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Journal of Oral Science & Rehabilitation Volume 2 | Issue 4/2016 17 O p e n h e a l i n g : A r e t r o s p e c t i v e a n a l y s i s Introduction Theaimofimplanttherapyistoensureanoptimal functional and esthetic outcome as well as good long-term results. The use of regenerative tech- niquesisoftennecessarytomaintainoraugment sufficient bone and soft-tissueforimplant place- ment.Among the bone substitutes, a deprotein- ized bovine bone mineral (DBBM) has been shown to be effective in bone augmentation1–4 and ridge preservation procedures.5–8 Studies with long-term follow-ups have shown that the regenerated bone is maintained over time.9, 10 Histologicalanalyseshaveindicatedthattheslow resorption rate of DBBM is responsible for the long-term stability of the augmented bone vol- ume.11 DBBM is often used in combination with a semipermeablemembrane.Accordingtotheprin- ciple of guided bone regeneration (GBR), the membraneisusedtoexcludeepithelialcellsfrom the bone defect, thereby allowing bone form- ation.12 In the early days of GBR, nonresorbable ePTFE (expanded polytetrafluoroethylene) barri- ers were successfully used to cover bone de- fects.13, 14 However, postoperative wound dehis- cenceoccurredfrequently.Itwasoftenassociated with infections that required early membrane removal and impaired bone regeneration.15–17 A resorbable native bilayer collagen membrane (NBCM) was shown to reduce the risk of mem- brane exposure and achieve comparable results to the ePTFE barriers with regard to bone rege- neration.16 Ifwounddehiscenceoccurredwiththe NBCM, healing was uneventful. Other studies have confirmed the promising healing characte- ristics of this membrane.18, 19 Ingeneral,itisrecommendedtoachievecom- plete, but tension-free, primary wound closure over the collagen membrane. However, when bone augmentation procedures are performed, closing the flap without tension may become challenging. Splitting of the periosteum and ex- tensive soft-tissue mobilization may then be necessary.This mayincrease morbidity, swelling and the rate of wound dehiscence because of impaired blood supply in a thinned flap. In addi- tion, an insufficient vestibular depth, lack of ke- ratinized tissue or scars may compromise the esthetic results and require additional surgical interventions. Apossibleapproachtoavoidflapmobilization is to allow open healing of the membrane. We started to use various collagen membranes and Materialsandmethods Evaluation included patients from a private practice who were treated between August 2005 and June 2014 using an open-healing approach. Patients underwent implant therapy to replace hopeless or missing teeth. Surgical interventions were performed as well as pre- and postoperative care administered according to our standard procedures. Membranes were applied in ridge preservation and in bone aug- mentation procedures, which were performed simultaneously with or before implant place- ment. In ridge preservation procedures, hopeless teeth were extracted atraumatically. The ext- raction socket was cleaned and all granulation tissue was removed carefully. A DBBM (Geist- lich Bio-Oss, Geistlich Pharma,Wolhusen, Swit- zerland) was applied into the socket according to the manufacturer’s instructions and covered with a membrane. In three-wall defects, that is, if the buccal bone wall was partially or comple- tely missing, and if the defect was narrow and deep, a soft-tissue pond was prepared and the ice-cream cone technique20 was used. In patients with missing teeth, a reduced full-thickness flap was prepared. If sufficient primary stability could be ensured, implants were placed immediately according to the ma- nufacturers’ instructions. Bone augmentation was performed using DBBM or autogenous bone harvested from the drill hole. If the defect was large or if several bone walls were missing, mechanical stability was ensured using a tita- nium mesh (Synthes, Umkirch, Germany). A membrane was applied overlapping the defect. Membrane margins were placed under the flap and the flap was sutured tension-free, leaving the membrane partially exposed. The following membrane materials were used: – Geistlich Bio-Gide (NBCM; Geistlich Pharma) – Jasonmembrane(JM;botissbiomaterials,Ber- lin, Germany) – Socket Repair Membrane (SRM; Zimmer Biomet, Freiburg, Germany) – DynaMatrix (DM; Keystone Dental,Alfter, Ger- many) – Geistlich Mucograft Seal (CMXs; Geistlich Pharma) – Histoacryl(HIA; B. Braun Medical, Melsungen, Germany). Volume 2 | Issue 4/201617