Evaluation of the stress distributions of the treatment options with 2 implants for 4 missing maxillary incisors with finite element analysis

The aim of this study is to evaluate the stress distributions in the bone level, implant and prosthesis parts with three-dimensional (3D) finite element analysis (FEA) in treatment options obtained by using two implants in different positions and different diameters in the four missing maxillary incisors region. Four 3D FEA models were obtained simulating the human maxilla with anterior 4 missing teeth. It is an in vitro study evaluated only by performing FEA with a computer program. Model 1 (M1): 4.3mm diameter implant to 2 central incisors regions, Model 2 (M2): 4.3mm diameter implant to 2 lateral incisors regions, Model 3 (M3): 3.3mm diameter implant to 2 lateral incisors regions and Model 4 (M4): 4.3mm diameter implant to central incisor region, 3.3mm diameter to lateral incisor region. Titanium implants and titanium abutments were used. Four-unit monolithic zirconia cemented fixed partial prostheses were designed on them. An oblique force of 100N was applied to the cingulum of each tooth on the prosthesis at an angle of 45 degrees to the long axis. The data obtained by performing FEA on the stress values in the implants, prosthesis parts and bone were evaluated. Maximum and minimum principal stress in the bone tissue was observed most in model 3 and least in model 1. Von Mises values in the abutment, implant, screw and prosthesis were highest in model 3. According to the obtained stress values, it may be considered the best option to place a standard diameter implant where the central incisors are in the anterior region in order to reduce the stress on the bone. Treatment with a narrow-diameter implant with lateral incisors can be avoided.