ABSTRACT
<p><b>OBJECTIVE</b>To clinically investigate the results of unilateral extraction in the treatment of special moderate crowding cases.</p><p><b>METHODS</b>22 patients with harmonic profile and moderate crowding were selected and treated by unilateral extraction with Edgewise technique. The patients crowding was 6 - 9 mm and focused on one side of the arch. 22 patients with moderate crowding were treated by bilateral extraction as control.</p><p><b>RESULTS</b>22 patients have been treated successfully within 18 months. Crowding was completely resolved. Midline coincidence was basically maintained.Good intercuspation was achieved. There is no significant difference in dental arch symmetry between unilateral extraction and bilateral extraction (P > 0.05).</p><p><b>CONCLUSION</b>Unilateral extraction can be successful in the treatment of special moderate crowding cases.</p>