DOI: 10.36347/sajb.2017.v05i01.006

Pages: 21-28

There has been much debate about the effect of extraction and non-extraction treatment on soft tissues and arch width. The aim of this retrospective study was to compare arch and buccal corridor width changes and to evaluate their correlation in extraction and non-extraction orthodontic treatment. Pre-treatment and post-treatment dental models and smile photographs of 59 cases (24 girls and 5 boys in extraction and 20 girls and 10 boys in non-extraction groups) were collected. The intercanine and intermolar widths of maxillary dental arches were measured using a digital caliper. Photographs of samples were evaluated for buccal corridor width in relation to canines and the last visible tooth. The mean intermolar width decreased 0.83 mm in the extraction group and increased 0.13 mm in the non-extraction group. Univarite analysis of covariance showed that post-treatment intermolar width with adjustment of ANB, upper crowding, and pre-treatment intermolar width were different between the two groups (P=0.006). There was a positive correlation only between the buccal corridor width in relation to canines and intercanine width (r value =0.406). Intra-class correlation coefficients for model and photographic variables were from 0.93 to 0.99. There was a significant difference in intermolar width between the two groups, but it did not necessarily result in a difference in buccal corridor width in relation to canines and the last visible tooth between the two groups.