Clinical Research Directory

Is Cross-linked Hyaluronic Acid a Biologic Alternative for Alveolar Ridge Preservation?

Even after atraumatic tooth removal and/or immediate implant placement, some reduction of the alveolar ridge dimension is expected. To counteract (or limit) this reduction, alveolar ridge preservation technique (ARP) was developed. However, standard ARP techniques, such as grafting with bone substitutes, have some concerns, such as a long healing time prior to implant installation, residual graft particles, and often the need of re-grafting at implant installation. To overcome some of these limitations biologics have been discussed as an alternative approach, such as cross-linked hyaluronic acid (xHyA). However, whether the use of biologics only can achieve comparable results to the standard techniques, has yet to be answered. The aim of the present single-blind, randomized controlled clinical trial is to test non-inferiority in terms of mid-buccal alveolar ridge height resorption 4 months after ARP between 1) control/standard treatment (i.e., grafting with bone substitutes and socket seal) and 2) test treatment (i.e., xHyA applied with a collagen sponge and socket seal) at maxillary non-molar teeth. Forty-eight patients will be included and randomly assigned to one of the following 2 groups: 1) control group: standard ARP with deproteinized bovine bone material and covering of the socket with a free gingival graft (FGG) (n=24), 2) test group: application of xHyA soaked in a collagen sponge and covered by a FGG (n=24). The primary outcome parameter is the extent of mid-buccal alveolar ridge height resorption after 4 months, i.e., prior to implant installation, and the sample size calculation is based on a non-inferiority limit of 0.6 mm. The secondary outcome parameters are frequency of additional grafting at implant installation due to 1) a bony dehiscence or fenestration, 2) a thin buccal bone (\< 1.5 mm), or 3) contour improvement, cervical alveolar ridge width, alveolar ridge volume, histomorphometric assessment of alveolar ridge healing, feasibility of implant installation, aesthetic outcome parameters, patient reported outcome measures, changes in keratinized mucosa width, soft tissue healing, and assessment of postoperative complications. Patients will be followed up to 1 year after prosthetic restoration.

Implant-supported Rehabilitation With SPAL Technique or Soft Tissue Augmentation

The primary aim of the present study is to compare the Sub-periosteal Peri-implant Augmented Layer (SPAL) technique and soft tissue augmentation (STA), performed simultaneously to implant placement, in terms of (i) implant survival rate and (ii) health/disease condition of the peri-implant tissues at 6 and 12 months following implant loading. The secondary aim of the project will be to compare the SPAL technique and STA in terms of intra- and post-operative morbidity. The study is designed as a single-blind, parallel-arm, randomized clinical trial. Patients will be recruited and treated at the Operative Unit of Dentistry, Azienda Unità Sanitaria Locale (A.U.S.L.) of Ferrara, Italy, and one University center (Research Centre for the Study of Periodontal and Peri-implant Diseases, University of Ferrara, Italy). Each patient will contribute the study with one sextant ("experimental sextant"). Each eligible patient will be randomly assigned to receive SPAL technique or STA according to a computer-generated randomization list. Surgical procedures will be performed by experienced periodontal and implant surgeons. Two calibrated, blinded examiners will take care of the assessment of clinical and radiographic parameters, Case Report Form (CRF) filling, as well as data extraction from CRFs for the preparation of the study database. The proportion of patients free from peri-implantitis at 12 months following loading will be the primary outcome variable of the study. The proportion of patients with complete resolution of the bone dehiscence (BD), dimensional variations and 12-months characteristics of BD, and patient-reported outcome measures will be the secondary outcomes. The design will test two hypotheses, with a non-inferiority trial in terms of primary outcome and a superiority trial in terms of secondary outcomes.

Titanium Reinforced d-PTFE Membrane Versus Collagen Membrane For Guided Bone Regeneration

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)