Referências linguais da coroa dentária para o posicionamento vertical de braquetes / Lingual references of the tooth crown for vertical bracket positioning

Objetivo: determinar o posicionamento vertical da crista marginal (PVCM) e do centro lingual da coroa clínica (PVCC), bem como comparar a discrepância vertical de posição entre cristas marginais (DVCM) e centros de coroas clínicas (DVCC) de dentes adjacentes. Material e métodos: uma amostra foi selecionada a partir de um grupo de 1.430 pacientes. Duzentos pacientes que preenchiam os critérios de seleção tiveram seus modelos de gesso iniciais selecionados. Após a padronização do posicionamento do modelo de gesso, o PVCM e PVCC dos dentes posteriores de ambos os arcos foram medidos, permitindo o cálculo da DVCM e DVCC. Um medidor digital de altura com precisão de 0,01 mm foi utilizado para as avaliações, e os dados foram comparados estatisticamente (p < 0,05). Resultados: em geral, os dentes posteriores adjacentes apresentaram diferentes PVCM e PVCC. As variáveis DVCM e DVCC foram significantemente diferentes, exceto entre pré-molares inferiores. As diferenças entre DVCM e DVCC foram clinicamente significantes (> 0,5 mm). O PVCC foi significantemente correlacionado com a idade do paciente. Conclusão: as diferenças entre DVCM e DVCC indicaram que o centro lingual da coroa clínica não foi uma referência anatômica confiável para predizer o nivelamento das cristas marginais. A idade do paciente parece ser um fator adicional que limita o uso adequado deste referencial.

Objective: to determine the vertical positioning of the marginal ridge (VPMR) and clinical crown center (VPCC) regarding the tip of the lingual cusp, and to compare the vertical discrepancy between adjacent marginal ridges (VDMR) and clinical crown centers of adjacent posterior teeth (VDCC). Material and methods: the sample was selected from a pool of 1.430 patients. Two hundred initial dental casts were selected from patients that met the selection criteria. After standardization of the dental cast positioning, VPMR and VPCC of posterior teeth were measured in both arches, allowing the calculation of VDMR and VDCC. Measurements were performed with a digital height gauge and accuracy of 0.01 mm. Data were statistically compared at p < 0.05. Results: in general, adjacent posterior teeth had different VPMR and VPCC. The variables VDMR and VDCC were significantly different, except between mandibular premolars. The differences between VDMR and VDCC were clinically significant (> 0.5 mm). Patient age and VPCC were significantly correlated. Conclusion: the differences between VDMR and VDCC showed that lingual center of the clinical crown was not a reliable anatomical reference to predict the marginal ridge leveling. Patient's age seems to be an additional factor limiting the adequate use of this landmark.

Angle Class II correction with MARA appliance.

OBJECTIVE: To assess the effects produced by the MARA appliance in the treatment of Angle's Class II, division 1 malocclusion. METHODS: The sample consisted of 44 young patients divided into two groups: The MARA Group, with initial mean age of 11.99 years, treated with the MARA appliance for an average period of 1.11 years, and the Control Group, with initial mean age of 11.63 years, monitored for a mean period of 1.18 years with no treatment. Lateral cephalograms were used to compare the groups using cephalometric variables in the initial and final phases. For these comparisons, Student's t test was employed. RESULTS: MARA appliance produced the following effects: Maxillary growth restriction, no change in mandibular development, improvement in maxillomandibular relationship, increased lower anterior facial height and counterclockwise rotation of the functional occlusal plane. In the upper arch, the incisors moved lingually and retruded, while the molars moved distally and tipped distally. In the lower arch, the incisors proclined and protruded, whereas the molars mesialized and tipped mesially. Finally, there was a significant reduction in overbite and overjet, with an obvious improvement in molar relationship. CONCLUSIONS: It was concluded that the MARA appliance proved effective in correcting Angle's Class II, division 1 malocclusion while inducing skeletal changes and particularly dental changes.

