.1016/j.ajodo.2026.01.026","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.01.026","url":null,"abstract":"<p><strong>Background: </strong>This study aimed to evaluate the effect of premolar extractions on masticatory performance and occlusal contact areas in patients who underwent orthodontic treatment with or without premolar extractions.</p><p><strong>Methods: </strong>Seventy-five patients (aged 18-40 years), who had completed their treatment ≥6 months prior, were divided into groups: maxillary 2-premolar extractions (n = 22), 4-premolar extractions (n = 22), and nonextraction (n = 31). A control group of 31 individuals with no history of orthodontic treatment was also included. Posttreatment quality was assessed using plaster models evaluated according to the American Board of Orthodontics objective grading system (ABO-OGS). Intraoral scans obtained with the iTero Element 5D scanner (Align Technologies, San Jose, Calif) were analyzed in OrthoCAD (version 5.9.1.50; Align Technology, San Jose, Calif) to determine posterior occlusal contact areas (near and tight) at maximum intercuspation. Masticatory performance was evaluated using a gum chewing test. The chewed samples were scanned with a color desktop scanner, and color mixing was analyzed using ViewGum software (version 1.4; dHAL Kifissia, Greece).</p><p><strong>Results: </strong>Significant differences were found between groups in terms of age, gender, ABO-OGS scores, and occlusal contact areas (P <0.05), whereas masticatory performance did not differ significantly (P >0.05). No significant correlations were found between ABO-OGS scores and occlusal contact areas, masticatory performance, or the time since treatment the lasted. Similarly, masticatory performance showed no significant correlations with contact areas and posttreatment time. A positive correlation was found between occlusal contact areas and time since treatment lasted (near contact: r = 0.440; tight contact: r = 0.429).</p><p><strong>Conclusions: </strong>Although differences in occlusal contact areas were observed, premolar extraction did not appear to negatively affect masticatory performance.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147576292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of mandibular movement and center of rotation after total arch intrusion.","authors":"Kye Myung Kwak, Jong-Suk Lee, Flavio Uribe, Ung Ki Cho, Yoon Jeong Choi","doi":"10.1016/j.ajodo.2026.02.013","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.02.013","url":null,"abstract":"<p><strong>Background: </strong>This study aimed to identify the center of mandibular autorotation (CRo) and evaluate the relationship between the amount of intrusion of the maxillary and mandibular dentition and changes in vertical and sagittal cephalometric parameters after total arch intrusion (TAI).</p><p><strong>Methods: </strong>Thirty-four adults (5 men and 29 women; mean age = 24.2 ± 6.2 years) treated with TAI were retrospectively analyzed, including 14 patients in the 4-premolar extraction group and 20 in the nonextraction group. Lateral cephalograms taken pretreatment and posttreatment were used to assess cephalometric changes. The CRo was determined based on positional changes of the gonion and pogonion. Paired-samples and independent-samples t tests were used for within-group (pretreatment vs posttreatment) and between-group (extraction vs nonextraction) comparisons.</p><p><strong>Results: </strong>After TAI, the mandible rotated counterclockwise, resulting in sagittal improvements-including increased SNB, decreased ANB, overjet, and forward movement of the pogonion, and vertical reductions in anterior facial height and mandibular plane angle (P <0.001). No significant differences were observed between the extraction and nonextraction groups (P >0.05). The amount of posterior intrusion was significantly correlated with decreases in anterior facial height, mandibular plane angle, and forward movement of the pogonion (P <0.001). The mean CRo was located 2.8 mm posterior and 18.9 mm inferior to the condylion, with no intergroup difference.</p><p><strong>Conclusions: </strong>TAI provides a practical nonsurgical approach for treating skeletal Class II malocclusion with vertical excess, associated with mandibular counterclockwise rotation and improved vertical and sagittal skeletal relationships. The CRo was consistently positioned posterior-inferior to the condylion, with individual variation.