title: A randomized, controlled clinical evaluation of a synthetic gel membrane for guided bone regeneration around dental implants: clinical and radiologic 1- and 3-year results.
abstract: OBJECTIVE
  The objective of this study was to determine whether a synthetic bioresorbable polyethylene glycol (PEG) hydrogel membrane could provide similar clinical and radiographic outcomes as a standard collagen membrane, both in combination with a membrane-supporting material, during follow-up periods of 1 and 3 years.
  
  
  METHODS
  This study enrolled patients requiring implant treatment with an expected osseous defect in the posterior maxilla or mandible. Defects around the implants were grafted with deproteinized bovine bone mineral and covered with either a collagen membrane or a PEG hydrogel membrane, which is applied as a liquid and becomes a solid gel in situ. Surgical re-entry was performed after 6 months, and fixed partial dentures were inserted subsequently. Patients were examined clinically and radiographically 1 and 3 years after loading.
  
  
  RESULTS
  Thirty-six of the 37 included patients were reexamined in the third year. The implant survival rate at 3 years was 100%. The peri-implant tissues were healthy, with no differences between the two groups. Compared to the time of surgery, the mean changes in the distance between the first bone-to-implant contact to the transition point (ie, rough implant surface to polished neck portion) were 0.43 ± 0.56 mm (PEG) and 0.21 ± 0.36 mm (collagen) at 1 year and 0.61 ± 0.89 mm (PEG) and 0.33 ± 0.64 mm (collagen) at 3 years. The respective differences between groups were 0.13 mm (1 year) and 0.31 mm (3 years), which were not significant at either time point (analysis of covariance).
  
  
  CONCLUSIONS
  The tested PEG hydrogel was as successful as a standard collagen membrane for the treatment of bony dehiscence defects around dental implants after follow-up periods of 1 and 3 years.
authors.affiliation: Department of Fixed and Removable Prosthodontics and Dental Material Science, University of Zurich, Zurich, Switzerland. christian.ramel@zzm.uzh.ch
authors.forename: Christian F
authors.initials: CF
authors.lastname: Ramel
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Wismeijer
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
mesh_terms: D020341:Absorbable Implants; D016301:Alveolar Bone Loss / Q000601:surgery; D000540:Alveolar Ridge Augmentation / Q000379:methods; D001672:Biocompatible Materials / Q000737:chemistry*; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration / Q000502:physiology*; D016723:Bone Remodeling / Q000502:physiology; D018786:Bone Substitutes / Q000627:therapeutic use; D003094:Collagen / Q000737:chemistry; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D003830:Denture, Partial, Fixed; D005500:Follow-Up Studies; D016557:Guided Tissue Regeneration, Periodontal / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008567:Membranes, Artificial; D008903:Minerals / Q000627:therapeutic use; D016348:Osseointegration / Q000502:physiology; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: C077540:Bio-Oss; D001672:Biocompatible Materials; D018786:Bone Substitutes; D015921:Dental Implants; D008567:Membranes, Artificial; D008903:Minerals; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D003094:Collagen