Angle Class II correction with MARA appliance

OBJECTIVE: To assess the effects produced by the MARA appliance in the treatment of Angle's Class II, division 1 malocclusion. METHODS: The sample consisted of 44 young patients divided into two groups: The MARA Group, with initial mean age of 11.99 years, treated with the MARA appliance for an average period of 1.11 years, and the Control Group, with initial mean age of 11.63 years, monitored for a mean period of 1.18 years with no treatment. Lateral cephalograms were used to compare the groups using cephalometric variables in the initial and final phases. For these comparisons, Student's t test was employed. RESULTS: MARA appliance produced the following effects: Maxillary growth restriction, no change in mandibular development, improvement in maxillomandibular relationship, increased lower anterior facial height and counterclockwise rotation of the functional occlusal plane. In the upper arch, the incisors moved lingually and retruded, while the molars moved distally and tipped distally. In the lower arch, the incisors proclined and protruded, whereas the molars mesialized and tipped mesially. Finally, there was a significant reduction in overbite and overjet, with an obvious improvement in molar relationship. CONCLUSIONS: It was concluded that the MARA appliance proved effective in correcting Angle's Class II, division 1 malocclusion while inducing skeletal changes and particularly dental changes.

OBJETIVO: avaliar os efeitos proporcionados pelo aparelho MARA no tratamento da má oclusão de Classe II, 1ª divisão. MÉTODOS: utilizou-se uma amostra de 44 jovens, divididos em dois grupos - Grupo MARA, com idade inicial média de 11,99 anos e tratado com o aparelho MARA por um período médio de 1,11 ano; e Grupo Controle, com idade inicial média de 11,63 ano e observado por um período médio de 1,18 ano, sem nenhum tratamento. Utilizou-se as telerradiografias em norma lateral para comparar os grupos quanto às variáveis cefalométricas das fases inicial e final. Para essas comparações, aplicou-se o teste t de Student. RESULTADOS: o aparelho MARA proporcionou efeitos na restrição do crescimento maxilar, sem nenhuma alteração do desenvolvimento mandibular, com melhora da relação maxilomandibular, aumento da altura facial anteroinferior e inclinação anti-horária do plano oclusal funcional. Na arcada superior, os incisivos foram lingualizados e retruídos, e os molares foram distalizados e inclinados para distal. Na arcada inferior, ocorreu vestibularização e protrusão nos incisivos, e mesialização e inclinação mesial dos molares. Por fim, observou-se uma redução significativa nos trespasses horizontal e vertical, e uma melhora evidente na relação molar. CONCLUSÃO: pode-se concluir que o aparelho MARA foi eficaz na correção da má oclusão de Classe II, 1ª divisão, promovendo alterações esqueléticas e, principalmente, dentárias.

Influência da largura do septo inter-radicular sobre a estabilidade dos mini-implantes / Influence of inter-root septum width on mini-implant stability

OBJETIVO: este estudo teve como objetivo avaliar a influência da largura do septo inter-radicular no local de inserção de mini-implantes autoperfurantes sobre o grau de estabilidade desses dispositivos de ancoragem. MÉTODOS: a amostra consistiu de 40 mini-implantes inseridos entre as raízes do primeiro molar e segundo pré-molar superiores de 21 pacientes, com o intuito de fornecer ancoragem para retração anterior. A largura do septo no local de inserção (LSI) foi mensurada nas radiografias pós-cirúrgicas e, sob esse aspecto, os mini-implantes foram divididos em dois grupos: grupo 1 (áreas críticas, LSI<3mm) e grupo 2 (áreas não críticas, LSI>3mm). A estabilidade dos mini-implantes foi avaliada mensalmente pela quantificação do grau de mobilidade e a partir dessa variável foi calculada a proporção de sucesso. Avaliou-se também: a quantidade de placa, altura de inserção, grau de sensibilidade e período de observação. RESULTADOS: os resultados obtidos demonstraram que não houve diferença estatisticamente significativa para o grau de mobilidade e proporção de sucesso entre os mini-implantes inseridos em septos de largura mesiodistal crítica e não crítica. A proporção de sucesso total encontrada foi de 90 por cento e nenhuma variável demonstrou estar relacionada ao insucesso dos mini-implantes. No entanto, observou-se maior sensibilidade nos pacientes cujos mini-implantes apresentavam mobilidade, e que a falha desses dispositivos de ancoragem ocorria logo após sua inserção. CONCLUSÃO: a largura do septo inter-radicular no local de inserção não interferiu na estabilidade dos mini-implantes autoperfurantes avaliados neste estudo.

