title: Effect of absorbable membranes on sandwich bone augmentation.
abstract: OBJECTIVE
  This study was conducted to evaluate the effect of barrier membranes on sandwich bone augmentation (SBA) for the treatment of implant dehiscence defects.
  
  
  METHODS
  Twenty-six implant-associated buccal dehiscence defects in 22 patients were treated according to the SBA concept - mineralized human cancellous allograft (inner layer), mineralized human cortical allograft (outer layer) and coverage with barrier membrane. The defects were randomly assigned to the bovine collagen membrane (BME) group; acellular dermal matrix (ADM) group; and no membrane group. Measurements at baseline and 6 months re-entry included defect height (DH: from smooth-rough junction to the most apical part of the defect), defect width (DW: at the widest part of the defect), and horizontal defect depth (HDD: at three locations - smooth-rough junction, middle, and most apical portion of the defect). All measurements were taken from a reference stent. Statistical analyses were performed for comparison of intra- and inter-group comparisons.
  
  
  RESULTS
  All implants placed were successfully osseointegrated. DH at baseline for three groups were not significantly different (P=0.858). Mean % DH reductions for ADM, BME, and control groups at 6 months were 73.9+/-17.6%, 68.1+/-30.1%, and 63.6+/-23.9%, respectively, with no significant difference among the groups (P=0.686). Mean horizontal bone gain, however, was significantly greater for membrane groups (1.7 mm for ADM, 1.6 mm for BME) compared with control group (1 mm) (P=0.044). Implant exposure resulted in significant reduction in total height gain (79.1+/-14.3% vs. 57+/-23.5%, P=0.021).
  
  
  CONCLUSIONS
  Within the limit of this study, it is concluded that SBA technique achieved predictable clinical outcomes. The addition of absorbable membranes enhanced bone gain in thickness compared with membrane-treated sites.
authors.affiliation: School of Dentistry, University of Maryland, Baltimore, MD 21201, USA. sbpark@umich.edu
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Kwang-won
authors.initials: KW
authors.lastname: Lee
authors.forename: Tae-Ju
authors.initials: TJ
authors.lastname: Oh
authors.forename: Carl E
authors.initials: CE
authors.lastname: Misch
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Shotwell
authors.forename: Hom-Lay
authors.initials: HL
authors.lastname: Wang
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D000368:Aged; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000704:Analysis of Variance; D000818:Animals; D001861:Bone Regeneration; D016025:Bone Transplantation; D002417:Cattle; D003094:Collagen; D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth / Q000009:adverse effects; D005260:Female; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D016037:Single-Blind Method; D017768:Skin, Artificial; D013529:Surgical Wound Dehiscence / Q000209:etiology / Q000601:surgery
chemical_list: C440568:Alloderm; D008567:Membranes, Artificial; D003094:Collagen