Diagnostic accuracy of endoscopy and operating microscopy in periradicular surgery

Objectives: To compare the accuracy of endoscopic and operating microscope diagnostics with the scanning electron microscope (SEM) in evaluating elements on the cut end root face during periradicular surgery, especially cracks. Methods: Twenty-six extracted human molars were subjected to the following treatments: orthograde root-canal obturation and root-end resection. After this initial treatment the cut root face was inspected with an operating microscope (magnifications 16x; 24x) and with an endoscope (magnifications 8x; 64x). Subsequently, the roots were duplicated for SEM evaluation. Operating microscope and endoscope findings were compared to those obtained with SEM serving as the 'gold standard' with a blinded observer. The presence of the following structures was assessed: isthmuses, accessory canals, obturation gaps and cracks. Sensitivity and specificity values were calculated for every test situation. Computed kappa statistics compared the agreement of the four test configurations with the SEM. Results: The specificity and sensitivity of the identification of isthmuses and accessory canals was 100% or 95-100% respectively for both devices. The sensitivity for the identification of obturation-quality findings such as gaps and leakages ranged between 95% and 97%. The specificity of the same parameters was 7% for each test. The sensitivity for crack assessment ranged between 68% and 93%. To sum up endoscopic diagnosis at hight magnification (64x) ranged at the highest sensitivity values (>80% / p<0.05) and showed the smallest variation. The best specificity values were achieved with the operating microscope at medium magnification (16x). The endoscope at high magnification (64x) showed the best agreement with SEM overall (kappa > 0.7). Conclusion: Endoscope as well as operating microscope are both excellent devices for intraoperative diagnosis of cut root faces with respect to potential pathological findings during periradicular surgery. The use of these devices can be highly recommended.