Transverse dental cast measurements used in this study. U3-U3, the distance between the tips of the left and right upper canines; U4-U4, the distance between the buccal cusp tips of the left and right upper first premolars; U5-U5, the distance between the buccal cusp tips of the left and right upper second premolars; U6-U6, the distance between the mesiobuccal cusp tips of the left and right upper first molars; L3-L3, the distance between the tips of the left and right lower canines; L4-L4, the distance between the buccal cusp tips of the left and right lower first premolars; L5-L5, the distance between the buccal cusp tips of the left and right lower second premolars; L6-L6, the distance between the mesiobuccal cusp tips of the left and right lower first molars.