Finite Element Analysis Of The Influence Of The Buccal And Lingual Offset Placement Of An Implant On Stress Distribution

ObjectiveIn clinical practice, due to topological conditions of the posterior region, occlusal relationship and limitation of mouth opening of the patients and other aspects, the implants can not be inserted in a suitable buccolingual position, which may produce localized excessive stress in the implant-bone interface, thus the long-term successful rate of the implant prostheses is affected. From biomechanical point of view, this study investigated the influence of different buccolingual position of an implant on Von-Mises stress distribution of implant-bone interface, in order to obtain a suitable buccolingual position of the implant and provide theoretical basis for clinical implant placement. MethodsA series of three-dimensional finite element models of partial mandible which includes implant-supported mandibular first molar was established by using reverse engineering modeling and digital parametric modeling. The occlusal relationship between the crown and the opposite teeth was unchanged in each model, the position of the implant was moved from central to buccal and lingual respectively. The vertical and 45° lateral load of 235 N were applied on the crown of the models, the distribution of stress of implant-bone interface in each model was analyzed. Results1. The finite element model of partial mandible with implant-supported mandibular first molar was constructed, and on this basis 9 three-dimensional finite element models of implant in different buccolingual position were created.2. Under the vertical loading, the maximum equivalent stress of the implant and the cortical bone was detected at the buccal of implant combined with alveolar ridge crest; Under the oblique loading, the maximum equivalent stress of the implant and the cortical bone was located on the lingual of implant combined with alveolar ridge crest. The equivalent stress of the cancellous bone was mainly distributed in the neck and root of the implant, and the maximum equivalent stress values were less than the maximum equivalent stress values of the cortical bone.3. Under the vertical loading, the trend of the peak stress in implant-bone interface was gradually decreasing as offset placement of the implant from lingual to buccal; While under the oblique loading, the trend of the peak stress in implant-bone interface was increasing by degrees as offset placement of the implant from lingual to buccal. And the peak stress values were greater under the oblique loading when compared with the vertical loading(except for the position of M1). Conclusion1. The stress distribution of implant-bone interface can be significantly altered by buccally and lingually offset placement of the implant, there is an increased risk of stress no matter buccal or lingual offset placement.2. It is suggested that the oblique force and cantilever can be avoided or reduced when formulating implant restoration program in clinical work.