RESUMO

A Classe II representa uma parte considerável dos problemas ortodônticos a serem tratados nas clínicas odontológicas. Para a correção desta má oclusão existem atualmente diversas formas de tratamento. Dentre os aparelhos ortopédico funcionais, o aparelho de Herbst tem se destacado devido a sua eficiência e praticidade por ser fixo e não necessitar da colaboração do paciente. O objetivo deste artigo é apresentar, através de um relato de caso clínico, o tratamento da má oclusão Classe II com aparelho de Herbst modificado com "splint" de acrílico inferior. A paciente do sexo feminino, apresentava inicialmente 11 anos e 11 meses, dentição permanente, retrusão mandibular e atresia das arcadas. Inicialmente, foi utilizado disjuntor maxilar e expansor inferior, seguido do aparelho de Herbst e finalizado com Ortodontia fixa. Ao final do tratamento o aparelho de Herbst modificado mostrou-se efetivo proporcionando uma relação molar Classe I, melhora do perfil da paciente e diminuição do espaço entre os lábios em repouso. (AU)

Class II represents a considerable part of orthodontic problems to be treated in dental clinics. To correct this malocclusion, there are currently several forms of treatment. Among the functional orthopedic devices, the Herbst device has stood out due to its efficiency and practicality for being fixed and not requiring the collaboration of the patient. The purpose of this article is to present, through a clinical case report, the treatment of class II malocclusion with a modified Herbst appliance with a lower acrylic splint. The female patient initially had 11 years and 11 months, permanent dentition, mandibular retrusion and atresia of the arches. Initially, a maxillary circuit breaker and lower expander were used, followed by the Herbst appliance and finished with fixed orthodontics. At the end of the treatment, the modified Herbst appliance proved to be effective, providing a class I molar relationship, improving the patient's profile and decreasing the space between the resting lips. (AU)

Assuntos

RESUMO

ABSTRACT The Herbst appliance can be very effective in treatment of Class II patients with mandibular retrognathism. Because of the continuous action in a full-time basis, treatment time using it normally takes from six to ten months, and is usually followed by a second phase of full fixed appliances, in order to obtain both occlusal refinement and long term stability. Despite Herbst appliance's effectiveness in the occlusal and dentoalveolar perspectives, its facial results may differ among patients with different growth patterns, as well as in distinct stages of skeletal maturation. In the current paper, two patients with different facial patterns are presented, who were treated under the same protocol, using Herbst and full fixed appliances in different skeletal maturation stages, and both dentoalveolar and facial results are compared and discussed.

RESUMO Um número significativo de pacientes que procuram o tratamento ortodôntico apresenta má oclusão de Classe II acompanhada pelo retrognatismo mandibular. Abordagens ortopédicas para avanço mandibular são comumente utilizadas enquanto houver crescimento facial remanescente e, nesses casos, o estágio de maturação esquelética deve ser avaliado para definir a melhor época de intervenção terapêutica. Após concluída a fase ortopédica, normalmente é realizada uma segunda fase ortodôntica para refinamento oclusal, com o intuito de oferecer maior estabilidade das correções em longo prazo. No presente artigo, serão discutidos os resultados do avanço mandibular ortopédico considerando-se diferentes estágios de crescimento.

