Introduction: Variation in growth pattern in different facial forms affect the space available for tooth eruption, therefore the mandibular third molar impaction has correlation with different skeletal facial types.Objective: To determine the position of impacted mandibular third molar in different skeletal facial types in Nepalese samples.Materials & Method: This cross sectional study was carried out on pre-treatment lateral cephalogram and orthopantomogram records of 207 orthodontic patients visiting Kantipur Dental College and Hospital. Age range of the sample was 16-33 years. Various facial forms were determined with the help of mandibular plane angle (SN-GoGn); for which Nemoceph software was used. Beta angle was used to determine the angle of impaction of mandibular third molar. Impaction pattern was classified as per Pell & Gregory and Winter’s system. SPSS version 20 was used for statistical analysis.Result: Overall rate of mandibular third molar impaction was 63.77% (11.11% unilateral and 52.66% bilateral impaction). The most common type of impaction bilaterally was mesioangular based on Winter’s classification, Class II Position B based on Pell & Gregory’s classification. Higher rate of mandibular third molar impaction was found in dolichofacial type of face (49.2%).Conclusion: Decreased mandibular third molar impactions are seen in brachyfacial type compared to mesofacial and dolichofacial types

Maxillary first molar is one of the longest standing teeth in the dental arch which serves as a key of occlusion 1 and anchorage in most of the orthodontic treatments.However, they are susceptible to various insults such as dental caries, attrition etc. The tooth is very important in masticatory process and overall balance of the occlusion; hence it is strategically important to maintain the tooth in dental arch as far as possible, which often requires endodontic treatment.Success of endodontic treatment is attributed to adequate cleaning, disinfecting, shaping, and three dimensionally sealing the root canal system.2 The process is routinely challenged by the complexity of root canal morphology. Knowledge of root canal morphology is a key factor which aids in successful treatment outcome. A total of 72 scans with the presence of 115 permanent first molars on either one side or two sides of the maxillary arch were selected based on the inclusion criteria. The subjects selected were within the age range of 16-60 years. The scans were excluded if the tooth had incomplete root development, fused root, developmental anomaly, endodontically involved or obturated root canal, crown restoration, root resorption or gross loss of coronal tooth structure. Blurred or unclear images were also excluded.The data were anonymized before evaluation. The data was recorded in excel sheet and was statistically analyzed using SPSS 20 software. Statistical tests were done by using chi square test to check the association between M2 canal and gender and arch side. Independent t-test was used to compare the statistical difference between distance between the canals and gender. Level of significance was set at p<0.05.Kappa test was done to check the inter-observer reliability between the oral radiologist and endodontist. Cronbach alpha test was done to check the inter-observer reliability in measuring the distance between MB1 and MB2 canals. Vertucci's Classification of root canal morphology Type Description ConfigurationType I A single canal from pulp chamber to the canal terminus 1-1Type II Two separate canals leaving the chamber but merging short of the canal terminus to form a single canal 2-1Type III A single canal that divides into two and subsequently merges to exit as one 1-2-1Type IV Two distinct canals from pulp chamber to the canal terminus 2-2Type V A single canal leaving the chamber and dividing into two separate canals at the canal terminus 1-2 Type VI Two separate canals leaving the pulp chamber, merging in the body of the root, and dividing again into two distinct canals short of the canal terminus 2-1-2Type VII A single canal that divides, merges and exits into two distinct canals short of the canal terminus 1-2-1-2Type VIII Three distinct canals from pulp chamber to the canal terminus 3-3 The study revealed that 30.4% of maxillary first molars showed the presence of MB2 canal in mesiobuccal root.The most common canal configuration was Vertucci's Type I (60.9%), followed by Type II (19.1%), Type IV (7.8%) (Graph 1). There...