title: Efficacy of a solar-powered TiO2 semiconductor electric toothbrush on P. gingivalis biofilm.
abstract: OBJECTIVE
  To determine the efficacy of a solar-powered TiO2 semiconductor electric toothbrush on Porphyromonas gingivalis biofilm.
  
  
  METHODS
  P. gingivalis cells were cultivated on sterilized coverslips under anaerobic conditions and were used as a biofilm. To evaluate the efficacy of the solar-powered TiO2 electric toothbrush on the P. gingivalis biofilm, the bacterial cell biofilm coverslips were placed into sterilized phosphate buffered saline (PBS) and brushed for 1 minute. Following mechanical brushing, the coverslips were stained with 1% crystal violet (CV) for 10 seconds at room temperature. The efficacy of P. gingivalis biofilm removal by the solar-powered TiO2 electric toothbrush was measured through the absorbance of the CV-stained solution containing the removed biofilm at 595 nm. The antimicrobial effect of the solar-powered TiO2 semiconductor was evaluated by the P. gingivalis bacterial count in PBS by blacklight irradiation for 0 to 60 minutes at a distance of 7 cm. The electrical current though the solar-powered TiO2 semiconductor was measured by a digital multimeter. The biofilm removal by the solar-powered TiO2 semiconductor was also evaluated by scanning electron microscopy (SEM).
  
  
  RESULTS
  The biofilm removal rate of the solar-powered TiO2 electric toothbrush was 90.1 ± 1.4%, which was 1.3-fold greater than that of non-solar-powered electric toothbrushes. The solar-powered TiO2 semiconductor significantly decreased P. gingivalis cells and biofilm microbial activity in a time-dependent manner (P< 0.01). The electrical current passing through the solar-powered TiO2 semiconductor was 70.5 ± 0.1 µA, which was a 27-fold higher intensity than the non-solar-powered brush. SEM analysis revealed that the solar-powered TiO2 semiconductor caused a biofilm disruption and that cytoplasmic contents were released from the microbial cells.
authors.forename: Takenori
authors.initials: T
authors.lastname: Sato
authors.forename: Naoki
authors.initials: N
authors.lastname: Hirai
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Oishi
authors.forename: Gerry
authors.initials: G
authors.lastname: Uswak
authors.forename: Kunio
authors.initials: K
authors.lastname: Komiyama
authors.forename: Nobushiro
authors.initials: N
authors.lastname: Hamada
mesh_terms: D058491:Bacterial Load; D001431:Bacteriological Techniques; D018441:Biofilms; D004396:Coloring Agents; D003593:Cytoplasm / Q000648:ultrastructure; D003773:Dental Plaque / Q000382:microbiology; D055615:Electrical Equipment and Supplies; D005840:Gentian Violet; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016966:Porphyromonas gingivalis / Q000502:physiology* / Q000648:ultrastructure; D012666:Semiconductors; D012993:Solar Energy; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014099:Toothbrushing / Q000295:instrumentation*; D014466:Ultraviolet Rays
chemical_list: D004396:Coloring Agents; C009495:titanium dioxide; D014025:Titanium; D005840:Gentian Violet