Management Strategies for Open Bite Relapse: A Systematic Review and Meta-Analysis.

The purpose of orthodontic therapy is to correct malocclusion and produce a stable outcome that endures over time. Long-term stability can be difficult to achieve, and many patients relapse after treatment, particularly in instances of open bite relapse (OBR). This systematic review aimed to analyze different types of management strategies for OBR and conduct a meta-analysis to find the best method of dealing with relapse. A comprehensive search was carried out across six major online databases using relevant keywords pertaining to our study, including "open bite relapse," "orthodontic retention," "orthodontic surgery," "orthodontic appliance," "orthodontic management," "orthodontic treatment," "orofacial myofunctional therapy (OMT)," "skeletal anchorage," and "treatment follow-up period." Eleven studies were selected after the application of relevant inclusion and exclusion strategies. The mean follow-up period of treatment for the studies ranged from six months to 4.5 years. Of all the management strategies assessed, OMT was found to be the least effective for OBR management. Surgical management modalities, such as mandibular repositioning and molar intrusion using skeletal anchorage, in conjunction with the usage of orthodontic appliances, were found to be noticeably effective, especially in the cases of participants who were <18 years of age. However, when utilized on a singular basis, either of them was found to be lacking the desired effect. The overall odds ratio (OR) of 0.48 (0.37, 0.64) and risk ratio (RR) of 0.62 (0.51, 0.74) were obtained after the meta-analysis of the different interventions for OBR, indicating statistical significance. There were only 11 studies included in the study, so it's possible that not all management strategies for OBR were fully understood. The limited number of studies may also have affected the generalizability of the findings. Although statistical differences were obtained to a certain degree, more clinical trials are needed to assess the effect of such surgical modalities as a viable management tool for OBR, since these represent a significant limiting factor in terms of the overall cost of the treatment placed upon the patient. Prior to the start of the research, registration was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. The research protocol was created to meet the goals and was properly filed with the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023401991).

Effectiveness of Invisalign Treatment on Open Bite Correction.

Background: Open bite is a common orthodontic malocclusion that can have functional and aesthetic implications. Traditional orthodontic treatments have been used to correct open bites, but the effectiveness of Invisalign, a clear aligner therapy, in open bite correction remains a topic of interest. Materials and Methods: A retrospective analysis was conducted on a cohort of 50 patients with open bites who underwent Invisalign treatment. Pre-treatment and post-treatment records, including cephalometric radiographs, dental models, and clinical photographs, were assessed. The open bite was defined as a negative overbite greater than 2 mm. Treatment duration, number of aligners used, and patient compliance were also recorded. Statistical analysis, including paired t-tests and subjective patient feedback, was employed to evaluate the treatment outcomes. Results: The mean pre-treatment open bite was -3.5 mm (SD = 1.2), and the mean treatment duration was 18 months (SD = 2.5). On average, patients received 24 sets of aligners (SD = 4.1) during the treatment. Post-treatment evaluation showed that the mean overbite improved to + 1.5 mm (SD = 0.8), indicating successful open bite correction. The paired t-test revealed a statistically significant difference between pre-treatment and post-treatment open bite measurements (P < 0.001). Patient satisfaction was high, with 90% of participants reporting improved aesthetics and comfort. Conclusion: Invisalign treatment demonstrates effectiveness in correcting open bites, with statistically significant improvements in overbite measurements.

Effects of Froggy Mouth Appliance in Pediatric Patients with Atypical Swallowing: A Prospective Study.

Atypical swallowing has a high incidence in growing subjects. Orthopedic treatment with orthodontic appliances and speech therapy are the main approaches to this problem. The aim of this prospective study was to evaluate the changes in the dental arches induced by one year of treatment with the Froggy Mouth myofunctional appliance designed to correct atypical swallowing. In total, 16 patients with atypical swallowing were instructed to use the Froggy Mouth appliance. A digital intraoral impression was taken at baseline (T0). The Froggy Mouth appliance had to be used for 15 min/day throughout the treatment period. At the end of the first year of treatment (T1), another impression was taken with the same intraoral scanner. Digital casts of the T0 and T1 impressions were obtained using software and the two casts were superimposed to record the following measurements: upper intercanine distance, upper arch diameter, upper arch width, overbite and overjet. The data were statistically analyzed (significance threshold: p < 0.05). Student's t-test was used to compare pre- and post-treatment measurements. Linear regressions were performed to assess the influence of arch width on anterior and posterior diameters. A significant increase was found for the upper arch diameters (p < 0.05), whereas no statistically significant difference was found for the incisor relationship (overjet/overbite) (p > 0.05). To date, the efficacy of this appliance has not been extensively studied. According to the present prospective study, the Froggy Mouth protocol could be a valuable method as a myofunctional therapy for atypical swallowing, but further studies are needed to confirm these preliminary results.

