Assessment of the middle mesial canals of mandibular first molars using cone-beam computed tomography: an in vivo study

OBJECTIVE

For a successful root canal therapy, it is necessary to locate all the canals debride and seal them with an inert filling material. The clinician must be aware of the internal morphology and variations in a permanent tooth. Mandibular first molars are widely studied to identify variations in the anatomy of the pulp space. In this study, the primary objective was to measure the distance between the mesiobuccal (MB) and mesiolingual (ML) canals in patients with and without a middle mesial canal (MMC) using cone-beam computed tomography (CBCT). The secondary objectives were to assess the tapering degree of the mesial root and to measure the dentinal thickness in relation to the danger-zone area in patients with and without an MMC.

MATERIALS AND METHODS

A total of 200 CBCT scans were evaluated for the presence of an MMC. Two observers performed the observations, and the results obtained were subject to statistical analyses.

RESULTS

The results revealed the prevalence of MMC was 5%. The average distance between the MB and ML canals was higher when there was an MMC [M(SD) = 3.61 (0.6) vs. 2.69 (0.66)]. However, there were no differences between the groups in the distance to the danger-zone area and the tapering degree of the mesial root. On CBCT images, the MMC was clearly visible 3 mm apical to the level of the cementoenamel junction; beyond 3 mm, the MMC could not be traced.

CONCLUSIONS

Based upon the results of this study, the average distance between the MB and ML canals was higher when there was an MMC. A lesser degree of taper would be preferred to prepare the MMC than to prepare the other canals. It is recommended that careful examination of the canal 3 mm apical to the cementoenamel junction should be carried out when attempting to detect an MMC.

Apical fenestration in endodontically treated teeth: A report of two cases

Root canal therapy in teeth with root fenestrations can present with pain on apical palpation or persistent pain. The signs and symptoms of root fenestration in the absence of mucosal fenestration may be misleading, which may be misdiagnosed as non-odontogenic pain. Although CBCT is superior to periapical radiographs for the diagnosis of root fenestration, it failed to detect the intact cortical plate in the middle third in our cases. Therefore, the type was different in CBCT from its actual size surgically. Repeated non-surgical root canal treatment would not alleviate pain in the presence of root fenestration and may lead to apical root fracture. Root-resection relieves pain, unless the fenestration is accompanied by fracture. The aim of these two case reports was to describe the diagnosis and treatment of endodontically treated teeth with a persistent pain. Also, the difference of root fenestration type between CBCT and its actual size was described.

Morphometric analysis of the apical foramina in extracted human teeth

BACKGROUND

The aim of the study was to analyze the morphology of shapes and positions of the apical foramen in permanent maxillary and mandibular human teeth.

METHODS

The anatomic parameters include shapes (rounded, oval, uneven, flat and semilunar) and location (center, buccal/labial, lingual/palatal, mesial, and distal) of the apical foramina was evaluated. The shapes and locations of apical foramen based on arch (maxillary and mandibular), position (anterior and posterior) and Tooth type (central incisor, lateral incisor, canine, premolars, and molars) were used for the analysis. All the teeth were investigated for the apical foramina shape and location using a stereomicroscope at a magnification of 10X. Descriptive statistics performed using SPSS (Version 21.0, Chicago, Illinois, USA) at p value less than 0.05.

RESULTS

The common shape of apical foramina was round (65%) and location was center (32%). The frequency of deviation of apical was 68% in overall teeth. Apical foramina in maxillary anterior teeth showed more deviation while posterior teeth in mandibular teeth. The most common shape of apical foramina was round (65.1%) followed by (31%) and flat and semilunar shapes are very rare in studied subjects.

CONCLUSIONS

The most frequent direction of deviation is the distal surface, followed by the mesial surface. The variation is more common in mandibular posterior teeth, while maxillary posteriors showed the least difference. The commonest shape of the apical foramen is of a round shape, followed by the oval. The oval shape of the apical foramen is most frequent with central incisors.