Diagnostic accuracy of endoscopy for the detection of isthmuses of mandibular molar teeth using micro-CT as reference.

Purpose: The aim of this study was to evaluate the efficacy of endoscopic visualisation to detect the presence and type of isthmuses within the mesial root canals of mandibular first molar teeth compared with micro-computed tomography (micro- CT) images as reference.

Materials and methods: Thirty-two mesial roots of mandibular first molars presenting isthmuses were selected based on micro-CT scans. In all, 12 type I and 20 band-shaped isthmuses were collected. The specimens were mounted in the posterior socket of dental phantom manikin for endoscopic visualisation. The ability of endoscopes to visualize the presence of isthmuses and distinguish the type of isthmuses was compared. Micro-CT images of the specimens were used as references. Data were analyzed using Fisher's exact tests.

Results: Sensitivity of endoscope to detect isthmuses were also calculated for each isthmus type. In 37.5% of the samples, isthmus presence was correctly diagnosed via orthograde endoscopic visualization. Type I istmuses were significantly more detected than band-shaped isthmuses (P<0.05). Endoscope showed higher sensitivity to detect type I isthmus than band-shaped isthmus.

Conclusion: The endodontic endoscope could detect type I isthmuses more accurately than band- shaped isthmuses.