Efficacy of the Prefabricated Myofunctional Appliance T4FTM in Comparison to Twin Block Appliance for Class II Division 1 Malocclusion Treatment: A Randomized Clinical Trial

@#Introduction: The aim of the study was to compare the changes in the skeletal and dentoalveolar structures in Malay patients with Class II Division 1 malocclusion treated by prefabricated re-mouldable customizable functional appliance (T4FTM) and Twin Block (TB) appliance. Methods: A randomised clinical trial was carried out with samples randomly assigned to active (TB appliance) and experimental (T4FTM appliance) groups. Pre- and post-treatment lateral cephalometric radiographs were taken for each subject and the overjet was clinically measured at the same intervals. 20 angular and linear measurements were chosen and measured separately. Results: Independent t test was used to compare the changes between the two groups. A significant difference between the groups was seen with overjet at 2.14 mm (p < 0.01), Sv_Pog distance at 1.83mm (p < 0.05), Sv_ii distance at 2.55 mm (p < 0.001), horizontal distance from the upper to the lower incisor tip at 1.81 mm which was statistically significant (p < 0.05). The other variables SNB and ANB angles too showed a significant difference. However, all the favourable changes were noted in the TB group. Conclusion: T4FTM appliance could be an effective appliance for the management of British Standard Institute's Class II Division 1 malocclusion on Class II skeletal pattern. However, the TB group differed significantly and had a more favourable correction in terms of the sagittal skeletal and dentoalveolar discrepancy.

Morphological characteristics of soft tissue profile of Angle's class II division i malocclusion before and after orthodontic treatment / Características morfológicas del perfil de tejido blando de la clase II de la división I de maloclusión de ángulo antes y después del tratamiento de ortodoncia

SUMMARY: By analysing cephalometrics before and after the treatment of Angle's class II division 1 malocclusion, soft tissue profile changes were observed, and to explore whether there was a correlation between the change of posterior occlusal plane (OP-P) and soft tissue profile. The study aimed to provide a theoretical reference in the clinical diagnosis and orthodontic treatment of early permanent dentition of Angle class II division 1 malocclusion patients. We randomly selected 20 cases of orthodontics in Shanxi Medical University orthodontics patients (aged 12-18 years) of the lateral cephalograms, Winceph 8.0 software was used to measure the posterior occlusal plane (OP-P), TUL-EP, TLL-EP, nasolabial angle, upper lip base thickness, upper lip tension, lower lip H line distance, chin soft tissue thickness and Z angle. And SPSS 22.0 software was used to analyze the correlation between OP-P and other measurement indexes. The change of posterior occlusal plane was positively related to the distance from upper lip to the esthetic plane, the distance from lower lip to the esthetic plane, the tension of the upper lip and distance from lower lip to H line, and the change of posterior occlusal plane was negatively related to nasolabial angle and Z angle. The change of posterior occlusal plane had no significant correlation with upper lip base thickness and soft tissue chin thickness. The change of posterior occlusal plane has an important guiding significance for orthodontic treatment,by focusing on the change of the posterior occlusal plane to achieve the purpose of changing the soft tissue profile.

RESUMEN: Se realizó un estudio cefalométrico antes y después del tratamiento de ortodoncia en pacientes portadores de maloclusión clase II división 1 de Angle. Se observaron cambios en el perfil de los tejidos blandos y se exploró si había una correlación entre el cambio del plano oclusal posterior (OP-P) y el perfil de los tejidos blandos. El objetivo de este estudio fue otorgar una referencia teórica en el diagnóstico clínico y el tratamiento de ortodoncia de los pacientes con dentición permanente temprana con maloclusión clase II división 1 de Angle. Seleccionamos al azar 20 casos cefalometrías de pacientes de ortodoncia de la Universidad Médica de Shanxi (entre 12 y18 años). Para ello, se utilizó el software Winceph 8.0 para medir el plano oclusal posterior (OP-P), TUL-EP, TLL-EP, ángulo nasolabial, grosor de la base del labio superior, tensión del labio superior, distancia entre líneas del labio inferior H, grosor del tejido blando del mentón y ángulo Z. Se utilizó el software SPSS 22.0 para analizar la correlación entre OP-P y otros índices. El cambio del plano oclusal posterior tuvo una correlación positiva con la distancia desde el labio superior al plano estético, la distancia desde el labio inferior hasta el plano estético, la tensión del labio superior y distancia del labio inferior a la línea H. El cambio del plano oclusal posterior tuvo una correlación negativa con el ángulo nasolabial y el ángulo Z. El cambio del plano oclusal posterior no tuvo una correlación significativa con el grosor de la base del labio superior y la barbilla de tejido blando. El cambio del plano oclusal posterior tiene un importante significado de orientación para el tratamiento de ortodoncia, de tal manera que al cambiar el plano oclusal posterior se podrá lograr el propósito de cambiar el perfil del tejido blando.

