Clinical relevance of distolingual roots and periodontal status in mandibular first molars: a cross-sectional study employing CBCT analysis

OBJECTIVES: Distolingual root of the permanent mandibular first molar (PMFM-DLR) has been frequently reported, which may complicate the treatment of periodontitis. This study aimed to assess the morphological features of PMFM-DLR and investigate the correlation between the morphological features of PMFM-DLR and periodontal status in patients with Eastern Chinese ethnic background. MATERIALS AND METHODS: A total of 836 cone beam computed tomography (CBCT) images with 1497 mandibular first molars were analyzed to observe the prevalence of PMFM-DLR at the patients and tooth levels in Eastern China. Among them, complete periodontal charts were available for 69 Chinese patients with 103 teeth. Correlation and regression analyses were used to evaluate the correlation between the morphological features of DLR, bone loss, and periodontal clinical parameters, including clinical attachment loss (CAL), probing pocket depth (PPD), gingival recession (GR), and furcation involvement (FI). RESULTS: The patient-level prevalence and tooth-level prevalence of DLR in mandibular first molars were 29.4% and 26.3%, respectively. Multiple linear regression analysis suggested that bone loss at the lingual site and CAL were negatively affected by the angle of separation between distolingual and mesial roots in the transverse section, while they were significantly influenced by age and the angle of separation between distobuccal and mesial roots in the coronal section. CONCLUSIONS: The prevalence of PMFM-DLR in Eastern China was relatively high in our cohort. The morphological features of DLR were correlated with the periodontal status of mandibular first molars. This study provides critical information on the morphological features of DLR for improved diagnosis and treatment options of mandibular molars with DLR.

Mandibular incisors with two canals are associated with the presence of the distolingual root in mandibular first molars: a cone-beam computed tomographic study

Background

This study aimed to evaluate the root canal configurations and the association between mandibular first molars and distolingual root (DLR) and mandibular incisors using cone-beam computed tomography (CBCT).

Methods

Mandibular first molars and incisors were evaluated using CBCT images of 150 patients. Mandibular first molars were classified according to the presence or absence of DLR. The curvature of the DLR was evaluated using Schneider’s method in buccolingual and mesiodistal orientations. The angle of the mesiolingual–distolingual–distobuccal canal orifices (ML–DL–DB) was evaluated at the pulpal floor level. The mandibular central and lateral incisors were classified as either single canal or two canals. The association between the root canal system of the mandibular first molar and mandibular incisors was evaluated. Data were analyzed using the Chi-square test, Student’s t-test, and odds ratios from binary logistic regression. The significance level was set at 5%.

Results

The frequency of mandibular first molars with DLR was 27.0% and that of mandibular incisors with two canals was 25.8%. The curvature of the DLR was 37.1° in the buccolingual orientation and 10.4° in the mesiodistal orientation. The angle of ML–DL–DB was 79.0°. The presence of two canal systems in mandibular incisors was associated with the presence of DLR in the mandibular first molar (left central incisors: p = 0.001, odds ratio = 4.25; left lateral incisors: p < 0.001, odds ratio = 3.8; right central incisors: p = 0.003, odds ratio = 3.86; right lateral incisors: p = 0.001, odds ratio = 3.44) but not with the curvature of the DLR or angle of the ML–DL–DB orifice (p > 0.05).

Conclusions

The mandibular first molar showed a high incidence of separate DLRs. It was confirmed that DLR in the mandibular first molar is highly associated with the presence of two-canal system in the mandibular incisors. This association can aid clinicians in successful endodontic treatments.

Evaluation of radix entomolaris in mandibular first and second molars using cone-beam computed tomography and review of the literature

OBJECTIVES

The aim of the present study is to identify the prevalence of radix entomolaris in mandibular first and second molars and to determine morphological classifications and associations with other root and canals.

METHODS

Mandibular first and second molar teeth of 850 Turkish patients were evaluated using cone-beam computed tomography. A total of 2800 mandibular first molars and second molars were screened. The CBCT examination was performed at five different axial levels. The prevalence of total radix entomolaris, unilateral-bilateral, right-left side and gender distributions, and the classification of radix entomolaris's canal configurations were measured.

RESULTS

Radix entomolaris was found in 2.9% (n = 25) of the patients and 1.2% (n = 34) of the teeth. The prevalence of radix entomolaris in mandibular first molars was higher than in mandibular second molars (p < 0.01), in males than in females (p < 0.05) and in right side than left side. An additional tubercle was found in 23% of the teeth with radix entomolaris. For buccolingual orientation, Type A canal variation was the highest and Type C canal variation was the lowest. Regarding locations of cervical parts, Type III canal variation was the highest while Type I canal variation was the lowest.

CONCLUSIONS

The prevalence of radix entomolaris was lower in the Turkish population than in other Asian populations but, in multiethnic societies, it needs attention. Before starting endodontic treatment, the clinician should examine the radiography thoroughly and apply advanced radiography methods when necessary. Cone-beam computed tomography is a valuable advanced radiography method for assessing such anatomical variations in vivo.

Root Canal Configuration of Human Permanent Mandibular First Molars of an Indo-Dravidian Population Based in Southern India: An In vitro Study

Aim:

This study aims to analyze root canal configuration of human permanent mandibular first molars of an indo-Dravidian population based in southern India.

Materials and Methods:

A total of 1147 mandibular first permanent molars were collected, cleansed, and stored. The number of roots was recorded, access preparations made, pattern of orifices recorded after pulpal floor debridement, dye injected into the canals using apical negative pressure and subjected to a clearing technique. They were then analyzed using a stereo microscope and the canal configurations recorded (Vertucci). The number of roots, the pattern of orifices and canal configuration were recorded.

Results:

The pattern of orifices was triangular (87.9%), rectangular (8.5%), C-shaped (3.0%), and two orifice pattern (0.6%). About 95.6% of teeth had two roots, and 4.4% had three roots. The most common canal system configuration in mesial root was Vertucci type IV (52.3%), followed by type II (35%). Root canal configuration of the distal root revealed type I configuration in 62.7%, followed by types II (14.5%) and IV (12.4%). The distolingual root had a type I configuration.

Conclusion:

Awareness of canal configuration, adequate clinical skills, use of specialized techniques of diagnosis, debridement and obturation will pave the way for successful treatment outcomes.