title: A comparative study on the disinfection potentials of bioactive glass S53P4 and calcium hydroxide in contra-lateral human premolars ex vivo.
abstract: OBJECTIVE
  To evaluate the effects of bioactive glass S53P4 versus calcium hydroxide when used as dressings in contra-lateral human premolars infected with Enterococcus faecalis ATCC 29212.
  
  
  METHODS
  Pairs of contra-lateral premolar teeth plus single control premolars were obtained from 23 individuals aged 10-26 years undergoing orthodontic treatment. Root canals of teeth with fully formed apices (nine contra-lateral pairs, seven controls) were instrumented using a size 60 FlexoFiles 2 mm short of canal length. Canals with open apices (six contra-lateral pairs, four controls) were circumferentially instrumented using a FlexoFile. Root canals were rinsed with 1% sodium hypochlorite and 10% citric acid. Teeth were then suspended in tryptic soy broth (TSB) and autoclaved. Positive controls and study teeth were infected with E. faecalis ATCC 29212 for 2 weeks in TSB, while negative controls were kept in sterile TSB. Subsequently, contra-lateral premolars were dressed with bioactive glass S53P4 (BAG) or calcium hydroxide suspensions for 10 days. Dentine samples were obtained from teeth with fully formed apices using ISO-size 70, 80 and 90 FlexoFiles to working length and cultured. Teeth with open apices were fixed, fractured and examined using scanning electron microscopy (SEM).
  
  
  RESULTS
  Calcium hydroxide had a strong antibacterial effect and was significantly more effective than BAG in preventing residual bacterial growth (P < 0.01). SEM analysis revealed apparent substance-specific modes of action.
  
  
  CONCLUSIONS
  Calcium hydroxide was an effective disinfectant in human teeth.
authors.affiliation: Division of Endodontology, Department of Preventive Dentistry, Periodontology, and Cariology, University of Zürich Center of Dental Medcine, Zürich, Switzerland. matthias.zehnder@zzmk.unizh.ch
authors.forename: M
authors.initials: M
authors.lastname: Zehnder
authors.forename: H U
authors.initials: HU
authors.lastname: Luder
authors.forename: M
authors.initials: M
authors.lastname: Schätzle
authors.forename: E
authors.initials: E
authors.lastname: Kerosuo
authors.forename: T
authors.initials: T
authors.lastname: Waltimo
mesh_terms: D000293:Adolescent; D000328:Adult; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D001458:Bandages; D001641:Bicuspid / Q000382:microbiology*; D002126:Calcium Hydroxide / Q000494:pharmacology*; D002648:Child; D013293:Enterococcus faecalis / Q000187:drug effects*; D005898:Glass; D006801:Humans
chemical_list: D000891:Anti-Infective Agents, Local; C403922:bioactive glass S53P4; D002126:Calcium Hydroxide