Worldwide Assessment of the Mandibular First Molar Second Distal Root and Root Canal: A Cross-sectional Study with Meta-analysis.

INTRODUCTION: This study assessed the prevalence of radix entomolaris and 2 canals at the distal aspect of mandibular first molars among different geographic regions by means of cone-beam computed tomographic imaging. METHODS: Precalibrated observers from 23 worldwide geographic locations followed a standardized screening protocol to assess 5750 cone-beam computed tomographic images of mandibular first molars (250 per region), gathering demographic data and recording the presence of radix entomolaris and a second canal at the distal aspect of teeth. Intra- and interrater reliability tests were conducted and comparisons among groups were performed using proportions and odds ratio forest plots. The significance level was set at 5%. RESULTS: The results of intra- and interrater tests were above 0.79. The prevalence of radix entomolaris varied from 0.9% in Venezuela (95% confidence interval [CI], 0%-1.9%) to 22.4% in China (95% CI, 17.2%-27.6%). Regarding the proportion of a second distal canal, it ranged from 16.4% in Venezuela (95% CI, 11.8%-21.0%) to 60.0% in Egypt (95% CI, 53.9%-66.1%). The East Asia subgroup was associated with a significantly higher prevalence of an extra distolingual root, whereas the American subgroup, the American native ethnic group, and elderly patients were linked to significantly lower percentages of a second canal at the distal aspect of teeth. No significant differences were noted between male or female patients. CONCLUSIONS: The overall worldwide prevalence rates of radix entomolaris and a second canal at the distal aspect of the mandibular first molar were 5.6% and 36.9%, respectively. The East Asia geographic region and Asian ethnic group had a higher prevalence of a second distal root.

Worldwide Prevalence of a Lingual Canal in Mandibular Premolars: A Multicenter Cross-sectional Study with Meta-analysis.

INTRODUCTION: The presence of multiple root canals is an important morphologic aspect of mandibular premolars. This study aimed to perform a worldwide analysis on the prevalence of a lingual canal in mandibular premolars and to evaluate its influence on patients' demographics in 23 countries using cone-beam computed tomographic images. METHODS: Observers from 23 countries were instructed to evaluate cone-beam computed tomographic images of 300 first and 300 second premolars (13,800 teeth) regarding the presence of a lingual canal, canal configuration, and data related to patients' ethnicity, age, and sex following a standardized screening methodology. Intra- and interrater evaluations were performed using the Cohen kappa test and intraclass correlation coefficient. Proportion and odds ratio forest plots were calculated in order to compare groups. Statistical significance was set at 5%. RESULTS: Both kappa and intraclass correlation coefficient values were above 0.60, and the percentage of agreement was 94.9% (first premolar) and 97.8% (second premolar). A significant statistical difference was observed between the worldwide proportion of a lingual canal in mandibular first (23.8%; range, 12.0%-32.7%) and second (5.3%; range, 1.0%-15.3%) premolars (P < .05). Asians and patients over 60 years old were associated with the lowest proportions of a lingual canal (P < .05), whereas Africans and younger groups were associated with the highest proportions (P < .05). The prevalence of a lingual canal in males (27.9%) was higher than females (20.0%) for the first premolar only (P < .05). Males were associated with 1.533 and 1.597 higher odds of presenting a lingual root canal in the first and second premolars, respectively. CONCLUSIONS: The worldwide proportion of a lingual root canal was 23.6% and 5.3% for the first and second premolars, respectively. Ethnicity, geographic region, age, and sex had an influence on the outcomes.

Worldwide Analyses of Maxillary First Molar Second Mesiobuccal Prevalence: A Multicenter Cone-beam Computed Tomographic Study.

INTRODUCTION: Maxillary first molar second mesiobuccal (MB2) root canal prevalence may change among different populations. The aim of this study was to analyze the worldwide prevalence of the MB2 root canal and understand its possible relation with sex, age, side, and root configuration using in vivo cone-beam computed tomographic (CBCT) assessment. METHODS: Observers from 21 regions were calibrated to achieve a similar CBCT assessment methodology and instructed to collect data from 250 maxillary first molars in previously existing examinations. Intra- and interrater reliability tests were performed. The sample size included 5250 molars and was defined by way of a preliminary trial. Data collected included MB2 presence, sex, age, side, number of roots per tooth, and mesiobuccal root configuration. The z test for proportions in independent groups was used to analyze the differences among subgroups. P < .05 was considered significant. RESULTS: The worldwide CBCT-assessed MB2 prevalence was 73.8%, ranging from 48.0% in Venezuela to 97.6% in Belgium. The prevalence in males and females was 76.3% and 71.8%, respectively (P < .05). Significantly higher MB2 proportions were found in younger patients and 3-rooted molar configurations. The group intraclass correlation coefficient and the percentage of agreement for the MB2 presence were 0.95 and 0.91, respectively. The intrarater Cohen kappa value was above 0.61 for all observers. CONCLUSIONS: MB2 prevalence in the analyzed regions varied widely. The differences may be associated with specificities within each region but also patient demographics. Males, younger patients, and 3-rooted configurations were associated with higher MB2 proportions.

