implants - international magazine of oral implantology International Edition

overview I I 29implants4_2013 Fig. 4a–f_Common augmentation materials: a) bone chips from the implant bed, b) bone mill for particularization of blocks, c) bone scraper, d) commercial biomaterial. Fig. 5_Bone harvesting sites in the jaw: metal, Crista zygomaticoalveolaris and Tuber maxillae; Linea oblique of the mandibula and the angle of the jaw. characterized as: autologous (fresh or frozen), allo- geneic (e.g. DBM "demineralized bone matrix"), and xenogeneic.Importantmaterialpropertiesconcerning bone healing are pore size and interconnectivity, re- sorbability without severe inflammation and macro stabilityofparticlematerial.74 Someofthesefactorsare evaluatedscientificallylikeporesizesandsurfaceprop- erties,whileotherfactorsaremostlyclinicallybasesex- periences like macro stability.29.30 Materials can be fur- thercharacterizedbytheirpotentialtoinfluencebone healing:6 osteoconductive (promotes bony ingrowth); osteoinductive (induces bone tissue generation by re- ceptor-mediated cell activation); osteogeneic (mater- ial contains living bone cells or bone cell precursors). Most common particulate materials are bone chips fromtheimplantsite,milledboneblocks,scrapedbone chips, mesh grafts with alloplastic materials (Fig. 4). Growth factors and tissue engineering are future op- tionincompromisedbonehealingandcomplexrecon- structive surgery.18,22,39,41,44-47, 75-81 Conceptional prob- lems arise, if these novel techniques concerning cost and carcinogenic risks of growth factors are not ad- dressed.18,22,45,45,47,76,82,83 Dentalimplantologytherefore offerslimitedindicationsfortheseoptions. Donorsitesforbonetransplants Choosingtheappropriatedonorsiteforbonetrans- plantsisthesecondstepafteranalysisofthedefectand augmentation planning. Most common donor sites are:74 –Mandible (chin,angle,lineaobliqua,corpusmandibulae)84 –Maxillary (tuber,spinanasalis,cristazygomaticoalveolaris) –Calvaria(tabulaexterna) –Pelvicrim –Tibia. Local donor sites are of special interest for applica- tions in oral and maxillofacial surgery. Intraoral donor sites are shown to be less painful for patients (Fig. 5).85 Bigdefectsrequireextraoraldonorsitesmostlyfromthe pelvicrimregion.Qualityandhealingpropertiesofvar- ious bone transplants concern their ontological origin inparticular.Whilelocalskullboneisbranchialtissueof mesektodermal origin, pelvic and most other bone transplants are mesenchymal tissues.25-28 Mandibular bone is the most common transplant in dentistry with severaldonorregions:chin,lineaobliqua,angle,corpus mandibulae, lingual exostosis.69, 74 ,85, 86 Bone is har- vested as a block for either immediate transplantation or generation of particles in a bone mill or similar de- vice.84, 87 Usingascraperisamodernwayofdirectlygen- eratingbonechips.87 Thechinregionbearsmoredonor site morbidity problems due to the mental muscle at- tachment and should be limited to augmentations in thesameregiontoavoidasecondsurgerysiteorother seriousindications.85 Thelineaobliquaareaoffersaver- satile donor site with limited risks and complications if the anatomyofthealveolarnerveis carefully evaluated.74 The area of the mandibular angle is an- other site in the same area and similarly difficult with risks for thelocalnervelikethelingualex- ostosis. The maxilla offers only limited amounts of bone mate- rial. However, using tuber bone orscrapingchipsfromtheante- riorwallincombinationwithsinusliftsurgerycanbethe right option.Harvesting bone from the pelvic rim is the method of choice for most indications requiring large amounts of autologous bone due to limited risks and goodapproach.88-90 Thereisananteriorandaposterior approach.88, 89, 91 It is discussed that the rarer posterior approach is offering more bone and less morbid- ity.88, 89, 92 Complications of this donor site are pain, bleeding, nerve lesions (N. cutaneus femoris lateralis), andfracturesofthepelvicbone.88 _ Editorial note: To be continued in implants 1/2014 with osteotomy and complex bone augmentation techniques. Acompletelistofreferencesisavailablefromthepublisher. Prof.Dr Dr Florian Draenert Devissi Implantology Institute Xaver-Weismor-Str.60a 81829 Munich,Germany Tel.:+49 160 6127828 draenert@floriandraenert.com _contact implants Fig. 4a Fig. 4b Fig. 4c Fig. 4d Fig. 4fFig. 4e