Permanent Mandibular First Molars Research Articles

Single rooted, single canalled mandibular first molar in association with multiple anomalies: Report of a rarest case with literature review

Knowledge on variations in roots and canal morphology of teeth is very important for successful endodontic treatment. Most of the times, permanent mandibular first molar (PMFM) usually have two roots one mesial and one distal with three root canals. Although variations in root and canals of this tooth have been extensively discussed in the endodontic literature, existence of a single root with a single canal is not well-documented. The aim of this report is to present an unusual anatomy of the PMFM having a single root and single canal along with other peculiar multiple anomalies such as tooth agenesis, single-rooted maxillary first molars and three rooted primary mandibular second molar in the same patient.

Endodontic Management of the Three-Rooted Mandibular First Permanent Molar: a Case Report.

The distal root of the mandibular first permanent molar (MFPM) contains one or two canals. More rarely, the second/third distal canal is found in a separate root in a distolingual (DL) position - a radix entomolaris (RE). In Caucasians, this occurs in less than 4% of cases, but it is equally important to be aware of this possibility. Careful examination of the preoperative periapical radiographs (orthoradial and mesially angled) and inspection of the pulp chamber floor during endodontic management may indicate that this radicular variant is present. RE's lingual inclination and buccolingual curvature must be taken into account during cleaning and shaping of the canal within this root to avoid procedural errors, such as straightening and ledging of the root canal, perforation or instrument fracture. The aim of the present paper was to discuss a case report of a young patient, referred to an endodontic office after a ledge was created by inappropriate instrumentation of a buccolingually curved RE canal.

The relation between the mesio-distal crown widths of the deciduous second molars and the permanent first molars

Background: This study aimed to find whether there is a relation between the mesio-distal crown diameters of the deciduous second molars and the permanent first molars in an Iraqi sample from Baghdad city. Material and methods: The sample consisted of 54 Iraqi children aged 8-9 years at the mixed dentition stage. The measurements included the mesio-distal crown width of the deciduous second molars and the permanent first molars on the study casts using digital sliding vernier. Results: The results revealed absence of the side difference of the widths of teeth measured. High significant gender difference was detected for the permanent first molars and the deciduous second molars except mandibular permanent first molar. On the other hand, high significant difference was found between the maxillary and mandibular arches for the permanent first molars and the deciduous second molars except for the permanent first molar in males. A direct strong significant correlation was found between the width of the permanent first molars and the deciduous second molars. Conclusion: The findings of the present study may be used as predictive factor for tooth – jaw disharmony and the possibility for the crowding in the future.

Morphological changes related to age in mesial root canals of permanent mandibular first molars.

The aim of this study was to evaluate age-related morphological canal changes in mesial root canals of mandibular first molars of known ages. Fifty-six specimens were selected for this study and distributed into the following four age groups (n. 14): a) Group of children under 13 years, b) Group of adolescents (from 14 to 19 years), c) Group of young adults (from 20 to 39 years) and d) Group of older adults (over 40 years). The specimens were in perfect condition because after extraction they were carefully cleaned, sterilized, identified and stored in water. In order to improve the cleaning, they were placed in 1% sodium hypochlorite solution for four hours and rinsed in 10 vol. hydrogen peroxide for 8 hours. After that, a clearing technique was performed to illustrate root canal anatomy. Digitalized images of all samples were obtained by use of a stereomicroscope. Canals were noticeably simpler in older adults: they were sharply defined and narrow, sometimes too narrow. Calcification nuclei were not found and there were only a few remains of internuclear spaces. The canal system appeared cleaner, clearer and more sharply defined than in the other age groups. It may be concluded that there is a correlation between aging and morphological changes in the mesial root canals of mandibular first molars.

INTERNAL ROOT MORPHOLOGY IN MANDIBULAR FIRST PERMANENT MOLARS IN A KENYAN POPULATION.

To determine the internal root morphology and gender variations in mandibular first permanent molars in a Kenyan population. In vitro descriptive cross sectional study. School of Dental Sciences, University of Nairobi The mesial root of mandibular first molars had two canals in 96.3% of the teeth in both males and females and-type IV canal configuration was most prevalent in the mesial root. The distal root of the mandibular first molar had one canal in 57.7% of the teeth in males and females. There were significant gender variations in the number of canals and canal configurations in the distal root. Two canals were more prevalent in females (53.6%) compared to males (30.4%) and a single canal was more frequent in males (69.6%) compared to females (46.4%) (P=0.001). Canal types 1, 11 and IV were the most frequent in the mandibular distal root. The gender variation in the frequency of canal types I, II and IV in the distal root was statistically significant (P=0.001). Most of the mandibular first molars have three canals (56%). Two canals in the distal root are more frequent among females (53.6%) compared to males (30.4%).

