Correction of bimaxillary protrusion with four first premolar extractions and T-Loop mechanics: A case report

@#Bimaxillary protrusion is a condition characterized by proclined upper and lower incisors with an increased prominence of the lips. This is a case of a 18-year-old with bimaxillary protrusion, mild crowding on the maxilla and mandible, and mandibular dental midline shift to the left by 1 mm. The four first premolars were extracted using a pre-adjusted bracket. This bracket had in-built prescriptions of torque, tip, and in-out for orthodontic cases. There were three pre-adjusted orthodontic bracket systems: Andrews, Roth, and MBT. T-loop was also used to achieve controlled space closure. After 26 months of orthodontic treatment, the patient’s profile was straighter and a pleasant smile was achieved at the end of treatment.

Comparison of the impacts of two kinds of brackets on external apical root resorption in orthodontic treatment of bimaxillary protrusion patients / 中国组织工程研究

BACKGROUND: In orthodontic treatment, there will be different degrees of external apical resorption. Severe root resorption will reduce the root/shoot ratio, reduce the stability of teeth, and even cause teeth to loosen and fall out. OBJECTIVE: To compare the difference of external apical root resorption between high torque self-locking bracket and traditional straight wire bracket in orthodontic treatment of bimaxillary protrusion patients. METHODS: Forty-nine patients with bimaxillary protrusion, aged 13-16 years, who were treated in the Hospital of Stomatology of Southwest Medical University from January 2016 to December 2019, were enrolled in this study. The patients were divided into the high torque self-locking bracket group (n=24) and the traditional straight wire bracket group (n=25). Cone beam CT was taken before and after orthodontic treatment. The root morphology and length of maxillary central incisors and lateral incisors were observed by CS 3D Imaging Software. The amount of external apical root resorption between maxillary incisor and lateral incisor was calculated. This study was approved by the Medical Ethics Committee of Hospital of Stomatology of Southwest Medical University. RESULTS AND CONCLUSION: (1) The two groups after orthodontic treatment had achieved a good correction effect. The course of treatment was shorter in the high torque self-locking bracket group than that in the traditional straight wire bracket group (P 0.05). In the same appliance group, the amount of external apical root resorption of the maxillary central incisors was less than the lateral incisors (P < 0.05). (4) Results indicate that compared with the traditional straight wire bracket, the high torque self-locking bracket may have the advantages of short treatment course and low risk of apical absorption in the orthodontic treatment of bimaxillary protrusion.

Treatment of bimaxillary protrusion using intra- and extra-alveolar miniscrews associated to self-ligating brackets system

ABSTRACT Introduction: Moderate and severe bimaxillary protrusion impair the passive lip sealing and the facial and smile esthetics. The extraction of premolars can be avoided by the use of skeletal anchorage to retract both dental arches. This approach brings many advantages such as: prevents premolars extraction; simplifies orthodontic mechanics; there is no volume reduction of a premolar when smiling; control of overbite and gingival exposure. The utilization of this therapeutic approach, when associated with self-ligating brackets, can bring the possibility of spacing the appointments without damage to the treatment efficiency, and allows selection of the most appropriate torque prescriptions for each case. The intra-alveolar miniscrews are indicated for mild cases of bimaxillary protrusion, while extra-alveolar miniscrews may also be indicated for more severe cases. Objective: To report the treatment of three cases of mild, moderate and severe bimaxillary protrusion, in which intra- and extra-alveolar miniscrews were used, according to the retraction required. Conclusion: The retraction of both upper and lower dental arches using orthodontic intra- and extra-alveolar miniscrews, associated with self-ligating brackets, is an excellent tool to correct mild to severe bimaxillary protrusion, thus reducing the need of premolar extraction and simplifying the orthodontic management.

RESUMO Introdução: As biprotrusões moderadas e severas dificultam o selamento labial passivo, comprometem a estética facial e do sorriso. As extrações de pré-molares podem ser evitadas quando se utiliza a ancoragem esquelética como recurso para retrair ambas as arcadas. Essa abordagem traz as seguintes vantagens: evita que o paciente seja submetido ao processo da extração dos pré-molares; simplifica a mecânica ortodôntica; não reduz o volume de um pré-molar de cada lado no sorriso; e auxilia no controle da sobremordida e da exposição gengival. A utilização dessa terapêutica, quando associada aos aparelhos autoligáveis, possibilita maiores intervalos entre as consultas, sem comprometer a eficiência do tratamento, e permite a seleção dos torques mais adequados para essa mecânica. Os miniparafusos intra-alveolares podem ser utilizados na correção de biprotrusões mais suaves, enquanto os extra-alveolares podem ser indicados, também, nos casos mais severos. Objetivo: Relatar os tratamentos de três casos clínicos de biprotrusão leve, moderada e severa, respectivamente, efetuando a retração das arcadas em uma única fase, utilizando miniparafusos intra- e extra-alveolares, conforme a magnitude da retração necessária. Conclusão: A retração das arcadas superior e inferior com miniparafusos ortodônticos intra- e extra-alveolares associados aos aparelhos autoligáveis é um excelente recurso para a correção das biprotrusões de suave a severa, diminuindo a necessidade de extrações de pré-molares e simplificando a mecânica ortodôntica.