Analysis on curative effect of functional orthodontic treatment in patients with Class II division 1 malocclusion / 吉林大学学报(医学版)

Objective: To detect the clinical effect of T win-Block appliance in the treatment of the patients with Class II division 1 malocclusion, and to provide the basis for clinical treatment. Methods: A total of 30 patients with class II division 1 malocclusion were treated with Twin-Block appliance. The variables of the patients before and after treatment were measured with Ricketts cephalometric radiographys. Results: Compared with before treatment, the length of corpora mandibulae (Xi-Pm) of the patients after treatment was increased by 2. 50 mm (P<0. 05), the SNB angle was increased by 2. 58° (P<0. 05), and the ANB was decreased by 2. 71 (P<0. 01); the molar relationship distance and the Overjet were decreased by 2. 81 mm and 3. 68 mm, respectively (P<0. 01); the Ll-OP was decreased by 1.89 mm, the distance of Ll-APog was increased by 1.84 mm, and the angle Ul-APog was decreased by 7. 35° (P<0. 01); the Ls-TVL was increased by 1. 85 mm, the Sm-TVL was increased by 2. 12 mm (P<0. 05), and the Pos-TVL was increased by 2. 89 mm (P<0. 05). Conclusion: The Twin-Block appliance could obviously promote the development of mandibular bone, upright the anterior teeth and improve the lip angle of upper anterior teeth and the proflie in the treatment of the patients with class II division 1 malocclusion in the growth development period.

Comparsion of soft and hard tissue profiles of adolescent patients with class II division 1 malocclusion between before and after treated with two different kinds of tooth extraction methods / 吉林大学学报(医学版)

Objective: To compare the changes of soft and hard tissue profiles of the adolescent patients with class II division 1 malocclusion between before and after treated with two different kinds of tooth extraction methods, and to provide the reference for clinical treatment. Methods: A total of 60 adolescent patients with class II division 1 malocclusion were included, and they were divided into 44/44 group (n=30) and 44/55 group (n= 30) based on different kinds of tooth extraction methods. Four first premolars of the patients in 44/44 group were extracted and 2 maxillary first premolars and 2 mandibular second premolars of the patients in 44/55 group were extracted. The measurement indexes of pre-treatment (Tl) and post-treatment (T2) and their difference values (T2 -Tl) of soft and hard tissues of the adolescent patients were detected by lateral cephalometric radiographs. Results: As for the hard tissue, compared with before treatment, the Overjet, SNA, ANB, Ul-NA, distance of Ul-NA, Ul-SN, NA-PA, and A-NP of the adolescent patients in two groups after treatment were decreasd (P0. 05). Conclusion: The changes of soft and hard tissue profiles of the adolescent patients after treated with two different kinds of tooth extraction methods are not significant.

Morphological characteristics of the cranial base of early Angle's class II division 1 malocclusion in permanent teeth / Características morfológicas de la base de cráneo en la maloclusión temprana clase II división 1 de Angle en dientes permanentes

