title: Optimum force and duration of toothbrushing to enhance gingival fibroblast proliferation and procollagen type I synthesis in dogs.
abstract: BACKGROUND
  Toothbrushing enhances gingival fibroblast proliferation, which promotes wound healing. Optimum force and duration of toothbrushing for stimulation of fibroblast proliferation are key factors in maximizing effects of toothbrushing on periodontal wound healing. We therefore evaluated the effects of different durations and forces of toothbrushing on proliferative activity and procollagen synthesis of gingival fibroblasts.
  
  
  METHODS
  Twelve dogs were used. In each dog, buccal gingivae of 12 teeth were examined for 3 weeks. Nine of these 12 teeth were each assigned to 1 of 9 different combinations of brushing force (0.98, 1.96, or 2.45 N) and duration (10, 20, or 40 seconds). The remaining 3 teeth received plaque removal without brushing, via a scaler.
  
  
  RESULTS
  Force and duration of toothbrushing affected both proliferating cell nuclear antigen (PCNA)-positive and procollagen Type I C-peptide (PIP)-positive fibroblast ratios (P < 0.05). The highest ratio of PCNA-positive fibroblasts was produced by brushing at 1.96 N for 20 seconds. The highest ratio of PIP-positive fibroblasts was produced by brushing at 1.96 N for 10 seconds.
  
  
  CONCLUSIONS
  Toothbrushing at certain forces and durations enhanced the proliferative activity and procollagen synthesis of gingival fibroblasts. The toothbrushing duration that increased procollagen synthesis (10 seconds) was shorter than that which increased fibroblast proliferative activity (20 seconds).
authors.affiliation: Department of Oral Health, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Tomofuji
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ekuni
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masazumi
authors.initials: M
authors.lastname: Horiuchi
authors.forename: Tomonori
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Watanabe
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002455:Cell Division; D024042:Collagen Type I / Q000096:biosynthesis*; D004285:Dogs; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D005881:Gingiva / Q000166:cytology*; D010446:Peptide Fragments / Q000032:analysis; D011347:Procollagen / Q000032:analysis / Q000096:biosynthesis*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D011897:Random Allocation; D013314:Stress, Mechanical; D013997:Time Factors; D014099:Toothbrushing
chemical_list: D024042:Collagen Type I; D010446:Peptide Fragments; D011347:Procollagen; D018809:Proliferating Cell Nuclear Antigen; C042813:procollagen type I carboxy terminal peptide