Impact of Cone-beam Computed Tomography on Treatment Planning for External Cervical Resorption and a Novel Axial Slice-based Classification System.

INTRODUCTION: The aim of this study was to compare treatment plans for external cervical resorption (ECR) developed from periapical (PA) radiographs and cone-beam computed tomographic (CBCT) imaging. The secondary aim of this study was to test a new classification system for ECR based on CBCT axial slice analysis.

METHODS: ECR was identified in 56 teeth (47 patients) from a database of 928 CBCT images. Strict exclusion criteria resulted in a sample of 30 ECR teeth (25 patients) and 10 ECR-free control teeth. Six examiners evaluated CBCT and matched PA images in separate sessions. Examiners classified ECR according to the Heithersay classification system and the novel Rohde classification system and provided a treatment plan.

RESULTS: All 30 ECR cases were identified by CBCT imaging and 29 by PA radiography. Interrater agreement was uniformly higher with CBCT imaging, and treatment plans developed from CBCT scans differed from those developed with PA radiographs in 56.7% of the cases. Examiners recommended ECR repair in the majority of cases (59.8% of CBCT images and 56.7% of PA radiographs). The Heithersay classification was dependent on the method of imaging with a greater prevalence of class 4 reported with CBCT imaging (P = .0016). The Rohde classification system significantly predicted the recommended treatment plan (P = .002 for Rohde class 2 and P = .043 for Rohde class 3). All Heithersay classifications failed to statistically predict treatment plans.

CONCLUSIONS: Treatment plans changed between PA and CBCT imaging in the majority of cases evaluated. If CBCT imaging is available, the Rohde classification system may help guide treatment planning for cases of ECR.