To investigate the effects of morphological characteristics of cranial base on malocclusion by analyzing characteristics of sagittal and vertical facial types of Angle's class II division 1 malocclusion so as to provide theoretical references for clinical diagnosis and correction of early Angle's class II division 1 malocclusion in permanent teeth. We randomly selected lateral radiographs of the skull of 80 patients at the age of 12­14 years old from the Department of Orthodontics, Stomatological Hospital, Shanxi Medical University, China. There were 20 cases of Angle's class I malocclusion with average angle, 20 cases of Angle's class II division 1 malocclusion with average angle, 20 cases of Angle's class II division 1 malocclusion with low angle, and 20 cases of Angle's class II division 1 malocclusion with high angle. Winceph 8.0 software was used to measure 39 hard tissue markers and 13 indicators reflecting the characteristics of cranial base structure. One-way t-test was used in the average-angle class II division 1 group and average-angle class I group. Least significantdifference was utilized in patients with different vertical types of class II division 1 malocclusion.nterior (S-N) and posterior (S-Ba) cranial base lengths,and total cranial base length(Ba-N) were significantly longer in the class II division 1 patients compared with the class I patients. Significant differences in anterior cranial floor base angle (CF-PM), middle cranial floor base angle (Ba-SE-PM), and posterior cranial base inclination (SBa-FH) were determined between class II division 1 malocclusion and class I malocclusion patients. CF-PM angle and SBa-FH were smaller in class II division 1 subjects than in class I subjects. Ba-SE-PM angle and cranial floor base angle (Ba-SE-FMS) were larger in class II division 1 subjects than in class I subjects. No significant difference in cranial base angle (N-S-Ba) and anterior cranial base inclination (SN-FH) was detected between class II division 1 subjects and class I subjects. Morphology of cranial base and cranial floor base has a significant effect on sagittal and vertical facial types of Angle's class II division 1 malocclusion. The changes in the length of the posterior skull base and the inclination of the anterior skull base are mainly presented in the sagittal direction. Angle of cranial base and cranial floor base plays a certain role in vertical facial type of Angle's class II division 1 malocclusion.

El objetivo de este trabajo consistió en investigar los efectos de las características morfológicas de la base craneal sobre la maloclusión, a través del análisis de los siferentes tipos faciales de maloclusión Clase II de Angle (sagital y vertical), para proporcionar referencias teóricas para el diagnóstico clínico y la corrección temprana de la maloclusión de clase II división 1 de Angle en dientes permanentes. Se seleccionaron al azar radiografías laterales de cráneo de 80 pacientes, entre 12-14 años de edad, del Departamento de Ortodoncia, Hospital de Estomatología, Universidad Médica de Shanxi, China. Hubo 20 casos de maloclusión clase I de Angle con ángulo promedio, 20 casos de maloclusión clase II de Angle con ángulo promedio, 20 casos de maloclusión Clase II de Angle con ángulo bajo y 20 casos de maloclusión clase 1 de Angle con ángulo alto. Se utilizó el software Winceph 8.0 para medir 39 marcadores de tejido duro y 13 indicadores que reflejan las características de la estructura de la base de cráneo. Se usó la prueba t de una vía en el grupo clase II de división 1 con ángulo promedio y el grupo clase I con ángulo promedio. Se detectaron diferencias mínimas significativas en pacientes con diferentes tipos verticales de maloclusión clase II división 1. Las longitudes de la base de cráneo posterior (SN) y posterior (S-Ba), y la longitud total de la base craneal (Ba-N) fueron significativamente mayores en la clase II, en comparación con los pacientes de la clase I. Se determinaron diferencias significativas en el ángulo de la base del piso craneal anterior (CF-PM), el ángulo de la base del piso craneal medio (Ba-SE-PM) y la inclinación de la base craneana posterior (SBa-FH) entre la maloclusión clase II división 1 y los pacientes con maloclusión de clase I. Los ángulos de CF-PM y SBa-FH fueron más pequeños en la clase II división 1 que en la clase I. El ángulo de Ba-SE-PM y el ángulo de base del piso craneal (Ba-SE-FMS) fueron mayores en sujetos de clase II división 1 que en sujetos de clase I. No se detectaron diferencias significativas en el ángulo de la base craneana (N-S-Ba) y la inclinación de la base craneal anterior (SN-FH) entre los sujetos de la clase II división 1 y los de la clase I. La morfología de la base craneal y de la base del suelo craneal tiene un efecto significativo en los tipos faciales sagital y vertical de maloclusión Clase II división 1 de Angle. Los cambios en la longitud de la base posterior del cráneo y la inclinación de la base anterior del cráneo se presentaron principalmente en la dirección sagital. El ángulo de la base craneal y la base del suelo craneal tiene cierto rol en el tipo facial vertical de la clase II de Angle.

