title: Comparative study of NMP-preloaded and dip-loaded membranes for guided bone regeneration of rabbit cranial defects.
abstract: Guided bone regeneration (GBR) has been utilized for several decades for the healing of cranio-maxillofacial bone defects and, particularly in the dental field, by creating space with a barrier membrane to exclude soft tissue and encourage bone growth in the membrane-protected volume. Although the first membranes were non-resorbable, a new generation of GBR membranes aims to biodegrade and provide bioactivity for better overall results. The Inion GTR™ poly(lactide-co-glycolide) (PLGA) membrane is not only resorbable but also bioactive, since it includes N-methylpyrrolidone (NMP), which has been shown to promote bone regeneration. In this study, the effects of loading different amounts of NMP onto the membrane through chemical vapour deposition or dipping have been explored. In vitro release demonstrated that lower levels of NMP led to lower NMP concentrations and slower release, based on total NMP loaded in the membrane. The dipped membrane released almost all of the NMP within 15 min, leading to a high NMP concentration. For the in vivo studies in rabbits, 6 mm calvarial defects were created and left untreated or covered with an ePTFE membrane or PLGA membranes dipped in, or preloaded with, NMP. Evaluation of the bony regeneration revealed that the barrier membranes improved bony healing and that a decrease in NMP content improved the performance. Overall, we have demonstrated the potential of these PLGA membranes with a more favourable NMP release profile and the significance of exploring the effect of NMP on these PLGA membranes with regard to bone ingrowth. Copyright © 2014 John Wiley & Sons, Ltd.
authors.affiliation: Oral Biotechnology and Bioengineering, Department of Cranio-maxillofacial and Oral Surgery, University Hospital Zurich, and Center for Dental Medicine, University of Zurich, Switzerland.
authors.forename: Lindsay S
authors.initials: LS
authors.lastname: Karfeld-Sulzer
authors.affiliation: Oral Biotechnology and Bioengineering, Department of Cranio-maxillofacial and Oral Surgery, University Hospital Zurich, and Center for Dental Medicine, University of Zurich, Switzerland.
authors.forename: Chafik
authors.initials: C
authors.lastname: Ghayor
authors.affiliation: Oral Biotechnology and Bioengineering, Department of Cranio-maxillofacial and Oral Surgery, University Hospital Zurich, and Center for Dental Medicine, University of Zurich, Switzerland.|Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Siegenthaler
authors.affiliation: Oral Biotechnology and Bioengineering, Department of Cranio-maxillofacial and Oral Surgery, University Hospital Zurich, and Center for Dental Medicine, University of Zurich, Switzerland.
authors.forename: Bebeka
authors.initials: B
authors.lastname: Gjoksi
authors.affiliation: Inion Ltd, Tampere, Finland.
authors.forename: Timo H
authors.initials: TH
authors.lastname: Pohjonen
authors.affiliation: Oral Biotechnology and Bioengineering, Department of Cranio-maxillofacial and Oral Surgery, University Hospital Zurich, and Center for Dental Medicine, University of Zurich, Switzerland.|Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland.|Centre for Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Switzerland.
authors.forename: Franz E
authors.identifier: 0000-0003-1670-2296
authors.initials: FE
authors.lastname: Weber
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes / Q000737:chemistry; D048091:Guided Tissue Regeneration / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry*; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011760:Pyrrolidinones / Q000737:chemistry*; D011817:Rabbits
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D008567:Membranes, Artificial; D011760:Pyrrolidinones; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C038678:N-methylpyrrolidone
keywords: NMP; PLGA; calvarial defect; guided bone regeneration; membrane