title: Effects of toothbrushing frequency on proliferation of gingival cells and collagen synthesis.
abstract: BACKGROUND
  Mechanical stimulation by toothbrushing enhances proliferation of fibroblasts and junctional epithelium (JE). These changes in gingiva may depend on the interval between toothbrushing. The effects of toothbrushing frequency on proliferation of gingival fibroblasts and basal cells of JE were evaluated.
  
  
  METHODS
  Twelve mongrel dogs were used. Each tooth was brushed for 20 s at 1.96 N. The subepithelial connective tissue of JE was examined for proliferating cell nuclear antigen (PCNA)-positive fibroblasts and procollagen type-I C-peptide (PIP)-positive fibroblasts. JE was examined for PCNA-positive basal cells.
  
  
  RESULTS
  Gingiva that received brushing twice a day showed increases in the density of fibroblasts and ratio of PCNA-positive fibroblasts to total fibroblasts at 4 weeks. The ratio of PIP-positive fibroblasts increased at 8 weeks in gingiva brushed twice a day and once a day. PCNA-positive basal cell ratio increased at 4 weeks in gingiva brushed twice a day and once a day.
  
  
  CONCLUSIONS
  A high frequency of brushing was associated with increased numbers of PCNA-positive fibroblasts, PIP-positive fibroblasts and PCNA-positive basal cells. Gingival cell proliferation increased and reached a plateau earlier in gingiva brushed twice a day than in gingiva brushed once a day.
authors.affiliation: Department of Oral Health, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8525, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tomofuji
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ekuni
authors.forename: Tomonori
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Masazumi
authors.initials: M
authors.lastname: Horiuchi
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002452:Cell Count; D002455:Cell Division; D003094:Collagen / Q000096:biosynthesis*; D003239:Connective Tissue Cells / Q000166:cytology; D004285:Dogs; D004846:Epithelial Attachment / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology; D005881:Gingiva / Q000166:cytology* / Q000378:metabolism; D010446:Peptide Fragments / Q000032:analysis; D011347:Procollagen / Q000032:analysis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D013997:Time Factors; D014099:Toothbrushing
chemical_list: D010446:Peptide Fragments; D011347:Procollagen; D018809:Proliferating Cell Nuclear Antigen; C042813:procollagen type I carboxy terminal peptide; D003094:Collagen