title: Toothbrushing promotes gingival fibroblast proliferation more effectively than removal of dental plaque.
abstract: OBJECTIVE
  Removal of dental plaque is an essential element of periodontal treatment. However, there have also been studies of the effects of the mechanical stimulation provided by toothbrushing on gingival host-defense mechanisms. The aim of the study was to evaluate the effects of toothbrushing on gingival fibroblast proliferation in dogs over time, compared to effects of plaque removal without brushing.
  
  
  METHODS
  The mouths of six mongrel dogs were divided into four quadrants: two for daily toothbrushing, and two for daily plaque removal with a curette. After 1, 3 and 5 weeks of treatment, histometrical analyses were performed to assess inflammatory cell infiltration, proliferating cell nuclear antigen (PCNA)-positive fibroblasts, procollagen type I-positive fibroblasts in the subepithelial connective tissue of junctional epithelium.
  
  
  RESULTS
  Toothbrushing increased the number of PCNA-positive fibroblasts in the first week, increased the number of type I procollagen-positive fibroblasts at the fifth week, and reduced inflammatory cell infiltration at the third week.
  
  
  CONCLUSIONS
  These findings suggest that mechanically stimulated fibroblasts begin proliferating within a week, and this cell division results in an increased number of fibroblasts at the third week. It takes 5 weeks before differences in collagen synthesis between brushing and plaque removal areas are detectable.
authors.affiliation: Department of Preventive Dentistry, Okayama University Dental School, Okayama, Japan.
authors.forename: Masazumi
authors.initials: M
authors.lastname: Horiuchi
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tomofuji
authors.forename: Akira
authors.initials: A
authors.lastname: Ishikawa
authors.forename: Manabu
authors.initials: M
authors.lastname: Morita
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D002455:Cell Division; D016009:Chi-Square Distribution; D024042:Collagen Type I / Q000096:biosynthesis; D003773:Dental Plaque / Q000628:therapy*; D012534:Dental Scaling; D004285:Dogs; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005881:Gingiva / Q000166:cytology* / Q000378:metabolism; D005891:Gingivitis / Q000517:prevention & control*; D010812:Physical Stimulation; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D018709:Statistics, Nonparametric; D014099:Toothbrushing
chemical_list: D024042:Collagen Type I; D018809:Proliferating Cell Nuclear Antigen