Worldwide Prevalence of Mandibular Second Molar C-Shaped Morphologies Evaluated by Cone-Beam Computed Tomography.

INTRODUCTION: The aim of this study was to evaluate and compare the C-shaped mandibular second molar prevalence in different regions around the world with the aid of cone-beam computed tomography technology. METHODS: Nine field observers from 9 different geographic regions were calibrated. A total of 400 samples were collected in each region. The prevalence of C-shaped anatomy was calculated. The number of roots and the configuration of the C-shaped canals at 3 different axial levels were also evaluated. The z-test was used to analyze the difference between the means of each independent group. Intrarater reliability was also tested. RESULTS: A total of 3600 teeth from 2735 patients were included in this research; 499 teeth presented C-shaped root canal configuration, representing a global prevalence of 13.9%. China had a prevalence of 44.0%, which was significantly higher than any other region. The C-shape prevalence in women was 16.5%, which was significantly higher than the 10.4% prevalence found in men. No difference between sides (37 or 47) was evident in the global sample. CONCLUSIONS: Cone-beam computed tomography is a valuable tool to evaluate the C-shaped root canal configuration in vivo. In the present study, China presented the highest prevalence of C-shaped mandibular second molars when compared with other regions. Women exhibited a higher prevalence than men.

Evaluation and endodontic management of a patient with 6 single-rooted molars: a case report.

This case report describes a patient with unusual tooth morphology involving the bilateral presence of 6 maxillary and mandibular first and second molars with a single root and a single canal. The article also discusses the endodontic management of a single-rooted maxillary molar and the use of cone beam computed tomography for evaluation and diagnosis of these anatomical variations.

Evaluation of an Indigenously Prepared Herbal Extract (EndoPam) as an Antimicrobial Endodontic Irrigant: An Ex Vivo Study.

BACKGROUNDG: Root canal irrigation plays a pivotal role in endodontics. Constant increase in antibiotic resistance and side effects caused by synthetic irrigants has shifted the research toward developing herbal alternatives. The current study aims to assess the ex vivo effectiveness of an indigenously prepared herbal extract "EndoPam" and compare it with the conventional endodontic irrigants for disinfection of root canals infected with Enterococcus faecalis. MATERIALS AND METHODS: As a preliminary study of the antimicrobial efficacy of the test irrigants, an Agar diffusion study was conducted, and zone of inhibition measured. Forty extracted mandibular premolars with straight root canals were selected and standardized to 12 ± 1 mm in length. Root canals were prepared using rotary ProTaper system until F3 instrument and were infected with the culture of E. faecalis for three weeks. Specimens were divided into four groups (n = 10). Group 1: EndoPam (. INGREDIENTS: Syzigium aromaticum, Eucalyptus globulus, Cinnamomum zeylanicum and Mentha piperita), Group 2: 2% chlorhexidine, Group 3: 5.25% Sodium hypochlorite, Group 4: Normal Saline. Irrigation was performed for each group. Samples were inoculated and incubated for 24 h at 37°C for qualitative analysis qualitative analysis. RESULTS: In the preliminary Agar diffusion study, EndoPam exhibited a zone of inhibition comparable to that of sodium hypochrorite. The diameter of the inhibition zone was in the following order: 2% chlorhexidine gluconate > EndoPam > 5.25% NaOCl > Normal Saline. The qualitative assay done by culturing the bacteria after a period of 3 weeks showed no bacterial growth in any of the tested irrigants, except in normal saline. CONCLUSION: It was found that the experimental product was as effective as conventional irrigants in reducing the microbial count.

Dentine microhardness changes following conventional and alternate irrigation regimens: An in vitro study.