Cephalometric evaluation of the effects of the Twin Block appliance in subjects with Class II, Division 1 malocclusion amongst different cervical vertebral maturation stages

ABSTRACT Objectives: To evaluate the cephalometric changes in skeletal, dentoalveolar and soft tissue variables induced by Clark's Twin Block (CTB) in Class II, Division 1 malocclusion patients and to compare these changes in different cervical vertebral maturation stages. Methods: Pre- and post-treatment/observation lateral cephalograms of 53 Class II, Division 1 malocclusion patients and 60 controls were compared to evaluate skeletal, dentoalveolar and soft tissue changes. Skeletal maturity was assessed according to cervical vertebral maturation stages. Pre- and post-treatment/observation mean changes and differences (T2-T1) were compared by means of Wilcoxon sign rank and Mann-Whitney U-tests, respectively. Intergroup comparisons between different cervical stages were performed by means of Kruskal-Wallis test and Mann-Whitney U-test (p ≤ 0.05) . Results: When compared with controls, there was a significant reduction in ANB angle (p < 0.001), which was due to a change in SNB angle in CS-2 and CS-3 (p < 0.001), and in SNA (p < 0.001) and SNB (p = 0.016) angles in the CS-4 group. There was significant increase in the GoGn-SN angle in CS-2 (p = 0.007) and CS-4 (p = 0.024), and increase in Co-Gn and Go-Gn amongst all cervical stages (p < 0.05). There was significant decrease in U1-SN and increase in IMPA amongst all cervical stages (p < 0.05). There was significant retraction of the upper lip in CS-3 (p = 0.001), protrusion of the lower lip in CS-2 (p = 0.005), increase in nasolabial angle in CS-4 (p = 0.006) and Z-angle in CS-3 (p = 0.016), reduction in H-angle in CS-2 (p = 0.013) and CS-3 (p = 0.002) groups. When pre- and post-treatment mean differences were compared between different cervical stages, significant differences were found for SNA, SNB and UI-SN angles and overjet. . Conclusions: The Twin-Block along with the normal craniofacial growth improves facial esthetics in Class II, Division 1 malocclusion by changes in underlying skeletal and dentoalveolar structures. The favorable mandibular growth occurs during any of the cervical vertebral maturation stages, with more pronounced effect during CS-3 stage.

RESUMO Objetivo: avaliar as alterações em variáveis cefalométricas esqueléticas, dentoalveolares e do perfil tegumentar, induzidas pelo aparelho Twin Block de Clark (TBC), em pacientes com má oclusão de Classe II, divisão 1, e comparar as alterações nos diferentes estágios de maturação das vértebras cervicais. Métodos: telerradiografias laterais pré- e pós-tratamento de 53 pacientes com má oclusão de Classe II, divisão 1, foram comparadas às telerradiografias de 60 pacientes controle, para avaliar as alterações esqueléticas, dentoalveolares e no perfil tegumentar. A maturação esquelética foi avaliada de acordo com os estágios de maturação das vértebras cervicais. As alterações médias e as diferenças entre o pré- e o pós-tratamento (T2 - T1) foram comparadas por meio do teste de postos sinalizados de Wilcoxon e do teste U de Mann-Whitney, respectivamente. Foram realizadas comparações intergrupos para os diferentes estágios de maturação das vértebras cervicais, por meio do teste de Kruskal-Wallis e teste U de Mann-Whitney (p ≤ 0,05). Resultados: em comparação aos pacientes do grupo controle, constatou-se que houve uma redução significativa do ângulo ANB (p < 0,001), em virtude de alterações no ângulo SNB nos estágios CS2 e CS3 (p < 0,001), e nos ângulos SNA (p < 0,001) e SNB (p = 0,016) no estágio CS4. Houve um aumento significativo do ângulo GoGn-SN nos estágios CS2 (p = 0,007) e CS4 (p = 0,024), e um aumento em Co-Gn e Go-Gn em todos os estágios de maturação das vértebras cervicais (p < 0,05). Houve redução significativa em U1-SN e um aumento do IMPA em todos os estágios de maturação das vértebras cervicais (p < 0,05). Houve retração significativa do lábio superior em CS3 (p = 0,001), protrusão do lábio inferior em CS2 (p = 0,005), aumento do ângulo nasolabial em CS4 (p = 0,006) e do ângulo Z em CS3 (p = 0,016), além de redução do ângulo H em CS2 (p = 0,013) e CS3 (p = 0,002). Quando as diferenças médias entre pré- e pós-tratamento foram comparadas entre os diferentes estágios de maturação das vértebras cervicais, foram identificadas diferenças significativas para os ângulos SNA, SNB e UI-SN, assim como para o overjet. Conclusões: o uso do aparelho Twin-Block, associado ao crescimento craniofacial normal, melhora a estética facial em pacientes com má oclusão de Classe II, divisão 1, por meio de alterações nas estruturas esqueléticas e dentoalveolares subjacentes. Esse crescimento mandibular mais favorável pode ocorrer durante qualquer um dos estágios de maturação das vértebras cervicais, com um efeito mais acentuado durante o estágio CS3.