Assuntos

RESUMO

INTRODUCTION: There is no consensus regarding which mode of activation or mandibular advancement (stepwise [SW] or maximum bite-jumping [BJ]) of fixed or removable functional appliances (FFA; RFA) for correction of Angle class II malocclusion is advantageous to produce dental, skeletal or condylar effects and has the lowest rate of undesired dental or technical side-effects. METHODS: A systematic search was conducted up to Oct. 20, 2019 in the MEDLINE, EMBASE, Scopus, Central Cochrane Library, and BBO databases. Included were preadolescent, adolescent, and adult humans with initial (pretreatment) Angle class II malocclusion, without further restriction. The intervention group was composed of subjects treated with FFA or RFA in SW mandibular advancement; the control group received BJ advancement. Search terms included prospective randomized and nonrandomized trials in English, German, Spanish, and Portuguese with the primary outcomes of skeletal and dental class II correction, effects on condylar growth, lower incisor proclination, overjet and overbite reduction. The risk of bias (ROB) was assessed using the Cochrane Collaboration's ROB2 tool. Mean differences were calculated and pooled by a meta-analysis using a random effects model. RESULTS: Data from five randomized controlled trials (RCT) with 401 participants (mean age 13.84 years; SD 1.53) were included; 331 derived from four studies were included in the meta-analysis. The ROB in the selected articles was high. We detected a slightly increased reduction of the ANB (mean difference [MD] -0.95°, 95% confidence interval [CI] -1.80 to -0.10°; I2 = 72%) that may be attributed to a slightly more pronounced increase of the SNB angle in SW-advanced mandibles (MD 0.27°; 95% CI -0.47 to 1.00°; I2 = 38%). SW advancement tended to reduce the undesired side effect of lower incisor proclination (MD = -1.59°; 95% CI -3.98 to 0.8°; I2 = 0%), indicating more pronounced mandibular incisor changes with bite-jumping advancement. CONCLUSION: There is weak evidence indicating a slightly increased reduction of the ANB and less lower incisor proclination with SW advancement compared to BJ, but the clinical relevance is debatable due to the small overall magnitude and small number of high-quality papers. REGISTRATION: Prospero #CRD42017075469 (www.crd.york.ac.uk/prospero).

Assuntos

RESUMO

Resumo O tratamento ortodôntico possui diversos objetivos, sendo que um dos mais importantes é a estabilidade das correções alcançadas. A estabilidade longitudinal dos resultados do tratamento é uma das chaves para o tratamento ortodôntico bem-sucedido. Desta forma, este artigo se destina a descrever um caso clínico de uma paciente com má oclusão de Classe II Divisão 1, tratada com o aparelho de Herbst. Na primeira fase do tratamento a paciente utilizou um aparelho de Herbst com splint de acrílico inferior removível. Na segunda fase, utilizou aparelho fixo nas arcadas superior e inferior. Como contenção, utilizou uma placa de Hawley modificada superior e uma contenção fixa 3×3 inferior. A avaliação 11 anos após o final do tratamento permite concluir que o tratamento da Classe II com o aparelho de Herbst em duas fases foi eficaz, promovendo alterações esqueléticas, dentárias e faciais que se mostraram estáveis.(AU)

Abstract Orthodontic treatment has several objectives, one of the most important of which is the stability of the corrections achieved. Longitudinal stability of treatment results is one of the keys to successful orthodontic treatment. Thus, this article is intended to describe a clinical case of a patient with Class II Division 1 malocclusion, treated with the Herbst appliance. In the first phase of treatment, the patient used a Herbst appliance with removable lower acrylic splint. In the second phase, she used a fixed appliance in the upper and lower arches. As a retainer, she used a modified upper Hawley plate and a fixed 3×3 lower retainer. The evaluation 11 years after the end of the treatment allows us to conclude that the Class II treatment with the Herbst appliance in two phases was effective, promoting skeletal, dental and facial changes that were stable. (AU)

Assuntos

RESUMO

O aparelho de Herbst tem sido amplamente utilizado no mundo todo para tratar a má oclusão de Classe II com retrognatismo mandibular. Entretanto, no Brasil tem sido pouco utilizado. O custo do aparelho, a curva de aprendizado acentuada para manipular o aparelho e a falta de laboratórios com conhecimento para confeccioná-lo adequadamente têm contribuído para este fato. Sendo assim, o objetivo deste artigo é mostrar o fluxo digital para a confecção do aparelho MiniScope Herbst e demonstrar as facilidades de trabalhar desta forma. Após a confecção e instalação do aparelho aqui mostrado, pode-se concluir que a utilização de modelos digitais, juntamente com o sistema MiniScope e a soldagem a laser, tornou a confecção do aparelho de Herbst muito mais previsível e confiável. Espera-se assim contribuir para a facilidade de utilização clínica do aparelho e para diminuir o número de intercorrências. (AU)