OBJECTIVE: The purpose of this study was to evaluate the influence of the inter-radicular septum width in the insertion site of self-drilling mini-implants on the stability degree of these anchorage devices. METHODS: The sample consisted of 40 mini-implants inserted in the inter-radicular septum between maxillary second premolars and first molars in 21 patients to provide skeletal anchorage for anterior retraction. The post-surgical radiographs were used to measure the septum width in the insertion site (ISW). In this regard, the mini-implants were divided in two groups: group 1 (critical areas, ISW<3 mm) and group 2 (non-critical areas, ISW>3 mm). The degree of mobility (DM) was monthly quantified to determine mini-implant stability, and the success rate of these devices was calculated. This study also evaluated the sensitivity degree during miniscrew load, amount of plaque around the miniscrew, insertion height, and total evaluation period. RESULTS: The results showed no significant difference in mobility degree and success rate between groups 1 and 2. The total success rate found was 90 percent and no variable was associated with the miniscrew failure. Nevertheless, the results showed that greater patient sensitivity degree was associated to the mini-implant mobility and the failure of these anchorage devices happened in a short time after their insertion. CONCLUSION: Septum width in the insertion site did not influence the self-drilling mini-implant stability evaluated in this study.

Class III subdivision malocclusion corrected with asymmetric intermaxillary elastics.

Correcting a Class III subdivision malocclusion is usually a challenge for an orthodontist, especially if the patient's profile does not allow for any extractions. One treatment option is to use asymmetric intermaxillary elastics to correct the unilateral anteroposterior discrepancy. However, the success of this method depends on the individual response of each patient and his or her compliance in using the elastics. The objectives of this article were to present a successful treatment of a Class III subdivision patient with this approach and to illustrate and discuss the dentoskeletal changes that contributed to the correction.

Orthodontic treatment alternative to a class III subdivision malocclusion.

Class III malocclusions are considered one of the most complex and difficult orthodontic problems to diagnose and treat. Skeletal and/or dental asymmetries in patients presenting with Class III malocclusions can worsen the prognosis. Recognizing the dentoalveolar and skeletal characteristics of subdivision malocclusions and their treatment possibilities is essential for a favorable nonsurgical correction. Therefore, this article presents a nonsurgical asymmetric extraction approach to Class III subdivision malocclusion treatment which can significantly improve the occlusal and facial discrepancies.

Variáveis relevantes no tratamento da má oclusão de Classe II: [revisão] / Relevant variables of Class II malocclusion treatment: [review]

Os resultados do tratamento da má oclusão de Classe II podem ser influenciados por características que são inerentes ao paciente - como a idade, a severidade da má oclusão e o grau de colaboração - ou, ainda, por fatores relacionados à conduta do profissional - como a escolha do protocolo de tratamento. Basicamente, o tratamento da Classe II pode ser realizado sem extrações ou com extrações de dois ou quatro pré-molares. Contudo, uma maior proporção de sucesso do tratamento pode ser esperada com extrações de dois pré-molares superiores, independentemente do padrão facial e da relação maxilomandibular. Considerando esta revisão, pôde-se concluir que os resultados oclusais do tratamento da Classe II são fortemente influenciados pelo protocolo de tratamento, enquanto o padrão facial não parece exercer uma influência significativa.

Results of orthodontic Class II malocclusion treatment can be influenced by inherent characteristics such as patient age, malocclusion severity and degree of compliance, or even by factors regarding the orthodontist's subjective preference such as the treatment protocol. Basically, Class II treatment protocols involve nonextraction or extraction of two or four premolars. However, a greater treatment success rate can be expected with the extraction protocol of two maxillary premolars, regardless of the skeletal pattern or the amount of maxillomandibular anteroposterior discrepancy. According to this review, it was concluded that Class II malocclusion treatment results are strongly influenced by the treatment protocol, while skeletal characteristics do not seem to exert significant influence.

