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implants - international magazine of oral implantology

research I I 21implants1_2013 penetrateintothescaffoldinvitroandthenvasculari- sationtooccurinvivo.6 Itshouldalsodegradeatasuit- able rate to match the rate of tissue formation.7 How- ever,micron-sizedhydroxyapatite(HA)particlesmight leadtoalowresorbabilityandfragileconstructs.8 Over- coming the constraints in applying calcium phosphate ceramics as well as enhancing their bio-reactivity has become the latest concern in biomaterials. Thereby, uniqueadvantagesofnanotechnologycanbeexplored. Nanotechnologycanhelpimprovethebio-reactivityof HAasaboneconstituent,thusincreasingthebiomate- rial-bone interface. The chemico-physical and biologi- cal properties of HA are strictly related to their dimen- sions, the regulation of which requires a high level of chemical control at the nanoscale. Because of their composition, structure and their nano-dimensional and –morphological likeness to bone crystals, bio- mimeticHAsyntheticcrystalsarebelievedtobeagreat hope for orthopaedics. In comparison to particle-sized traditional materials, nanostructured biomimetic ma- terials show a better performance, resulting from their large surface-to-volume ration and rare chemical and electronicsynergisticeffects.9 In addition, the bone-mineral phase with carbon- ated HA crystals of a length of 100 nm, a width of 20–30 nm and a thickness of 3–6 nm results in a bio- mimetic need for synthesising with similar nanoscale dimensions. Moreover, a low crystallinity, a non-stoi- chiometriccompositionandcrystallinedisorderaswell as the presence of carbonate ions in the crystal lattice areindicated.ThegoodbiologicalqualityofHA,forex- amplenon-toxicity,itslackofinflammatoryandimmu- nity response as well as high bio-resorbability are in- creased even more by decreasing the crystallinity of syntheticapatite. Size and crystallinity of the HA particles are impor- tantwithregardtostabilityandinflammatoryresponse in collagen-HA implants. In bones, carbonate-substi- tuted HA crystals are mineralised in small gaps of the collagenfibrilsandhavebeenfoundtohavealengthof 50nm,awidthof25nmandathicknessof2–5nm.10 As thelocalsourceofcalciumtothesurroundingcells,they becomeintegratedwithcollagenfibrils,thusachieving the high mechanical properties of bone. Nontheless, small sintered particles of a size of less than 1 µm have beenwarnedagainstwhenusedinboneimplants.Rea- sonsforthisaretheirhighinflammatoryresponse11 and theircelltoxicityinvitro.12 Contrarily,smallerplate-like particles (200 nm x 20 nm x 5 nm) have been shown to create increased osteoblastic adhesion and prolifera- tionwhencomparedtolargerHAparticles,suchascar- bonate-substituted HA particles, unsintered and pro- ducedatphysiologicaltemperetures.13 A nanocrystalline HA in a silica-gel matrix (NanoBone, ARTOSS) with a very large internal surface (about 84 m2 /g) was used in this study.14 In addition, nanocristalline HA showed faster bone formation and resorption in animal studies when compared to com- merciallyavailableHA,tricalciumphosphatesandgela- tine sponges15 , resulting from their porous structure, rough surface and interconnecting pores of 10–20 nm ofthesilicagel. Signs of osteoconduction and osteoinduction,16 high biocompatibility and angiogenic response17 be- came visible in histological and immunohistochemical investigations after implantation. Furthermore, it was postulated that nanocrystalline HA has osteoconduc- tiveandbiomimeticpropertiesandisintegratedintothe host’s physiological bone turnover at a very early stage.18 Newly formed bone of limited quantities was foundatthreemonthsofhealing19 ,whilenewtrabecu- lar bone was found at six month of healing20 in recent histological investigations of human biopsies from si- nusaugmentationswithnanocristallineHA. The aim of the present study was to compare the clinical outcome of and radiographic bone changes in augmentedridgesutilisingasyntheticNanoBoneblock versusanallograftboneblock,andtoinvestigatehisto- logicallythesuccessofasyntheticNanoBoneblockver- sus an allograft bone block for augmenta- tion. _Materials and methods Subjectselection Twenty patients ranging between the agesof35and55wereincludedinthisstudy. All patients selected for this study required bone augmentation procedures because of severealveolarridgeatrophyintheposterior mandible, either unilateral or bilateral, with standing anterior teeth. Furthermore, the participantswerehealthyandfreefromany systemic conditions. Other than any sys- temic condition that might have affected bone formation, osseointegration or soft- tissue rehabilitation (such as immune sys- temicdisease,diabetes,pulmonarydiseases, renal and cardiovascular diseases, and blood diseases), exclusion criteria were ma- lignant neoplasias, hepatitis, drug abuse, chemotherapy and radiotherapy. In addi- tion,smokerswereexcludedfromthestudy. Alltheparticipantswereinformedaboutthe study and completed an informed consent form. The participants were divided ran- domly into two groups of ten patients. The first group (group A) underwent ridge aug- mentation using a NanoBone block and the second group (group B) underwent ridge augmentationusinganallograftboneblock. ® by www.omniaspa.eu OMNIA S.p.A. Via F. Delnevo, 190 - 43036 Fidenza (PR) Italy Tel. +39 0524 527453 - Fax +39 0524 525230 VAT. IT 01711860344 - R.E.A. PR 173685 Company capital € 200.000,00 Since our beginnings, we have always been focused on quality and innovation toward the battle against cross - contamination and infections. In the last 20 years, we have ensured safety and protection to you and your patients, with advanced and reliable products. Tools that represent the ideal solution for who is operating in dentistry, implantology/oral surgery and general surgery. With Omnia sure to be safe. Cologne, 12-16.03.2013 Visit us! Hall 4.1 Stand C088- D089 AD