implants - international magazine of oral implantology

I case report _ ridge preservation and GTR 16 I implants3_2011 tooth extraction. They observed that there was an av- erageof35%ofridgeresorptioninnaturalhealingand only12%inthegraftedsites(Araújo&Lindhe2009). Thematerialsandthesurgicaltechniquesinuseto- day simplify ridge preservation before implant place- mentandenableclinicianstoensurethefunctionaland aesthetic outcome of the implants and subsequent restorationsmorepredictably.Variousnaturalandsyn- thetic bone graft materials are available for the clini- cian to use for ridge preservation. Bone grafts in gen- eralaredividedintofourmajorcategories:autogenous, allografts,xenograftsandalloplasts.Althoughthegold standard is the autogenous graft, studies have proven thereliabilityandfunctionalityofusingeitheranallo- graftorxenograft,whichavoidsthecreationofanad- ditional surgical site for bone harvesting. In addition, thereisrapidresorptionofautogenousgrafts,whichis muchslowerwithmineralisedallograftsorxenografts (Artzietal.2000;Venceetal.2004;Irinakis2006). The use of barrier membranes has become a stan- dard of care in guided bone regeneration and for alveolar ridge preservation and/or augmentation. The membrane excludes fast growing cells—epithelial and connective tissue cells—while enabling mesenchymal progenitor cells to proliferate and to differentiate into osteoblasts. When this surgical technique was estab- lished initially, membranes made of expanded polyte- trafluoroethylene(ePTFE)wereused.Althoughclinical and experimental studies found excellent treatment results using ePTFE membranes, wound healing com- plications with infection sequelae arose following the exposure of membranes. Therefore, clinicians and re- searchers have advocated the use of bioabsorbable barrier membranes (Zellin et al. 1995). There are two main materials used to manufacture bioabsorbable membranes: collagen derived from an animal source and synthetic materials. The ability of collagen to pro- moteprogenitorcelladhesion,chemotaxis,homeosta- sis and physiological degradation, along with its ease of manipulation and low immunogenicity, make it an idealbarriermaterial(Rothameletal.2004). Successful regeneration is possible, provided that cell exclusion and space maintenance prevails for the timeneededforrepopulationofthesitewithprogeni- tor cells. This period may vary between three to 12 months for bone regeneration in edentulous areas. The structural integrity of implanted bioabsorbable barrier membranes needs to be preserved for an ade- quateperiodtoallowmaturationofthenewlyformed tissueunderthemembrane-protectedspace. The purpose of the present case report is to evalu- ateclinicallyandhistologicallyaridgepreservationus- ingaxenograftandresorbablecollagenmembranefol- lowingtoothextraction. _Case A 40-year-old female patient was selected for this case report. Other than localised periodontal disease around a right temporary mandibular second molar, she had no systemic disease. The patient was referred for extraction of this molar. The reason for the extrac- tion was type III mobility and the radiological image (Figs.1&2). Fig. 7_The flaps were replaced and were sutured without obtaining com- plete socket coverage. Figs. 8 & 9_Clinical and radiographic view at six months following ridge preservation. Fig. 10_Surgical re-entry for implant placement. Clinically, xenograft par- ticles were well integrated into the alveolus, and the regenerated area is easily distinguished from the original bone tissue. Figs. 11 & 12_A bone biopsy specimen was harvested in the area previously regenerated using a bone trephine drill. Fig. 9 Fig. 10 Fig. 11 Fig. 6 Fig. 7 Fig. 8