Orthodontic treatment alternative to a class III subdivision malocclusion

Class III malocclusions are considered one of the most complex and difficult orthodontic problems to diagnose and treat. Skeletal and/or dental asymmetries in patients presenting with Class III malocclusions can worsen the prognosis. Recognizing the dentoalveolar and skeletal characteristics of subdivision malocclusions and their treatment possibilities is essential for a favorable nonsurgical correction. Therefore, this article presents a nonsurgical asymmetric extraction approach to Class III subdivision malocclusion treatment which can significantly improve the occlusal and facial discrepancies.

Avaliação da precisão de um guia radiográfico-cirúrgico para inserção de mini-implantes / Accuracy evaluation of a radiographic-surgical guide for mini-implant placement

PROPOSIÇÃO - Avaliou-se radiograficamente o grau de precisão de um guia radiográfico-cirúrgico na predição do posicionamento final de mini-implantes inseridos no septo inter-radicular e, sequencialmente, determinou-se um índice de risco para normatizar a indicação do procedimento de inserção dos mini-implantes. MATERIAL E MÉTODOS - Um total de 53 mini-implantes foram inseridos no septo inter-radicular vestibular da região posterior da maxila e/ou mandíbula de 27 pacientes com idade média de 19,17 ± 9,06 anos (idade mínima de 12,72 anos e máxima de 56,37 anos). O Guia Radiográfico-Cirúrgico Graduado (GRCG) foi utilizado para inserir os mini-implantes no centro do septo de forma equidistante em relação às raízes dos dentes adjacentes. As distâncias entre o mini-implante e as raízes dos dentes adjacentes foram mensuradas nas 53 radiografias pós-cirúrgicas com intuito de avaliar a precisão do GRCG a partir do grau de centralização do mini-implante no septo. O grau de imprecisão do GRCG foi associado à largura do septo e ao diâmetro do mini-implante para compor a fórmula do índice de risco utilizada na avaliação do risco cirúrgico de inserção dos mini-implantes. RESULTADOS - O grau de imprecisão do GRCG mostrou que, em média, os mini-implantes foram inseridos com um desvio de 0,13mm (±0,13) em relação ao centro do septo. O valor médio do índice de risco (IR) foi menor do que 1, significando um reduzido risco cirúrgico. CONCLUSÕES - A ligação estabelecida entre os procedimentos radiográfico e cirúrgico proveu ao GRCG um reduzido grau de imprecisão de 0,13mm, e uma acurada predição do posicionamento final do mini-implante no septo inter-radicular, contribuindo para um reduzido risco cirúrgico (IR < 1).

OBJECTIVE - This study evaluated the radiographic-surgical guide accuracy to predict post-surgical mini-implant positioning in the interradicular septum. Additionally, a risk index to standardize surgical procedure indication for mini-implant insertion was determined. MATERIAL AND METHODS - A total of fifty-three titanium mini-implants were placed in the buccal interradicular septum of the posterior maxillary and/or mandibular region of 27 patients with a mean age of 19.17 ± 9.06 years (ranging from 12.72 to 56.37 years). The Graduated Radiographic-Surgical Guide (GRSG) was used to insert mini-implants in the interradicular septum in a centralized and equidistant position regarding adjacent tooth roots. The fifty-three post-surgical radiographs were used to measure the distances between mini-implants and adjacent tooth roots to evaluate GRSG accuracy in obtaining mini-implant centralized position in the septum. The GRSG inaccuracy degree was related to the septum width and the mini-implant diameter to obtain risk index formula, which was used to predict surgical risks during mini-implants insertion. RESULTS - The GRSG inaccuracy degree showed that, on average, the mini-implants were 0.13mm (±0.13) displaced regarding the centralized position initially intended. The risk index (RI) presented a mean value smaller than 1, indicating a reduced surgical risk. CONCLUSION - The link established between radiographic and surgical procedures propitiated a small GRSG inaccuracy degree of 0.13mm, allowing an accurate prediction of the final mini-implant positioning in the interradicular septum, which contributed to a low surgical risk (RI < 1).

