Finite element analysis of mini implant biomechanics on peri-implant bone

Mini dental implant whose diameter is between 1.8 and 2.4 mm is a dental implant design currently implemented as bone screw in in orthodontics, as support for denture, and in situations when smaller diameter implant is the feasible option. Biomechanics of the peri-implant bone inserted by mini dental implant is of interest in this study where relevant studies are lacking. This study was intended to investigate using finite element analysis the induced stress and strain on peri-implant bone when a mini dental implant is loaded. The thread pitch of the mini dental implant and the peri-implant bone type were varied, with a constant loading (100 MPa pressure) applied on the mini implant. First, the mini dental implant with three different thread pitches (0.5 mm, 1.0 mm and 1.5 mm) were inserted into a type II bone. It was found that the higher the thread pitch, the higher the maximum stress (increased from 53.2 to 78.6 MPa) and the less distributed the stress on the peri-implant bone. Next is a mini dental implant with 1.0 mm thread pitch was inserted into peri-implant bone types II, III and IV. When the bone type changes from II to III, the maximum stress becomes lower (from 57.8 to be 51.7 MPa) but more high stress was distributed in the cortical bone. The strain was more than doubled (from 0.82 to be 1.76%) on the cancellous bone. When the bone type changes from III to IV, the maximum stress was doubled (from 51.7 to be 104.8 MPa) and more high stress was distributed over the cortical bone. In cancellous bone, the maximum stress was lower (from 9.1 to be 5.3 MPa), but the strain increases almost three folds (from 1.76 to be 5.07%)