Cone-beam computed tomography-based diagnosis and treatment simulation for a patient with a protrusive profile and a gummy smile / 대한치과교정학회지

For patients with bimaxillary protrusion, significant retraction and intrusion of the anterior teeth are sometimes essential to improve the facial profile. However, severe root resorption of the maxillary incisors occasionally occurs after treatment because of various factors. For instance, it has been reported that approximation or invasion of the incisive canal by the anterior tooth roots during retraction may cause apical root damage. Thus, determination of the position of the maxillary incisors is key for orthodontic diagnosis and treatment planning in such cases. Cone-beam computed tomography (CBCT) may be useful for simulating the post-treatment position of the maxillary incisors and surrounding structures in order to ensure safe teeth movement. Here, we present a case of Class II malocclusion with bimaxillary protrusion, wherein apical root damage due to treatment was minimized by pretreatment evaluation of the anatomical structures and simulation of the maxillary central incisor movement using CBCT. Considerable retraction and intrusion of the maxillary incisors, which resulted in a significant improvement in the facial profile and smile, were achieved without severe root resorption. Our findings suggest that CBCT-based diagnosis and treatment simulation may facilitate safe and dynamic orthodontic tooth movement, particularly in patients requiring maximum anterior tooth retraction.

Therapeutic effect of anterior subapical osteotomy combined with postoperative orthodontic treatment for bimaxillary protrusion based on surgery-first approach / 中华整形外科杂志

Objective@#To invesigate the therapeutic effect of anterior subapical osteotomy combined with postoperative orthodontic treatment for bimaxillary protrusion based on surgery-first approach(SFA).@*Methods@#From April 2015 to April 2016, 22 adult patients with bimaxillary protrusion were treated with bimaxillary anterior subapical osteotomy without peroperative orthodontic treatment. Digital computer-aided technology was used for preoperative design and dental model simulation surgery. Then the occlusal guide plate was made for intraoperative built-up of temporary occlusion. Two weeks after orthognathic surgery, a short-term orthodontic treatment was carried out to improve the occlusion. Cephalometric analysis was done to evaluate the treatment effects. 19 cephalometric parameters about hard and soft tissues were measured and compared in all cases before and after SFA combined treatments. All data were statistically analyzed by SPSS software package.@*Results@#Primary healing was achieved in all the 22 cases without any infection or necrosis of bone and dental pulp. During the follow-up period of 6-12 months, all the patients were satisfied with the profile contour. The cephalometric parameters of hard and soft tissues changed remarkably. U1E-McN and L1E-McN set back (-10.5±4.9) mm and (-8.0± 6.9) mm respectively. Upper and lower lip set back obviously. SNA decreased from (82.5±2.8) to (77.9±2.3) degrees on average. SNB decreased from (79.1±5.4) to (74.6±3.8) degrees on average. Upper and lower lip protrusion decreased obviously. TUL-E line decreased from the mean value of (2.7±2.7) mm to (0.5±3.2) mm and TLL-E line from (5.2±4.0) mm to (1.4±2.7) mm. The aesthetic contours were remarkably improved.@*Conclusions@#Anterior subapical osteotomy combined with postoperative orthodontic treatment based on SFA could correct adult bimaxillary protrusion effectively with normal occlusion, satisfactory soft tissue aesthetic profile.

Therapeutic evaluation of the correction of the severe bi-maxillary protrusion cases by Tweed-Merrifield technique / 北京大学学报(医学版)

