Biologic Response of Immediately versus Delayed Loaded Implants Supporting Ill-Fitting Prostheses: An Animal Study

Abstract

This study indicates that prosthesis misfit does not per se lead to biologic failure of immediately loaded or of already osseointegrated implants. In addition, immediately loaded implants seem to topographically adapt to the prosthesis, thereby minimizing the existing misfit.

The Precision of Fit of Milled Titanium Implant Frameworks (I‐Bridge®) in the Edentulous Jaw

“…The misfit of prosthesis unavoidably affects the preloads in the screw joints and in the bone surrounding the implants 27–29 . On the other hand, animal studies have not been able to prove that misfit of 1000 or 500 µm, per se , negatively influences the osseointegration and bone remodeling at implants 30,31 . Instead, the preload in the screw joint seems to be of more importance than the magnitude of the misfit with regard to the bone response 29 .…”

“…Because no long‐term studies are available on prostheses connected to the implants, the consequences of this potential risk of higher stress levels due to misfit on the implant‐bone interface are unknown. However, short‐term static load of implants in animal models has not negatively influenced the osseointegration and bone remodeling at implants 31,41,42 . Duyck and colleagues tested in a rabbit model immediate loading and conventional loading of implants connected to prostheses with a vertical misfit of 500 µm.…”

“…Duyck and colleagues tested in a rabbit model immediate loading and conventional loading of implants connected to prostheses with a vertical misfit of 500 µm. The immediately loaded implants were displaced toward the prosthesis, thus reducing the gap during healing, and no difference in biologic response was registered 31 . Controversy on whether a framework with “poor” fit, including microgaps, is responsible for any adverse biologic effects still exists.…”

Stress distribution in fixed-partial prosthesis and peri-implant bone tissue with different framework materials and vertical misfit levels: a three-dimensional finite element analysis

“…Previous studies performed in primates (9) and rabbits (10,30,31) evaluated the consequences of different levels of vertical misfit on the peri-implant bone tissue. However, these studies had some limitations; it was impossible to evaluate the influence of vertical misfit when under occlusal loads (16) and the consequences in the prosthetic structures, which are important factors in the success of treatment.…”

Direct High‐Frequency Stimulation of Peri‐Implant Rabbit Bone: A Pilot Study

“…11,12 Ossification of regenerating tissue is only possible in case of a low hydrostatic strain environment and in the absence of shear strain. Both animal experiments 21,22 and clinical studies 12,[23][24][25] have shown that immediately loaded oral implants acting as support for a prosthesis can osseointegrate provided that the forces and implant micro-motion are controlled. 14 Premature implant loading can promote early peri-implant osteogenesis [14][15][16][17][18] in case of limited interfacial micromotion and an optimal biomechanical coupling between the implant and the surrounding tissues.…”