RESUMO Objetivo: Avaliar as alterações dentárias e esqueléticas decorrentes do uso exclusivo do aparelho extrabucal durante 15 ± 4 meses para tratamento de pacientes com má oclusão de Classe II divisão 1 (Grupo Experimental, GE). Métodos: As diferenças entre o início (T1) e imediatamente após o término da terapia (T2) com o aparelho extrabucal de tração cervical (Grupo Experimental, GE, n = 23) foram comparadas àquelas apresentadas por um grupo composto por indivíduos não tratados (Grupo Controle, GC, n = 22), com má oclusão e faixa etária cronológica compatíveis. As variáveis cefalométricas avaliadas foram: ANB, GoGn.SN, AO-BO, S’-ENA, S’-A, S’-B, S’-Pog e S’-U6 (primeiro molar superior). Os testes de Shapiro-Wilk e Levene foram aplicados para avaliar os resultados. Resultados: Diferenças significativas entre T1 e T2 foram encontradas para as variáveis ANB, S’-U6, AO-BO, S’-ENA, S’-A, S’-B e S’-Pog, quando comparados os dois grupos. Nenhuma diferença estatisticamente significativa foi encontrada em relação ao ângulo GoGn.SN. Conclusão: O uso do aparelho extrabucal com tração cervical promoveu movimento para distal do primeiro molar superior e restringiu o deslocamento anterior da maxila, sem afetar significativamente o ângulo GoGn.SN.

ABSTRACT Objective: Evaluate dental and skeletal changes resulting from the exclusive use of the cervical headgear for 15 ± 4 months in the treatment of patients with Class II division 1 malocclusion. Methods: Differences between the beginning (T1) and immediately after the end of the therapy (T2) with the cervical headgear in growing patients (Experimental Group, EG, n = 23) were examined and compared, during compatible periods, with those presented by a group of untreated individuals (Control Group, CG, n =22) with similar malocclusions and chronological age. The cephalometric variables evaluated were: ANB, GoGn.SN, AO-BO, S'-ANS, S'-A, S'-B, S'-Pog and S'-U6 (maxillary first molar). The Shapiro-Wilk and Levene tests were used to evaluate the results. Results: Significant differences were found relative to the ANB, S'-U6, AO-BO, S'-ANS, S'-A, S'-B and S'-Pog variables between T1 and T2 when comparing both groups. No statistically significant variation was found regarding the GoGn.SN angle. Conclusions: The use of cervical headgear promoted distal movement of the maxillary first molars and restricted the anterior displacement of the maxilla, without significantly affecting the GoGn.SN angle.

OBJETIVO: avaliar a prevalência de reabsorções radiculares externas severas e identificar prováveis fatores de risco decorrentes do tratamento ortodôntico. MÉTODOS: utilizou-se uma amostra selecionada aleatoriamente, composta de radiografias periapicais de incisivos superiores e inferiores, obtidas no mesmo centro radiológico, de pré- e pós-tratamento ortodôntico ativo, de 129 pacientes, de ambos os sexos, tratados por meio da técnica Edgewise Standard. Dois examinadores mensuraram e definiram a reabsorção radicular de acordo com índice proposto por Levander et al., e o grau de reabsorção foi registrado, definindo a reabsorção em quatro graus de severidade. Para avaliar a reprodutibilidade intra- e interexaminadores, adotou-se o índice de coeficiente kappa ponderado. O teste chi-quadrado (χ2) foi adotado para avaliar a relação entre a quantidade de reabsorção radicular e o sexo dos pacientes, arcada dentária (superior ou inferior), tratamentos com ou sem extrações, duração do tratamento, forma radicular, estágio do ápice radicular (aberto ou fechado), overjet e overbite no início do tratamento. RESULTADOS: os incisivos centrais superiores apresentaram a maior porcentagem de reabsorção radicular severa, seguidos dos incisivos laterais superiores e dos incisivos laterais inferiores. Entre 959 dentes avaliados, 28 (2,9%) apresentaram reabsorção radicular severa. Os fatores de risco relacionados foram: dentes localizados na região anterossuperior, overjet maior ou igual a 5mm ao início do tratamento, tratamentos envolvendo extrações dentárias, tempo prolongado de terapia e formação radicular completa à época do início do tratamento ortodôntico. CONCLUSÃO: o estudo demonstrou que cuidados devem ser tomados em tratamentos ortodônticos envolvendo extrações, com grande retração de incisivos superiores, tratamentos prolongados e/ou ápice radicular completamente formado no início da terapia ortodôntica.

OBJECTIVE: To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. METHODS: A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. RESULTS: Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. CONCLUSION: This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset.

AIM: In order to determine the reliability between two of these methodologically different method, this study evaluated the systematic and random errors of the method proposed by Tanaka and Johnston, which is based on the sum of mandibular permanent incisors, and the Huckaba method, which uses radiographs. METHODS: In a random sample of 28 plaster models of mandibular dental arches belonging to individuals of both genders, aged six to eleven years old, a single investigator performed the measurement of required space, according to the two methods evaluated. After 15 days, the measurements were repeated, and each of them was performed twice in sequence to calculate the repeatability and reproducibility conditions, and the systematic and random errors for each method. RESULTS: The random error of the method proposed by Huckaba was larger in terms of reproducibility (1.53 mm) and repeatability (0.57 mm) compared with the analysis proposed by Tanaka and Johnston (0.20 mm and 0.12 mm, respectively). CONCLUSIONS: The method proposed by Huckaba was proved to be inadequate in relation to reproducibility, with respect to the random error, and should be used with caution to measure the required space in the mandibular arch.