Effects of callus and bonding on strains in bone surrounding an implant under bending.

Descriptions of the healing and adaptation of endosseous implants have been provided; however, their effects on mechanical parameters such as maximum and minimum principal strains, strain energy density, and maximum shear strain have not been addressed. Three linear, elastic, and partially anisotropic finite element models were generated to simulate the immediate postoperative period, time of provisional loading, and long-term adaptation of bone surrounding implants. In each model, unbonded and bonded interface conditions were imposed. Bone geometry was estimated from dental implants placed in femurs of hounds. A lateral load was applied and the mechanical parameters were calculated. Interface bonding decreased the peak minimum principal strain 2.6 to 6.4 fold, while the presence of a callus reduced it 3 to 7 fold. These data document the critical stabilizing roles of callus and bond formation.