Progress in Orthodontics最新文献

{"title":"Comparison of spontaneous eruption and modified closed eruption technique with palatal traction in alignment of impacted maxillary central incisor teeth.","authors":"Ivo Marek,&nbsp;Anna Janková,&nbsp;Martin Starosta,&nbsp;Michal Novosad,&nbsp;Josef Kučera","doi":"10.1186/s40510-023-00470-7","DOIUrl":"https://doi.org/10.1186/s40510-023-00470-7","url":null,"abstract":"<p><strong>Background: </strong>Central incisor impaction is a rare condition with potentially severe clinical and psychological implications for the patient. Treatment techniques vary according to the pretreatment situation and individual factors. The aim of this study was to compare the esthetic outcomes and treatment times between two different approaches.</p><p><strong>Materials and methods: </strong>In this retrospective study, thirty-one consecutive patients (13 boys, 18 girls; average age 9.5 ± 2.3 years) with a total of 34 impacted permanent upper central incisors were included in the study. Patients were divided into two groups according to method of treatment. Group A comprised patients in whom spontaneous eruption occurred after space opening (n = 12), and Group B comprised patients in whom teeth showed no eruption and required treatment with a modified closed eruption method with palatally oriented traction (n = 19). Treatment time and esthetic outcomes were assessed and compared between groups.</p><p><strong>Results: </strong>The mean treatment time was 22.0 ± 6.7 months, and all teeth were successfully aligned. No statistically significant difference in average treatment time was found between groups in baseline characteristics (p > 0.05). The amount of attached gingiva was significantly smaller when compared to contralateral reference teeth in the closed eruption group (Group B; p = 0.03). However, no difference in amount of attached gingiva was found between both groups (p = 0.26). Additionally, no difference in the clinical crown length was found between groups (p = 0.27).</p><p><strong>Conclusion: </strong>The closed eruption method with palatal traction directed at the peak of the alveolar crest provided results comparable to the physiologic tooth eruption.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"17"},"PeriodicalIF":4.8,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10290968/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10072070","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":"Dentofacial effects of miniscrew-anchored maxillary protraction on prepubertal children with maxillary deficiency: a randomized controlled trial.","authors":"Ahmed Mohamed Kamel,&nbsp;Nour Eldin Tarraf,&nbsp;Ahmed Maher Fouda,&nbsp;Ahmad Mohammed Hafez,&nbsp;Ahmed El-Bialy,&nbsp;Benedict Wilmes","doi":"10.1186/s40510-023-00473-4","DOIUrl":"https://doi.org/10.1186/s40510-023-00473-4","url":null,"abstract":"<p><strong>Background: </strong>The introduction of bone-anchored maxillary protraction eliminated the side effects of facemask in the early treatment of patients with maxillary retrusion. This study aimed to evaluate the effects of miniscrew-anchored maxillary protraction (MAMP) and compare them with the growth changes in an untreated control group in growing patients with Class III malocclusion.</p><p><strong>Methods: </strong>Forty growing patients with Class III malocclusion and retrognathic maxilla were randomly allocated into two groups: treated and control groups. In the treated group, patients were treated with full-time intermaxillary Class III elastics (C3E) anchored by a hybrid hyrax (HH) in the maxilla and a bone-supported bar in the mandible. Protraction was stopped after obtaining a positive overjet. Cephalometric radiographs were acquired before and after the treatment. Data were statistically analyzed on an intention-to-treat basis. Intergroup comparisons were also made using analysis of covariance with the readings at T0 as a covariate.</p><p><strong>Results: </strong>Forty patients agreed to participate, and 30 of them completed the study (treated group, n = 17; control group, n = 13). The average treatment duration was 11.9 months. MAMP resulted in a significant maxillary advancement (A-VR, 4.34 mm) with significant control over the mandibular growth. No significant increase in the mandibular plane angle was found in the treated group compared with the control group. The upper and lower incisors showed significant protrusion in the treated group.