title: Healing of critical-size cranial defects in guinea pigs using a bovine bone-derived resorbable membrane.
abstract: OBJECTIVE
  To investigate the healing of critical-size cranial bone defects (9-mm-diameter) in guinea pigs treated with a bovine bone-derived resorbable membrane.
  
  
  METHODS
  A sample of 42 guinea pigs was divided into test (n = 20), control (n = 20), and standard (n = 2) groups. A full-thickness trephine defect was made in the fronto-parietal bone of each animal. In the test group, the internal and external openings of the defect were each closed with a separate membrane, and the space between them was filled with blood clot and a central spacer. In the control group, the defect was filled only with the blood clot and spacer. At 1, 3, 6, and 9 months later, the calvarias (5 per period) for both the test and control groups were collected, fixed, radiographed, and histologically processed. The standard-group animals were sacrificed immediately after surgery and used to determine the initial size of defect radiographically. The areas of defects in the radiographs were measured with image-analysis software and were compared between groups and periods by multiple regression analysis with the Bonferroni correction.
  
  
  RESULTS
  At 1 and 3 months, newly formed woven bone was histologically observed in both test and control groups. Radiographically, this new bone occupied an average of 32% of the defect area at 1 month and 60% at 3 months in the test group. In the control group, 21% of the defect was filled at 1 month and 39% at 3 months. However, the differences between treatments were not statistically significant (P > .05). At 6 and 9 months, a significant increase in newly formed lamellar bone was seen histologically in both groups. Radiographically, for the test group, the new bone occupied an average of 82% of the defect area at 6 months and 96% at 9 months. For the control group, new bone composed an average of 45% of the defect area at 6 months and 40% at 9 months. The differences between the test and control groups were statistically significant at 6 and 9 months (P < .05). Complete or almost complete filling of the defect was observed in several cases.
  
  
  CONCLUSIONS
  It was concluded that the bovine bone-derived membrane is highly biocompatible and is able to promote good healing of critical-size defects in calvaria of guinea pig.
authors.affiliation: Department of Prosthodontics, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Márcio Luiz de Lima
authors.initials: ML
authors.lastname: Taga
authors.forename: Jośe Mauro
authors.initials: JM
authors.lastname: Granjeiro
authors.forename: Tania Mary
authors.initials: TM
authors.lastname: Cestari
authors.forename: Rumio
authors.initials: R
authors.lastname: Taga
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001857:Bone Matrix / Q000637:transplantation; D001861:Bone Regeneration; D002417:Cattle; D048091:Guided Tissue Regeneration / Q000379:methods*; D006168:Guinea Pigs; D007091:Image Processing, Computer-Assisted; D020007:Implants, Experimental; D008297:Male; D008567:Membranes, Artificial; D010294:Parietal Bone / Q000601:surgery; D012044:Regression Analysis
chemical_list: D008567:Membranes, Artificial