implants - international magazine of oral implantology International Edition

I research Figs. 3 & b_X400, H&E stained section showing NanoBone granules undergoing degeneration by osteoclast cells, surrounded by dense connective tissue with plentiful osteoblast cells. Figs. 4a–c_X100, H&E stained section showing numerous blood vessels in NanoBone graft. Figs. 5a & b_X100, H&E stained section showing numerous inflammatory cells, few blood vessels and few new bone formation in the Fisiograft group. Fig. 6_X400, H&E stained section showing less vascular vessels and large remnants of Fisiograft. Fig. 7_X100, H&E stained section showing small remnants of NanoBone graft. Figs. 8a & b_Showing NanoBone block immediately after augmentation (a) and six month after augmentation which was firm and strongly attached to natural bone (b). veloped vascular network. It is theorized that these os- teoblasts resorb phase 1 bone in a normal remodelling replacement cycle. As both the phase 1 bone and non- viableoriginalcancellousbonetrabeculaeareresorbed, bone morphogenic protein and IGF-I and IGF-II are re- lease. As with normal bone turnover, BMPs, IGF-I and IGF-II act as the link between bone resorption and new bone apposition. Such growth and differentiation fac- torsaredepositedintothemineralmatrixofbonebyos- teoblasts during osteoid production. Stem cells in the graft from local tissues and the circulation respond to the released BMPs, IGF-1 and IGF-II by osteoblast dif- ferentiationandnewboneformation.Thisnewphase2 boneformsasthejawandgraftinfunction.Itresponds to the demands placed on it and develops mature Havarsian systems and lamellar bone capable of with- standingthenormalshearforcesplacedonthejaw.The bone is capable of tolerating the forces typically of im- plantprostheticfunctions.Histologically,thegraftsen- ter a long-term remodelling consistent with normal skeletalturnover.Aperiosteumandendosteumdevelop aspartofthislongtermremodellingcycle.Thegraftcor- tex never becomes as thick as a normal jaw cortex, and the graft itself remains a dense, cancellous trabecular pattern.Thispatternisadvantageousinpromotingos- seointegration and is adaptable to a variety of func- tionalstresses.Overseveralyears,thegrafttakesonthe radiographic morphology and cortical outlines of a mandibleormaxilla. _Histological results DuringprocessingofNanoBoneandFisiograftsam- ples,wenoticedthatthesamplesofaugmentedbonedo not need more than ten days to be decalcified in EDTA whiletheremainingpart(normalbone)ofthebonecore stillcalcified.Amicroscopicanalysisatx100magnifica- tion allowed the author to observe numerous miner- alised areas of newly formed bone of various sizes, which were scattered in all the NanoBone group (Figs. 1–3), and limited in the Fisiograft group (Fig. 5). These bone areas were surrounded by an osteoid layer com- posed of osteoblasts, which synthesize the organic componentoftheextracellularmatrix(theosteoidsub- stance)andcontrolitsmineralization.Microscopicob- servationofthesampleathighermagnificationshowed some osteoclast cells were found near the remaining spiculesofthebonegraft,multipleosteoblastsandnu- merous osteocytes situated within well-defined lacu- nae(Fig.3).Insomeareas,newbonecontainedsmallis- lands of residual bone graft; these could be distin- guished from live bone by empty osteolytic lacunae (Figs. 5–7). They were showing signs of continuous re- sorptionbyosteoclastsandsimultaneousdepositionof bone.ThepresenceoflargeamountFisiograftremnants wasseeninallgroupsections(Fig.6),whileinNanoBone group specimens the NanoBone graft remnants were few and at the periphery of the specimens (Fig. 6). The presence of blood capillaries, defined by endothelial 24 I implants4_2013 Fig. 3a Fig. 3b Fig. 8a Fig. 8b Fig. 4a Fig. 4c Fig. 5a Fig. 5b Fig. 4b Fig. 6 Fig. 7