Relapse of maxillary anterior crowding in Class I and Class II malocclusion treated orthodontically without extractions

Objective: The present study aimed to retrospectively compare the postretention stability of maxillary anterior incisors alignment in patients with Class I and Class II malocclusions. Methods: Sample comprised 38 patients of both genders, treated with no extraction and Edgewise mechanics, divided into two groups: Group 1 comprised 19 patients, at a mean age of 13.06 years, with Class I malocclusion and initial maxillary anterior crowding greater than 3 mm. Group 2 comprised 19 patients, at a mean age of 12.54 years, with Class II malocclusion, and also with an initial maxillary anterior crowding greater than 3 mm. In the dental casts of pretreatment, post-treatment and postretention, the Little irregularity index, intercanine width and width between first and second premolars, intermolar width and maxillary arch length were measured. For intragroup comparison among the three evaluation times the one-way ANOVA was used followed by Tukey test. Intergroup comparison was performed by independent t test. To verify the presence of correlation, the Pearson correlation test was used. Results: Results evidenced greater stability of treatment in Group 2 (Class II), because during the postretention period it was observed a smaller relapse of maxillary anterior crowding in Group 2 (0.80 mm) than in Group 1 (1.67 mm). Conclusion: It was concluded that treatment of maxillary anterior crowding is more stable in Class II malocclusion than in Class I malocclusion. Abstract