This study was conducted to provide an understanding of the biomechanical behavior of
different diameters MDIs and compare it with conventional diameter implants when supporting
an overdenture . Three different models were designed .The first model has two standard diameter
implants (3.8x12mm) (D1), the second (D2) has 2 mini-dental implants (2.4x12mm) and the third
model (D3) has 2 of ultra-small diameter (1.8 x 12mm) all implants were placed at canines region.
3D finite elements stress analysis was performed to evaluate biomechanical situation in both the
implants and the peri-implant bone under vertical and oblique loading of the overdentures. It can be
concluded that the stress values affecting the peri-implant bone and the implants are reciprocal to
dental implant diameter and the use of MDIs as overdenture abutments should be limited to cases
with limited bone quantity.