Changes in mandibular incisor alignment and intercanine width subsequent to orthodontic treatment

Abstract

The study was prompted by the paucity of information regarding the stability of orthodontic results. The intention is to present a descriptive appraisal of the frequency of malalignment of the mandibular anterior teeth and the permanency of changes in the mandibular intercanine widths following orthodontic treatment. To this end, 36 cases were arbitrarily selected from the files of the Department of Orthodontics of Boston University School of Graduate Dentistry. The records analysed were plaster models obtained prior to treatment, immediately upon completion of treatment, and following a period of lS-24 months post treatment. Measurements were made in each of the above periods with respect to mandibular incisor alignment, overbite, overjet, and intercanine width. The data collected was subjected to statistical analysis. The median values and ranges were calculated. Pearson's Product Moment Correlation Coefficients were also determined. Indications were that post treatment mandibular incisor recrowding was a frequent occurrence, intercanine expansion produced during orthodontic treatment was generally unstable, and extraction procedures did not decrease the incidence of incisor malalignment or intercanine contraction following treatment. Statistically significant correlations were obtained between incisor malalignment and intercanine contraction, overbite increase, overjet decrease. andibular incisor alignment correlated significantly with intercanine expansion. All individual correlations obtained were not large enough to have clinical significance. However, by combining these 3 variables, there is a strong association with lower incisor relapse.