Correlation between Malocclusion and Mandibular Fractures: An Experimental Study Comparing Dynamic Finite Element Models and Clinical Case Studies.

Mandibular fractures are very common in maxillofacial trauma surgery. While previous studies have focused on possible risk factors related to post-operative complications, none have tried to identify pre-existing conditions that may increase the risk of mandibular fractures. We hypothesized, through clinical observation, that anatomical conditions involving poor dental contacts, such as malocclusions, may increase the risk of mandibular fractures. This work was subdivided into two parts. In the first part, Digital Imaging and Communications in Medicine (DICOM) data of four healthy patients characterized by different dentoskeletal occlusions (class I, class II, class III, and anterior open bite) have been used to develop four finite element models (FEMs) that accurately reproduce human bone structure. A vertical and lateral impact have been simulated at increasing speed on each model, analyzing the force distribution within the mandibular bone. Both vertical and lateral impact showed higher level of stress at the impact point and in the condylar area in models characterized by malocclusion. Specifically, the class III and the open bite models, at the same speed of impact, had higher values for a longer period, reaching critical stress levels that are correlated with mandibular fracture, while normal occlusion seems to be a protective condition. In the second part of this study, the engineering results were validated through the comparison with a sample of patients previously treated for mandibular fracture. Data from 223 mandibular fractures, due to low-energy injuries, were retrospectively collected to evaluate a possible correlation between pre-existing malocclusion and fracture patterns, considering grade of displacement, numbers of foci, and associated CFI score. Patients were classified, according to their occlusion, into Class I, Class II, Class III, and anterior open bite or poor occlusal contact (POC). Class I patients showed lower frequencies of fracture than class II, III, and open bite or POC patients. Class I was associated with displaced fractures in 16.1% of cases, class II in 47.1%, class III in 48.8% and open bite/POC in 65.2% of cases (p-value < 0.0001). In class I patients we observed a single non-displaced fracture in 51.6% of cases, compared to 12.9% of Class II, 19.5% of Class III and 22.7% of the open bite/POC group. Our analysis shows that class I appears to better dissipate forces applied on the mandible in low-energy injuries. A higher number of dental contacts showed a lower rate of multifocal and displaced fractures, mitigating the effect of direct forces onto the bone. The correlation between clinical data and virtual simulation on FEM models seems to point out that virtual simulation successfully predicts fracture patterns and risk of association with different type of occlusion. Better knowledge of biomechanics and force dissipation on the human body may lead to the development of more effective safety devices, and help select patients to plan medical, orthodontic/dental, and/or surgical intervention to prevent injuries.

An evaluation of cephalometric predictors of anterior open bite; An assessment of dental and skeletal parameters in an orthodontic population.

BACKGROUND: Anterior open bite (AOB) malocclusion is one of the highly challenging malocclusions. Cephalometric radiographs have been used for the diagnosis of occlusal anomalies in the vertical and anteroposterior directions. This study aims to compare skeletal and dental features in open and non-open bite subjects to identify factors that help predict and categorize open bites in a Nigerian population. MATERIALS AND METHODS: Pretreatment cephalometric radiographs of 82 patients were recruited into this study. This study comprised 41 AOB patients and 41 (Class 1 malocclusion) patients (control group). The radiographs were obtained from the orthodontic unit, Department of Child Dental Health of the Lagos University Teaching Hospital, Idi-Araba Lagos. Cephalometric tracing and analysis of the obtained radiographs were used to identify and compare the skeletal and dental differences between the two groups. RESULTS: The mean age of the participants was 20.47 ± 8.05 years. The patients consisted of 26 (31.7%) males and 56 (68.3%) females. There was a significant difference in the open bite depth indicator (ODI) of the open bite (P value < 0.001). There was a statistically significant increase in the vertical skeletal parameters - lower facial height (LFH), total facial height (TFH), posterior facial height (PFH), Frankfort-mandibular plane angle (FMA), mandibular-maxillary angle (MMA), and gonial angle in the AOB group compared to the control group. The vertical height of the dentoalveolar segments measured was all significantly increased in the open bite group compared to the control group. CONCLUSION: The results suggest that the skeletal and dental vertical parameters, including ODI of the open bite subjects, varied compared with the non-open bite subjects in the Nigerian population studied and could be used to predict AOB tendency.