Three-dimensional evaluation of tooth movement in Class II malocclusions treated without extraction by orthodontic mini-implant anchorage / 대한치과교정학회지

OBJECTIVE: The aim of this study was to analyze tooth movement and arch width changes in maxillary dentition following nonextraction treatment with orthodontic mini-implant (OMI) anchorage in Class II division 1 malocclusions. METHODS: Seventeen adult patients diagnosed with Angle's Class II division 1 malocclusion were treated by nonextraction with OMIs as anchorage for distalization of whole maxillary dentition. Three-dimensional virtual maxillary models were superimposed with the best-fit method at the pretreatment and post-treatment stages. Linear, angular, and arch width variables were measured using Rapidform 2006 software, and analyzed by the paired t-test. RESULTS: All maxillary teeth showed statistically significant movement posteriorly (p 0.05) and the intercanine, interfirst premolar, intersecond premolar, and interfirst molar widths increased significantly (2.2 mm, p < 0.01; 2.2 mm, p < 0.05; 1.9 mm, p < 0.01; 2.0 mm, p < 0.01; respectively). CONCLUSIONS: Nonextraction treatment with OMI anchorage for Class II division 1 malocclusions could retract the whole maxillary dentition to achieve a Class I canine and molar relationship without a change in the vertical position of the teeth; however, the second molars were significantly extruded. Simultaneously, the maxillary arch was shown to be expanded with distal-in rotation of the molars.

Preliminary three-dimensional analysis of tooth movement and arch dimension change of the maxillary dentition in Class II division 1 malocclusion treated with first premolar extraction: conventional anchorage vs. mini-implant anchorage / 대한치과교정학회지

OBJECTIVE: This study aimed to compare the effects of conventional and orthodontic mini-implant (OMI) anchorage on tooth movement and arch-dimension changes in the maxillary dentition in Class II division 1 (CII div.1) patients. METHODS: CII div.1 patients treated with extraction of the maxillary first and mandibular second premolars and sliding mechanics were allotted to conventional anchorage group (CA, n = 12) or OMI anchorage group (OA, n = 12). Pre- and post-treatment three-dimensional virtual maxillary models were superimposed using the best-fit method. Linear, angular, and arch-dimension variables were measured with software program. Mann-Whitney U-test and Wilcoxon signed-rank test were performed for statistical analysis. RESULTS: Compared to the CA group, the OMI group showed more backward movement of the maxillary central and lateral incisors and canine (MXCI, MXLI, MXC, respectively; 1.6 mm, p < 0.001; 0.9 mm, p < 0.05; 1.2 mm, p < 0.001); more intrusion of the MXCI and MXC (1.3 mm, 0.5 mm, all p < 0.01); less forward movement of the maxillary second premolar, first, and second molars (MXP2, MXM1, MXM2, respectively; all 1.0 mm, all p < 0.05); less contraction of the MXP2 and MXM1 (0.7 mm, p < 0.05; 0.9 mm, p < 0.001); less mesial-in rotation of the MXM1 and MXM2 (2.6degrees, 2.5degrees, all p < 0.05); and less decrease of the inter-MXP2, MXM1, and MXM2 widths (1.8 mm, 1.5 mm, 2.0 mm, all p < 0.05). CONCLUSIONS: In treatment of CII div.1 malocclusion, OA provided better anchorage and less arch-dimension change in the maxillary posterior teeth than CA during en-masse retraction of the maxillary anterior teeth.

Avaliação cefalométrica dos resultados do aparelho de protração mandibular (APM) associado ao aparelho fixo em relação às estruturas dentoalveolares e tegumentares em pacientes portadores de má oclusão de Classe II, 1ª divisão / Cephalometric evaluation of the effects of a mandibular protraction appliance (MPA) combined with fixed orthodontic appliance on dentoalveolar and soft tissue structures of Class II, division 1 patients