The Herbst appliance has been widely used worldwide to treat Class II malocclusion with mandibular retrognathism. However, in Brazil it has been little used. The cost of the device, the steep learning curve for handling the device, and the lack of laboratories with the knowledge to properly manufacture it have contributed to this fact. Therefore, the objective of this article is to show the digital flow for the manufacture of the MiniScope Herbst device and demonstrate the facilities of working in this way. After making and installing the device shown here, it can be concluded that the use of digital models, together with the MiniScope system and laser welding made the fabrication of the Herbst appliance much more predictable and reliable. Thus, it is expected to contribute to the ease of clinical use of the device and to reduce the number of complications (AU)

Assuntos

RESUMO

OBJECTIVES: To perform a three-dimensional evaluation of the position of the condyles in patients treated with Herbst appliance (HA) in two stages of cervical vertebral maturation. SETTING AND SAMPLE POPULATION: Retrospective case-control study. Pubertal Herbst group (PHG; n = 24, mean age 14.5 years, CS 3 and CS 4) and pre-pubertal Herbst group (PPHG; n = 17, mean age 9.9 years, CS 1 and CS 2) were contrasted with comparison groups of non-orthopaedically treated Class II patients in pubertal (PCG; n = 17, mean age 13.9 years) and pre-pubertal maturational stages (PPCG; n = 18, mean age 10.6 years). MATERIALS AND METHODS: Cone-beam computer tomography scans were taken before treatment (T0) and at T1 after 8 to 12 months. Point-to-point measurements of the displacement of the condyles between T0 and T1, relative to the glenoid fossae, were performed in the X, Y, Z and 3D perspectives. Qualitative assessments using semi-transparent overlays and colour mapping also were produced. RESULTS: The displacement of the condyles within the glenoid fossae in the treated groups was small (<0.75 mm; P > .05). Relative to the glenoid fossa, condylar position at T1 was similar to T0 in pre-pubertal and pubertal groups (P > .05). Similar condylar rotations from T0 to T1 were observed in Herbst and comparison groups, and no significant difference was found between pre-pubertal and pubertal patients. CONCLUSIONS: Regardless the stage of skeletal maturation, HA treatment did not change the condyle-glenoid fossa relationship.

Assuntos

RESUMO

OBJECTIVES: Three-dimensional evaluation of skeletal mandibular changes following Herbst appliance treatment. SETTING AND SAMPLE POPULATION: Retrospective case-control study, based on a sample size calculation. Twenty-five pubertal patients treated with Herbst appliance (HAG), and 25 matched Class II patients who received other non-orthopaedic dental treatments (CG). MATERIAL AND METHODS: Three-dimensional models were generated from pre-treatment (T0) and post-treatment (T1) cone beam computed tomograms. Volumetric registration on the cranial base was used to assess mandibular displacement; volumetric regional registration was performed to evaluate mandibular growth. Quantitative measurements of X, Y, Z and 3D Euclidian changes, and also qualitative visualization by colour-mapping and semi-transparent overlays were obtained. RESULTS: Downward displacement of the mandible was observed in both HAG and CG (2.4 mm and 1.5 mm, respectively). Significant forward displacement of the mandible was observed in the HAG (1.7 mm). HAG showed greater 3D superior and posterior condylar growth than the CG (3.5 mm and 2.0 mm, respectively). Greater posterior growth of the ramus was noted in the HAG than in CG. CONCLUSIONS: Immediately after Herbst therapy, a significant mandibular forward displacement was achieved, due to increased bone remodelling of the condyles and rami compared to a comparison group. Three-dimensional changes in the direction and magnitude of condylar growth were observed in Herbst patients.

Assuntos

RESUMO

OBJECTIVE: To test the following two hypotheses regarding the consequences of Herbst appliance (HA) insertion: 1) a significant clockwise mandibular rotation will occur and 2) the displacement of the condyles will follow the same magnitude of the changes of overjet (OJ) and overbite (OB). METHODS: Virtual 3D surface models of 25 patients were generated from cone-beam computed tomographs taken before treatment and immediately after HA insertion. Scans were registered on the cranial base and were analyzed using point-to-point measurements, color-coded maps, and semitransparent overlays. Statistical tests included correlation and simple regression analysis. RESULTS: Pitch rotation, ranging from -2.2° to 2.2° (mean, 0.2°), was observed in clockwise and counterclockwise directions. Condylar sagittal displacement presented a positive correlation with OJ changes. Each millimeter of OJ correction resulted in an anterior condylar displacement of approximately 0.95 mm. Vertical condylar displacement correlated with OB changes and varied mostly between 2 mm and 4.5 mm. CONCLUSION: Immediately after HA insertion, no significant clockwise mandibular rotation was observed. The condyles were displaced anteriorly and inferiorly. Condylar anterior displacement and OJ correction presented a ratio close to 1:1. The vertical displacement of the condyles did not follow the same magnitude of OB changes.