</p><p><strong>Conclusions: </strong>Within the limitations of this study and high attrition rate, the MAMP protocol can effectively increase maxillary forward growth with good control over the growth of the mandible antero-posteriorly and vertically.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"22"},"PeriodicalIF":4.8,"publicationDate":"2023-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10258186/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9629311","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 analysis of miniscrew position changes during bone-borne expansion in young and late adolescent patients.","authors":"Marco Migliorati,&nbsp;Anna De Mari,&nbsp;Fabio Annarumma,&nbsp;Hussein Aghazada,&nbsp;Giovanni Battista,&nbsp;Alessandra Campobasso,&nbsp;Maria Menini,&nbsp;Antonino Lo Giudice,&nbsp;Lucia H S Cevidanes,&nbsp;Sara Drago","doi":"10.1186/s40510-023-00469-0","DOIUrl":"https://doi.org/10.1186/s40510-023-00469-0","url":null,"abstract":"<p><strong>Introduction: </strong>Maxillary expansion in patients at the end of their growth relies on the possibility to use miniscrew supported expanders to apply expansion forces directly to the midpalatal suture. Although miniscrews provide a stable anchorage unit, several studies have reported that they do not remain in exactly the same position during treatment. The aim of the present study was to analyze miniscrew position changes after the expansion using bone-borne appliances in late adolescent patients.</p><p><strong>Methods: </strong>Nineteen patients (13 females, 6 males), with a mean age of 17.81 (SD = 4.66), were treated with a Bone-Borne Expander Device. The appliance was designed with 4 miniscrews: 2 in the anterior palatal area, at the third rugae level; 2 in the posterior area. A CBCT and an intraoral scan were obtained before treatment (T0), and then, a second CBCT was obtained after the expansion (T1). Data on peri-suture bone thickness were collected at T0, then the CBCTs were superimposed, and changes between mini-screws position on T0 and T1 were evaluated, both by linear and angular displacements.</p><p><strong>Results: </strong>Significant longitudinal differences were found in the distance of the head and the tip of miniscrews measured at the occlusal plane, as well as angular changes. Correlations between displacement measurements and peri-suture bone thickness and height measurements were found as well.</p><p><strong>Conclusions: </strong>While acting as bone anchor units, miniscrews do not remain in the same position during bone-borne expansion. The amount of displacement was related to peri-sutural total bone height and cortical thickness, especially in the anterior area of the naso-frontal maxillary complex.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"20"},"PeriodicalIF":4.8,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10239743/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9906389","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":"Long-term effectiveness of non-surgical open-bite treatment: a systematic review and meta-analysis.","authors":"Maria-Zoi Theodoridou,&nbsp;Athanasia-Eirini Zarkadi,&nbsp;Vasileios F Zymperdikas,&nbsp;Moschos A Papadopoulos","doi":"10.1186/s40510-023-00467-2","DOIUrl":"https://doi.org/10.1186/s40510-023-00467-2","url":null,"abstract":"<p><strong>Background: </strong>The etiology of open bite is complex, involving various genetic or environmental factors. Several treatment alternatives have been suggested for the correction of open bite, yet their long-term effectiveness remains controversial.</p><p><strong>Objective: </strong>To assess the long-term effectiveness of open-bite treatment in treated with non-surgical approaches versus untreated patients, through lateral cephalometric radiographs.</p><p><strong>Search methods: </strong>Unrestricted search of 16 electronic databases and manual searches up to November 2022.</p><p><strong>Selection criteria: </strong>Randomized or non-randomized controlled trials reporting on the long-term effects of open-bite treatment through angular lateral cephalometric variables.</p><p><strong>Data collection and analysis: </strong>Only angular variables on lateral cephalometric radiographs were considered as primary outcomes. For each outcome, the mean differences and 95% confidence intervals were calculated using the random-effects model to consider existing heterogeneity. The revised Cochrane risk-of-bias tool (R.o.B. 2.0) and the risk-of-bias tool for non-randomized studies for interventions (ROBINS-I) were utilized for the randomized and non-randomized trials, respectively.