AIM: To compare the changes in microhardness of root dentin caused by two novel irrigation regimens with conventional irrigation. MATERIALS AND METHODS: Forty extracted human permanent incisor teeth were selected. Decoronated roots were separated longitudinally to get 80 specimens that were embedded in autopolymerizing acrylic resin and grounded flat with silicon carbide abrasive papers. Of these, 60 root segments without any cracks or defects were selected and divided into four groups according to the irrigation regimen used (n = 15). Group I: 5% sodium hypochlorite (NaOCl) + 17% ethylenediaminetetraacetic acid (EDTA) + 0.2% chlorhexidine digluconate (CHX) (conventional). Group II: 6% Morinda Citrifolia Juice + 17% EDTA (MCJ). Group III: 5% NaOCl + Q Mix 2 in 1 (QMix). Group IV: Distilled water (control). Irrigation regimens were performed for 5 minutes. Dentin microhardness was measured with a Vickers indenter under a 200-g load and a 20-s dwell time at the midroot level of root dentin. The data were analyzed using Kruskal Wallis test and Dunn's multiple comparison tests. RESULTS: A significant difference was seen in the median values of the four groups. The control group showed the least reduction in microhardness when comparison with the other groups. Except for Group III (Q Mix), the other groups that were tested (MCJ and conventional regimens) showed statistically significant difference from the control group. CONCLUSION: Within the limitation of this study, it was concluded that NaOCl + Q Mix were least detrimental to root dentin microhardness when compared with MCJ and conventional irrigation regimens.

Endodontic and clinical considerations in the management of variable anatomy in mandibular premolars: a literature review.

Mandibular premolars are known to have numerous anatomic variations of their roots and root canals, which are a challenge to treat endodontically. The paper reviews literature to detail the various clinically relevant anatomic considerations with detailed techniques and methods to successfully manage these anomalies. An emphasis and detailed description of every step of treatment including preoperative diagnosis, intraoperative identification and management, and surgical endodontic considerations for the successful management of these complex cases have been included.

Palatogingival groove mimicking as a mutilated root fracture in a maxillary lateral incisor: a case report.

This article presents a case of a palatogingival groove (PPG) in tooth No. 12 that was misdiagnosed as a mutilated root fracture. A PPG is a developmental anomaly that predisposes a tooth to a severe periodontal defect. The initial diagnosis of mutilated root fracture on tooth No. 12 was made solely from radiographs that showed a vertical and horizontal radiolucent line with a radiolucent halo-shaped bone resorption in relation to the root apex. Transillumination, bite test, surgical visualization of the site, and the use of high-end diagnostic modalitieswere not considered prior to the final diagnosis. PPG was confirmed only after the tooth was extracted and observed under a dental operating microscope.

A permanent mandibular second molar with seven root canal systems.

This case report illustrates the nonsurgical endodontic management of a seven-canaled mandibular second molar. The root canal configuration presented as four mesial and three distal canals. Identification of the canal system was made with the aid of magnification, ultrasonics, and multiple angulated radiographs. Postoperative examination at 18 months showed a clinically asymptomatic tooth with resolution of the periapical pathology.

Morphologic variations in mandibular premolars: a report of three cases.

AIM: To report cases with morphologic variations in mandibular premolars. BACKGROUND: Mandibular premolars have earned the reputation for having aberrant anatomy. The occurrence of three canals with three separate (type V, Vertucci) foramina in mandibular premolars is very rare. In this report, three cases are presented involving the root canal treatment of mandibular premolars with three different root and canal configurations. The present report also emphasizes the use of the dental operating microscope to enhance visualization. CASE DESCRIPTION: Correlation between radiographic findings, use of dental operating microscope and knowledge of aberrant anatomy helps to identify, locate and treat the aberrant anatomy of the tooth. CLINICAL SIGNIFICANCE: The treatment was successful as all canals were identified and filled and also as evidenced by relief of symptoms. CONCLUSION: Success is largely dependent on the use of magnification, which aided in identifying the location of the three individual root canal orifices; thus emphasizing the need to familiarize ourselves with dental microscopy, to obtain maximal anatomic information in endodontic practice.

Effects of multiple root canal usage on the surface topography and fracture of two different Ni-Ti rotary file systems.

AIM: The purpose of this study was to evaluate the effect of multiple root canal usage on the surface topography and fracture of Twisted File (TF) and ProTaper (PT) rotary Ni-Ti file systems, using scanning electron microscope (SEM). MATERIALS AND METHODS: Ten sets of PT and TF instruments were used to prepare the mesial canals of mandibular first molars. TF 25, 0.06 taper and PT F1 instruments were analyzed by SEM when new and thereafter every three root canal usages. This sequence was repeated for both the TF and PT groups until 12 uses. Two images of the instrument were recorded, one of the instrument tip and the other 5 mm from the tip, both at × 100 magnification. The sequential use was continued till the instrument fractured and the number of root canal usages for the file to fracture was noted. All fracture surfaces were examined under the SEM. RESULTS: Fresh TF instruments showed no surface wear when compared to PT instruments (P < 0.05). Spiral distortion scores remained the same for both the groups till the 6 th usage (P > 0.05), while at the 9 th usage TF showed a steep increase in the spiral distortion score when compared to PT (P < 0.05). PT instruments fractured at a mean root canal usage of 17.4, while TF instruments showed a mean root canal usage of 11.8. Fractographically, all the TF instruments failed due to torsion, while all the PT instruments failed because of cyclic fatigue. CONCLUSION: PT instruments showed more resistance to fracture than TF instruments.

