Introduction: Impaction is defined as failure to erupt completely into a standard functional position of tooth within normal time.Mandibular nerve is one of the terminal branch of fifth cranial nerve.The main function of nerve is to supply general sensation within the head and is related to parasympathetic fibres of other cranial nerves.Extraction of impacted or erupted mandibular third molars (M3s) is one of the most frequently performed dentoalveolar surgical procedures.Preoperative radiographic assessment of the proximity of inferior alveolar nerve and lower third molar becomes a important measure before surgical removal of impacted mandibular third molars.The aim of the present study is to find out the Prevalence of age and sex in mandibular nerve impaction in lower 3rd molarlMaterials and Methods: This retrospective radiographic study was conducted among patients of saveetha dental college,Chennai during the period between October 2020-February 2021.A total of patient records were reviewed and analysed. 918 OPG’s of patients were evaluated out of which 268 were having an impacted 3rd molar in which 136 were male and 132 were female. Inclusion criteria include both male and female population,patients aged between 19 and 60 years.The data was tabulated and analysed using IBM SPSS version 23.0 software.Pearson’s Chi Square Test was used to assess the association between side of the lower jaw frequently affected and difficulty index of impacted third molars. Results And Discussion: There also seemed to be a significant male predilection (54.17%) and predilection towards the left side of the lower jaw (52.08%) presenting with Position C impacted third mandibular molar.The overall mean distance from the impacted mandibular third molars to the inferior alveolar canal was 0.50 mm. Most of the samples (61.8 %) extended beyond the superior border of the inferior alveolar canal with a mean distance of 4.40 mm. Mesioangular impactions were found to be in the close proximity (1.34 mm) to inferior alveolar canal than any other type. Interruption of the white line was the only statistically significant radiographic risk predictor sign p > 0.05 that indicates the close proximity of impacted mandibular third molars to inferior alveolar nerve canal. Conclusion: From the present study,we can conclude that assessment of third molars in terms of its position and level in relation to gender and arch is necessary to assess the difficulty level.Within the limits of the study,there is a significant male predilection with a prevalence of 17.01% in distoangular impaction in relation to the position of inferior alveolar nerve canal approximation and the incidence being least (5.2%) among female population with respect to crown fracture and mandibular nerve damage.

Impacted third molar, Inferior alveolar nerve, Mesioangular impaction, Distoangular impaction ,Orthopantomogram.