Collagen/hydroxylapatite implant for augmenting deficient alveolar ridges: a 24-month clinical and histologic summary

A new alveolar ridge augmentation material composed of purified fibrillar collagen (PFC) and particulate hydroxylapatite (HA) (Alveoform Biograft, Collagen Corp., Palo Alto, Calif.) was evaluated in the treatment of 77 edentulous patients in a multicenter study. All patients had mandibular augmentation; 22 also had maxillary implant augmentation. Mean ridge height was 15.4 mm before surgery. Twenty-four-month data showed a mean ridge augmentation of 4.1 mm. Prosthodontists rated the ridge firmness "good" to "excellent" in 96.6% of patients after 2 years. All adverse effects with the exception of some residual paresthesia/dysesthesia resolved spontaneously within 24 months. Bone-graft interface samples were examined histologically in five patients 1 year after mandibular ridge augmentation. No evidence of PFC was found, and the HA particles were surrounded by dense, fibrous, host-connective tissue or trabeculae of woven and lamellar bone. Assessment of PFC/HA-augmented ridges at 24 months showed clinically and histologically significant results.