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This study evaluated the influence of intrusion mechanics combined with anterior retraction on root resorption of the maxillary incisors. A sample of 56 patients was divided into two groups: group 1 comprised 28 patients (12 females and 16 males), presenting with an increased overjet and deep overbite (6.48 and 4.78 mm, respectively) treated with reverse curve of Spee intrusion mechanics and group 2 comprised 28 patients (12 females and 16 males) with an increased overjet of 5.67 mm and a normal overbite of 1.12 mm. The initial mean ages for groups 1 and 2 were 13.41 and 13.27 years, respectively. Pre- (T1) and post- (T2) treatment periapical radiographs were used to evaluate root resorption. The groups were compared using the Mann-Whitney U-test. Correlation between root resorption and tooth movement was investigated with Spearman's correlation coefficient. The subjects in group 1 had statistically greater root resorption (P < 0.05) than those in group 2. The initial overbite severity and the amount of correction had significant positive correlations with root resorption (r = 0.324 and r = 0.320, respectively). The combination of anterior retraction with intrusive mechanics causes more root resorption than anterior retraction of the maxillary incisors alone.

BackgroundStudies that show frequencies of different orthodontic treatment protocols can be used as valuable parameters in the interpretation of treatment tendency with time. The purpose of this retrospective study was to evaluate all orthodontic treatment planning conducted at the Orthodontic Department at Bauru Dental School, University of São Paulo, Brazil, since 1973, in order to investigate extraction and non-extraction protocol frequencies selected at each considered period.MethodsThe sample comprised 3,413 records of treated patients and was evaluated according to the protocol choice, divided into 10 groups: Protocol 0 (non-extraction); Protocol 1 (four first premolar extractions); Protocol 2 (two first maxillary and two second mandibular premolars); Protocol 3 (two maxillary premolar extractions); Protocol 4 (four second premolars); Protocol 5 (asymmetric premolar extractions); Protocol 6 (incisor or canine extractions); Protocol 7 (first or second molar extractions); Protocol 8 (atypical extractions) and Protocol 9 (agenesis and previously missing permanent teeth). These protocols were evaluated in seven 5-year intervals: Interval 1 (1973 to 1977); Interval 2 (1978 to 1982); Interval 3 (1983 to 1987); Interval 4 (1988 to 1992); Interval 5 (1993 to 1997); Interval 6 (1998 to 2002); Interval 7 (2003 to 2007). The frequency of each protocol was compared between the seven intervals, using the proportion test (P < 0.05).ResultsThe results showed that 10 protocol frequencies were significantly different among the 7 time intervals.ConclusionsThe non-extraction protocol frequency increased gradually with consequent reduction of extraction treatments. The four premolar extraction protocol frequency decreased gradually while the two maxillary premolar extraction protocol has maintained the same frequency of indications throughout time.

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As alternativas de tratamento ortodôntico em casos apresentando Classe II completa bilateral são bastante variadas e podem ou não incluir extrações. Quando a opção é por extrações, o protocolo incluindo apenas dois pré-molares facilita enormemente a correção sagital da Classe II. Ao optarmos pela correção por meio da distalização bilateral dos segmentos posteriores, fica bastante evidente uma maior demanda mecânica e principalmente uma exigência muito maior por cooperação para que o sucesso do tratamento seja alcançado. Desta forma, decidiu-se avaliar e comparar o nível de cooperação apresentado por 73 pacientes apresentando Classe II completa, planejados sem extrações ou com duas extrações no arco dentário superior, e assim verificar se a conduta terapêutica inicial, associada à cooperação, teve influência nos resultados finais. Os resultados demonstraram que a decisão terapêutica baseada na correção sagital da Classe II sem extrações, baseada em mecânicas distalizadoras extrabucais, ficou nitidamente refém da cooperação dos pacientes, forçando este grupo a um replanejamento para que o sucesso terapêutico pudesse ser alcançado, prolongando significativamente o tempo de tratamento ortodôntico. ResumoPalavras-chave: Cooperação. Extrações. Replanejamento. Classe II.