Abstract
Orthodontic corrections involving tooth size arch length discrepancies (TSALD) often require the extraction of premolar teeth, to achieve the desired profile changes. General guidelines, suggest extraction of first premolars when the TSALD source area is primarily in the anterior portion of the arch. However, the basic indication for second premolar extraction is when there is moderate anterior crowding with no protrusion and the patient has good facial balance. Cephalometric radiographs of 60 adult BMP patients who underwent orthodontic retraction of anterior teeth following extraction of all first premolars or all second premolars reporting to a private dental center between January 2013 and January 2019 and fulfilling the inclusion criteria were included for the study. Analysis of the digital cephalometric radiographs was done using Dolphin Imaging (R) Software, Version 10.0 (Dolphin Imaging and Management Solutions, Chatsworth, California, USA). Paired comparison between pre-treatment and post-treatment cephalometric values, following 1st premolar and 2nd premolar extraction, were done using IBM SPSS Statistics Version 20. The statistical analysis of extracted data revealed that 1st premolar extraction treatment resulted in greatest change in upper and lower incisor inclination per unit change in upper or lower incisor retraction, as predicted through regression analysis. In the present study, the lower incisor retraction and proclination has proved to be a predictor of the need for second premolar extraction (p< 0.05). Hence the, decision to extract first or second premolar can be predicted on the pre-treatment position of the lower incisors and the desired amount of lower incisor tooth retraction.