Class II treatment efficiency in maxillary premolar extraction and nonextraction protocols.

INTRODUCTION: In this study, we compared the efficiency of nonextraction and 2-maxillary-premolar-extraction protocols in complete Class II malocclusion treatment. METHODS: A sample of 112 records from patients with complete Class II malocclusion was divided into 2 groups with the following characteristics: group 1, comprising 43 patients treated nonextraction with an initial mean age of 12.63 years; and group 2, comprising 69 patients treated with extraction of 2 maxillary premolars with an initial mean age of 13.91 years. To compare the efficiency of each treatment protocol, the initial and final occlusal statuses were evaluated on dental casts with the peer assessment rating (PAR) index, and the treatment time of each group was calculated from the clinical charts. Treatment efficiency was calculated by the ratio between the percentage of PAR reduction and the treatment time. PAR scores, treatment times, and treatment protocols' efficiencies of the groups were compared with the t test. RESULTS: The 2-maxillary-premolar-extraction protocol had a smaller final PAR score, a greater percentage of PAR reduction, and greater treatment efficiency than the nonextraction protocol of complete Class II malocclusion. CONCLUSION: The 2-maxillary-premolar-extraction protocol has greater treatment efficiency than the nonextraction protocol of complete Class II malocclusion.

Third molar availability in Class II subdivision malocclusion.

INTRODUCTION: In this study, we compared retromolar available space and third molar angulation between the Class I and Class II sides in patients with Class II subdivision malocclusion. METHODS: Two samples were obtained from 46 subjects grouped according to the following characteristics: group 1 comprised 29 subjects (17 male, 12 female) with Class II subdivision malocclusion at a mean age of 14.73 years. Group 2 was the control to assist in the asymmetry evaluation and included 17 subjects (11 female, 6 male) with normal occlusion at a mean age of 21.73 years. Corrected oblique radiographs of each patient side were obtained to evaluate right and left retromolar available space and third molar angulation. The retromolar space and third molar angulations in the Class I and Class II sides in each group were compared with paired t and Wilcoxon tests. Asymmetry between the Class I and Class II sides of the Class II subdivision malocclusion group was compared with asymmetry between the right and left sides of the normal occlusion group with independent t and Mann-Whitney tests. RESULTS: The results demonstrated significant differences between the Class I and Class II retromolar available spaces in the Class II subdivision malocclusion group. Significant angular asymmetry between these sides was observed only for the mandibular third molars. However, when retromolar space asymmetry and third molar angular asymmetry were compared between the Class II subdivision malocclusion and the normal occlusion groups, there were significant differences only for retromolar space asymmetry. CONCLUSIONS: Patients with Class II subdivision malocclusion have asymmetric amounts of maxillary and mandibular retromolar available space and asymmetric angulation of the mandibular third molars between the Class I and Class II sides.

Orthodontic treatment time in 2- and 4-premolar-extraction protocols.

INTRODUCTION: The purpose of this study was to compare the treatment times of complete Class II malocclusions treated with 2- and 4-premolar-extraction protocols. METHODS: Ninety-seven patients were selected and divided into 2 groups, according to the 2 extraction criteria. Group 1, treated with 2 maxillary premolar extractions, consisted of 49 patients (30 male, 19 female) with a mean age of 14.35 years. Group 2, treated with 4 premolar extractions, consisted of 48 patients (27 male, 21 female) with a mean age of 13.03 years. Treatment times of the groups were compared with the t test. RESULTS: Treatment times were significantly shorter with the 2-premolar-extraction protocol compared with the 4-premolar-extraction protocol. CONCLUSIONS: Treatment time will be shorter and the occlusal results more predictable with a 2-premolar-extraction protocol compared with 4 premolar extractions.