OBJETIVO: avaliar cefalometricamente as alterações tegumentares e dentoalveolares em jovens brasileiros portadores de má oclusão de Classe II, 1ª divisão, tratados com APM associado à Ortodontia corretiva fixa. MÉTODOS: a amostra consistiu-se de 28 pacientes (16 do sexo feminino e 12 do sexo masculino), com idade média de 13,06 anos, tratados por um período médio de 14,43 meses. As alterações foram medidas em 56 cefalogramas específicos, obtidos das telerradiografias laterais feitas antes e após o tratamento, por dois examinadores calibrados para identificar as alterações tegumentares e dentoalveolares, utilizando-se grandezas cefalométricas lineares e angulares. As variáveis independentes (sexo, idade, padrão facial, tipo de APM, arco, técnica e tempo de tratamento) foram consideradas e analisadas com as grandezas cefalométricas lineares e angulares. As respostas ao tratamento foram analisadas e comparadas pelos testes Wilcoxon Signed Ranks e Mann-Whitney para um nível de significância de 5 por cento. RESULTADOS: os resultados mostraram mudanças dentoalveolares de grande magnitude, provocando, assim, mudanças favoráveis no tecido mole. Observou-se, ainda, que as variáveis idade, tipo de APM e técnica utilizada influenciaram no tratamento. CONCLUSÕES: o APM mostrou-se uma alternativa eficaz para o tratamento da má oclusão de Classe II, 1ª divisão, propiciando alterações dentoalveolares e tegumentares com resultados clínicos satisfatórios.

OBJECTIVE: To perform a cephalometric evaluation of dentoalveolar and soft tissue changes in Brazilian youths with Class II, division 1 malocclusion, treated with a mandibular protraction appliance (MPA) combined with fixed corrective orthodontics. METHODS: The sample consisted of 28 patients (16 females and 12 males) with a mean age of 13.06 years, treated for a mean period of 14.43 months. The changes were measured on 56 specific cephalometric analysis obtained from lateral cephalograms taken before and after treatment by two calibrated examiners in order to identify soft tissue and dentoalveolar changes using linear and angular cephalometric measures. The independent variables sex, age, facial pattern, MPA model, archwire, technique and treatment time were registered and analyzed using linear and angular cephalometric measures. Treatment responses were analyzed and compared by the Wilcoxon Signed Ranks and Mann-Whitney tests at a significance level of 5 percent. RESULTS: The results showed dentoalveolar changes of great magnitude, which caused positive changes in soft tissue. It was also noted that the variables age, MPA model and technique influenced the treatment. CONCLUSIONS: MPA proved to be an effective alternative in the treatment of Class II, division 1 malocclusion, inducing dentoalveolar and soft tissue changes with satisfactory clinical results.

Estudo da reabsorção radicular apical após o uso de aparelho extrabucal no tratamento da má oclusão do tipo Classe II, 1ª divisão dentária / Study of apical root resorption after occipital headgear wear on the treatment of dental Class II, division 1 malocclusion

OBJETIVO: o presente estudo verificou o efeito do uso do aparelho extrabucal (AEB) sobre a intensidade da reabsorção radicular apical nos primeiros molares permanentes superiores submetidos à ação do aparelho. MÉTODOS: foram avaliadas as radiografias periapicais da região dos primeiros molares permanentes superiores, bilateralmente, de 19 jovens leucodermas, do gênero feminino, com idades entre 8 e 10 anos, com má oclusão do tipo Classe II, 1ª divisão dentária, pré e pós-tratamento com AEB de tração alta. As 76 radiografias foram divididas em dois grupos, de acordo com o grau de formação radicular. O grupo A consistiu de 18 radiografias com formação radicular incompleta, com exceção da raiz palatina, ao início do tratamento e 18 ao final. O grupo B consistiu de 20 radiografias com formação radicular completa ao início do tratamento e 20 ao final. Mensurou-se os comprimentos radiculares utilizando um paquímetro digital e submeteu-se as medidas obtidas ao teste de erro do método e à análise estatística (teste t de Student) para verificar as diferenças no comprimento radicular antes e após o tratamento com o AEB. RESULTADOS: no grupo A ocorreu um aumento significativo dos comprimentos radiculares, enquanto no grupo B as diferenças dos comprimentos radiculares não foram significativas. As medidas pós-tratamento no grupo A não diferiram das medidas pré-tratamento no grupo B, ou seja, os dentes com formação radicular incompleta ao início do tratamento apresentaram crescimento radicular normal durante o tratamento ativo. CONCLUSÃO: concluiu-se que o uso do AEB não influenciou negativamente na formação radicular e não provocou reabsorção apical nos molares submetidos à ação do aparelho, sugerindo que o AEB não apresentou riscos à estrutura e formação radicular quando corretamente indicado e aplicado.

