Evaluation of a Collagen-Glycosaminoglycan Dermal Substitute in the Dog Palate RICARDO OPHOF, D.D.S., JAAP C. MALTHA, Ph.D., ANNE-MARIE KUIJPERS-JAGTMAN, Ph.D., D.D.S., and JOHANNES W. VON DEN HOFF, Ph.D. ABSTRACT Tissue shortage complicates surgery of cleft lip and palate. The healing of defects on the palate impairs growth of the dentoalveolar complex because of scar tissue formation. Implantation of a matrix into the wound might overcome this adverse effect. Integra with and without a silicone top layer was implanted into standardized full-thickness wounds (Ø 6 mm) in the palatal mucoperiosteum in beagle dogs. In some wounds, the silicone layer was re- moved after 14 days. Control wounds did not have an implant. At 2 and 4 weeks post-surgery, the wounds were assessed for epithelialization, inflammation (hematoxylin and eosin, leucocyte protein L1), num- ber of myofibroblasts (alpha smooth muscle actin), and general histological characteristics. Wounds filled with Integra without the silicone layer showed fewer myofibroblasts and inflammatory cells than the sham wounds. Collagen fibers were more randomly orientated in these wounds than in the sham group. Wound closure was found to be retarded, and many inflammatory cells were present when Integra with silicone was implanted. The silicone layer was lost within 4 weeks in these wounds. We conclude that, in the moist oral environment, the silicone of Integra is not required. Re-epithelialization and tissue integration proceed more favorably without it. Further research in the dentoalveolar develop- ment with Integra will be conducted in a simulated cleft palate repair in the dog model. INTRODUCTION L IKE SURGICAL RECONSTRUCTIONS OF THE SKIN, a shortage of tissue often complicates reconstructions of the oral mucosa. During closure of a palatal cleft using the Von Langenbeck method, for example, there is a lack of muco- sal tissue, which leaves areas of denuded bone on the palate. Generally, no autologous grafts are used to cover these wounds. Instead, they are left to heal by secondary intention, which means that proliferation and migration of cells, as well as wound contraction, occurs. This results in extensive scar tissue, which is firmly anchored to the palatal bone. 1 Intraoral wound contraction and scar tissue formation during the growth of the maxillofacial complex, as is the case in cleft palate repair, counteracts normal development of the face because of long-term impairment of skeletal growth and the development of dentition. 2–4 Studies have been performed to prevent the attachment of scar tissue to the palatal bone after palatal surgery by modifying the surgical techniques. Surgical techniques that reduce the denudation of the palatal bone show some bene- ficial effects, 5,6 but the use of biodegradable poly-(L-lactic) acid membranes or tissue expansion did not show any sig- nificant beneficial long-term effect in animal models. 7,8 An- other generation of biodegradable membranes composed of collagen and glycosaminoglycans has been described for the reconstruction of large-surface-area burns and for neck con- traction therapy with promising results. 9,10 The implantation Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. TISSUE ENGINEERING Volume 13, Number 11, 2007 # Mary Ann Liebert, Inc. DOI: 10.1089/ten.2006.0368 2689 Downloaded by Radboud Univ Nijmegen from www.liebertonline.com at 12/22/07. For personal use only.