Migration of the root complex after coronectomy occurs within the first year after surgery: a 5-year radiographic analysis and protocol suggestion.

Objectives: Currently, there are no studies evaluating the radiographic follow-up protocol after coronectomy. This study aims to assess root migration after coronectomy of mandibular third molars in panoramic images taken 1, 3 and 5 years after surgery.

Study Design: This was a prospective cohort study of patients undergoing coronectomy of a mandibular third molar. The patients followed a 5-year follow-up regimen with panoramic examinations at 1, 3 and 5 years after the surgical intervention. Three observers assessed the panoramic images in a blinded randomized order to evaluate bone coverage; superimposition of the roots and the mandibular canal; and migratory changes of the roots. Descriptive statistics were used to describe changes. Furthermore, reproducibility among the observers was calculated.

Results: Sixty-two patients were included. Ingrowth of bone superior to the root complex during the first year was registered by all observers (observer 1: 100%; observer 2: 77.4%; and observer 3: 85.5%). Superimposition of the mandibular canal and the root complex in the panoramic images taken in the immediate postoperative period and after 1 year showed that 53.2% to 62.9% went from superimposition to no superimposition. Interobserver reproducibility was high.

Conclusions: Migration of the root complex occurs primarily within the first year after coronectomy. Therefore, a routine radiographic follow-up after 1 year only is recommended.