Biomechanical Study On The Effects Of Occlusal Contact Types Of First Molar And Angulation Of Dental Implantation On The Implant-Prosthetic

Objective:The purpose of this article was to use three-dimensional finite element method to analyze the stress distribution transmitted by a ceramic crown contacting with tooth in the upper jaw by seven types(ABC、AB、AC、BC、 A、B、C)and associated with an implant placed at different inclinations (0,5, 10,15,20 degrees) in the first molar region of the mandible ridge. And to find a appropriate type for angle abutment.Method and materials:A volunteer’s mandible missing 36 teeth scanned by CBCT, the implant and the prosthesis were been imported in ANSYS program to establish a 3-dimensional finite element model. The model include the mandible, the implant with five angle abutments, the upper prosthesis with seven contacted types and the tooth in the maxilla. Loading the vertical load of 178N on the mandibular-bone.We compared the Von-Mises stress distributions on the prosthesis,implant,mandible and the tooth.Results:1. the contacts in the first molar(Class I) of the mandible were been recorded.ABC type accounted for 20%,AB type accounted for 10%,BC type accounted for 40%,B type accounted for 24%,AC type accounted for2%,A type accounted for 4%.There is no c type in the Class I.2.1n each angle abutment,The Von-mises of crown contacted types of ABC^ AB、BC are the lowest,B、AC、A are second, C is the highest. From 0°to 20° abutment,The Von-mises of crown are largely unchanged under 15° angle abutment. From the stress nephogram, the loading area as the center, according to the strengths of local force, is to expand the area radiate out around.3.In each angle abutment,The Von-mises of implant in seven types(ABC> AB、AC、BC、A、B、C)little changed except types of A,B and C in 0°abutment. From 0°to 20°abutment,The Von-mises of implant Showed a mild downward trend.4.In each angle abutment,The Von-mises of mandibular-bone in seven types(AB、AB、AC、BC、A、B、C)little changed except types of A and C in 0°abutment.From 0°to 20°abutment,The Von-mises of mandibular-bone Showed a mild downward trend.5. The periodontal ligament hydrostatic pressure and the Von-mises of tooth no significant change in each angle abutment with B+type.Conclusion:The contacts with B+type are more suitable for the angle abutment applied on the Lingual inclination implant. With the increase of angle of abutment,The Von-mises of crown are largely unchanged under 15° angle abutment. The Von-mises of implant showed a mild downward trend. The Von-mises of mandibular bone showed a mild downward trend. The periodontal ligament hydrostatic pressure and the Von-mises of tooth no significant change in each angle abutment with B+ type.