AIM: The aim of this study was to verify the effect of occipital headgear wear on the intensity of apical root resorption of the upper first permanent molars submitted to the action of the appliance. METHODS: Were evaluated periapical X-rays of 19 leucoderms young female - with ages between 8 and 10 years, with dental Class II, division 1 malocclusion, before and after orthodontic treatment, using high-pull headgear. The 76 X-rays were divided into two groups according to their root formation. Group A consisted of 18 X-rays with incomplete root formation, except for the palatine root, before treatment and 18 after treatment. Group B consisted of 20 X-rays where root formation was completed before treatment and 20 after treatment. The root lengths were measured with digital caliper and the registered measures were submitted to the error of the method and statistical analysis, Student t test, to verify the differences regarding the root length before and after the treatment with occipital headgear. RESULTS: In group A, there was a significant increase of the root lengths, while in the group B the differences were not significant. Posttreatment Group A showed no significant differences with the mean root lengths of pretreatment group B, in other words, teeth with incomplete root formation at onset of orthodontic treatment presented normal root growth during the active treatment. CONCLUSION: Therefore, it was concluded that high-pull headgear didn't influence negatively in the root formation and it didn't provoke apical resorption of the molars submitted to the action of the appliance, suggesting that occipital headgear doesn't present risks to the root structure and formation when correctly indicated and applied.

A cephalometric investigation on the craniofacial configurations of Class II division 1 and 2 in Korean / 대한치과교정학회지

Numerous studies have revealed the similarities and discrepancies in two divisions of class II malocclusion, since these malocclusion groups have been postulated to be disparate criterion, much as classified under one diagnostic umbrella. This study was undertaken to describe the craniofacial configurations of class II division 1 and 2, and consequently to discriminate the morphologic differences between the two malocclusion groups in Korean sample. Lateral headfilms of 34 class II division 1 and 29 division 2 were employed, while those of 142 adults of normal occlusion served as a control. The landmarks were digitized and 26 variables were statistically analyzed for one way: 1. There manifested no statistically significant difference in maxillary position anteroposteriorly. Normal occlusion group exhibited most anteriorly positioned mandible, whereas class II division 1 showed the most retroposition. Class II division 1 disclosed clockwise rotation tendency of mandible, which resulted in position of the chin posteriorly. 2. Class II division 1 showed greater in SN to MP, SN to PP significantly than other groups. 3. Class II division 2 showed smaller gonial angle and larger mandibular body length than other groups. 4. Class II division 1 revealed greater anterior lower face height than other groups, whereas division 2 dictated significantly greater posterior face height. 5. Class II division 2 expressed the most retroclined lower incisor, while division 1 manifested the most proclination. The largest interincisal angle resided in Class II division 2 group. There were no significant differences in upper molar position anteroposteriorly.

An evaluation of treatment effects of modified teuscher appliance in Class II division 1 malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate treatment effects of the modified Teuscher appliance (MTA) in early Class II division 1 malocclusion. For this purpose, treatment effects of the bionator were compared with those of the MTA. The twenty subjects who were treated excellently with bionator and MTA were selected in each group. In pre- and post-treatment lateral cephalograms, 50 variables were measured, and then the differences between pretreatment and posttreatment data of the bionator and the MTA were statistically evaluated by t-test. The results were as follows : 1. The linear measurements that showed large difference between the bionator group and the MTA group are U1 to FH, U1 to PP, U6 to FH, U6 to PP, Ar-Pog, ramus height, L1 to A-Pog, L1 to facial plane (p0.05). These results suggest that the bionator influence the mandiblar growth and lower dentoalveolar structures more than the MTA, and the MTA influence upper jaw and upper dentoalveolar structures more than the bionator comparatively in early Class II division I malocclusion.

