Este trabalho teve como objetivo avaliar cefalometricamente a estabilidade das medidas SNA, SNB, ANB, 1.NA, 1-NA, 1 .NB, 1 -NB, 1.ENP-ENA, IMPA e 1.1 a longo prazo, de pacientes tratados ortodonticamente com extrações dos quatro primeiros pré-molares e verificar, paralelamente a isto, se foram realizadas as compensações dentárias na mecânica ortodôntica e se estas foram preservadas cinco anos após o término do tratamento. Vinte e sete pacientes foram analisados no início (T1), no final (T2) e cinco anos após a finalização terapêutica (T3). No início do tratamento, a idade média era de 13 anos e 5 meses e todos os componentes apresentavam o ângulo ANB maior que 4º. Quatorze componentes apresentavam más oclusões Classe II, 1ª divisão de Angle, 12 componentes apresentavam más oclusões Classe I e 1, má oclusão Classe II, 2ª divisão. Os casos foram tratados com a técnica Edgewise. Nas três fases de estudo os cefalogramas laterais foram realizados manualmente, obtendo-se as oito grandezas angulares e as duas lineares. A análise estatística indutiva envolveu a análise de variância a um critério para identificar as alterações interfases no valor de cada variável estudada, e o teste de Tukey para indicar, especificamente, entre quais fases de estudo estaria ocorrendo diferenças estatisticamente significantes. Utilizou-se o coeficiente de correlação de Pearson, no afã de relacionar a medida cefal ométrica 1.1 com as demais medidas nas três fases de estudo. De acordo com os resultados obtidos, todas as medidas estudadas entre as fases inicial e final se alteraram significantemente refletindo a influência da mecânica ortodôntica sobre os movimentos dentários e entre as fases final e cinco anos após, todas as medidaspermaneceram estáveis. Obtiveram-se as compensações dentárias necessárias no final do tratamento ortodôntico e estas foram preservadas a longo prazo

The main objective of this study was to evaluate the long-term stability of the following cephalometric measurements: SNA, SNB, ANB, 1.NA, 1-NA, 1 .NB, 1 -NB, 1.ENP-ENA, IMPA, 1.1 . This analysis was carried out in orthodontically treated patients which had the four first pre-molars extracted. Alternatively, this study also determined the influence of the proposed treatment at the dento-basal arrangements by orthodontic mechanics and its preservation after five years of treatment completion. The sample of this study was comprised of twenty-seven patients that were assessed at the beginning (T1), at the end (T2) and five years later (T3). At the beginning of treatment the patients age averaged thirteen years and five months and all the subjects displayed an ANB angle over than 4 degrees. Among the studied sample, 14 subjects were classified as Angle Class II, Division 2 malocclusion, 12 subjects displayed Angle Class I, and 1 Angle Classe II, Division 2. All the subjects were orthodontically treated by means of edgewise appliances. During all the three phases of the study the radiological data were obtained through lateral cephalograms, which were performed manually, depicted eight angular and two linear measurements. The statistical analysis in which the data were processed included one way analysis of variance in order to identify the changes between the phases related to each studied measurement. As an adjunctive method, the Tukey test was conducted to indicate in which phases of the proposed study the statistically significant changes were occurring. The Pearson Product Moment Correlation was recorded to relate the 1.1 cephalometric measurements with all the remaining measurements obtained throughout the three phases of the study. According to the obtained results, all the studied measurements, between phases T1 and T2, significantly changed reflecting the influence of orthodontic mechanics on the dental movement. Between the T2 and T3 phases, all the measurements remained stable. By the end of the orthodontic treatment all the necessaries dental arrangements were performed and preserved in a long-term fashion.