Noninvasive conservative management of anterior open bite treated with TADs versus clear aligner therapy.

OBJECTIVES: Anterior open bite can be treated non-surgically via molar intrusion using temporary skeletal devices (TAD). Clear aligner therapy (CAT) is recognized as a viable therapeutic modality for non-extraction treatment of adults with mild open bite. This study aimed to compare the treatment effect and mechanisms of open bite closure between patients treated with braces and TADs double arch intrusion and those treated with CAT. Treatment success at T3 was based on 1- positive overbite on ceph; 2- Change in the vertical dimension 3- post treatment POSI score equal to zero. MATERIAL AND METHODS: The TAD group includes 18 consecutively treated patients from the main author. The CAT group consisted of 16 selected patients from three different orthodontists. The observation time points were as follows: pretreatment (T1), end of molar intrusion and positive overbite achieved (T2), end of treatment (T3), at least 6-month follow-up (T4). Treatment changes were assessed by cephalometric analysis and frontal intraoral photo. RESULTS: At the end of treatment, 100% of the patient of the TAD group and 78,6% of the CAT group had a posi score of 0. The TAD group showed a significant reduction in vertical measurements (SN-MPA: -1,55° ± 0.41, LAFH: -3,05 ± 0.51 mm, U6-PP: -1.48 ± 0.30 mm), but the CAT group did not have significant changes for these variables. Both groups had significant increases in overbite from T1 to T3 (TAD: 4,32 ± 0,5 mm; CAT: 2,33 ± 0.56 mm), and overbite remained stable at T4. The CAT group did not have a significant upper molar intrusion, but a significant extrusion of 1.22 ± 0.42 mm of the lower incisor occurred. CONCLUSION: The TAD group achieved bite closure by upper molar intrusion, lower molar and incisors vertical control, and mandibular plane counterclockwise rotation, resulting in an improved AP and vertical relationship. The CAT group achieved bite closure through the lower incisor extrusion without significant change in the vertical dimension. CLINICAL RELEVANCE: This study provides relevant information about the skeletal and dental changes of open bite treatment with TADs double arch intrusion. The comparison with a control group treated with CAT confirms known information.

Short- and Long-Term Effects of Maxillary Expander with Tongue Crib in Growing Open-Bite and Skeletal Class II Patients: A Retrospective Study.

The purpose of this study was to evaluate short- and long-term changes in growing patients with Class II malocclusion and open bite after rapid maxillary expansion (RME). A retrospective cohort study was conducted with 16 growing patients with open-bite malocclusion enrolled in a group treated with a rapid maxillary expander (RME) with a crib (TG), and 16 untreated patients with similar malocclusion in the control group (CG). Cephalograms were recorded before starting the treatment (T0), at the end of the latency phase (T1), and before the fixed therapy (T2) in order to analyze skeletal and dental changes in vertical, transversal, and sagittal relationships. Statistical analysis was performed with α = 0.05 as level of significance. At the end of the active expansion (T1), all subjects in the TG showed a corrected overbite with a statistically significant difference compared to the CG (p > 0.05). A significant decrease in jaw divergence was found in the TG compared to the CG (p < 0.05). At T2, all treated patients maintained a correct overbite. Statistical analysis revealed a significant decrease in maxillary, mandibular, and intermaxillary divergence in the TG compared to the CG (p < 0.05). This protocol could be effective in growing open-bite patients, showing a long-term decrease in facial divergence. The fixed crib allowed to normalize myofunctional activity.

