Study of overbite relapse related to the curve of Spee, in Class II division 1 patients, in the postretention stage

Karina Maria Salvatore de FREITAS, Adriana CREPALDI, Marcos Roberto de FREITAS, Ruy Carlos FONSECA, Marcus Vinicius CREPALDI

Introduction: the long-term stability of the treatment outcomes presents as one of the main points in orthodontic literature, without conclusive answers. The overbite is defined as the vertical distance between upper and lower incisors, and it is important for evaluation of treatment and its stability. Aim: this study aimed to evaluate, in cephalograms and study casts, the overbite relapse and its relation with the curve of Spee. Methods: the sample (experimental group) comprised 29 patients of both genders, presenting Class II, division 1 malocclusion and an overbite of at least 3.5mm, treated by Edgewise mechanics. This experimental group was compared to a control group of normal occlusion, comprising 29 subjects. Both groups are part of the records from Orthodontics Department at Bauru Dental School, University of São Paulo. For the experimental group, cephalograms and study casts of the pretreatment, posttreatment and 5 years post retention were studied, and for the control group, cephalograms in two times of evaluation, compatible with the treatment time of the experimental group. The independent t test was used for the intergroup comparison, and the one way ANOVA and Tukey test, for intragroup comparison. In order to verify the relation between the overbite relapse and the curve of Spee, a Pearson’s correlation test was performed. Results: the results showed that the overbite was significantly corrected by the orthodontic treatment, when compared to control group, and presented a significant relapse in the post retention stage. Conclusion: the overbite relapse presented significant correlation with the curve of Spee in the post retention stage.

Keywords: Overbite. Curve of Spee. Relapse. Stability.

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