Healing of mandibular ridge augmentations using hydroxylapatite with and without autogenous bone in dogs

Dog mandibles were augmented with either hydroxylapatite (HA) alone or HA combined with autogenous bone. Within the limited time frame of this experiment (16 weeks) the group which received HA alone did not demonstrate the induction of bony ingrowth further than 1-2 mm into the augmented ridge. However, the animals augmented with HA combined with autogenous bone demonstrated an active, lamellar-type bony ingrowth, maturing bony haversian systems, and vascular elements forming throughout the entire area, extending to the overlying soft tissue interface. The clinical assessment of both types of augmented ridges (HA and HA and bone) were similar; both formed hard, firm ridges at approximately the same rate. This observation is consistent with human clinical experience with HA or HA mixed with bone. However,for patients who have severe mandibular atrophy and for whom increased mandibular bony bulk is crucial, a combination of HA and bone should be advantageous because of the increased extent of bony ingrowth.