A Dynamic Finite Element Analysis Of Stress Distribution In The Supporting Bone Of Mandibular Posterior Implant-borne Cantilever Fixed Partial Denture

ObjectiveA three-dimensional finite element model of a human mandibular molar implant-borne cantilever fixed partial denture has been established to investigate the stress distributions in bone tissue surrounding implants under transient dynamic loads, so as to provide theoretical references of biomechanics for clinical application of implant-borne cantilever fixed partial denture.MethodsA three-dimensional finite element model of mandibular molar implant-borne cantilever fixed partial denture and the corresponding periodontal substance was builded with CT scanning aided model building technology, Pro/E software and ANSYS software. Finite element analysis was performed on the model under dynamic loads in various directions and positions in a circle of mastication. The stress distributions were analyzed to study the biomechanical behavior of bone tissue surrounding implants.Results1 The three-dimensional finite element model was good in geometry and mechanics, which could serve for the needs of the three-dimensional stress analysis.2 In vertical loading and unloading phases, no significant difference of stress distributions in implant-bone interface was found between before and after the fixed prosthodontics (P> 0.05); in oblique loading stage, after the fixed prosthodontics, the stress in (?) implant-bone interface increased (P<0.05), in lingua loading stage, the maximum stress increased by 46.4% and 14.7% respectively, in buccal loading stage, the maximum stress in (?) implant-bone interface increased slightly while (?) increased by 162%.3 Longitudinal stress distribution in (?) implant-bone interface:the stress was concentrated on the cervical of cortica bone under different loading, where the maximum stress value was up to 156.489 MPa and 268.228 MPa respectively; followed by the junction of Cancellous bone and cortica bone, the maximum stress value was 51.987 MPa and 133.587 MP respectively; While the maximum stress value in the cervical of cancellous bone was 13.578 MPa and 27.488 respectively, which was the third biggest; apical stress was smaller, the maximum stress values was 5.592 Mpa and 6.351 MPa respectively; Smallest is the central of cancellous bone which maximum stress values were 1.832 MPa and 2.031 MPa respectively.4 Transverse stress distribution in (?) implant-bone interface:the Stress distribution varies with the loading time, Vertical loading and lingua loading phases, the stress was concentrated on the cervical of lingual cortica bone; buccal loading phase, the stress was concentrated on the cervical of buccal cortica bone; unloading phase, the stress was concentrated on the cervical of lingual cortica bone.5 After the fixed prosthodontics, oblique loading stage, the stress of (?) was concentrated on the cervical of cortica bone significantly, the maximum stress value was 156.489 Mpa and 268.228 MPa, which was 2.04 times and 3.44 times as Large as the vertical loading phase respectively.Conclusions1 After the implant-borne cantilever fixed prosthodontics, the stress was concentrated on the cervical of cortica bone; and the stress in root was smaller.2 the oblique loading affect the periodontal health most.3 The requirements for conditions of the cortica bone cervical of the abutment nearest to the Pontic are much higher than those of other abutment.