Abstract
The aim of this study was to determine the maxillary expansion index (MET) for Pakistani population. Also to determine the sexual disparities in sum of incisors perimeter, arch width and expansion indices of maxillary arch. Hirox digital stereomicroscope was used for the fabrication of the digital models. The estimated sample size was 128 Pakistanis (64 females and 64 males; age range from 18-24 years). The perimeters of the maxillary permanent incisors, as well as intercanine, interpremolar, and intermolar arch widths, were measured on digital dental models Significant sexual disparities were observed (***p < 0.001). There was significant difference observed in arch length and arch perimeter group of maxilla. For the prediction of ideal arch width in intercanine, interpremolar, and intermolar region to be achieved at the finishing stage, orthodontist can forecast the arch width before the initiation of orthodontic treatment. The new formula and the new indexes of arch width can be a helpful adjunct in the orthodontic treatment.