implants - international magazine of oral implantology

I research 08 I implants3_2013 Thesignificanceofearlymembraneexposureonthere- generative outcome has been somewhat controversial inguidedtissueregenerationandGBRprocedures.Sev- eral studies have shown better responses when the membranes remained submerged than when they be- cameexposedduringhealing.11,12 However,otherstud- iesfailedtoshowsuchdifferences.13,14 Itmustbepointedoutthatpatientsaffectedbypar- tialedentulismdonoteasilyacceptmajorsurgicalpro- cedures that may imply hospitalisation or general anaesthesia. These disadvantages, together with the factthatdentalimplantsdonotdemandalargeamount of bone, lead to the growing use of autogenous block bonegraftsfromintraoralsourcesratherthanfromex- traoral.15-20 The use of the mandible as a donor site is said to be lessinvasive,tosavesurgicalandanaesthetictimeand to be accomplished in the outpatient operatory.13,21,22 Harvesting of bone grafts from the retromolar region hasbeenreportedseveraltimesbefore.22-26 Intherepair oflocalisedalveolardefects,bonegraftsfromtheretro- molar region offer several benefits: a) the proximity of donor and recipient sites that reduces operative and anaesthetic time; b) conventional surgical access; and c) making them ideal for outpatient implant surgery. Minimal discomfort and decreased morbidity are also reported for this type of bone grafting.27-29 This tech- nique can be combined with impacted third molar ex- tractions.30 The purpose of the present retrospective study was toevaluatethesurgicalsuccessandtoassesstherateof complications that arise from harvesting retromolar bone grafts in a group of partially edentulous patients priortoimplantplacement. Weusedatwo-stagetech- nique. In the first surgical stage, one or more cortico- cancellous bone blocks harvested from the retromolar region were fixed with osteosynthesis titanium screws to the recipient site as onlay grafts to achieve a hori- zontal and/or vertical augmentation of the ridge vol- ume.Inthesecondprocedure,threetosixmonthslater, thescrewswereremovedandimplantswereplaced.The resultsregardingboneaugmentation,donorandrecip- ient site morbidity, bone graft stability and resorption prior to implant placement were recorded during the postoperativeperiodandhealingphase.Complications associatedwiththisproceduremostlyinvolveinfection, incisionlineopening,nervedysfunction,wounddehis- cence, loss of portion of the bone graft, and graft mo- bilisation (Table 1).31 A short review of the literature is presentedinTable2. _Materials and methods Aconsecutiveretrospectivestudywasconductedon patients who underwent retromolar onlay bone graft- ingfromJanuary2008untilJanuary2011.Filesof86pa- tients(77malesand9females)reporting104bonegraft operations were reviewed. Patients ranged in age from 20 to 58 years (average 37.9 years). From the current study, patients were excluded if their data covered: a) grafting of bone defects caused by tumour resections, osteoradionecrosis and bisphosphonate-associated osteonecrosis, b) grafting of bone defects in syndrome patients with craniofacial involvement and with con- genitalmalformations,suchascleftpatients,c)grafting ofextractionsocketsandintraalveolardefectssimulta- neously with immediate implant placements and d) augmentationsincludingtheapplicationofdistraction osteogenesis. Medical history, cause of tooth loss and smokingstatusatthetimeofoperationwererecorded. All patients underwent primary clinical and radi- ographic examinations and were diagnosed as having aninadequatequantityofboneforimplantplacement. Figs. 8 & 9_Filling of the small gaps between bone graft and alveolar crest with corticocancellous bone. Fig. 10_Periosteal releasing incisions. Fig. 11_Orthopantomographic control to evaluate the outcome of the surgical procedure. Fig. 12_Crestal incision and subperiosteal dissection of the alveolus, removal of the fixation screws. Implant site preparation with guidance from the laboratory-made splint. Positioning of the implants. Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12