The Decision Of Third Molar In Mandibular Angle Fracture And Condylar Fracture And Its Three-dimensional Finite Element Analysis

Purpose It has been suggested that third molars increase mandibular fragility because they do not contribute to its strength.For ethical reasons,a human study design that would permit the elucidation of this interference is not possible.This study evaluated the impact of the presence of erupted third molars on the mandibular angle of resistance when submitted to trauma.MethodsThis study included 298 patients of which have the disease of mandibular fracture.The etiology,anatomical distribution,treatment modality and complications of maxillofacial fractures were examined.A three-dimensional(3D)mandibular model was obtained through finite element methodology using computed tomography(CT)with the geometry and mechanical properties to reproduce a normal mandibular structure.In the mandibular chin,we load the force of 2000 N horizontal direction to observe the bilateral mandibular stress distribution.Result In 298 cases of mandibular fracture patients,the proportion of male and female is about 6:1.28.9% patients are between 19 and 28 years old,and they get the highest incidence.The main reason for mandibular fracture is traffic accidents.Fracture is often associated with other parts of the maxillofacial fracture,the upper jaw fractures occurred in a higher rate,mandibular foramen area and condyle is the high-frequent site,for the rest is the body of mandible,mandibular angle and mandibular ramus.Mandibular angle fracture is easy to unoccur in the presence of the mandibular third molar,and the condylar fracture is easy to occur in the presence of the mandibular third molar.Approximated Von Mises equivalent stress of mandibular angle region was about 10 MPa higher in the mandible with teeth than in the mandible without teeth.In the condylar region it was 57 MPa when the third molar was present and 67 MPa when it was absent.Conclusion The digital models created proved that the mandibular angle becomes more fragile in the presence of third molars.When they are absent the energy concentrates on the lateral e posterior aspect of the condylar neck.