Surgery-first in interdisciplinary class II cases.

OBJECTIVES: To present an interdisciplinary case treated with a surgery-first orthognathic approach, followed by orthodontic and prosthodontic treatment. CLINICAL CONSIDERATIONS: After an accurate pre-operative virtual planning, a young patient with skeletal class II, retrognathia, and an anterior open bite was treated with bimaxillary orthognathic surgery without pre-surgical orthodontic decompensation. Orthodontic treatment was carried out post-operatively. The treatment was completed with a prosthodontic phase to improve the final esthetic outcome of the smile. CONCLUSIONS: A surgery-first approach allowed to achieve esthetic and functional results in a reduced treatment duration that remained stable over the course of 1 year. The outcomes were consistent with prior research in terms of advantages brought by following an accurately planned surgery-first protocol. Nevertheless, longer-term follow-up was required to evaluate the treatment stability. CLINICAL SIGNIFICANCE: An accurately planned surgery-first approach significantly helped in shortening the duration of the treatment, while providing a stable, functional, and esthetic solution to the patient's problems.

Anterior open bite correction via molar intrusion: Diagnosis, advantages, and complications.

Anterior open bite can be effectively treated nonsurgically via molar intrusion. This technique, involving the intrusion of posterior teeth using temporary skeletal anchorage devices, prompts counterclockwise rotation of the mandible. This rotation not only corrects anterior open bite but also contributes to a decrease in anterior facial height, improvements in lip incompetency, and forward movement of the chin. For successful outcomes, temporary skeletal anchorage devices, installed on both the buccal and palatal sides, must deliver equivalent intrusion force to the maxillary teeth. Treatment planning should consider factors such as skeletal discrepancies, vertical excess, incisor exposure, and configuration of the occlusal plane. Clinicians are advised to closely monitor periodontal changes and consider overcorrection to ensure lasting stability and maintenance of incisal overlap post-treatment.

Changes in occlusal relationships observed using an intraoral scanner in patients with an acquired open bite: A case report.

PATIENTS: This case report describes a procedure for assessing changes in occlusal relationships in patients with acquired open bites due to temporomandibular joint disease using an intraoral scanner (IOS). A digital impression was made using the IOS at the initial visit. Subsequent impressions were made every 6 months using the IOS and magnetic resonance imaging (MRI) or computed tomography (CT). Standard triangulated language (STL) image files of two digital impressions at different points in time were superimposed, including the occlusal relationship with reference to the maxillary dentition. Finally, three-dimensional (3D) changes in the occlusal relationship over time were evaluated. DISCUSSION: In Case 1, the superimposed STL image indicated almost no evident deviation of the mandible. Therefore, an orthodontic treatment was initiated. In contrast, in cases 2 and 3, where changes in the occlusal relationship continued, secondary treatment was postponed and patients continued to be monitored periodically. In case 3, even though left condyle resorption was progressive, the degree of open bite on the right side improved after 6 months. However, the open bite continued to progress for another 6 months despite the stability of the condyle. CONCLUSIONS: Changes in the condylar shape observed using imaging may not always reflect changes in the occlusal relationship. In addition to changes in the condyles and eminences of the temporomandibular joint (TMJ), changes in the occlusal relationships of patients with acquired open bite should be evaluated using an intraoral scanner.

Surgical-orthodontic with atypical extraction pattern as a treatment for an anterior open bite: A case report.

This case report described th e surgical- orthodontic interdisciplinar y t reatment of a patie nt with skeletal anterior open bite, class III skelet al pa ttern, steep mandibular plane, increa sed lower face heigh t, and thin mandibular sym physis. The or thodontic p reparation included an unusual extraction pattern (maxillary right first molar, maxillary left second premolar, and mandibular right central incisor), combined with two-jaw surger y comprised of maxillar y advancement and d ifferential impac tion, b ilateral malarplasty augme ntation and man dib ula r asymmetric bilateral sagittal split osteotomy setback. The follow-up of a rare complication of surgical hooks breakage during surgery is reported. Guided by 3- dimesional digital platforms, treatment planning and execution, resulted in a more ba lan ced a nd proportionate face with functional occlusion, and the case stability is shown i n a 32-m onth follow-up.

