CT Scan Evaluation of Periapical Repair after Root Canal Treatment

Periapical conventional and digital radiographs are currently used to evaluate the periapical repair after root canal treatment. However this technique is not considered accurate as Computed Tomography (CT) Scan to study intraosseous defects. Objective: To evaluate the periapical repair after root canal treatment in dogs teeth using the CT Scan. Methods: The animals were divided in 3 groups according to the endodontic treatment performed: Group 1 (Single visit) - endodontic treatment in teeth without chronic periapical disease (CPD), Group 2- Single visit endodontic treatment in teeth with CPD and Group 3- Endodontic treatment in teeth with CPD using calcium hydroxide as a root canal dressing. The Group 4 (control) consisted of teeth with CPD without treatment. The radiographic and tomographic evaluations were performed by 3 blind examiners. After induction of CPD, the radiolucent areas were measured. The measure of the lesions before and after the root canal treatment was used to calculate the percent rate reduction of the CPD. Results: 45 days after CPD induction there was discontinuity of the lamina dura and CPD in all teeth from groups 2, 3, and 4 evaluated by tomography and radiography. Radiographicaly, 180 days after root canal treatment, there was no periapical lesion in 25% of teeth from group 3 and all teeth from group 1, different from groups 2 and 4 (p<0,01). The highest reduction in the CPD size was observed on group 3 (p<0,05). According to the tomographic results, there was decrease of the size of the CPD on groups 2 and 3, also with the higher decrease on group 3. Conclusion: CT Scan revealed periapical lesions with larger mesio-distal extension if compared with radiography, both 45 days after CPD induction and 180 days after root canal treatment (Supported by Grant FAPESP 06/51161-0 to FWGPS and Grant FAPESP 06/59072-7 to LABS).