</p><p><strong>Results: </strong>From the initially identified 26,527 hits, only 6 studies (1 randomized and 5 retrospective controlled trials) were finally included in this systematic review reporting on 244 open-bite individuals (134 patients and 110 untreated controls), while five of them were included in the meta-analyses, assessing either the interval ranging from treatment start to post-retention (T3-T1) or from end of treatment to post-retention period (T3-T2). Regarding the vertical plane, for the T3-T2 interval, no significant differences were found for the assessed skeletal measurements, indicating a relative stability of the treatment results. Similarly, with regard to the T3-T1 interval, no significant differences could be identified for the examined skeletal variables, implying that the produced effects are rather minimal and that the correction of the open bite was performed mainly through dentoalveolar rather than skeletal changes. Further, no significant changes could be identified regarding the inclination of the upper and lower incisors. Only the nasolabial angle was significantly reduced in the treated patients in the long term.</p><p><strong>Conclusions: </strong>According to existing evidence, the influence of non-surgical treatment of open bite on the skeletal tissues and the inclination of the incisors is rather minimal in the long term, while only the nasolabial angle was significantly reduced.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"18"},"PeriodicalIF":4.8,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10232685/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9565069","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":"Correlation between dental arch form and OSA severity in adult patients: an observational study.","authors":"Domenico Ciavarella,&nbsp;Alessandra Campobasso,&nbsp;Elisa Conte,&nbsp;Giuseppe Burlon,&nbsp;Laura Guida,&nbsp;Graziano Montaruli,&nbsp;Michele Cassano,&nbsp;Michele Laurenziello,&nbsp;Gaetano Illuzzi,&nbsp;Michele Tepedino","doi":"10.1186/s40510-023-00464-5","DOIUrl":"https://doi.org/10.1186/s40510-023-00464-5","url":null,"abstract":"<p><strong>Background: </strong>The role of interdental widths and palatal morphology on the development of obstructive sleep apnea (OSA) has not been well investigated in adult patients yet. The aim of this paper was to assess the morphology of maxilla and mandibular dental arches on three-dimensional (3D) casts and to correlate these measurements with the severity of OSA.</p><p><strong>Methods: </strong>Sixty-four patients (8 women and 56 men, mean age 52.4) with a diagnosis of mild-to-moderate OSA were retrospectively enrolled. On each patient, home sleep apnea test and 3D dental models were collected. Apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were recorded, as well as the dental measurements including inter-molar distance, anterior and posterior widths of maxillary and mandibular arches, upper and lower arch lengths, palatal height, and palatal surface area. The respiratory and dental variables were then correlated.</p><p><strong>Result: </strong>A statistically inverse correlation was found between ODI and anterior width of lower arch, maxillary arch length, palatal height, and palatal area. AHI showed a significant inverse correlation with anterior width of mandibular arch and maxillary length.</p><p><strong>Conclusion: </strong>A significant inverse correlation between maxillary and mandibular morphology and respiratory parameters was shown in the present paper.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"19"},"PeriodicalIF":4.8,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10225445/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9545158","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":"The effect of maxillary molar distalization with clear aligner: a 4D finite-element study with staging simulation.","authors":"Bochun Mao,&nbsp;Yajing Tian,&nbsp;Yujia Xiao,&nbsp;Jing Li,&nbsp;Yanheng Zhou","doi":"10.1186/s40510-023-00468-1","DOIUrl":"https://doi.org/10.1186/s40510-023-00468-1","url":null,"abstract":"<p><strong>Introduction: </strong>Long-term simulation of tooth movement is crucial for clear aligner (CA) treatment. This study aimed to investigate the effect of maxillary molar distalization with CA via an automatic staging simulation.