Authors : Avik Ghosh, Praveen Mehrotra, Sudhir Kapoor, Sonahita Agarwal, Geeta Verma
DOI : 10.18231/j.jco.2018.022
Volume : 2
Issue : 3
Year : 2018
Page No : 1-6
Background: The most commonly observed skeletal discrepancy in the orthodontic population is class II. It has been observed that there are conflicting results in order to characterize the dental arch form of patients with Class II malocclusion. Therefore, this study was done to compare the effect of all four first premolar extractions on the mandibular intercanine archwidth of orthodontically treated samples with Angle’s Class I and Class II division 1 malocclusion using occlusograms.
Materials and method: Occlusograms of pre and post treatment mandibular study models of patients with Class I (n = 30) and Class II division 1 (n = 30) treated with extractions were included in the study. The data was analyzed by ANOVA followed by Tukey’s multi comparison test.
Results: There was no statistically significant difference in the pre and post treatment mandibular intercanine arch width between the two groups. However in both groups a significant increase in mandibular intercanine arch width was observed post treatment which was 1.35 ± 0.76 mm in Group I and 1.44 ± 0.84 mm in Group II. Interestingly mean change in mandibular intercanine arch width of both the did not differ significantly (p = 0.667) though it was 6.2% higher in Group II as compared to Group I.
Conclusion: Since the change in mandibular intercanine arch width is significant in both Class 1 and Class II division 1 malocclusions, the tendency for relapse in such cases is high. Hence greater emphasis must be given upon planning the retention phase so as to prevent the increased tendency to relapse. The retention protocol has to be followed strictly in cases treated with extraction of premolars.
Keywords: Mandibular intercanine width; Occlusogram; Extraction therapy, Class I malocclusion; Class II division 1 malocclusion.