Class II division 1 malocclusion treatment with extraction of maxillary first permanent molars: cephalometric evaluation of treatment and post-treatment changes

Objective: To investigate the cephalometric outcome and post-treatment changes following the orthodontic treatment involving the extraction of maxillary first molars in patients presenting with a Class II division 1 malocclusion. Methods: A retrospective longitudinal study was conducted involving 83 patients treated by fixed appliances and the extraction of 16 and 26. The mean age at commencement was 13.2 +/- 1.5 years. Lateral cephalograms were available pre-treatment (T1), immediately post-treatment (T2), and at 2.6 years post-treatment (T3). The sample was divided into hypodivergent (n = 18), normodivergent (n = 17), and hyperdivergent (n = 48) facial types. Mean increments, standard deviations, and 95% confidence intervals were calculated for T2-T1 and T3-T2. Increments were tested using paired-samples .tests, and variables between groups by applying ANOVA followed by Tukey's post hoc test. Linear regression was used to examine the effect of facial type, age, and gender. Results: Significant changes occurred during treatment for most cephalometric variables. Post-treatment, the growth pattern showed a tendency to return to the original form. Facial type had only a minor influence on cephalometric increments during and after treatment. Conclusions: Post-treatment skeletal, soft tissue, and dentoalveolar changes were limited. Facial type had only a minor influence during and after treatment and care must be taken to control lower incisor inclination.