Effects of lateral and frontal forces on the tilted implants in the atrophic mandible by using finite element analysis

The aim of this study is to analyse the stress of lateral and frontal forces on the vertical, 17 and 30 tilted implants placed in the interforaminal region of atrophic mandible by using finite element analysis in order to determine the possible effects on mandibular fracture. The edentulous atrophic mandible using cone beam computed tomography with DICOM format was used. Three dimensional (3D) model and computer aided design (CAD) model were created by using MIMICS and Geomagic 3D softwares, respectively. Implants in diameter of 3.75 mm and 8,10,12,15mm length were inserted in to the mandible by using SOLIDWORKS software. The vertical,17 and 30 tilted implants were placed into mandible. After determining nodes and elements number by using ANSYS software, 10 MPa lateral and frontal static forces applied for 1 second. The maximum equivalent stress of implants and maximum equivalent strain of bone were recorded. On lateral force, the maximum equivalent stress was greater in 30 bicortical implant in the opposite site, while on frontal force the maximum equivalent stress was greater in 30 monocortical implants. The maximum equivalent strain was greater in 30 monocortical model on lateral force and in 30 bicortical model on frontal force. We concluded that higher stress levels at the bicortically placed implants created by both forces and at the increased angulation of implants caused by frontal force could be risk for mandibular fracture.