Comparison of mesiodistal angulations of premolars and molars in anterior open bite subjects with different sagittal malocclusions: A retrospective study.

INTRODUCTION: Mesiodistal angulation of premolars and molars can be altered by forces of open bite malocclusion. The aim of this study was to compare the mesiodistal angulations of the posterior teeth in class I, II, and III individuals with anterior open bite (AOB) versus individuals with harmonious occlusion. METHODS: This comparative cross-sectional study used 299 lateral head radiographs of individuals with permanent dentition. There were 4 groups (harmonious occlusion [n=89], Class I open bite [OB] [n=75], Class II OB [n=66], and Class III OB [n=69]). Premolar (1UPM, 2UPM) and molar (1UM, 2UM) angulations were measured relative to the occlusal plane and the palatal or mandibular plane by a trained and calibrated evaluator. ANOVA and Scheffe tests were used for statistical analyses (P<0.05). RESULTS: The mesial angulation of the upper premolars showed greater angulation of between approximately 2° and 5° in the OB groups compared to the harmonious occlusion group (P<0.05). Only in the Class II OB group did the first and second upper molars show distal angulation in relation to the palatal plane (1UM 81.85°±5.42°; 2UM 75.32±7.4°) (P<0.05). The Class III OB group presented the greatest distal angulations of the lower premolars and molars (between 3° to 5° of difference, P<0.05) in relation to those of the harmonious occlusion group. CONCLUSIONS: The upper first premolars in all the AOB groups and the lower second premolars in the Class II OB group had greater mesioangulation. Additionally, the upper molars of the Class II OB group and the lower molars of the Class III OB group showed distoangulation compared with the molars in the group with harmonious occlusion.

Adult female skeletal anterior open bite treated by customized lingual orthodontic appliance with miniscrews-assisted in vertical control for perfect orthodontic compensation: A case report with 5-year follow-up.

The benefits of lingual orthodontics go beyond appearance. In this case study, a 30-year-old female patient was treated with a custom lingual orthodontic appliance for a Class II high-angle malocclusion, anterior open bite, incisor biprotrusion and crossbite, unilateral second molar scissor bite and dysfunctional tongue thrust. To achieve a counterclockwise rotation of the mandible, implant anchorage was used to control the vertical height. To complete the compensatory therapy, four first premolars were removed. As well as ensuring aesthetics over the 20-month treatment period, the treatment also established a Class I molar relationship, normal overbite and overjet, and improved the facial profile. After a five-year follow-up, the treatment results remained stable.

Orthodontic correction of anterior open bite using skeletal anchorage: systematic review and meta-analysis.

The purpose of this study was to investigate the scientific evidence on the short- and long-term effects of orthodontic correction of anterior open bite (AOB) using skeletal anchorage (SA). Clinical studies on the use of SA for AOB in patients with permanent dentition, or at least 12 years of age, were searched. Short- and long-term (≥2 years) outcomes were collected. Mean differences were calculated from pooled data. Twenty-four eligible articles with a total of 362 subjects were selected for inclusion in the meta-analysis. There was a significant increase in overbite (3.88 mm, P < 0.001) and maxillary molar intrusion (-2.15 mm, P < 0.001). The mandible showed counterclockwise rotation with anterosuperior chin movement (all P < 0.001). Long term, the decrease in overbite was 19.9% and decrease in molar intrusion was 22.9%. The decrease in the mandibular projection was 14.6% for ANB (A-point-nasion-B-point angle) and 46.2% for mandibular anteroposterior position. The overall risk of bias in the included studies was rated as moderate to high, and publication bias existed for several key variables. SA for maxillary molar intrusion effectively improved dental and skeletal outcomes, but there was a long-term decrease in overbite and maxillary molar position. The variable data quality, heterogeneity, and publication bias in investigated outcomes are limitations in interpreting the findings.

Effect of occlusal hypofunction on centre of resistance in maxillary central incisor using the finite element method.

