Influence of Flat Occlusal Splint on Stresses Induced on Implants for Different Fixed Prosthetic Systems.

Objective The flat occlusal plate has been recommended to reduce stress concentration in implant prosthesis treatments. The purpose was to investigate the influence of the occlusal splint on three-element implant-supported fixed prosthesis. Materials and methods A three-dimensional virtual model was created consisting of a cortical and spongy bone block simulating the region from first premolar to the maxillary first molar using two HE or MT implants (4 x 11mm) with Ti and/or Y-TZP abutments. The second premolar was the pontic of the prosthesis. The three-element fixed prosthesis with a zirconia infrastructure and Y-TZP coating were cemented, in addition to using a flat occlusal splint made of acrylic resin in the region. Combined axial and oblique loads of 100N and 300N were applied. Results The tensile stresses on MT implant bone tissue produced values of 4-19% lower than those of HE implants. The lowest differences were observed for oblique loading with an occlusal splint, with a 4% (Ti-Y-TZP) and 9% (Ti-Ti) decrease. When the compressive stresses were evaluated, HE implants produced lower values than MT implants. Conclusion A significant increase was observed in the oblique loading stresses in the absence of occlusal splints, regardless of the applied load.