Porous hydroxylapatite (PHA) blocks and granules were used in the augmentation of 30 maxillary and mandibular ridges in 28 patients. The postoperative evaluation period was 2 years in all cases. The patients were evaluated clinically and radiographically, and by patient questionnaires. An increased incidence of dehiscence was noted with the blocks as compared with the granules. Overall prosthodontic assessment showed 95% improvement among the granule cases when compared with the preoperative ridge, and 88% improvement noted among the block cases. Patient rating of their general satisfaction with their dentures showed 82% improvement in the granule patients, and 55% in the block cases. Radiographically, the granules showed an average decrease in augmentation area of 10%, and the blocks showed an average decrease of 8%. The results of this study show that PHA granules can be used as satisfactory alveolar ridge augmentation material, while the blocks show an increased number of complications and should be used only in very selected cases.