Sinus augmentation with phycogene hydroxyapatite: histological and histomorphometrical results after 6 months in humans. A case series.

BACKGROUND: Phycogene hydroxyapatite is a biological hydroxyapatite derived from calcifying maritime algae, and is prepared by hydrothermal conversion by pyrolitical segmentation of the calcium carbonate of native algae into fluorhydroxyapatite. The aim of the present study was a histological and histomorphometrical evaluation, in humans, of specimens retrieved from sinuses augmented with phycogene hydroxyapatite, after a healing period of 6 months. CASE SERIES: Ten healthy patients with noncontributory past medical history (four women and six men, all nonsmokers, mean age 59 years, range 54-65 years) were included in this study. All patients were candidates for augmentation in the posterior maxilla in order to receive fixed restorations. The maxillary sinuses were filled with phycogene hydroxyapatite (Algipore®, Dentsply Friadent, Mannheim, Germany). Twenty-three implants (XiVE®, Dentsply Friadent, Mannheim, Germany) were placed in the augmented sinuses after a healing period of about 6 months. The bone cores were retrieved and were processed for histology. Most particles of phycogene hydroxyapatite were surrounded by a mineralized tissue, and the biomaterial particles had served as an osteoconductive scaffold. Most particles were bridged by newly formed bone characterized by the presence of large osteocytic lacunae, also around the phycogene hydroxyapatite particles, which appeared to be partially resorbed and substituted by new bone. No inflammatory cells or foreign body reaction cells were present around the biomaterial. No gaps were present at the bone-particle interface, and the bone was always in close contact with the particles. Histomorphometry showed that the percentage of newly formed bone was 35.2 ± 3.6%, marrow spaces 35.6 ± 2.3%, and residual grafted material 37.1 ± 3.8%. DISCUSSION: In conclusion, the present results support the literature findings that phycogene hydroxyapatite can be used, successfully, for sinus augmentation procedures.