Table 3. Comparisons of pretreatment values and changes in maxillary dental and alveolar arch widths between the extraction and nonextraction groups (mm).

Values are presented as median (interquartile range).

DA-M1, Dental arch width at the first molar level; DA-PM2, dental arch width at the second premolar level; AA-M1, alveolar arch width at the first molar level; AA-PM2, alveolar arch width at the second premolar level.

^*p < 0.05, ^**p < 0.01.