Objective: To investigative the influence of immediate loading on the stress distribution around dental implants with reductions in buccal cortical bone thickness.
Materials and Methods: Three bone level dental implants (3.8mm, 4.5mm and 5.0mm diameters and a standard length of 10mm) were modeled and each placed in three mandibular bone segments having variations in buccal cortical bone thickness (2.0mm, 1.5mm and 1.0mm). A total of 9 such models were created and discretized with tetrahedral elements of parabolic displacement function. Implant-bone interface was simulated with non-linear contacts zone with friction. Implants were assumed to be placed at an insertion torque of 40Ncm and the fixation force was mathematically calculated for each of the three implants. A uniformly distributed vertical static load of a 150N was applied to the horizontal surfaces of the abutments. The overall stress distribution of von Mises criteria and micro-strain were recorded along the contact areas of implant and surrounding bone and statistically analyzed.
Results: At an insertion torque of 40Ncm the pre-load calculations indicate a reduction in the compressive stresses as the diameters of the implants increase with fixation forces of 93.14N, 83.49N and 75.49N for the 3.8mm, 4.5mm and 5.0mm diameter implants. The maximum stresses were seen in the upper one third of the buccal cortical bony plates which tends to reduce as the diameter of the implant increases. The peak von Mises stresses were 173MPa, 126MPa and 98MPa for the 3.8mm, 4.5mm and 5.0mm implants. The total maximum mesh displacement seen for the 3.8mm, 4.5mm and 5.0mm models was 55