</p><p><strong>Method: </strong>A finite-element method (FEM) model of maxillary dentition, periodontal ligaments, attachments, and corresponding CA was established, and a prescribed 2-mm distalization with 0.1 mm each step of the second molar was simulated. The long-term tooth movement under orthodontic force was simulated with an iterative computation method. The morphologic changes of CA during staging were simulated with the thermal expansion method.</p><p><strong>Results: </strong>Twenty steps of molar distalization were simulated. Significant distal tilting of the second molar was revealed, along with the proclination of anterior teeth, which caused the 'reversed bow effect'. For the second molar, 4.63°distal tilting at the 20th step was revealed. The intrusion of the incisors and the second molar were 0.43 mm, 0.39 mm, and 0.45 mm, respectively, at step 20. All the anterior teeth showed a proclination of approximately 1.41°-2.01° at the 20th step. The expression rate of the designed distalization of the second molar was relatively low (approximately 68%) compared to the high efficacy of interdental space opening between molars with CA (approximately 89%).</p><p><strong>Conclusion: </strong>A novel method of simulating long-term molar distalization with CA with FEM was developed. The FEM results suggested distal tilting of the second molar and the proclination of anterior teeth during the molar distalization.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"16"},"PeriodicalIF":4.8,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10183381/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9828657","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":"Spontaneous changes in mandibular incisor crowding from mixed to permanent dentition: a systematic review.","authors":"Cibelle Cristina Oliveira Dos Santos,&nbsp;Renata Travassos da Rosa Moreira Bastos,&nbsp;Silvio Augusto Bellini-Pereira,&nbsp;Daniela Garib,&nbsp;David Normando","doi":"10.1186/s40510-023-00466-3","DOIUrl":"https://doi.org/10.1186/s40510-023-00466-3","url":null,"abstract":"<p><strong>Introduction: </strong>Dental crowding is the most prevalent malocclusion in the mixed and permanent detitions and can have a major impact on dentofacial esthetics. However, adjustments to the development and growth of the dentition can potentiate self-correction of dental crowding during childhood.</p><p><strong>Objective: </strong>To evaluate the physiological behavior of mandibular incisor crowding in the transition from mixed to permanent dentition.</p><p><strong>Methodology: </strong>Five electronic databases (PubMed, Scopus, Web of Science, LILACS and LIVIVO) and part of the gray literature (Proquest and Google Scholar) were investigated, based on the eligibility criteria associated with the acronym PECO, until June 2022. The risk of bias was assessed using the ROBINS-E tool and the certainty of evidence, the GRADE tool.</p><p><strong>Results: </strong>Among the 2.663 studies identified, five were selected for qualitative analysis, of which one have a low risk of bias, and four, a moderate risk. A total of 243 patients were evaluated. Evidence with a high level of certainty was generated indicating a tendency for improvement in mandibular incisor crowding from mixed to permanent dentition, with mandibular incisor crowding decreasing from 0.17 to 4.62 mm on average. The mandibular incisor crowding reduction seems to be associated with the amount of initial crowding and spontaneous dental arch dimensional changes that occur in the mixed dentition and culminate in the increase in arch perimeter, leeway space, incisor protrusion and transverse growth of the maxillary and mandibular arch.</p><p><strong>Conclusion: </strong>Based on moderate scientific evidence, spontaneous longitudinal changes in dental arch in the transition from the mixed to the permanent dentition demonstrate a spontaneous improvement in mandibular incisor crowding by up to 4.62 mm. These evidence provide a scientific basis for planning only longitudinal follow-up in patients with mild to borderline moderate mandibular incisor crowding in the mixed dentition avoiding overtreatment.