Histomorphometric assessment of bone formation in sinus augmentation utilizing a combination of autogenous and hydroxyapatite/biphasic tricalcium phosphate graft materials: at 6 and 9 months in humans

Bone Graft Packing and Its Association with Bone Regeneration in Maxillary Sinus Floor Augmentations: Histomorphometric Analysis of Human Biopsies

Research in maxillary sinus floor augmentation (MSFA) focussed on the optimisation of microstructural parameters such as microporosity and particle size of bone substitute particles (BS). However, little is known about the impact of BS packing and the corresponding (void) interparticular space on bone regeneration. The aim of this study was to characterise the spatial distribution of BS and its association with BS integration 6 ± 1 months after MSFA. Histological thin-ground sections of 70 human sinus biopsies were histomorphometrically analysed: In serial zones of 100 µm proceeding from the sinus floor (SF) up to the apical end of the biopsy, we measured the distribution of BS particles within these zones in terms of volume (BSV/TV), number and size of BS particles, interparticle spacing (BS.Sp) and bone-to-BS contact. BS particles were not homogeneously distributed over the length of biopsies: The first 200 µm directly adjacent to the SF represented a zone poor in BS particles but with high osteogenic potential. Graft packing density increased from the SF towards the apical part of the AA. Integration of BS particles was inversely associated with the distance to the SF and the graft packing density. A high packing density through excessive compaction of BS particles should be avoided to optimise the macrostructural environment for bone regeneration.

Osteoconduction and Bioresorption of Bone Allograft versus Anorganic Bovine Bone Xenograft: A Histomorphometric Study in Humans

This clinical study evaluated the tissue repair process using different bone grafts. Nine dental patients with indication for posterior implantodontic treatment were submitted to maxillary sinus lifting procedures associated to grafting. After 6 months, bone biopsies (6 sites with allogenous bone grafting and 13 sites with bovine xenogenous bone grafting/OsseusTM) were removed and processed for histopathological and histomorphometric analyses (ANOVA and Tukey's test). Both groups had tissue biocompatibility without significant inflammatory response, only punctual presence of multinucleated giant cells in xenograft group. Osteoconductive potential was evidenced by new bone tissue surrounding and in direct contact with the granules of both grafts. Volume density of connective tissue was similar between groups, although there were significant differences in allograft group in comparison to xenograft as the presence of new bone formation (48.50%±13.93 versus 29.83±9.56, respectively, p<0.05) and remnant biomaterial (1.57±2.39 versus 22.23±12.41, respectively, p<0.001), suggesting a greater osteoconductivity and faster bioresorption in the allograft group. These results demonstrate that allogenous bone and OsseusTM can be satisfactorily used as grafts in minor oral surgeries for bone augmentation in humans.