After tooth extraction, shrinkage of the bone is expected with 50% reduction of alveolar width. Patients at least 3months after tooth extraction and in need of single oral implant placement in the anterior maxilla with both neighboring teeth present, were invited to participate in an inter-subject RCT if insufficient residual alveolar bone was left for proper implant placement. Guided bone regeneration has been used to recreate bone volume. A combination of xenogenous bone (Creos Xenogain , Nobel Biocare AB, Göteborg, Sweden) and autologous bone chips in a 1:1 ratio, is protected by a membrane fixated in the bone. A resorbable, non-stable membrane (Creos Xenoprotect, Nobel Biocare AB, Göteborg, Sweden) or non-resorbable titanium reinforced d-PTFE membrane (Creos Syntoprotect , Nobel Biocare AB, Göteborg, Sweden) can be used.
This study aims to compare the effectivity of the two membranes by measuring changes in bone dimensions. The resorbable membrane has the advantage that it does not need to be removed, whereas the titanium reinforced membrane can protect the rebuilt volume better against external forces.
Patients start to take systemic antibiotics (Amoxicilline 1g) and anti-inflammatory medication (ibuprofen 600 mg) 1h pre-operatively. Following local anesthesia (Septanest special, Septodont, Saint Maur des Fossés, France) and oral disinfection (Corsodyl mouth rinse, GSK, Wavre, Belgium), a large mucoperiosteal flap will be raised with two vertical releasing on each side of the edentulous space and at the distal aspect of the second neighboring tooth. The flap extends to the base of the alveolar process to allow full access. Autogenous bone chips are harvested from the retromolar area with bone scrapers and/or from an edentulous site using ACM bone collector (NeoBiotech, Guro-gu Seoul, Republic of Korea). DBBM particles (Xenogain, Nobel Biocare, Göteborg, Sweden) soaked in blood are mixed with autogenous bone chips to a ratio of 1/1. After having made multiple bone perforations at the buccal aspect of the recipient site, the mixture of bone chips and DBBM is applied. An individualized collagen membrane (Xenoprotect, Nobel Biocare, Göteborg, Sweden) or a non-resorbable titanium reinforced d-PTFE membrane is attached on top using membrane fixation pins. Prior to fixation of the final pin, bone grafting material is additionally applied from the lateral aspect to ensure that it is properly packed under the membrane and fully stable. Following release of the periosteum and muscle insertion, tension-free primary wound closure is achieved with horizontal mattress 4/0 titanium reinforced d-PTFE sutures and single 6/0 monofilament sutures. Patients continue the intake of antibiotics and anti-inflammatory medication for 7 days and use an oral mouthrinse during 2 weeks. Sutures are removed after 2 weeks, and an implant is installed after 9 months following 3D implant planning.
A sample size calculation indicated 17 patients to be included per group. To compensate for one drop-out, 18 patients would be treated with collagen membrane and 18 would be treated with titanium reinforced d-PTFE.
Changes in horizontal bone dimensions over time is the primary outcome. Prior to surgery, immediately after GBR, at 9 months, at 3 years and 5 years a CBCT is taken. Every CBCT is superimposed to the baseline CBCT in designated software and horizontal buccal bone dimensions are measured.
Secondary outcomes include
* Membrane exposure
* Intrasurgical changes in bone crest width over time
* Intrasurgical assessment of bone quality at implant placement at the palatal, midcrestal and buccal aspect
* Need for re-grafting at implant placement
* Need for soft tissue grafting at implant placement
* Need for augmentation of keratinized mucosa at implant placement
* Volumetric increase in buccal bone at 3 and 5 years
* Peri-implant health at 3 and 5 years by means of intra-oral radiograph
* Esthetic outcomes at 3 and 5 years
* Histomorphometric analysis on 20 cases (10 per group)