Effect of different tilting angels of third molar on the stress distribution of the rigid fixed bridge in deletion of first molar and second molar in mandibular

Objective: To evaluate the influence of different tilting angles of the mandibular third molar on the stress distribution in the restoration,odontal tissue and periodontal membrane as bridge abutments after the restoration of fixed partial denture.Methods: Based on a 3-D finite element model of three abutments of the rigid fixed bridge in deletion of first molar and second molar in mandibular,evaluate the influence of the mandibular third molar with different tilting angles of 0°,10°,20°,30°and 40°on the stress distribution in the restoration,odontal tissue and periodontal membrane by a software named Ansys.Results: When the tilting angle of third molar was increasing,the max Von Mises stresses of the restoration,odontal tissue and periodontal membrane were increasing.When third molar tilted at 30°,the Von Mises stress peak value(9.11MPa) on the peridental membrane of third molar was 2.4 times than the normal third molar(3.81MPa).Conclusions: The tooth tilted more than 30°could not be selected as an abutment in the restoration of fixed partial denture,and the clinicians should lower the height of the cusp to reduce the oblique load of the abutment when fixed bridge was used as a treatment.