OBJECTIVES: To determine differences in the location of centre of resistance (Cres) between functional and hypofunctional teeth and to evaluate the relationship between the pulp cavity volume and locations of the Cres, using the finite element (FE) method. DESIGN: Retrospective cohort study. PARTICIPANTS: FE models of right maxillary central incisor, derived from cone-beam computed tomography (CBCT) images of 46 participants, were divided into normal function (n = 23) and hypofunction (n = 23) groups using anterior overbite and cephalometric measurements. METHODS: Measurements of the tooth and pulp cavity volume were made from the CBCT. Cres levels were presented as percentages of the root length from the root's apex. All data were analysed and compared using the independent t-test (P < 0.05). The relationship between the location of Cres and volume ratios were evaluated statistically. RESULTS: The means of the pulp cavity/tooth volume and root canal/ root volume ratio of the maxillary central incisor in the anterior open bite group were significantly greater than those in the normal group. The average location of Cres in the anterior open bite group was 0.6 mm (3.7%) apically from the normal group, measured from root apex. The difference was statistically significant (P < 0.01). There was a significant correlation between root canal/root volume ratio and locations of Cres (r = -0.780, P < 0.001). CONCLUSIONS: The Cres in the hypofunctional group was located more apical than the functional group. As the pulp cavity volume increased, the level of Cres shifted apically.

Digitization and validation of the open bite checklist manifesto: a step toward artificial intelligence.

OBJECTIVES: To introduce and validate newly designed computer software to aid in the diagnosis of anterior open bite (AOB). MATERIALS AND METHODS: The software was constructed based on the algorithm of a standardized open bite checklist, which considered skeletal, dental, and soft tissue components, as well as smile characteristics. Feeding the software with this input yielded a digital form output (DFO) in the guise of a diagnostic report characterizing the AOB phenotype, contributing components, severity, associated problems, and functional factors. For validation, DFO was compared to a conventional form output (CFO), created in a standardized manner according to expert opinions. Agreement between the DFO and CFO in terms of AOB phenotype was the primary outcome, while the secondary outcome was the number of missing diagnostic components in either method. RESULTS: Percentage of agreement between CFO and DFO was 82.2%, with a kappa coefficient of 0.78, which is considered a good level of agreement. There was a statistically significant relationship between the number of missing diagnostic components in CFO and level of disagreement, which rendered the DFO more reliable. CONCLUSIONS: Newly constructed software represents an efficient and valid diagnostic tool for AOB and its contributing components. There was good agreement between CFO and DFO, with the latter being more comprehensive and reliable. The algorithm built in the software can be used as the basis for a future artificial intelligence model to aid in the diagnosis of AOB.

The effect of vertical skeletal proportions on overbite changes in untreated adolescents: a longitudinal evaluation.

OBJECTIVES: To evaluate the change in overbite within an untreated cohort from 9 to 18 years of age and to compare age-related changes in overbite depth based on vertical skeletal proportion. MATERIALS AND METHODS: Lateral cephalograms were obtained from the American Association of Orthodontists Foundation (AAOF) Craniofacial Growth Legacy Collection Project. All cephalometric outcome measures were assessed at ages 9-11 (T1), 13-15 (T2), and 17-19 (T3) years. Generalized estimating equation (GEE) regression models were fit to examine the effect of MP-SN on overbite adjusted for age and gender. RESULTS: A total of 130 subjects from the Denver, Bolton Brush, and Oregon Growth Studies were included. Overbite was relatively constant from T1 to T3 irrespective of facial type, with a minor decrease (0.15 mm) being observed overall. There was a transient increase between T1 and T2 (0.31 mm) that was canceled out by changes during later adolescence. Based on the GEE regression model adjusted for time and gender, a minor but statistically significantly greater reduction in overbite arose as MP-SN increased (coefficient = -0.080; 95% confidence interval -0.12, -0.04; P < .01). CONCLUSIONS: In hyperdivergent subjects, a marginal decrease in overbite was observed from 9 to 18 years of age, with a transient increase from the period spanning 9-11 years to 13-15 years, which was negated in later adolescence. There are limited data to suggest that observation of vertical growth is required in most patients with marginally increased vertical facial proportions in the juvenile and pubertal phases.

A 3D Finite Element Analysis of biomechanical effects on teeth and bone during true intrusion of posteriors using miniscrews.