Incidence of three roots and/or four root canals in the permanent mandibular first molars in a Korean sub-population

The purpose of this study was to evaluate the prevalence of three-rooted permanent mandibular first molars (PMFMs) with four canals and their morphological characteristics among a Korean population from using cone-beam computed tomography scans (CBCTs). Among the 705 CBCTs screened, 472 patient cases possessing at least one PMFM were identified. A total of 780 PMFMs were evaluated in axial section series to determine the number of roots and canals. The incidences of three-rooted PMFMs were compared with regard to gender and location. For distal root(s) with two canals, inter-orifice distances (IOD) between distobuccal and distolingual canals were measured at pulpal floor and furcation levels. The difference of IOD between males and females was also analyzed using chi-square tests. Among the 472 CBCTs of 225 females and 247 males, 84 females and 107 males were found to have at least one three-rooted PMFM. Among the 780 PMFMs, 191 PMFMs (24.5%, 89 of 397 left and 102 of 383 right) were found to have three roots. The prevalence of distal root(s) with two canals was 34.2% (267 of 780). From the molars with two distal canals, the mean IOD between distobuccal and distolingual canals at the pulpal floor level was 3.1mm in males and 2.9mm in females (p = 0.0428). The occurrence of three-rooted PMFMs among a Korean population was 24.5% and was higher than other countries and ethnicities. Understanding the prevalence of PMFMs with a distolingual root and/or canal in a Korean population and the IOD between distobuccal and distolingual canals may be useful for successful endodontic treatments. Acknowledgment of potential incidence of three-rooted permanent mandibular first molars with four canals and the distance between two distal canals may increase the success rate of root canal treatment by reducing the missing canal untreated.

Establishment of the three dimensional finite element model of the first permanent mandibular molar

Objective To construct a rational and exact three - dimensional finite element model of the first permanent mandibular molar. Methods The first permanent mandibular molar was scanned by CT and the images were processed by softwares such as PhotoShop. Then special software SolidWorks2010 was used to establish a three - dimensional finite element model . Results A three - dinensional finite element model of the first permanent mandibular molar was established, including enamel, dentin, pulp, alveolar bone and periodontium. Conclusion The modeling method is effective and reliable. The three- dimensional finite element model has favorite similarities in geometry and biomechanics . It' s a simple and precise method for dentists to establish finite element models . Key words: Molar; Three- dimensional finite element; Model

A SECOND DISTAL ROOT IN A MANDIBULAR FIRST PERMANENT MOLAR TOOTH

Australian Endodontic NewsletterVolume 9, Issue 3 p. 10-11 A SECOND DISTAL ROOT IN A MANDIBULAR FIRST PERMANENT MOLAR TOOTH DR JOHN D. LE BROCQ, DR JOHN D. LE BROCQ 246 Queen Street Brisbane 4000Search for more papers by this authorDR RALPH J. REID, DR RALPH J. REID 246 Queen Street Brisbane 4000Search for more papers by this author DR JOHN D. LE BROCQ, DR JOHN D. LE BROCQ 246 Queen Street Brisbane 4000Search for more papers by this authorDR RALPH J. REID, DR RALPH J. REID 246 Queen Street Brisbane 4000Search for more papers by this author First published: April 1984 https://doi.org/10.1111/j.1747-4477.1984.tb00756.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume9, Issue3April 1984Pages 10-11 RelatedInformation

Removal of a Separated Nickel-titanium Instrument from a Three-rooted Mandibular First Molar

Permanent mandibular first molars usually have a mesial root and a distal root and three root canals, but variations in the number of roots and in canal morphology are not uncommon. The additional third root in permanent mandibular first molar variants that have three roots is typically distributed lingually. Herein, we report on a 20-year-old Chinese female who presented with a separated K3 nickel-titanium instrument in the distolingual root canal of her left mandibular first molar. We removed the nickel-titanium fragment using several ultrasonic tips under a dental operating microscope. The root canals were cleaned and shaped thoroughly and then obturated by a warmed gutta-percha compaction method. At 4-month follow-up, the patient was free of symptoms.

Establishment of the three-dimensional finite element model of the first permanent mandibular molar and its stress analysis

To establish more rational three dimensional finite element model (FEM) of the first permanent mandibular molar and to study the internal stress distribution. The FEM was applied to analyze the stress distribution of the first permanent mandibular molar under various loading conditions. Under all five loading conditions, the maximum von-Mises stress and compressive stress in enamel were larger than that in dentin, and the tensile stress in enamel was smaller than that in dentin. When vertical force and buccal-lingual oblique force were loaded, the stresses in the enamel and dentin were minimum; when lingual-buccal oblique force was loaded, the stresses were maximum; the stresses were mainly distributed at cervical region, furcation and apical area of the mesial-lingual root canal wall. The stress value changes and stress distribution in the enamel and dentin were closely related with the direction of the occlusion force.