title: A multicenter randomized controlled clinical trial using a new resorbable non-cross-linked collagen membrane for guided bone regeneration at dehisced single implant sites: interim results of a bone augmentation procedure.
abstract: OBJECTIVE
  To compare clinical performance of a new resorbable non-cross-linked collagen membrane, creos xenoprotect (CXP), with a reference membrane (BG) for guided bone regeneration at dehisced implant sites.
  
  
  METHODS
  This randomized controlled clinical trial enrolled patients with expected dehiscence defects following implant placement to restore single teeth in the maxillary and mandibular esthetic zone and premolar area. Implants were placed using a two-stage surgical protocol with delayed loading. Bone augmentation material placed at the implant surface was immobilized with CXP or BG membrane. Soft tissue health was followed during the healing period, and the defect size was measured at reentry and 6 months after implant placement.
  
  
  RESULTS
  Of the 49 included patients, 24 were treated with CXP and 25 with BG. Patient characteristics did not differ between the two arms. In the CXP arm, the defect height at implant insertion was (mean ± SD) 5.1 ± 2.1 mm (n = 24) and reduced at reentry by 81% to 1.0 ± 1.3 mm (n = 23). In the BG arm, the defect height at implant insertion was 4.9 ± 1.9 mm (n = 25) and reduced at reentry by 62% to 1.7 ± 2.1 mm (n = 24). Assuming a margin of non-inferiority of 1 mm, CXP was non-inferior to BG. Membrane exposure rate was highest at week 3 in both arms, reaching 16.7% for BG and 8.7% for CXP.
  
  
  CONCLUSIONS
  The new resorbable non-cross-linked collagen membrane facilitates bone gain to support implant placement in expected dehiscence defects. The observed trend toward higher mean bone gain and lower exposure rate with CXP compared to BG should be further investigated.
authors.affiliation: Private Clinic, Aachen, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Wessing
authors.affiliation: Graduate Implant Dentistry, Loma Linda, CA, USA.|Urban Regeneration Institute, Budapest, Hungary.
authors.forename: Istvan
authors.initials: I
authors.lastname: Urban
authors.affiliation: Section of Graduate Periodontology, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Montero
authors.affiliation: Department of Oral Surgery, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Werner
authors.initials: W
authors.lastname: Zechner
authors.affiliation: Division of Dental Student Training and Patient Care, Department of Oral Surgery, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Hof
authors.affiliation: Private Clinic, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Alández Chamorro
authors.affiliation: Private Clinic, Madrid, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Alández Martin
authors.affiliation: Private Clinic BSC, Verona, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Polizzi
authors.affiliation: Dentistry Unit, Department of Surgical, Microsurgical, and Medical Sciences, University Hospital of Sassari, Sassari, Italy.
authors.forename: Silvio
authors.initials: S
authors.lastname: Meloni
authors.affiliation: Section of Graduate Periodontology, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Sanz
mesh_terms: D000328:Adult; D016301:Alveolar Bone Loss / Q000628:therapy*; D001861:Bone Regeneration; D003094:Collagen / Q000627:therapeutic use*; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D005260:Female; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013529:Surgical Wound Dehiscence / Q000628:therapy*
chemical_list: D003094:Collagen
keywords: Guided bone regeneration; collagen membrane; dehisced implant sites; esthetic zone; randomized clinical trial; simultaneous implant placement