Prevalence of Root Canal Morphology of Mandibular Molar in Western Nepalese Population: A Cross-sectional Study

INTRODUCTION: A main variant in the mandibular molars is the presence of radix entomolaris (RE) and radix paramolaris (RP) in the mandibular first molars and fused roots in 2nd mandibular molar. Hence, the present prospective study intends to evaluate the prevalence of radix entomolaris, radix paramolaris and molars with fused roots in a local population of Western Nepal. MATERIAL AND METHODS: This is prospective cross-sectional study. The total of 336 patient's mandibular first and second permanent molars having radiological and clinical evidence of pulpal pathology were included in this study. The criteria for the identification of an extra root were justified by crossing of the translucent lines defining the pulp space and periodontal ligaments in the mandibular first molars, and for the mandibular second molars, the outline of the periodontal ligament was followed to see the presence of the fused roots. RESULTS: Thirty nine patients (24 females and 15 males) showed a supernumerary distolingual root (RE) in mandibular first molars and 42 patients (18 females and 24 males) showed mesiolingual root (RP). The prevalence of patients with radix entomolaris was 11.6% (39 of 336), 13.6% for females (24 of 176) and 9.3 % for males (15 of 160). The prevalence of radix paramolaris was 12.5%(42 of 336), 10.5%(18 of 176) for females and 15% (24 of 160) for males. 54 patients (27 females and 27 males) showed C-shaped canals in mandibular molars. The prevalence of C-shaped mandibular molars was 30% for females (27 of 90) and 34.6% (27 of 78) for males. There was statistically no significant difference in the prevalence of entomolaris, paramolaris and C-shaped canals among male and female population. CONCLUSION: Failure to diagnose radix entomolaris, paramolaris and fused root may lead to missed canal and incomplete debridement of canal resulting in compromised treatment outcome. The successful endodontic therapy employed all the roots and canals to be located, cleaned, shaped and obturated.

PREVALENCE OF SUPERNUMERARY ROOTS OF PERMANENT MANDIBULAR TEETH ACCODING TO CONE-BEAM COMPUTED TOMOGRAPHY STUDY

1800 pre-made cone beam computed tomograms (CBCT) were examined, of which 202 CBCT were selected. It was revealed that a prevalence of three-rooted mandibular first molar was 2,5 %, second molars – 4,5 %. First molar supernumerary root was always distolingual root (radix entomolaris). Second molar supernumerary root was distolingual root in 2,5 % (radix entomolaris), in 2 % mesialbuccal root (radix paramolaris)., The prevalence of double-root in the mandibular first premolar was 2 %, in the second premolar was 1 %, in the mandibular canines was 5 %, the bifurcation was located in the apical and middle third root canals of canine and premolar, which makes endodontic treatment of such teeth as difficult as possible.

Biometric analysis of apical surgery-related anatomy of mandibular first molars: a cone-beam computed tomography study in a Mongoloid population

Objective To evaluate the apical surgery-related anatomy of two-rooted and three-rooted mandibular first molars (MFMs) in a Mongoloid population. Methods A total of 502 cone-beam computed tomographic images were used to evaluate the root configuration, the distance from the buccal bone to each root, root dimensions, and the complete root resection distance at the resection level for roots of MFMs. Results The prevalence of two-rooted and three-rooted MFMs was 85.1% and 14.9%, respectively. At the resection level, the distance from the buccal bone to the mesial and distal roots of two-rooted MFMs was 2.24 and 3.15 mm, respectively, while the distance was 2.44, 2.01, and 8.55 mm for the mesial, distobuccal, and distolingual roots of three-rooted MFMs, respectively. The distance from the buccal bone to each root was longer in men than in women. The largest distance for complete root resection was detected for the distal root in two-rooted MFMs and for the distolingual root in three-rooted MFMs. Conclusions The prevalence of three-rooted MFMs is common in the Mongoloid population. The distance from the buccal bone to root apex differs according to root configurations and sex. Surgical access to the distolingual root is difficult because of the long access distance.

Frequency and variation of three-rooted lower first permanent molars in precontact Easter Islanders and in Pre-Conquest Peruvians

The purpose of this study was to evaluate the prevalence of mandibular first molars featuring a distolingual root in two archeological collections. A total of 172 teeth from Pre-Contact Easter Islanders and 281 teeth from three Pre-Conquest Peruvian sites were examined looking for the presence of three-rooted lower first permanent molars (3RLM1). The Easter Island teeth were recovered during the Ahu Tongariki excavation Project 1993-2001: we identified 70 M1s, 62 M2s and 40 M3s. The sample contained 20 lower molars with an extra root, meaning that there is 29% with 3RLM1. The Peruvian teeth are from three archeological sites: Nasca (Proyecto Nasca, n = 100), Arequipa (Proyecto Condesuyos, n = 28), and Tablada de Lurín (Proyecto Loma de Lesix, n = 153). We found 8% of 3RLM1 at Nasca, 1.2% at Tablada de Lurín, and 9% at Condesuyos (total frequency = 6%). The percentage of 3RLM1 in Easter Island, very high compared to the whole Polynesia and the Peruvian sample, shows the effect of a genetic bottleneck (accidental reduction of a population), which the settlers went through as they reached the island they named Rapa Nui. We conclude that founder effect and genetic drift have played an important role in regulating the past and present mosaic distribution of 3RLM1 in insular populations.