RESUMO

OBJECTIVE: To compare the clinical complications during treatment with either a removable mandibular acrylic splint (RMS) or with a cantilever (HC) Herbst appliance. METHODS: Records from 159 Class II, division 1, consecutively treated patients with a Herbst appliance were examined. The sample was composed of 82 male and 77 female patients with a mean age of 11.8 years. The Herbst appliance was used for a mean of 12 months (standard deviation 2.15 months). Two main Herbst groups were analyzed: group RMS (n  =  125) and group HC (n  =  34). They were further subdivided according to the telescopic system used (Dentaurum type 1 or PMA) and fixation mode (splint with crowns or Grip Tite bands). Patients' clinical records were assessed to identify clinical complications. RESULTS: The incidence of complications during treatment was 85.3% for the HC group and 88.0% for the RMS group, with no statistically significant difference (Mann-Whitney test, P > .05). The fixation mode (crown or band) also did not show a statistically significant difference (P > .05). Regarding the telescopic system used, the Dentaurum group had 2.9 times more susceptibility to complications than the PMA group, regardless of the Herbst type. CONCLUSIONS: On average, approximately 2.5 complications per patient were reported. Most patients had a maximum of three complications during Herbst treatment. Herbst appliance type (RMS or HC) and fixation mode (crowns or Grip Tite bands) did not influence the number of complications. The PMA (without screws) telescopic system seemed to be more reliable (regarding the number of complications) than Dentaurum type 1, regardless of the appliance design (RMS or HC).

Assuntos

RESUMO

OBJECTIVE: The present prospective clinical study was designed in order to evaluate horizontal and vertical skeletal alterations induced by the use of Herbst appliance in individuals with Class II, division 1 malocclusion during mixed dentition stage. METHODS: The sampling consisted of 15 pre-pubertal individuals (12 boys and 3 girls; initial age 9 years and 6 months), who were treated with Herbst appliance for a period of 7 months. The effects of the treatment were compared to a group of 15 individuals with Class II, division 1 malocclusion (8 boys and 7 girls, initial age averaged 9 years and 1 month), orthodontically untreated, who were followed up for a period of 12 months. Statistical analysis was performed with Student's t-test with significance level at 5%. RESULTS: It was showed that the treatment with Herbst appliance in mixed dentition stage has restricted maxilla growth. Mandibular and palatal planes have not undergone significant alteration; however, anterior and posterior facial heights have increased significantly. Facial convexity and maxillomandibular relationship were altered positively. Mandible has positioned significantly forward and its effective length increased 2.5 times more than the increase observed in control group. CONCLUSION: It was possible to conclude that Herbst appliance was able to provide satisfactory results in individuals during mixed dentition stage.

RESUMO

OBJECTIVE: This prospective clinical study was conducted with the purpose of evaluating the influence of the banded Herbst appliance on dental changes during the early treatment of Class II malocclusion. METHOD: The sample consisted of 15 prepubertal subjects (12 boys and 3 girls, initial age: 9 years and 6 months) who were treated with the Herbst appliance. Treatment effects were compared with those of a Class II Division 1 group of 15 subjects (8 boys and 7 girls, mean initial age 9 years and 1 month), not treated orthodontically. Statistical analysis was performed using Student t-test with 5% significance level. RESULTS: The results showed that treatment with the banded Herbst appliance in the mixed dentition stage tended to upright maxillary incisors (mean: 4.14°). The maxillary molars were distalized and intruded significantly (mean 2.65 mm and 1.24 mm, respectively), the lower incisors slightly protruded anteriorly (mean 1.64 mm) and the molars showed no significant changes in the horizontal and vertical directions. Furthermore, significant improvements were noted in overbite (1.26 mm), overjet (4.8 mm) and molar relationship (12.08 mm). CONCLUSIONS: Changes in the upper dental arch were found to be greater than changes in the lower arch. Furthermore, mandibular anchorage loss was reduced due to the anchorage system used in the study.

