title: A randomized clinical trial evaluating the efficacy of the sandwich bone augmentation technique in increasing buccal bone thickness during implant placement surgery: I. Clinical and radiographic parameters.
abstract: OBJECTIVE
  Sandwich bone augmentation (SBA) has been proposed to augment the width of edentulous ridges for implant placement. This study aimed to investigate the effect of a membrane on SBA for the regeneration of buccal implant dehiscence defects.
  
  
  METHODS
  Twenty-six healthy patients, each with a single defect, were randomly assigned into two groups. Both groups received an inner and outer layer of mineralized human cancellous and cortical particulate allograft. In the test group, a bovine pericardium membrane covered the bone grafts, while no membrane was placed in the control group. Cone beam computed tomography (CBCT) scans were taken before and immediately after implant placement and at 6 months post-surgery.
  
  
  RESULTS
  All implants placed were successfully osseointegrated at 6 months. Clinical re-entry measurements showed significant buccal bone gain in the test group compared with the control group (P < 0.05). The test group had 1.12, 2.21 and 2.44 mm more buccal bone thickness at 2, 4 and 6 mm below the bone crest. There were no significant differences in the mid-buccal vertical bone height, defect height and width reductions and bone fill between the two groups (P > 0.05). Cone beam computed tomography analysis demonstrated significant buccal bone gain of 1.22 mm in the test group. Radiographic vertical bone loss at 1-year post-surgery showed no significant differences between the groups.
  
  
  CONCLUSIONS
  Sandwich bone augmentation is a predictable technique for regenerating buccal bone on implant dehiscence defects. Addition of a barrier membrane prevented significant horizontal buccal bone resorption as space was maintained more effectively when compared with sites treated without a membrane.
authors.affiliation: Discipline of Periodontics, Faculty of Dentistry, National University of Singapore, Singapore.
authors.forename: Jia-Hui
authors.initials: JH
authors.lastname: Fu
authors.forename: Tae-Ju
authors.initials: TJ
authors.lastname: Oh
authors.forename: Erika
authors.initials: E
authors.lastname: Benavides
authors.forename: Ivan
authors.initials: I
authors.lastname: Rudek
authors.forename: Hom-Lay
authors.initials: HL
authors.lastname: Wang
mesh_terms: D000328:Adult; D000539:Alveolar Process / Q000000981:diagnostic imaging* / Q000601:surgery; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D001862:Bone Resorption / Q000517:prevention & control; D016025:Bone Transplantation / Q000379:methods*; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging* / Q000601:surgery; D008567:Membranes, Artificial; D008875:Middle Aged; D016348:Osseointegration; D010012:Osteogenesis; D016896:Treatment Outcome
chemical_list: D008567:Membranes, Artificial
keywords: bone grafts; bone regeneration; cone beam computed tomography; dental implants