Detection of Root Canal Isthmuses in Molars by Map-Reading Dynamic using CBCT images

Abstract

The aim of this study was to detect root isthmuses in maxillary and mandibular molars and evaluate their frequencies using map-reading dynamics in CBCT images. Two hundred extracted human maxillary and mandibular molars were used in ex vivo assay. A consecutive sample of two hundred maxillary and mandibular molars (first and second) was selected from CBCT exams. The isthmuses were detected from the pulp orifice to the apex and were recorded according to their beginning and their end, into categories: 1. begin and end in cervical third; 2. beginning in cervical third and end in middle third; 3. beginning in cervical third and end in apical third; 4. beginning and end in middle third; 5. begin in middle third and end in apical third; 6. beginning and end in apical third; 7. no isthmus. The scans were obtained in different planes with map-reading in axial slices of 0.5 mm/0.5 mm involved the coronal to apical direction. The frequencies of isthmus were analyzed according to the level of root and evaluated by Chi-square test. The level of significance was set at α=0.05. The presence of isthmus detected in maxillary molars was 86% in ex vivo assay and 62% in vivo assay, whereas in mandibular molars was observed 70% in ex vivo assay and 72% in vivo assay. The frequency of isthmus was high in both study models. The map-reading dynamics in CBCT images was found to be precise to detect the localization of isthmus.

Common Operative Procedural Errors and Clinical Factors Associated with Root Canal Treatment

“…The complex anatomy hampers the full and direct access. For example, root canal isthmus is a common anatomic structure in human permanent teeth (48,49,54,103), except in maxillary anterior teeth (54). Higher frequencies of root canal isthmuses (87.9%) have been found in mandibular first molars (54).…”

Frequency of Root Canal Isthmi in Human Permanent Teeth Determined by Cone-beam Computed Tomography

“…Root canal isthmi (RCI), defined as narrow extensions of either 1 or 2 main canals, have been classified as incomplete or complete (4,7). The unpredictable location and anatomic complexity of RCI make them difficult to clean and disinfect properly, which represents a significant challenge to endodontists (4)(5)(6)(7)(8)(9). The highest incidence of RCIs has been found at 3-5 mm from the apex of mesiobuccal roots of maxillary molars, whereas at 4 mm, 12% of the specimens had a complete isthmus, and 88% had a partial isthmus (4).…”

“…RCIs have been investigated by using periapical radiography, vertical and cross-sectional cutting, clearing and staining, stereomicroscopy, surgical microscopy, dissecting microscopy, plastic casts, scanning electronic microscopy, cone-beam computed tomography (CBCT), and micro-computed tomography (MCT) (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19).…”

Role of Cone Beam Computed Tomography in Dentistry

“…The distance between the cortical plate and the palatal root apex can be measured, and the proximity to maxillary sinus or nasal floor can be assessed ( Figure 5D, 5E) [38]. The presence of isthmuses can be identified [40]. The amount of remaining supporting alveolar bone support can be assessed, and the need for grafts and membranes can be judged pre-operatively.…”