RESUMO

OBJETIVO: verificar e comparar os tipos de complicações durante o tratamento com o aparelho de Herbst com cantiléver (CBJ) e com splint removível inferior. MÉTODOS: vinte e um pacientes tratados consecutivamente com o CBJ foram comparados a vinte e um pacientes tratados consecutivamente com o aparelho de Herbst com coroas de aço nos primeiros molares superiores e com splint de acrílico inferior removível. A idade inicial média para o grupo com CBJ foi de 12 anos e 3 meses, e para o grupo com splint foi de 11 anos e 3 meses. Ambos os grupos utilizaram o aparelho por um período de 12 meses. A partir da ficha clínica dos pacientes foi realizado um levantamento de ocorrências de complicações acontecidas durante o tratamento com os aparelhos de Herbst. RESULTADOS: o número total de ocorrências de complicações foi de 24 para o grupo com CBJ e de 53 para o grupo com splint. O teste de Mann-Whitney (p<0,05) demonstrou diferença significativa entre os dois tipos de tratamento em relação ao total de ocorrências de complicações durante o tratamento. A prevalência de pacientes que apresentaram alguma complicação durante o tratamento foi de 66,67 por cento para os pacientes tratados com CBJ, e de 85,71 por cento para os pacientes tratados com splint. CONCLUSÕES: o grupo com CBJ apresentou menor número de complicações durante o tratamento com o aparelho de Herbst. Em ambos os grupos, nenhum paciente apresentou individualmente um grande número de complicações. O aparelho CBJ é preferível ao modelo com splint de acrílico inferior removível, devido à economia de tempo clínico e laboratorial.

OBJECTIVE: To assess and compare the type of complications during Herbst treatment with Cantilever Bite Jumper (CBJ) and removable mandibular splint. METHODS: Twenty one consecutive Herbst patients treated with the CBJ were compared with twenty one patients consecutively treated with Herbst with stainless steel crowns on the maxillary first molars and a removable mandibular acrylic splint. The initial mean age for the CBJ group was 12 years and 3 months and for the Splint group was 11 years and 3 months. Both groups used the Herbst appliance for 12 months. Based on the patients' clinical records an occurrence survey of complications during Herbst treatment was performed. RESULTS: There were 24 complications for the CBJ and 53 for the Splint group, which were statistically different (Mann-Whitney test, p<0.05). The prevalence of patients exhibiting complications during treatment was 66.67 percent in the CBJ and 85.71 percent in the Splint group. The frequencies of complications were also statistically different between the groups. CONCLUSIONS: The CBJ exhibited a significantly smaller number of complications during Herbst appliance treatment than the removable mandibular splint. Herbst appliance with first molar crowns and a cantilever on the mandibular molars is preferable to the removable mandibular acrylic splint because of savings in clinical and laboratory time.

Assuntos

RESUMO

OBJETIVO: o propósito do presente estudo é avaliar o limite de resistência à flexão de um protótipo de mini-implante desenvolvido para ancoragem do aparelho de Herbst. MÉTODOS: após a realização de um cálculo do tamanho da amostra, quatro corpos de prova contendo os protótipos de mini-implantes foram submetidos a uma força de flexão por engastamento simples, utilizando-se uma máquina universal de ensaios mecânicos, sendo calculado o limite de resistência à força de flexão. RESULTADOS: após os ensaios mecânicos, os novos mini-implantes apresentaram o limite de resistência à força de flexão de 98,2kgf, que foi o menor valor encontrado. CONCLUSÃO: os protótipos de mini-implantes desenvolvidos para ancoragem do aparelho de Herbst foram capazes de suportar forças de flexão maiores do que as forças de mordida descritas na literatura.

