title: Reconstruction of mandibular segmental defects using the guided-bone regeneration technique with polylactide membranes and/or autogenous bone graft: a preliminary study on the influence of membrane permeability.
abstract: OBJECTIVE
  Bone maintenance after mandibular reconstruction with autogenous iliac crest may be disappointing due to extensive resorption in the long term. The potential of the guided-bone regeneration (GBR) technique to enhance the healing process in segmental defects lacks comprehensive scientific documentation. This study aimed to investigate the influence of polylactide membrane permeability on the fate of iliac bone graft (BG) used to treat mandibular segmental defects.
  
  
  METHODS
  Unilateral 10-mm-wide segmental defects were created through the mandibles of 34 mongrel dogs. All defects were mechanically stabilized, and the animals were divided into 6 treatment groups: control, BG alone, microporous membrane (poly L/DL-lactide 80/20%) (Mi); Mi plus BG; microporous laser-perforated (15 cm(2) ratio) membrane (Mip), and Mip plus BG. Calcein fluorochrome was injected intravenously at 3 months, and animal euthanasia was carried out at 6 months postoperatively.
  
  
  RESULTS
  Histomorphometry showed that BG protected by Mip was consistently related to larger amounts of bone compared with other groups (P <or= .0001). No difference was found between defects treated with Mip alone and BG alone. Mi alone rendered the least bone area and reduced the amount of grafted bone to control levels. Data from bone labeling indicated that the bone formation process was incipient in the BG group at 3 months postoperatively regardless of whether or not it was covered by membrane. In contrast, GBR with Mip tended to enhance bone formation activity at 3 months.
  
  
  CONCLUSIONS
  The use of Mip alone could be a useful alternative to BG. The combination of Mip membrane and BG efficiently delivered increased bone amounts in segmental defects compared with other treatment modalities.
authors: Department of Oral and Maxillofacial Surgery and Periodontics, Faculty of Dentistry of Ribeirao Preto, University of São Paulo, São Paulo, Brazil.
authors: Cassio E
authors: CE
authors: Sverzut
authors: Paulo E P
authors: PE
authors: Faria
authors: Carolina M
authors: CM
authors: Magdalena
authors: Alexandre E
authors: AE
authors: Trivellato
authors: Francisco V
authors: FV
authors: Mello-Filho
authors: Cleber A J
authors: CA
authors: Paccola
authors: Sylwester
authors: S
authors: Gogolewski
authors: Luiz A
authors: LA
authors: Salata
mesh_terms: D020341:Absorbable Implants; D000704:Analysis of Variance; D000818:Animals; D001861:Bone Regeneration; D016025:Bone Transplantation / Q000379:methods*; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D008297:Male; D008334:Mandible / Q000601:surgery*; D008567:Membranes, Artificial; D010539:Permeability; D011091:Polyesters; D016062:Porosity; D019651:Plastic Surgery Procedures / Q000379:methods
chemical_list: D008567:Membranes, Artificial; D011091:Polyesters; C033616:poly(lactide)