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147576334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of rinsing and curing conditions on the biocompatibility of 3-dimensional-printed resin orthodontic brackets.","authors":"Hope Grandy, Thomas Lallier, Amir H Nejat, Richard Ballard, Paul Armbruster","doi":"10.1016/j.ajodo.2026.01.030","DOIUrl":"https://doi.org/10.1016/j.ajodo.2026.01.030","url":null,"abstract":"<p><strong>Background: </strong>The incorporation of 3-dimensional (3D) printing into orthodontics offers new opportunities for in-office fabrication of resin brackets. However, concerns remain regarding the cytotoxic effects of residual monomers because of incomplete polymerization during postprocessing. This study evaluates the biocompatibility of two 3D-printed dental resins using varying postprocessing protocols.</p><p><strong>Methods: </strong>Two resins, SprintRay ceramic crown (SprintRay Inc, Los Angeles, Calif) and SprintRay crown (SprintRay Inc), were 3D printed into standardized discs and processed under 3 experimental conditions: (1) no postprint cure vs postprint cure; (2) postprint cured with prolonged rinsing; and (3) air cured vs glycerin cured. Human periodontal ligament fibroblasts were exposed to each disc for 24 hours. Cell viability was evaluated with Calcein AM (Invitrogen,Thermo Scientific, Carlsbad, Calif) staining and fluorescence quantification. Statistical analysis used Student t test with significance set at P <0.05.</p><p><strong>Results: </strong>Uncured discs displayed significantly higher cytotoxicity than cured discs (P <0.05). Prolonged rinsing for 1 week significantly reduced cytotoxicity in both resins, with no further reduction at 2 weeks. Glycerin immersion during curing further reduced cytotoxicity and eliminated significant differences between the 2 resins (P >0.05).</p><p><strong>Conclusions: </strong>Postcuring reduces the cytotoxicity of 3D-printed resins, though not entirely. Prolonged rinsing and glycerin immersion significantly improved the biocompatibility. These postprocessing modifications can enhance the clinical biocompatibility of 3D-printed orthodontic brackets and support the need for optimized postprocessing protocols in clinical applications.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147576370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does the maxillary sinus floor affect orthodontic tooth movement and root resorption after premolar extraction? A retrospective cone-beam computed tomography study.","authors":"Nasser Saeed Bahaj, Barakat Al-Tayar, Tianyu Fu, Lijie Zhang, Qian Ye, Xiaoli An","doi":"10.1016/j.ajodo.2026.02.011","DOIUrl":"10.1016/j.ajodo.2026.02.011","url":null,"abstract":"<p><strong>Background: </strong>This study aimed to evaluate the impact of maxillary sinus-root relationship (SRR) on orthodontic tooth movement and root resorption measured by using cone-beam computed tomography (CBCT) during first premolar extraction space closure in adults receiving traditional treatment (TT) and clear aligner therapy (CAT).</p><p><strong>Methods: </strong>This retrospective study analyzed pre and posttreatment CBCT scans of 80 Chinese adults (type I vs type V SRR; TT vs CAT), with 40 patients in each SRR type and equal allocation to TT and CAT groups. All measurements were performed on CBCT images at T1 and T2 using InVivo 6.0.3 software (Anatomage, San Jose, Calif).</p><p><strong>Results: </strong>Greater mesial molar movement was observed in type I SRR than in type V SRR. In the TT group, mesial root movement was greater in type I SRR (between-group mean difference [ΔΔT] = -1.24 mm; confidence interval = -2.35 to -0.13; P = 0.029). In the CAT group, type I SRR showed greater mesial root movement (ΔΔT = -1.12 mm; confidence interval = -1.84 to -0.41; P = 0.003) and larger cusp displacement at mesial and distal cusps (ΔΔT = -2.12 mm; ΔΔT = -1.54 mm). Within type I SRR, the CAT group produced greater cusp movement than TT (ΔΔT = 1.29 mm; ΔΔT = 0.90 mm). No significant TT vs CAT group differences were observed in type V SRR. All groups had significant root resorption; TT group was associated with greater resorption than CAT group, particularly in the second premolar (ΔΔT = 0.36 mm; P = 0.010), palatal root of the first molar in type I SRR (ΔΔT 0.37 mm; P = 0.006), and distobuccal root in type V SRR (ΔΔT = 0.30 mm; P = 0.013).</p><p><strong>Conclusions: </strong>The findings suggest that molar movement may be greater when the sinus floor is farther from the roots, and CAT may induce more tipping, whereas TT may cause more root resorption. Sinus proximity did not appear to increase resorption risk. However, the imbalance in treatment duration between TT and CAT remains a potentially biasing limitation.</p>","PeriodicalId":50806,"journal":{"name":"American Journal of Orthodontics and Dentofacial Orthopedics","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147532853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}