AIM: The purpose of this study was to evaluate the limit of flexural strength of a mini-implant prototype designed for Herbst appliance anchorage. METHODS: After sample size calculation, four specimens with the new mini-implant were submitted to a single cantilever flexure test using a universal testing machine. The limit of flexural force strength was calculated. RESULTS: The mini-implant prototype showed a limit of flexural force strength of 98.2 kgf (982 N), that was the lowest value found. CONCLUSION: The mini-implant prototype designed for Herbst appliance anchorage can withstand flexural forces higher than the maximum human bite forces reported in the literature.

Assuntos

RESUMO

OBJETIVO: o objetivo deste estudo prospectivo de 32 adolescentes com má oclusão de Classe II, divisão 1, associada a retrognatismo mandibular, tratados com aparelho de Herbst, construído sobre bandas e coroas metálicas, foi avaliar cefalometricamente as possíveis mudanças no padrão de crescimento facial. METODOLOGIA: as telerradiografias laterais foram obtidas ao início do tratamento (T1) e imediatamente após 12 meses de tratamento com o referido aparelho ortopédico (T2). Foram utilizados o quociente de Jarabak e o VERT de Ricketts (modificado) para determinação do padrão facial em T1 e T2. RESULTADOS: utilizando o quociente de Jarabak, os resultados evidenciaram que 27 casos (84,4 por cento) apresentaram padrões hipodivergentes em T1 e permaneceram da mesma forma em T2. Cinco casos (15,6 por cento) apresentaram padrão neutro em T1 e não exibiram mudanças em T2. Quando avaliado o VERT de Ricketts (modificado), não ocorreram mudanças no padrão facial em 31 pacientes. Em apenas um caso ocorreu mudança do tipo facial. CONCLUSÃO: baseado nos resultados obtidos, pode-se concluir que, após 12 meses de tratamento com aparelho de Herbst, não ocorreram mudanças verticais no padrão de crescimento facial dos pacientes estudados.

OBJECTIVE: The aim of this prospective study was to evaluate through the exam of cephalograms the occurrence of changes in facial growth pattern. The sample was composed by 32 adolescent with Angle Class II, division 1 malocclusion and mandibular retrognathism. All patients were treated with the Herbst appliance built over bands and metal crowns. METHODOLOGY: Lateral cephalograms were taken at the beginning of treatment (T1) and immediately after 12 months of treatment with Herbst appliance (T2). Jarabak's coefficient and Ricketts' VERT (modified) were used to establish the facial pattern in T1 and T2. RESULTS: According to Jarabak's coefficient, in T1, 84.4 percent (27 cases) presented hypodiverging pattern and 15.6 percent (5 cases) presented neutral pattern. The facial growth pattern was maintained in all patients from T1 to T2. When the (modified) Ricketts' VERT was used, 31 patients showed the same growth pattern from T1 to T2. Only one patient exhibited a different pattern. CONCLUSION: Based on the results it can be concluded that, after 12 months of treatment with the Herbst appliance, there were no vertical changes in the facial growth pattern of the studied subjects.

Assuntos

RESUMO

OBJETIVO: Realizou-se um estudo cefalométrico, em telerradiografias, objetivando-se determinar os efeitos no complexo craniofacial de pacientes com más oclusões de Classe II, divisão 1 submetidos ao tratamento com o aparelho de Herbst com cantiléver. METODOLOGIA: Para tanto, utilizou-se uma amostra composta por dois grupos, sendo um experimental e um controle. O grupo experimental originou-se da Faculdade de Odontologia de Bauru - USP, com 25 pacientes tratados com o aparelho ortopédico funcional e a idade inicial média de 12,01 anos. O grupo de controle, pareado cronologicamente ao grupo experimental, foi composto por pacientes não tratados ortodonticamente e/ou ortopedicamente, oriundos do arquivo de documentações denominado Burlington Growth Centre, localizado na Faculdade de Odontologia da Universidade de Toronto, Canadá. Para cada componente dos dois grupos, obtiveram-se as telerradiografias ao início (T1) e ao final (T2) do período de tratamento ou de observação, sendo traçadas manualmente e digitalizadas para um programa de cefalometria. Foram estabelecidas 33 grandezas cefalométricas. RESULTADOS E CONCLUSÕES: A comparação estatística entre o grupo experimental e o grupo controle (teste t de Student, com nível de significância p<0,05) evidenciou que a terapia corrigiu, em curto prazo, a má oclusão inicial, com grandes alterações dentoalveolares, em decorrência da perda substancial de ancoragem dentária, mesializando os molares inferiores e vestibularizando os incisivos inferiores. A terapia restringiu o desenvolvimento normal no sentido vertical dos dentes póstero-superiores, contribuindo decisivamente para a correção da relação molar de Classe II e manutenção do padrão de crescimento craniofacial dos pacientes.

