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Immediate loading of newly placed dental implants is a consideration when attempting to meet patients' demands. However, immediate loading may induce implant failure to osseointegrate, particularly in the case of a patient who can generate a biting force that can reach approximately 1300 Newtons (N) in the posterior jaws. The range of biting forces that prevent osseointegration of newly placed implants is currently unknown. However, it is suspected that osseointegration may fail if an implant is luxated in bone more than 50 µm, in which case fibrous tissue will be formed instead of bone. This pilot study was focused on finding the amount of horizontal off-axial force required to move a nonosseointegrated 4.3 × 13-mm implant 50 µm. The initial data show that the amount of horizontal force required to displace such an implant by 50 µm was on the order of 150 N. Assuming that the angle between the direction of the biting force and the vertical lies between 0° and 20°, our data show that a 4.3 × 13-mm implant may fail to osseointegrate for biting forces that are as low as 440 N. One implication of our study is that implants having smaller diameters may move and fail to osseointegrate for even lower biting forces.
Key Words: luxate dental implant
INTRODUCTION
Edentulous dental patients are generally disappointed when they learn of the long healing period required for osseointegration of a dental implant. They have been known to apply verbal pressure to the treating dentist to speed treatment time so that their new implants may be able to function sooner. There have been studies that examine the success of immediately functionally loaded implants.1 Implant immobility is necessary for proper osseointegration to occur. It may be the case that if a healing implant undergoes a micromovement (displacement) larger than 50 to 150 µm, a microhemorrhage may occur, which induces subsequent fibrous growth that may cause failure of the osseointegration of the implant.2
The occlusal forces generated by the jaws are more powerful in the posterior than the anterior area. Forces in the molar area are in the range of 244 to 1243 Newtons (N), while the anterior forces are generally about a third of that.3-5 During function, the jaws impart a load...