Intercanine width changes in the mandibular arch of Class I malocclusion patients orthodontically treated

Patricia Regina Rizzo ARAÚJO, Heloísio de Rezende LEITE, Hélio Henrique de Araújo BRITO

Introduction: Intercanine width changes in the mandibular arch during orthodontic treatment are considered unstable. Aim and Methods: In order to observe the post treatment alterations in the lower intercanine width, 30 patients with Class I malocclusion were selected from the files of the graduate orthodontic clinic of the Catholic University of Minas Gerais based on the availability of records. The measurements were made on study models, taken in two areas (cuspid tip and buccal surface) and in three different periods of time: T1 (pre treatment); T2 (post treatment) and T3 (at least one year out of retention). Results and Conclusions: There was a significant increase in the intercanine width during treatment and a reduction in the post retention period at the cuspid tip and the buccal surface. When the area of measurement was considered, there was no difference between T3 and T1 at the cuspid tip. At buccal surface it was significantly greater in T3 than in T13. There were no statistical differences in the intercanine width related to gender and time out of retention. The extraction group showed a significantly greater increase in the intercanine width than the non extraction group in the cuspid tip and in the buccal surface. The extraction group showed a significant greater reduction of the intercanine width measured at the cuspid tip when compared to measurements at the buccal surface. The extraction cases were more stable than the non extraction cases considering the buccal surface. Considering the type of movement used for canine expansion, the translation cases were more stable with measurements at buccal surface than at cuspid tip, indicating a lingual inclination of the crowns of the canines in the post retention period.

Keywords: Intercanine width. Expansion. Relapse.

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