title: Effect of two bioabsorbable barrier membranes on bone regeneration of standardized defects in calvarial bone: a comparative histomorphometric study in pigs.
abstract: BACKGROUND
  The effect of two different bioabsorbable collagen membranes on bone regeneration was assessed in standardized, membrane-protected calvarial defects in pigs.
  
  
  METHODS
  Two standardized defect types (6 x 6 x 6 mm and 9 x 9 x 9 mm) were produced in the calvaria of pigs: empty defects without a membrane (group 1; eight defects per size); defects filled with deproteinized bovine bone mineral (DBBM) without a membrane (group 2; eight defects per size); defects filled with DBBM and covered by a collagen membrane (group 3; eight defects per size); and defects filled with DBBM and covered by a cross-linked collagen membrane (CCM) (group 4; eight defects per size). Sacrifice took place 16 weeks after surgery, and the following parameters were analyzed: descriptive histology; semiquantitative histology (SQH), assessing bone regeneration in the whole defect area; and histomorphometric analysis of the percentage of bone and DBBM in the regenerated area at three different depth levels of the defect.
  
  
  RESULTS
  Using SQH, both membrane types resulted in significantly better bone regeneration compared to groups 1 and 2, irrespective of the defect size (P <0.005), with no difference between the two membranes. In the histomorphometric analysis, the layer immediately below the surface exhibited a significantly higher percentage of bone in groups 3 (27%) and 4 (36%) versus the two other groups for the 9 x 9 x 9-mm defects. No such differences were apparent for the 6 x 6 x 6-mm defects or the other two depth levels (bottom and middle layer) for either defect size.
  
  
  CONCLUSIONS
  The two collagen membranes tested significantly enhanced bone regeneration, especially in the superficial level of the calvarial bone defects. The prototype CCM did not provide any further advantage in the present animal model.
authors: Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern, Switzerland. michael.bornstein@zmk.unibe.ch
authors: Michael M
authors: MM
authors: Bornstein
authors: Guy
authors: G
authors: Heynen
authors: Dieter D
authors: DD
authors: Bosshardt
authors: Daniel
authors: D
authors: Buser
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001847:Bone Diseases / Q000473:pathology / Q000601:surgery*; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration / Q000502:physiology*; D018786:Bone Substitutes / Q000627:therapeutic use; D002417:Cattle; D003094:Collagen / Q000737:chemistry; D024042:Collagen Type I / Q000737:chemistry; D024061:Collagen Type III / Q000737:chemistry; D004195:Disease Models, Animal; D008567:Membranes, Artificial; D008903:Minerals / Q000627:therapeutic use; D011474:Prosthesis Design; D011897:Random Allocation; D012886:Skull / Q000473:pathology / Q000601:surgery*; D013552:Swine; D013997:Time Factors
chemical_list: C106416:Bio-Gide; C077540:Bio-Oss; D001672:Biocompatible Materials; D018786:Bone Substitutes; D024042:Collagen Type I; D024061:Collagen Type III; D008567:Membranes, Artificial; D008903:Minerals; D003094:Collagen