Dental arch width stability after quadhelix and edgewise treatment in complete unilateral cleft lip and palate

OBJECTIVE: To evaluate the transverse stability of the dental arch in unilateral cleft lip and palate (UCLP) patients after orthodontic treatment with quadhelix and edgewise appliances. MATERIALS AND METHODS: Twenty repaired complete UCLP patients with posterior crossbites were chosen as the study subjects. All had ceased retention at least 15 months previously. Measurements were carried out directly on the pretreatment, posttreatment, and postretention study models using a three-dimensional dental cast analyzer. The interdental widths were measured for the canines, first premolars, second premolars, first molars, basal bone, and the alveolar arch. Two-way analysis of variance and Fisher's LSD was performed in comparing the difference between intervals. RESULTS: Lower inter-first-premolar width and upper arch widths of each region increased significantly (P < .05) after orthodontic treatment. The expansion was greater in the anterior than the posterior region in the upper arch, and the greatest increase was in the upper first premolar region. The upper arch width decreased after retention, with the decrease of the arch width in the upper canine (1.3 +/- 0.8 mm) and first premolar (1.5 +/- 0.8 mm) regions being statistically significant. The increased upper arch width in each region and the lower inter-first-premolar width maintained significant expansion after retention. CONCLUSIONS: The widths of the dental arch increased significantly after expansion with a quadhelix followed by preadjusted edgewise treatment. Relapse occurred, especially in the upper canine and first premolar region, but most of the treatment effect on the upper arch remained after retention.