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"15"},"PeriodicalIF":4.8,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10164666/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9807620","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":"Accurate gingival segmentation from 3D images with artificial intelligence: an animal pilot study.","authors":"Min Yang,&nbsp;Chenshuang Li,&nbsp;Wen Yang,&nbsp;Chider Chen,&nbsp;Chun-Hsi Chung,&nbsp;Nipul Tanna,&nbsp;Zhong Zheng","doi":"10.1186/s40510-023-00465-4","DOIUrl":"https://doi.org/10.1186/s40510-023-00465-4","url":null,"abstract":"<p><strong>Background: </strong>Gingival phenotype plays an important role in dental diagnosis and treatment planning. Traditionally, determining the gingival phenotype is done by manual probing of the gingival soft tissues, an invasive and time-consuming procedure. This study aims to evaluate the feasibility and accuracy of an alternatively novel, non-invasive technology based on the precise 3-dimension (3D) soft tissue reconstruction from intraoral scanning and cone beam computed tomography (CBCT) to predict the gingival biotype.</p><p><strong>Methods: </strong>As a proof-of-concept, Yorkshire pig mandibles were scanned, and the CBCT data were fed into a deep-learning model to reconstruct the teeth and surrounding bone structure in 3D. By overlaying the CBCT scan with the intraoral scans, an accurate superposition was created and used for virtual measurements of the soft tissue thickness. Meanwhile, gingival thicknesses were also measured by a periodontal probe and digital caliper on the buccal and lingual sides at 3 mm apical to the gingival margin of the posterior teeth and compared with the virtual assessment at the same location. The data obtained from virtual and clinical measurements were compared by Wilcoxon matched-pairs signed-rank analysis, while their correlation was determined by Pearson's r value. The Mann-Whitney U test was used for intergroup comparisons of the amount of difference.</p><p><strong>Results: </strong>Among 108 investigated locations, the clinical and virtual measurements are strongly positively correlated (r = 0.9656, P < 0.0001), and only clinically insignificant differences (0.066 ± 0.223 mm) were observed between the two assessments. There is no difference in the agreement between the virtual and clinical measurements on sexually matured samples (0.087 ± 0.240 mm) and pre-pubertal samples (0.033 ± 0.195 mm). Noticeably, there is a greater agreement between the virtual and clinical measurements at the buccal sites (0.019 ± 0.233 mm) than at the lingual sites (0.116 ± 0.215 mm).</p><p><strong>Conclusion: </strong>In summary, the artificial intelligence-based virtual measurement proposed in this work provides an innovative technique potentially for accurately measuring soft tissue thickness using clinical routine 3D imaging systems, which will aid clinicians in generating a more comprehensive diagnosis with less invasive procedures and, in turn, optimize the treatment plans with more predictable outcomes.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"14"},"PeriodicalIF":4.8,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10149545/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9398486","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":"Accumulated biomechanical effects of mandibular molar mesialization using clear aligners with auxiliary devices: an iterative finite element analysis.","authors":"Xinwei Lyu,&nbsp;Xing Cao,&nbsp;Luxian Chen,&nbsp;Yuyao Liu,&nbsp;Huilin Li,&nbsp;Cheng Hu,&nbsp;Jiali Tan","doi":"10.1186/s40510-023-00462-7","DOIUrl":"https://doi.org/10.1186/s40510-023-00462-7","url":null,"abstract":"<p><strong>Background: </strong>The biomechanics generated by the clear aligner (CA) material changes continuously during orthodontic tooth movement, but this factor remains unknown during the computer-aid design process and the predictability of molars movement is not as expected. Therefore, the purpose of this study was to propose an iterative finite element method to simulate the long-term biomechanical effects of mandibular molar mesialization (MM) in CA therapy under dual-mechanical systems.</p><p><strong>Methods: </strong>Three groups including CA alone, CA with a button, and CA with a modified lever arm (MLA) were created. Material properties of CA were obtained by in vitro mechanical experiments. MM was conducted by the rebound force exerted by CA material and the mesial elastic force (2N, 30° to the occlusal plane) applied to the auxiliary devices. Stress intensity and distribution on periodontal ligament (PDL), attachment, button and MLA, and displacement of the second molar (M2) during the iterations were recorded.