Endoscopic Evaluation of Cut Root Faces and Histologic Analysis of Removed Apices Following Root Resection: a Clinical Study

Objective: To evaluate the resection plane after root-end resection during apical surgery using endoscopy.
Methods: Following apicectomy of 69 roots, the cut root faces were inspected with a rigid endoscope for the presence of unfilled areas of the root canal space, gaps between the obturated root canal and dentinal wall, isthmi, ‘opaque’ dentine and cracks. Endoscopic pictures were captured and assessed using a 12-sector transparent grid for determination of location of the studied elements. Furthermore, the removed apices
were examined histologically (n=47). The surfaces of the removed apices opposite the cut root faces were histologically analysed for the same outcome measures.
Results: Endoscopy revealed the following findings: opaque dentine in 84.1%, unfilled parts of the root canal system in 59.4%, gaps between the existing root canal filling and dentinal walls in 49.3%, and cracks in 10.1% of cases. With regard to isthmi, histology of the removed apices demonstrated an isthmus in two-thirds of those seen with endoscopy at the root end. Ramifications were histologically observed only in 6 root apices.
Conclusion: The studied elements may cause failure of the root canal treatment, and conventional root canal retreatment or apical surgery may be indicated. The clinical significance of opaque dentine with regard to tooth prognosis after apical surgery remains unclear and warrants further research.