Skeletodental changes during treatment and retention in Class II division 1 malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate the changes of skeletodental patterns during Class II treatment and its retention period. Forty two patients of Class II malocclusion, which was treated with nonextraction or first premolar-extraction were selected and their lateral cephalograms were examined in this study. Various skeletodental changes in lateral cephalograms of pre-treatment, post-treatment and retention were measured by superimposition in reference to the cranial base for jaws, the palatal plane for maxillary teeth, and mandibular plane for mandibular teeth. The data were analyzed by paired t-test. In this study, occlusal plane showed the significant anterior downward steepening after active treatment, and remained during retention period. In the nonextraction group, maxillary incisors were retracted and extruded during treatment. Maxillary molars were extruded, and mandibular molars were uprighted, with no mesial movement. In the extraction group, both maxillary and mandibular incisors were retracted and extruded. Maxillary molars were extruded and moved mesially, and mandibular molars were extruded and moved mesially with no mesial tilting. During retention period in both groups, there were tendencies of labial tipping of maxillary incisor, and mesial tipping of maxillary and mandibular molar. But the changes were not significant and most of teeth showed no change in vertical and horizontal direction.

An evaluation on the indications of bionator in Class II division 1 malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate the indications of bionator in Class II division 1 malocclusion. The 48 subjects were classified into good result group(groupl) and poor result group(group2) in reference to posttreatment molar relation, posttreatment overbite and overjet, posttreatment profile, and relapse. Pretreatment lateral cephalograms were calculated and evaluated by t-test and stepwise discrminant analysis. The results were as follows; 1. In jaw bone relationship, ANB, facial convexity angle, AB to facial plane angle were significantly different between two treatment groups. In denture pattern, Ll to facial plane, Ll to A-Pog, FMIA, and Ul to facial plane were significantly different and in soft tissue profile, protuberance of lower lip and upper lip were significantly different between two treatment groups. 2. The results in according to discriminant analysis stated that Ll to facial plane, ANB, FMIA and protuberance of lower lip help prediction of treatment result of bionator. 3. 3 major influential variables were obtained by stepwise discriminant analysis - Ll to facial plane, articular angle and ANB difference. And Fisher discriminant function was made by these three major variables.

A study on treatment effects of different activator types in Angle's Class II div.1 malocclusion patients / 대한치과교정학회지

This research was carried out to compares the treatment effects of Horizontal and Vertical type activators in Angle's Class II div. 1 maloccusion patients with mandibular retrusion dand to find out whether different treatment effects or growth pattern were observed between sexes in each study groups. The results were as follows: 1. In Horizontal activator group, forward positioning of mandible and vertical increase in anteror face as examplified by increase of LAFH and AFH were observed when pre and post-treatment datas were evaluated. 2. Males samples in Horizontal activator group showed increase in mandiular length accmpanied by posterior positioning of maxilla, wheras female samples in Horizontal activator group showed increase in mandibular body length,labial inclination of mandibular incisors and increase in lower anterior facial height . 3. In vertical activator group, increase in AFH, LAFH, PFH and LPFH were observed when pre and post treatment datas were a aluated. 4. Male samples in Vertical activator group showed increase in mandibular body length and anterior and posterior facial heights, whereas females samples of Vertical activator group showed mainly increase in anterior facial height 5. When pre and post treatment datas of Horizontal and Vertical activator groups were compared, skeletal difference were mainly observed in eatrnnt datas but dental difference were observed in post treatment datas ,indicating that two actiators differ only in their effects to dental variables. 6. Difference between sexes were noted after treatment although no difference were observed between sexs in each groups before treatment This indicates that inherent growth effects in each sex exerts more influence than appliances used for treatment.

An evaluation of treatment effects of bionator in Class II division 1 malocclusion by finite element method / 대한치과교정학회지

The purpose of this study was to evaluate treatment effects of bionator in Class II division 1 malocclusion by FEM(Finite Element Method). The 73 subjects were classified into good result group and poor result group in reference to posttreatment molar relation, posttreatment overbite and overjet, posttreatment profile, and relapse. Pretreatment and posttreatment lateral cephalograms were taken and FEM was performed. The results were as follow; 1. There was no statistical significance in treatment changes between the sexes, and between the treatment result groups. 2. Treatment changes were not significantly different among the age groups. 3. The effect of treatment period groups on skeletal and dentoalveolar changes were analyzed using ANOVA. Body of maxilla, upper incisor, anterior face, ramus, upper anterior face, lower anterior face and treatment effect were correlated with the treatment period, but correlation coefficients were low. 4. The results of present investigation confirm that Class II bionator can assist in the correction of Class II division 1 malocclusion, mainly due to dentoalveolar changes. 5. There is significant difference in skeletal and dentoalveolar pattern between good result group and poor result group. In poor result group, maxilla was relatively downward and backward rotated, mandible was relatively backward rotated, upper incisor was in relatively lingual position, lower incisor was in relatively labial position.