A second cohort of 15 patients will receive EXD-952 Ceramic Self-ligating bracket on all mandibular incisors in a later phase of their ongoing orthodontic treatment. The mandibular incisor brackets will be removed and EXD-952 Ceramic Self-ligating brackets placed instead. Other mandibular brackets will remain in place. Tooth movement will be performed using 0.019x0.025" Stainless Steel archwires.