title: Comparison of unprocessed silk cocoon and silk cocoon middle layer membranes for guided bone regeneration.
abstract: BACKGROUND
  Silk cocoon is composed of multiple layers. The natural silk cocoon containing all layers was cut as a rectangular shape as defined as total group. The inner and outermost layers were removed from the total group and the remained mat was defined as the middle group. The objectives of this study was to compare the total group with the middle group as a barrier membrane for the guided bone regeneration.
  
  
  METHODS
  The effects of these materials on the cellular proliferation and alkaline phosphatase (ALP) expression of MG63 cells were explored. For comparing bone regeneration ability, bilateral bone defects were created in calvarial areas in ten adult New Zealand white rabbits. The defects were covered with silk membranes of the middle group, with silk membrane of the total group used as the control on the contralateral side. The defects were allowed to heal for 4 and 8 weeks. Micro-computerized tomography (μCT) and histological examination were performed.
  
  
  RESULTS
  The middle group exhibited a higher MTT value 48 and 72 h after treatment compared to the total group. ALP expression was also higher in the middle group. The results of μCT and histologic examination showed that new bone formation was significantly higher in the middle group compared to the total group 8 weeks postoperatively (P< 0.05).
  
  
  CONCLUSIONS
  In conclusion, the middle layer of the silk cocoon supports guided bone regeneration better than unprocessed silk cocoon.
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Dentistry, Gangneung-Wonju National University, Gangneung, Gangwondo 210-702 Republic of Korea.
authors.forename: Seong-Gon
authors.initials: SG
authors.lastname: Kim
authors.affiliation: Department of Oral and Maxillofacial Surgery, College of Dentistry, Gangneung-Wonju National University, Gangneung, Gangwondo 210-702 Republic of Korea.
authors.forename: Min-Keun
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Sericultural and Apicultural Materials Division, National Academy of Agricultural Science, Suwon, South Korea.
authors.forename: HaeYong
authors.initials: H
authors.lastname: Kweon
authors.affiliation: Sericultural and Apicultural Materials Division, National Academy of Agricultural Science, Suwon, South Korea.
authors.forename: You-Young
authors.initials: YY
authors.lastname: Jo
authors.affiliation: Sericultural and Apicultural Materials Division, National Academy of Agricultural Science, Suwon, South Korea.
authors.forename: Kwang-Gill
authors.initials: KG
authors.lastname: Lee
authors.affiliation: Department of Oral and Maxillofacial Surgery, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Jeong Keun
authors.initials: JK
authors.lastname: Lee
keywords: Bone defect; Guided bone regeneration; Membrane; Silk cocoon