title: Collagen implants do not preserve periodontal ligament homeostasis in periodontal wounds.
abstract: An improved understanding of the differentiation of periodontal ligament cells could facilitate the development of new treatment approaches for overcoming the loss of specialized cell types caused by periodontitis. To study healing of wounded periodontal tissues and the differentiation of mineralizing connective tissue cells in periodontal ligament, we have examined the influence of wound size and collagen implantation on the regeneration of periodontium and on immunohistochemical staining for osteopontin and bone sialoprotein. Four groups of Wistar rats were wounded by drilling through the alveolar bone and by extirpation of the periodontal ligament. Wounds were 0.6 or 1.8 mm in diameter and defects were either implanted with collagen gels or were treated without implants. Rats were killed at 1 wk or 2 months after wounding and tissue sections were stained with monoclonal antibodies against rat osteopontin and bone sialoprotein. Collagen implants strongly increased staining for osteopontin and bone sialoprotein in defects at 1 wk. By 2 months alveolar bone healed completely regardless of the wound size but in large defects, periodontal ligament width was significantly reduced with or without implants. In large wounds at 2 months, collagen implants inhibited bone regeneration and there was stronger staining for osteopontin and bone sialoprotein in the bone replacing the implant, indicating that collagen prolonged bone remodelling. We conclude that implantation of exogenous collagen affects alveolar bone healing but does not preserve the width of the regenerated periodontal ligament. Therefore collagen does not appear to contribute to homeostasis in the periodontium following wounding.
authors.affiliation: MRC Group in Periodontal Physiolgy, Faculty of Dentistry, University of Toronto, Ontario, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Nguyen
authors.forename: P
authors.initials: P
authors.lastname: Lekic
authors.forename: C A
authors.initials: CA
authors.lastname: McCulloch
mesh_terms: D000539:Alveolar Process / Q000473:pathology / Q000503:physiopathology; D000541:Alveolectomy; D000818:Animals; D001861:Bone Regeneration; D016723:Bone Remodeling; D002448:Cell Adhesion; D002454:Cell Differentiation; D003094:Collagen / Q000627:therapeutic use*; D004396:Coloring Agents; D003238:Connective Tissue / Q000473:pathology; D005500:Follow-Up Studies; D005782:Gels; D006706:Homeostasis; D007150:Immunohistochemistry; D058574:Integrin-Binding Sialoprotein; D008297:Male; D008903:Minerals / Q000378:metabolism; D053495:Osteopontin; D010513:Periodontal Ligament / Q000473:pathology / Q000503:physiopathology*; D010518:Periodontitis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D010750:Phosphoproteins / Q000032:analysis; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration; D012795:Sialoglycoproteins / Q000032:analysis; D014945:Wound Healing
chemical_list: D004396:Coloring Agents; D005782:Gels; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D008903:Minerals; D010750:Phosphoproteins; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin; D003094:Collagen