OBJECTIVE: This study investigated the treatment effects on the craniofacial growth of Class II patients treated with Herbst appliance. METHODOLOGY: The sample was comprised of two groups, one experimental and one control group. The experimental group originated from Bauru Dental School, University of São Paulo. This consisted of 25 patients treated by the Herbst appliance, with an initial mean age of 12,01 years. The control group, matched by age with the experimental group, was originated from the Burlington Growth Centre, located at the Faculty of Dentistry, University of Toronto, Canada. All patients were assessed at the beginning (T1) and at the end of the treatment or observation period (T2) and 33 cephalometric variables were established. RESULTS AND CONCLUSIONS: The statistical comparison between the experimental group and the control group (Student t test) showed in short-term fashion, the correction of the initial malocclusion with pronounced dental changes (loss anchorage). The effect in inhibiting the vertical development of the maxillary first molars, essential characteristic to correct the Class II molar relationship and to maintain the craniofacial growth pattern, was shown with the therapy.

Assuntos

RESUMO

OBJETIVO: o objetivo do presente estudo cefalométrico retrospectivo consistiu em investigar os efeitos induzidos pelo aparelho Herbst, complementados pela mecânica ortodôntica com aparelho Straight wire e elásticos de Classe II, na correção da má oclusão Classe II, divisão 1, Padrão II, com deficiência mandibular, na dentadura permanente. METODOLOGIA: foram traçadas telerradiografias iniciais (idade média de 12 anos e 10 meses) e finais (idade média de 14 anos e 8 meses) de 18 pacientes, 12 meninos e 6 meninas, para quantificar o comportamento de 12 grandezas cefalométricas representativas da posição sagital das bases apicais, convexidade facial, rotação mandibular e posição sagital dos incisivos superiores e inferiores. O tempo médio de tratamento foi de 22,5 meses, sendo 9,8 meses com o aparelho Herbst e 13 meses com a mecânica ortodôntica subseqüente. RESULTADOS E CONCLUSÕES: os resultados registraram: 1) ausência de influência no comportamento da maxila; 2) avanço mandibular; 3) redução na convexidade facial; 4) preservação da inclinação do plano mandibular e 5) presença de compensação dentária, sobretudo nos incisivos inferiores (vestibularização). Reitera-se, portanto, o fato de que, mesmo com aparelho ortopédico fixo, é mais previsível e mais fácil obter compensação dentária do que remodelação esquelética na correção ortopédica da deficiência mandibular.

AIM: The purpose of the current cephalometric study was to investigate the effects induced by the Herbst appliance followed by fixed orthodontic Straight wire mechanics and Class I elastics to correct a Class II division 1 malocclusion with a mandibular deficiency in the permanent dentition. MATERIAL AND METHODS: Initial (mean age of 12 years and 10 months) and final (mean age of 14 years and 8 months) cephalometric radiographs of 12 boys and 6 girls were traced to measure 12 cephalometric measurements that represented the sagittal position of the apical bases, facial convexity, mandibular rotation and sagittal position of the upper and lower incisors. Mean treatment time was 22.5 months, with 9.8 months using the Herbst appliance and 13 months with the fixed orthodontic mechanics. RESULTS AND CONCLUSIONS: The results showed: 1) no influence in the maxilla; 2) mandibular advancement; 3) reduction on the facial convexity; 4) maintenance of the mandibular plane inclination; 5) dental compensation mainly in the lower incisors (buccal tipping). Therefore, even with the Herbst fixed appliance it is more predictable and easy to obtain dental compensation than skeletal remodelling in the orthopedic correction of the mandibular deficiency.

Assuntos