title: Guided tissue regeneration using rigid absorbable membranes in the dog model of chronic furcation defect.
abstract: OBJECTIVE
  Absorbable membranes are used to promote the regeneration of periodontal defects by Guided Tissue Regeneration (GTR). However, their collapse into the defect is commonly reported, impairing regeneration. Therefore, absorbable but rigid membranes aiming at preventing such collapse were developed and analyzed in periodontal regeneration.
  
  
  METHODS
  Membranes were analyzed in class II furcation defects in dogs; procedures included periodontal disease induction, prophylaxis and GTR (treated groups) or open flap debridement alone (control group). For GTR, the membranes were made of either 25% hydroxyapatite (HA) in polyhydroxybutyrate matrix (PHB) or 35% HA in PHB. Animals were clinically evaluated for gingival recession, clinical attachment level (CAL) and biopsies were collected at 60 and 120 days. Bone volume, trabeculae number, trabecular thickness and trabecular separation were quantified by micro-computed tomography, followed by histology.
  
  
  RESULTS
  Membrane exposure was observed in both treated groups (25 and 35% HAP) from the 8(th) day after surgery, continuously progressing until 120 days. Mean CAL for all groups remained above normal values for dogs. Bone volumetric values were not significantly different. Partial formation of bone, cementum and periodontal ligament was observed in treated groups. An inflammatory infiltrate was observed in the dense connective tissue that partially filled the center of the treated defects with active osteoclasts on bone surface.
  
  
  CONCLUSIONS
  Although partial regeneration of the defect was observed, it was limited by wound contamination. Consequently, rigid absorbable membranes made of HA and PHB failed to improve the regeneration of class II furcation defects in dogs.
authors.affiliation: Departamento de Veterinária, Universidade Federal de Viçosa, Viçosa, Brazil. emilycarlo@yahoo.com.br
authors.forename: Emily Correna Carlo
authors.initials: EC
authors.lastname: Reis
authors.forename: Andrea Pacheco Batista
authors.initials: AP
authors.lastname: Borges
authors.forename: Ricardo Junqueira
authors.initials: RJ
authors.lastname: del Carlo
authors.forename: Paulo Miranda
authors.initials: PM
authors.lastname: Oliveira
authors.forename: Rodrigo Viana
authors.initials: RV
authors.lastname: Sepúlveda
authors.forename: Natália Alves
authors.initials: NA
authors.lastname: Fernandes
authors.forename: Lívia Marina Alvarenga
authors.initials: LM
authors.lastname: Martins
authors.forename: Tatiana Borges
authors.initials: TB
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D004195:Disease Models, Animal; D004285:Dogs; D017823:Furcation Defects / Q000601:surgery*; D048091:Guided Tissue Regeneration; D008567:Membranes, Artificial
chemical_list: D001672:Biocompatible Materials; D008567:Membranes, Artificial