Endosseous titanium implants during and after orthodontic load--an experimental study in the dog

An experiment was carried out to determine whether endosseous titanium implants (Brånemark) retain their clinical stability throughout a 26-week period of continuously applied force (2 N) and what kind of marginal peri-implant bone changes occur in the process. For this purpose 6 premolars (P3: mandible/maxilla and P4: mandible) were extracted from each of 2 foxhounds, and 12 implants (6 per dog) were positioned in the edentulous maxillary and mandibular areas after the alveolar healing period. Following a 25-week implant healing period, 8 fixtures (P3 areas) were used as anchoring elements for distalization of the 2nd premolars over a period of 26 weeks; 4 implants served as a control group (P4 areas of the mandible). There were no clinical or histological signs of implant dislocation after the load application period. In the presence of mild peri-implant gingivitis, no increase was found in the incidence of marginal bone resorption adjacent to the loaded implants compared with the non-loaded implants. In the absence of marginal resorption, subperiosteal bone apposition was detected especially around the test implants in the mandible. This suggests that endosseous titanium implants are suitable as anchoring units for longer-term orthodontic tooth movements. The applied force may moreover induce marginal bone appositions adjacent to the implants.