Correlation Research of Mandibular Third Molars' Crown and Root

Objective: Study the morphology of mandibular third molars.Methods: 200 specimens of the molars was studied on the crown height and the root length with clamp ruler,and the relationship between the numbers of dental cusp and the roots' shapes,and relationship between the increasing crown height and the roots changing complexities.Results: The crown average is 6.5 mm and root is length 11.2 mm in the mandibular third molars.The numbers of dental cusp increased possibley according to the height of the crown or the numbers of the cusps. Conclusion: The results suggest that the height of the crown and the numbers of the cusps should be checked carefully before the mandibular third molars are extracted.