Micro-computed tomography analysis of the relationship between root canal number and root concavity in maxillary first and second molars in a Japanese population

Rare root canal morphology of maxillary second molars: A report of three cases

Key Clinical Message

Endodontists should be aware that some maxillary second molars can have more than three roots. If any unusual anatomical features are detected during dental radiography or endodontic procedures, it is necessary to conduct cone-beam computed tomography (CBCT) scanning to prevent procedural mishaps.

Abstract

CBCT can provide three-dimensional reconstructed images of the root canal system. With the help of CBCT, variations in tooth root number and root canal morphology, such as extra canals, apical ramifications, apical deltas, and lateral canals, can be identified. Knowledge of the variations is very important for the success of endodontic treatment. This report suggests that endodontists must not assume that a MSM has only three tooth roots, which is the most prevalent number.

Endodontic treatment of the maxillary first molar with palatal canal variations: A case report and review of literature

BACKGROUND

Root canal variations frequently occur in maxillary first molars, which greatly affects the success of its treatment. The second mesiobuccal (MB) root canal is the most common root canal variation. However, only a few studies have been conducted on palatal root canal variations. Herein, we report the presence of two separate root canals in a palatal root of the maxillary first molar.

CASE SUMMARY

A 39-year-old woman complained of pain in the maxillary right region for 1 year, which recently worsened. Clinical examination revealed a poorly restored right maxillary first molar and caries detected at the filling marginal. Cold and heat test results indicated severe pain in the right maxillary first molar. The patient was diagnosed with irreversible pulpitis, and subsequently, root canal treatment (RCT) was performed. In total, five root canals were found in the maxillary first molar, including two separate root canals in the palatal root. RCT was successfully performed using an endodontic microscope and cone-beam computed tomography (CBCT). The CBCT image revealed a vertucci type I canal morphology in the distobuccal root, while the MB and palatal root canals were type Ⅳ. At the 1-mo follow-up, the maxillary first molar was completely asymptomatic, and the X-ray results indicated a successful RCT. Finally, the ceramic crown restoration was performed.

CONCLUSION

An endodontic microscope and CBCT are useful in effectively identifying and treating root canal variations.

Micro-tomographic analysis of the root trunk and pre-furcation area of the first mandibular molars

This study analyzed the root trunk (RT) and the pre-furcation area (PFA) of mandibular first molars. Thirty lower first mandibular molars extracted due to advanced periodontal disease were evaluated in a high-energy spiral computerized micro-tomography. Two gutta-percha markings on the cementoenamel junction (CEJ) and at the furcation entrance (FE) at buccal and lingual surfaces served as reference points for measurements of RT length, and PFA width and depth, at the levels of CEJ, 1 mm apical to CEJ, 2 mm apical to CEJ, and at the FE. The mean RT length was 2.49 mm at buccal and 3.18 mm at lingual sides. The mean widths of the PFA at CEJ, at 1 and 2 mm apical to CEJ, and at FE were 2.9, 3.4, 3.9 and 4.3 mm, respectively, while the mean depths were 0.19, 0.32, 0.57 and 1.1 mm, respectively. The PFA coincided with CEJ in 10 buccal and 10 lingual surfaces, representing 33.33% of the sample. There was a negative correlation between RT length and PFA dimensions. This study concludes that the RT length was smaller than previous studies. From the CEJ up to the furcation entrance, the PFA showed a progressive increase in width and depth. The coincidence of the PFA area beginning at the CEJ in 1/3, and the negative correlation between RT length and PFA dimensions may represent greater risk factor for the early development of furcation lesions.

Evaluation of root morphology of maxillary and mandibular second molars lost due to periodontitis

BACKGROUND AND OBJECTIVE

Little is known about the anatomical characteristics of root morphology in molars lost due to periodontal reason. The aim of this study was to study root morphology in maxillary and mandibular molars lost due to periodontitis by investigating the frequency of root fusion, classifying fusion types, and measuring radicular groove depth by micro-computed tomography.

MATERIAL AND METHODS

Ninety-eight posterior teeth were collected from 87 Japanese patients during the study period. Of these, maxillary (N = 36) and mandibular (N = 22) second molars lost most frequently were assessed for root fusion and morphology.

RESULTS

The 36 maxillary second molars included nine (25%) teeth with a single root, 14 (39%) with two roots, and 13 (36%) with three roots. Of the 23 maxillary second molars with fused (1 and 2) roots, there were 11 (48%), 2 (9%), 1 (4%), 1 (4%), 3 (13%), and 5 (22%) teeth with root types 1-6, respectively. The 22 mandibular second molars comprised 14 (64%) teeth with a single root, 7 (32%) with two roots, and one (4%) with three roots. Of the 14 mandibular second molars with a fused (1) root, 12 (86%) had a C-shaped root and two (14%) had a non-C-shaped root.

CONCLUSION

We observed a higher frequency of root fusion in the present study compared with that reported by previous studies using randomly selected second molars.