Revascularization for a necrotic immature permanent lateral incisor: a case report and literature review.

BACKGROUND: Revascularization is a valuable treatment in immature necrotic teeth that allows the continuation of root development. CASE REPORT: This article describes the successful revascularization treatment of an immature maxillary lateral incisor that was initially diagnosed with apical periodontitis. The tooth was asymptomatic and functional clinically and radiographically during the follow-up period of 5 years. CONCLUSION: The follow-up showed evidence of progressive thickening of the dentinal walls, development of root length and apical closure. The article also discusses the currently available literature regarding revascularization of immature permanent teeth.

Root anatomy and root canal configuration of human permanent mandibular premolars: a systematic review.

Introduction. Mandibular premolars have been reported with complex anatomical aberrations, making them one of the most difficult teeth to manage endodontically. Methodology. An exhaustive search was undertaken to identify associated anatomic studies of mandibular premolars through MEDLINE/PubMed database using keywords, and a systematic review of the relevant articles was performed. Chi-square test with Yates correction was performed to assess the statistical significance of any anatomic variations between ethnicities and within populations of the same ethnicity. Documented case reports of variations in mandibular premolar anatomy were also identified and reviewed. Results. Thirty-six anatomic studies were analyzed which included 12,752 first premolars and nineteen studies assessing 6646 second premolars. A significant variation in the number of roots, root canals, and apical foramen was observed between Caucasian, Indian, Mongoloid, and Middle Eastern ethnicities.The most common anatomic variation was C-shaped canals in mandibular first premolars with highest incidence in Mongoloid populations (upto 24%) while dens invaginatus was the most common developmental anomaly. Conclusions. A systematic review of mandibular premolars based on ethnicity and geographic clusters offered enhanced analysis of the prevalence of number of roots and canals, their canal configuration, and other related anatomy.

Maxillary first molar with three buccal roots evaluated with cone-beam computed tomography: a rare case report.

This case report describes the nonsurgical endodontic management of a maxillary first molar with the unusual morphology of three separate buccal roots. An accurate assessment of this morphology was made with the help of cone-beam computed tomography (CBCT). This report also describes the varied root morphology associated with maxillary first molars and the role of CBCT as a diagnostic tool for managing these complex cases successfully.

Four-rooted mandibular first molar with an unusual developmental root fusion line: a case report.

The paper describes the anatomical variation of four roots in a mandibular permanent first molar diagnosed using multiple angulated preoperative radiographs and its successful nonsurgical endodontic management. Careful observation and exploration of the pulpal floor using a dental operating microscope revealed a peculiar developmental root fusion line on the pulp chamber floor. Based on the above observation, a correlation between this unusual line and the existence of additional roots has been proposed and discussed.

A new anatomically based nomenclature for the roots and root canals-part 2: mandibular molars.

Several terminologies have been employed in the dental literature to describe the roots and root canal systems of mandibular molars with no consensus being arrived at, thus far. The anatomical relation of roots and their root canals were identified and a naming system was formulated. The proposed nomenclature attempts to make certain essential modifications to the traditional approach to accommodate the naming of various aberrations presented in mandibular molars. A simple, yet extensive nomenclature system has been proposed that appropriately names the internal and external morphology of mandibular molars.

A new anatomically based nomenclature for the roots and root canals-part 1: maxillary molars.

Numerous terminologies have been employed in the dental literature to describe the roots and root canal systems of maxillary molars. This multiplicity in naming of roots and canals makes the reader susceptible to misinterpretation and confusion. No consensus thus far has been arrived at for defining the names of roots and root canals in maxillary molars, including their various morphological aberrations. The anatomical relation of roots and their root canals were identified and were subsequently named based on definite sets of criteria. A new method for identification and naming of roots and root canal anatomy in maxillary molars, based on their root and canal relationship, was formulated and is presented in this paper. The nomenclature makes certain essential modifications to the traditional approach to accommodate naming of the various aberrations presented in the maxillary molars. A simple, yet extensive, nomenclature system has been proposed that appropriately names the internal and external morphology of maxillary molars.