Survival of labial inversely impacted maxillary central incisors: A retrospective cone-beam computed tomography 2-year follow-up.

INTRODUCTION: The aim of this study was to analyze the development and stability of roots and alveolar bone in orthodontically treated labial inversely impacted maxillary central incisors in a long-term follow-up by cone-beam computed tomography. Comparisons were made between the labial inversely impacted maxillary central incisors after treatment and normally erupted mature contralateral incisors. METHODS: The sample consisted of 12 participants, with a mean age of 7.80 +/- 0.91 years. Cone-beam computed tomography scanning data at the completion of treatment and the long-term follow-up were available for each participant.The mean length of follow-up was 24.57 +/- 4.33 months. Root length, crown height, root canal width, labial/lingual alveolar bone vertical loss, and bone thickness of the impacted and contralateral incisors were measured with the SimPlant Pro program (version 13.0; Materialise Dental, Leuven, Belgium). RESULTS: In the follow-up, the root lengths of both the labial inversely impacted dilacerated maxillary central incisors (10.99 +/- 1.96 mm) and the contralateral mature maxillary central incisors (11.65 +/- 1.37 mm) were significantly longer than at posttreatment (8.37 +/- 1.74 mm and 9.81 +/- 1.65 mm, respectively). The root canal widths of the impacted and contralateral incisors were significantly narrower during the follow-up. The size of the angle between the long axis of the crown and apical third of the root decreased significantly. The lingual alveolar bone loss of the impacted incisors was greater than that of the contralateral incisors. The labial bone thickness at the apex of the impacted incisors increased significantly during the follow-up period. CONCLUSIONS: The treated labial inversely impacted maxillary central incisors had continuous and similar growth as did the mature contralateral incisors in the follow-up period. The roots had an increase in length and a change in direction of the apex, with a relatively stable condition of the surrounding alveolar bone. Neither the labial inversely impacted maxillary central incisors nor the contralateral incisors had further alveolar bone loss.