Objective:To evaluate the influence of Tweed-Merrifield technique in correction of severe bimaxillary protrusion adult patients on the measurement of the dental and skeletal changes after orthodon-tic treatment by Johnston analysis and the regular cephalomatric analysis.Methods:Twelve adolescent patients with severe bimaxillary protrusion were included in this self-control retrospective study.Lateral cephalometric radiographs were taken before and after treatments.All the radiographs were traced and analyzed by the method of Johnston analysis.Other measurements were evaluated using a series of 1 3 li-near and angular measurements including SNA,SNB,ANB,U1 -SN,U1 -NA,U1 /NA,L1 -NB, U1 /NB,L1 /MP,U1 -L1 ,(U1 +L1 )/2-AB,MP/SN and MP/FH from regular cephalomatric analysis. These measurements were also applied to compare the differences between pre-and post-treatments,which clarify the dental and skeletal changes by Johnston analysis.The effect of orthodontic correction was de-termined using the non-parameters test.Results:The maxillary moved backforward by 1 .3 mm according to the stable skull base,while the mandible moved forward by 2.1 2 mm.The relative position between the maxillary and mandible (ABCH)changed 3.42 mm.The upper and lower incisors retracted signifi-cantly.The upper and lower molars moved slightly forward and the relative positions of upper and lower molars and anterior teeth after treatment were 3.44 mm and 4.23 mm respectively.After treatment,the parameters of ANB、U1 -NA、U1 /NA、U1 -SN、L1 -NB、L1 /NB and L1 -M were reduced by -(1 .98 ± 1 .55)°(P =0.01 2),-(5.08 ±4.6)mm (P =0.002),-(1 1 .79 ±1 .21 )°(P =0.004),-(1 3.55 ±6.32)°(P =0.047), -(3.1 7 ±3.07)mm (P =0.01 0), -(6.84 ±2.55)°(P =0.038)and-(4.1 3 ±2.24)°(P =0.048)on average,whose changes had the statistically significant effects.Con-clusion:Tweed-Merrifield technique (directional force technique)can stabilize anchorage molar,retract anterior teeth and significantly improve the hard and soft tissue profile for patients with bimaxillary protru-sion,and make a good vertical control which means this technique is applicable to the patients who need strong anchorage.Even for the severe bimaxillary protrusion adult patients,the Tweed-Merrifield tech-nique can control the anchoragewell and make the profiles improved greatly.

Evaluation of alveolar bone defects on anterior region in patients with bimaxillary protrusion by using cone-beam CT / 北京大学学报(医学版)

Objective:To investigate the alveolar bone defects of anterior alveolar bone in patients with bimaxillary protrusion by using cone-beam computed tomography ( CBCT ) . Methods: The samples consisted of 50 patients with bimaxillary protrusion, who were assigned to the teenage group[20 cases, (13. 1 ± 1. 0) years] and adult group[30 cases, (22. 9 ± 4. 2) years] . The adult group included 9 hy-po-divergent, 11 normo-divergent and 10 hyper-divergent patients. The images were obtained by using NewTom VG CBCT and the alveolar defects were evaluated. Results:The ratio of the patients had alveo-lar bone defects was 94. 00%. Meanwhile, the defects were associated with 38. 60% of all the teeth. Most defects occurred on labial alveolar bone ( 98 . 66%); fenestration was found more in the maxillary alveolar region and dehiscence occurred more in the mandible. The dehiscences (3. 06%) and defects prevalence (30. 13%) of the teenage group were significant lower than those of the adult group (11. 73% vs. 42. 46%), P0. 05). The hypo-divergent group had lower fenestrations prevalence (22. 22%) than the normo-divergent (33. 84%) and hyper-divergent groups (37. 50%), P<0. 05. The upper central incisor had the lowest alveolar bone defect prevalence. Conclusion: Alveolar bone defects are common findings in patients with bimaxillary protrusion before orthodontic treatment. The prevalence of defects is affected by age and vertical-growth type.

The Evaluation of Soft and Hard Tissue Change for Retraction of Lower Anterior Tooth in Bimaxillary Protrusion Patients according to Two Different Therapeutic Methods: Mandibular Anterior Segmental Osteotomy and Orthodontic Treatment with Teeth Extraction

The study of efficiency of corticotomy in treatment of bimaxillary protrusion

Observation on the effects of Tip-Edge Plus for bimaxillary protrusion / 重庆医科大学学报

Objective:To observe the clinical effects of Tip-Edge Plus appliance in treating bimaxillary protrusion patients and discuss its mechanics. Methods:20 patients with bimaxillary protrusion were treated with Tip-Edge Plus appliance. 4 premolars in all those cases were extracted. The results of cephalometric measurements of pretreatment and posttreatment were statistically analyzed to evaluate orthodontic effects. Results:20 patients received an average of 18 months of treatment,after treatment dental coverage and molar relations of these patients were in the normal range. Analysis of related projects cephalometric showed that patients with lateral outlook improved significantly,SNA,SNB and U1~L1 angle changes in hard tissue with significant difference in cephalometric measurements(P

Hard and soft tissue profile changes following anterior subapical osteotomy in bimaxillary dentoalveolar protrusion patients / 대한치과교정학회지

