Background: Dental implant therapy has become an accepted and predictable treatment modality for replacement of missing teeth. Anatomical features such as lingual undercut is common finding in the posterior mandibular region which is difficult to manage at times. This computer simulation study investigates incidence of lingual plate perforation in posterior mandibular edentulous first molar region and the risk of perforation in the area of lingual concavity by virtual implant placement. Methods: 102 CBCT were selected from the image database. Implants of different dimensions were placed using computer software and proximity between implant tip and lingual plate was measured using digital calliper for three types of mandibular cross sectional morphology (undercut(U), parallel(P) and convergent(C)) to assess incidence of lingual plate perforation. Results: 110 sites were available for analysis. The overall probability of perforation was 1.3% to 1.4%. Most implants which were within 1 mm from lingual plate occurred in sites with lingual concavity in type U–ridge. Conclusion: With proper diagnosis and treatment planning with the help of CBCT, most implant surgeries can proceed uneventfully and fulfill functional and esthetic demands.