OBJECTIVE: The primary objective of this study was to investigate the biomechanical effects and stresses on bone, PDL, cementum and displacement along X-,Y- and Z-axis during true intrusion of molars using mini-implants with finite element analysis; the secondary objective of the study was to find out the best method for posterior intrusion in clinical practice. MATERIAL AND METHODS: A 3D finite element method was used to simulate true molar intrusion using sliding mechanics. Two groups were made, with mini-implants placed on buccal side and palatal side with a cap splint for MODEL1, and a single mini-implant placed buccally with transpalatal arch (TPA) for MODEL2. The material characteristics which include the Young's modulus and Poison's ratio were assigned. von Mises stress, principal stress on PDL and alveolar bone, displacements in all the 3 planes were determined. RESULTS: Bone stress patterns showed compressive stresses on the buccal aspect and tensile stresses on the palatal aspect for both MODELS. Stresses in the PDL and cementum were mainly concentrated in the apex region, with a more uniform distribution of stresses for MODEL 1. Tooth displacement showed true intrusion for both MODELS, i.e. the Z axis, and a more controlled buccal tipping for MODEL 1. CONCLUSION: Of the modalities compared, the best controlled tooth movements for posterior intrusion in the treatment of open bite were obtained with mini-implants placed with a cap splint (MODEL 1).

Orthodontic correction of acquired open bite with TMJ degeneration: A retrospective study of outcomes and stability.

BACKGROUND/PURPOSE: Newly developed temporary anchorage devices (TADs) serve a strong orthodontic anchorage to intrude molars for correction of anterior open bite (AOB). We measured cephalometric changes in skeletal open bite patients which developed subsequently to temporomandibular joint disorders with bilateral point contacts at terminal molars. METHODS: We retrospectively recruited 32 patients who had been treated their TMD before orthodontic correction (overbite: -3.14 ± 1.86 mm). Partial orthodontic appliances were used to intrude posterior teeth using TADs until positive OB obtained (T1). Full fixed appliances were then used to achieve proper overjet and overbite (T2). We collected lateral cephalograms before (T0), during (T1) and after (T2) treatment, and at follow-ups (T3). Using ANOVA, we analyzed the differences among these time points to determine treatment changes and stability of orthodontic results. RESULTS: In this group predominantly comprising young adult women, orthodontic treatment with TADs significantly reduced upper posterior dental heights (T2-T0:-1.84 ± 0.66 mm) and facilitated the retraction and uprighting upper incisors (T2-T0: -9.92 ± 1.72°), to achieve appropriate OJ (T2-T0: -3.21 ± 0.49 mm) and OB (T2-T0: 4.10 ± 0.28 mm) with p < 0.05. Except upper posterior dental height, most of cephalometric changes including OJ, OB, and upper incisal axis remained significant at follow-ups with retention time of 3.7 ± 2.6 years. Only three out of 30 patients experienced small amount of open bite at T3. CONCLUSION: Orthodontic correction of OJ remained relatively stable among 90 % of patients with TMJ degeneration by intrusion via TADs. This modern but conservative orthodontic approach can improve occlusal functions in skeletal open bites.

Cone-beam computed tomography study of root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in high-angle Class Ⅱ open bite patients / 口腔疾病防治

Objective@#This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite, aiming to provide a reference for clinical treatment.@*. Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT images of eighty-one untreated patients (40 anterior open bite patients and 41 normal overbite patients) with high-angle skeletal Class Ⅱ malocclusion were selected before treatment. Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology, and the differences between the two groups were analyzed.@*Results@#There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group, significant differences were found in the root length of maxillary central incisor （11.12 ± 1.37） mm、mandibular central incisor（10.15 ± 1.09）mm, mandibular lateral incisor（11.27 ± 1.15）mm and mandibular canine（12.81 ± 1.48）mm between the open bite group and the normal overbite group（P<0.05）. On the other hand, the two groups were significantly different in crown-root morphology of the maxillary central incisor (1.10° ± 3.62° vs. 4.53° ± 2.30°, P<0.01) but not in the mandibular central incisor.@*Conclusion@#The root length of the maxillary central incisor, mandibular central incisor, mandibular lateral incisor, mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients, and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root. The crown-root angle is smaller, which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱ open bite patients.