The effect of mandibular distraction osteogenesis on the histology and immunohistology of keratinized gingiva.
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.
Kunimori
Kentaro
K
Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. kunimori.osur@tmd.ac.jp
Maruoka
Yutaka
Y
Sato
Masaru
M
Harada
Kiyoshi
K
Omura
Ken
K
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
D004277:DNA, Single-Stranded; D018809:Proliferating Cell Nuclear Antigen; D007633:Keratins