Long-term follow-up of the use of nonporous hydroxyapatite for augmentation of the alveolar ridge. Particulate hydroxyapatite (HA) was used in the augmentation of 18 mandibular and four maxillary ridges in 21 patients whose cases were followed postoperatively for 5 to 7 years. Patients were evaluated clinically, radiographically, and through questionnaires. Prosthodontic assessment of retention and stability of dentures showed improvement 5 years postoperatively. Patients receiving HA rated their dentures favorably using parameters of the Cornell Medical Index. The results of this study show that particulate HA alone can be used as a satisfactory material for augmentation of the alveolar ridge. 