Endodontic treatment of a mandibular second molar with four roots – A case report and literature review

ObjectivesThe most common configuration of the mandibular second molar is the presence of two roots, although the presence of one and three roots has also been reported. The objective of this work was to present a rare anatomic configuration with four roots diagnosed during an endodontic therapy.Materials and methodsEndodontic treatment was performed using a dental operating microscope. The anatomic configuration was confirmed with a cone beam computed tomography image analysis. An electronic database search was conducted to identify all the published reported cases of mandibular second molars with four roots.ResultsThe cone beam computed tomography analysis showed the presence of three mature normal length roots plus a smaller and conical radix entomolaris. The authors were unable to identify a single case in population's characterization researches with large samples by search in the available literature. Only one in vivo case report was available in the literature.ConclusionsA configuration with four roots is rare for the mandibular molars. This configuration has an incidence of 0.04% in the first lower molar with only three in vivo case reports available. For the second lower molar, no incidence ratio was found.     

Is the quality of root canal filling obtained by cone-beam computed tomography associated with periapical lesions? A systematic review and meta-analysis

Aim

To evaluate the influence of root canal filling quality on periapical lesion status using cone-beam computed tomography (CBCT).

Materials and Methods

The bibliographic search was conducted in electronic databases of PubMed, Embase, Scopus, and Web of Science without restrictions related to the year of publication and language. Inclusion criteria were prospective or retrospective cohort studies that followed periapical pathosis for, at least, 1 year. Three reviewers independently evaluated the eligibility for inclusion, extracted data, and assessed the risk of bias. The quality of the studies was based on the Newcastle–Ottawa Scale. This meta-analysis was performed to evaluate the quality of treatment by the homogeneity and apical extension of the filling.

Results

Of the 1179 studies initially recovered, six cohort studies were included, out of which four were considered with a low risk of bias. The results showed that the absence of gaps in the filling reduced the chance of unhealed periapical lesions by 2.39 times (RR?=?2.39; 95% CI: 1.62–3.53; p?<?0.00001; I² = 55%). An apical filling extension of 0–2 mm below the apex also contributed significantly to the absence of unhealed periapical lesions (RR?=?1.49; 95% CI: 1.15–1.94; p?=?0.003; I² = 2%).

Conclusion

The homogeneity and apical extension of the filling influenced the presence of unhealed periapical lesions in endodontically treated teeth evaluated using CBCT.

Clinical relevance

Apical extension of the filling ranging between 0 and 2 mm short of the apical foramen and the homogeneity of the filling without gaps are directly related to the success rate of root canal treatment.

     

Risk factors associated with inferior alveolar nerve injury after extraction of the mandibular third molar—a comparative study of preoperative images by panoramic radiography and computed tomography

In this study we investigated the relationships among the risk factors for inferior alveolar nerve injury (IANI), and the difference between preoperative imaging findings on panoramic radiographs and computed tomography (CT), by univariate and multivariate analyses. We determined the following to be significant variables by multivariate analysis: panoramic radiographic signs, such as the loss of the white line of the inferior alveolar canal or the diversion of the canal; excessive haemorrhage during extraction; and a close relationship of the roots to the IAN (type 1 cases) on CT examination. CT findings of type 1 were associated with a significantly higher risk (odds ratio 43.77) of IANI. In addition, many panoramic findings were not consistent with CT findings (275 of 440 teeth; 62.5%). These results suggest that CT findings may be able to predict the development of IANI more accurately than panoramic findings. Panoramic radiography alone did not provide sufficiently reliable images required for predicting IANI. Therefore, when the panoramic image is suggestive of a close relationship between the impacted tooth and the IAN, CT should be recommended as a means of conducting further investigations.     

Root and root canal variations of the human maxillary and mandibular third molars in a Chinese population: A micro–computed tomographic study

ObjectivesTo investigate the anatomical variations of the root and root canal configuration of the human third molars.DesignsA total of 130 maxillary and 130 mandibular third molars were collected from a native Chinese population. All teeth were scanned by micro–computed tomography. After 3D reconstruction, the root and canal morphology of each tooth was examined both qualitatively and quantitatively.ResultsFor maxillary molars, a single fused root (67 cases, 51.5%) and a single root canal system (64 cases, 49.2%) was most common root/canal form; the typical three-rooted molars were detected only in 33 cases (25.4%), and the secondary MB canals were detected only in 9 molars (6.9%). For mandibular molars, 62 teeth were single-rooted (47.7%) and 42 had a single root canal system (32.3%); 20 singled-rooted and 60 double-rooted molars exhibited independent mesial and distal root canal systems (61.5%), and the type 1-1 canal was the most common configuration for mesial (57 cases) and distal (81 cases) root canal systems. C-shaped canals were detected in 11 maxillary and 36 mandibular single-rooted molars. The mean root surface area, root and crown volume of mandibular third molars were significantly higher than the maxillary third molars (P < 0.01).ConclusionThe root canal system of the third molars may exhibit several anatomic variations. Whereas in most of cases, the degree of the canal differentiation was at a low level, and the canal form was not complicate.