The purpose of this study is to evaluate hard and soft tissue changes following the first four premolar extractions and anterior subapical osteotomy in bimaxillary dentoalveolar protrusion patients requiring maximal retraction of anterior segments. A sample of 20 adult female patients was selected. Surgical procedures were performed by the same surgeon, and modified segmental osteotomy and anterior subapical osteotomy techniques were employed on the maxilla and mandible respectively. Presurgical and post-surgical lateral cephalometric radiograms were traced and superimposed using the best-fit method and two reference planes. The results were as follows 1. The bodily movement of the maxillary anterior segment was achieved in a posterior direction. The mandibular anterior segment was moved posteriorly with a slight correction of the lower incisors. 2. The horizontal soft tissue measurements changed significantly after treatment, but Nt and Sn landmarks remained unchanged. The vertical soft tissue measurements indicated that Ls moved inferiorly and Li superiorly. 3. The correlation between hard and soft tissue changes indicated that deltaHId/deltaHLi, deltaHId/deltaLL-Eline, deltaHPt.B/deltaHILS, and deltaUI-FH/deltaNL were significant. 4. More lower lip relative to upper lip retraction was demonstrated in relation to Rickett's E-line. The ratio between upper incisor and upper lip displacement was 50%, and between the lower incisor and lower lip displacement was 60%. We conclude from the results that the anterior subapical osteotomy is an efficient treatment option for adult patients who have severe dentoalveolar protrusion and desire rapid results.

Correction of bimaxillary protrusion by using both orthognathic surgery and ort hodontics / 中华医学美学美容杂志

Objective To correct bimaxillary protrusion by using b oth orthognathic operation and orthodontic treatment. Methods 46 bimaxillary protrusion patients, 7 male, 39 female, aged from 19 to 31 years (mean 24.2 years), were surgically corrected since 1996. Of them 31 cases underwent preoperative orthodontic treatment. Cephalometric analysis and model s urgery were performed in all patients and 4 kinds of operation methods were used to correct the deformity. All osteotomy segments were fixed with rigid internal fixation. 39 cases underwent postoperative orthodontic treatment. Re sults 34 cases had been followed-up for ranged from 12 to 72 months (mean 27.7months). All osteotomy segments healed well. There were no severe com plications and evident relapse. The maxillary osteotomy segments were moved back for average (6.3?0.9) mm and mandibular osteotomy segments for average (5.2?1 .2) mm. Both occluding relation and facial contour were satisfied. Co nclusion Bimaxillary protrusion can be satisfyingly corrected by usi ng both of orthognathic operation and orthodontic treatment.

Study of craniofacial tissues of northeastern females with bimaxillary protrusion in non-surgical treatment / 实用口腔医学杂志

Objective:To study the craniofacial characters of non-surgical treatment of the female patients with bimaxillary protrusion in northeastern region of China.Methods:80 patients with bimaxillary protrusion in northeastern region of China received orthodontic treatment were divided into two groups,the ANB angles of the first group were no more than 4.7?,the second one exceeds 4.7?.Cephalograms were analyzed in all the subjects.Compared with the normals in Beijing.Results: Most of the female patients with bimaxillary protrusion had shorter anterior cranial bases,longer posterior cranial bases,longer and more prognathic maxillas,longer mandible lengths,higher anterior and anterior upper facial heights,obvious procumbency,thicker mental thickness,procumbent soft tissue profile with a low lip line.Different groups had the features as follows:the main abnormal factors were the maxilla in sagittal aspect of the first group.They had the suitable facial planes.The second group's abnormal factors were the mandible,they had the divergent facial plane.Conclusion:The non-surgical treatment′s patients of bimaxillary protrusion have unique character.The results suggest it is of critical importance to adjust the position of jaws to benefit the improvement of facial features.

Orthodontic treatment of Class III bimaxillary protrusion combined with subapical segmental osteotomy / 대한치과교정학회지

Bimaxiilary protrusion can be treated effectively in growing patients and in adults with conventional orthodontic therapy. However, In the adult patient, combined surgical and orthodontic treatment modalities may offer distinct advantages over such conventional therapy. In those cases complicate by vertical jaw dysplasia, sagittal dysplasia, or transverse skeletal discrepancy in addition to bimaxillary protrusion, the possibilities of obtaining successful results through orthodontic treatment alone greatly diminish. Surgical retraction of both maxillary and mandibular anterior segments with subapical osteotomies and ostectomies in the extraction site may be a good treatment alternative. Treatment time and possible adverse effects of lengthy orthodontic therapy may be reduced and optimum esthetic improvement may be facilitated. On the following cases, patient who had bimaxillary protrusion with Angle class Ill malocclusion was treated with combined orthodontic - surgical therapy by anterior subapical segmental osteotomies.

Comparative study of mini-implant for orthodontic anchorage and traditional anchorge in cuspid retration in adult patients with bimaxillary protrusion / 实用口腔医学杂志

0.05) . Conclusion: Mini-implant can replace traditional anchorge composed of extraoral arch and Nance arch in the moving of cuspid distally.