Changes of mandibular dental arch shape during adolescence and its influence on late mandibular incisor crowding.

The aim was to analyze the changes in mandibular dental arch shape during adolescence and assess its relation to late mandibular incisor crowding. Longitudinal study included 68 orthodontically untreated subjects (49% female) and analyzed their data for the ages of 12, 15, 18 and 21 years. Measurements included anterior arch depth, intercanine, interpremolar/anterior and intermolar/posterior width, Little's Irregularity and Bolton's index and the ratio between anterior arch depth and width.