title: The effect of mandibular distraction osteogenesis on the histology and immunohistology of keratinized gingiva.
abstract: OBJECTIVE
  We investigated distracted keratinized epithelium to elucidate any proliferative and degenerated changes and to estimate the stability of the gingival tissues in mandibular distraction osteogenesis in a rabbit model.
  
  
  METHODS
  Twenty-two rabbits were subjected to unilateral vertical osteotomy. After a latency period of 4 days, devices were activated 3, 6, and 10 days at a rate of 1 mm/day. We additionally investigated the recovery of the distracted gingiva in consolidation periods for 3 weeks. The animals were examined by histologic and immunohistologic methods using proliferating cell nuclear antigen (PCNA), single-stranded DNA (ssDNA), and keratin.
  
  
  RESULTS
  Atrophy of distracted gingiva was observed characterized by loss of rete ridges, acanthosis, vacuolation in the prickle cell layer, and cleavage of the keratin layer. Proliferating cell nuclear antigen-positive cells and ssDNA-positive cells were observed in the basal and prickle layers, respectively. During consolidation periods, slight recovery of rete ridges, thinning of the keratin layer, and immature epithelial layer was observed.
  
  
  CONCLUSIONS
  Proliferative and degenerated changes occurred to compensate for cell death and distracted space. Thickness of gingival tissues was maintained by high mitotic activity and delay in the rate of cell maturation. Immature epithelial layer was related to sensitive and weak resistance against various stimulating factors, such as cleavage of the keratin layer among distracted gingival tissues.
authors: Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. kunimori.osur@tmd.ac.jp
authors: Kentaro
authors: K
authors: Kunimori
authors: Yutaka
authors: Y
authors: Maruoka
authors: Masaru
authors: M
authors: Sato
authors: Kiyoshi
authors: K
authors: Harada
authors: Ken
authors: K
authors: Omura
mesh_terms: D000818:Animals; D016923:Cell Death; D049109:Cell Proliferation; D004277:DNA, Single-Stranded / Q000032:analysis; D005881:Gingiva / Q000473:pathology*; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000473:pathology*; D007633:Keratins / Q000032:analysis; D008297:Male; D008334:Mandible / Q000601:surgery*; D023421:Models, Animal; D019647:Oral Surgical Procedures / Q000009:adverse effects*; D019857:Osteogenesis, Distraction / Q000009:adverse effects*; D010027:Osteotomy / Q000009:adverse effects; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D011817:Rabbits
chemical_list: D004277:DNA, Single-Stranded; D018809:Proliferating Cell Nuclear Antigen; D007633:Keratins