Correlation between the morphologic index of crowns of mandibular incisors and stability of correction of mandibular anterior crowding

Renata Cristina Faria Ribeiro de CASTRO, Marcos Roberto de FREITAS, Guilherme JANSON, Karina Maria Salvatore de FREITAS

Aim: This study investigated the extent to which the mesiodistal and buccolingual dimensions of the crowns of mandibular incisors contribute with the stability of correction of mandibular anterior crowding. Methods: For that purpose, 56 white patients of both genders (27 females and 29 males) were evaluated, who initially presented Class I or Class II division 1 malocclusion (28 patients each), treated with extraction of the four first premolars and edgewise mechanics. No interproximal stripping was performed during or after treatment. Measurements were performed on the dental casts achieved from each case at pretreatment, posttreatment and postretention, adding up to 168 mandibular dental casts. The mean age at pretreatment was 13.23 years, the mean treatment time was 2.11 years and the mean post-retention time was 5.12 years. The Little irregularity index was used to quantify the mandibular anterior crowding, and the Peck and Peck index was applied for measurement of the mesiodistal and buccolingual ratios of the crowns of mandibular incisors. The Pearson correlation test was applied to determine the significance of correlation between the morphology of the crowns of mandibular incisors and stability. Dimorphism between genders and the existence of difference between the two types of initial malocclusion were also investigated by the independent t test. Results and Conclusion: Analysis of the results revealed that the morphology of crown of mandibular incisors was not significantly correlated with postretention stability. The gender and type of initial malocclusion also did not influence the stability of correction of mandibular anterior crowding at five years posttreatment.

Keywords: Crown morphology. Mandibular anterior crowding. Tooth extraction. Corrective orthodontics. Stability.

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