Impacted second premolars in cleidocranial dysplasia: Three-dimensional position and morphology characteristics and factors affecting the success rate of closed eruption.

INTRODUCTION

Orthodontic-aided closed eruption of impacted second premolars often fails in patients with cleidocranial dysplasia (CCD). This study aims to evaluate the 3-dimensional position and root morphology of impacted second premolars and identify factors affecting the success of orthodontic-guided closed eruption in CCD patients.

METHODS

Cone-beam computed tomography images from CCD patients with impacted second premolars were selected and evaluated. The original cone-beam computed tomography data were reconstructed using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif), and the 3-dimensional position, root morphology of impacted second premolars, along with factors associated with closed-eruption success, were analyzed.

RESULTS

Eleven patients (37 impacted second premolars) with CCD, comprising 7 males and 4 females, were included. The average duration of the closed-eruption treatment was 29.00 ± 6.84 months, yielding a success rate of 89.29%. In the 37 impacted second premolars, vertical impaction was the most common (23 [62.16%]), followed by palatal (10 [27.03%]) and buccal (4 [10.81%]). Moreover, 9 of the 37 impacted second premolars failed to erupt, of which 6 were in the low palatal position with a completed root apex. Chi-square tests revealed that the impacted second premolars in the coronal and axial positions, and Nolla's stages were significantly associated with closed-eruption failure (P <0.05).

CONCLUSIONS

Most impacted second premolars with failed eruption were at the mandibular palatal side and in Nolla's stages 9 and 10. Closed-eruption treatment in patients with CCD is primarily influenced by coronal and axial positions and Nolla's stage.