</p><p><strong>Results: </strong>There was a significant difference between the initial and cumulative long-term displacement. Specifically, compared to the beginning, the maximum stress of PDL decreased by 90% on average in the intermediate and final steps. The aligner was the main mechanical system at first, and then, the additional system exerted by the button and MLA dominated gradually. The stress of attachments and auxiliary devices is mainly concentrated on their interfaces with the tooth. Additionally, MLA provided a distal tipping and extrusive moment, which was the only group that manifested a total mesial displacement of the root.</p><p><strong>Conclusions: </strong>The innovatively designed MLA was more effective in reducing undesigned mesial tipping and rotation of M2 than the traditional button and CA alone, which provided a therapeutic method for MM. The proposed iterative method simulated tooth movement by considering the mechanical characteristic of CA and its long-term mechanical force changes, which will facilitate better movement prediction and minimize the failure rate.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"13"},"PeriodicalIF":4.8,"publicationDate":"2023-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10083150/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9651927","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":"Effectiveness of clear aligners in achieving proclination and intrusion of incisors among Class II division 2 patients: a multivariate analysis.","authors":"Xinyu Yan, Xiaoqi Zhang, Linghuan Ren, Yi Yang, Qingxuan Wang, Yanzi Gao, Qingsong Jiang, Fan Jian, Hu Long, Wenli Lai","doi":"10.1186/s40510-023-00463-6","DOIUrl":"10.1186/s40510-023-00463-6","url":null,"abstract":"<p><strong>Background: </strong>The predictability of incisor movement achieved by clear aligners among Class II division 2 patients is poorly understood. The aim of this retrospective study was to determine the effectiveness of clear aligners in proclining and intruding upper incisors and its influencing factors.</p><p><strong>Methods: </strong>Eligible patients with Class II division 2 malocclusion were included. For clear aligner therapy, three types of incisor movements were designed: proclination, intrusion and labial movement. Pre-treatment and post-treatment dental models were superimposed. The differences between predicted and actual (DPA) tooth movement of incisors were analyzed. Univariate and multivariate linear regression were used to analyze the potential influencing factors.</p><p><strong>Results: </strong>A total of 51 patients and their 173 upper incisors were included. Actual incisor proclination and intrusion were less than predicted ones (both P < 0.001), while actual labial movement was greater than predicted one (P < 0.001). Predictability of incisor proclination and intrusion was 69.8% and 53.3%, respectively. Multivariate linear regression revealed that DPA of proclination was significantly positively associated with predicted proclination (B = 0.174, P < 0.001), ipsilateral premolar extraction (B = 2.773, P < 0.001) and ipsilateral canine proclination (B = 1.811, P < 0.05), while negatively associated with molar distalization (B = - 2.085, P < 0.05). The DPA of intrusion was significantly positively correlated with predicted intrusion (B = 0.556, P < 0.001) while negatively associated with labial mini-implants (B = - 1.466, P < 0.001). The DPA of labial movement was significantly positively associated with predicted labial movement (B = 0.481, P < 0.001), while negatively correlated with molar distalization (B = - 1.004, P < 0.001), labial mini-implants (B = - 0.738, P < 0.001) and age (B = - 0.486, P < 0.05).</p><p><strong>Conclusions: </strong>For Class II division 2 patients, predicted incisor proclination (69.8%) and intrusion (53.3%) are partially achieved with clear aligner therapy. Excessive labial movement (0.7 mm) of incisors may be achieved. Incisor movement is influenced by predicted movement amount, premolar extraction, canine proclination, molar distalization, mini-implants and age.</p>","PeriodicalId":56071,"journal":{"name":"Progress in Orthodontics","volume":"24 1","pages":"12"},"PeriodicalIF":4.8,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10068686/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9253173","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}