title: Effect of whitening agents containing carbamide peroxide on cariogenic bacteria.
abstract: OBJECTIVE
  The purpose of this study was to investigate the in vitro antibacterial effects of three different carbamide peroxide products (Nitewhite, Opalescence, and Proxigel) on cariogenic microorganisms (mutans streptococci [MS] and lactobacilli), and to evaluate the effects of a 10% carbamide peroxide solution (Proxigel) on salivary levels of MS and lactobacilli clinically.
  
  
  METHODS
  Growth inhibition studies were performed to determine the concentration and exposure time of carbamide peroxide to give total inhibition of recoverable growth of MS and lactobacilli. Paraffin-stimulated saliva samples were collected from subjects before and after 6 weeks of treatment with 10% carbamide peroxide in bleaching trays, and levels of MS and lactobacilli were determined.
  
  
  RESULTS
  The growth inhibition studies showed no visible growth of MS or lactobacilli at 24-, 48-, or 72-hour incubation, after a 2-hour exposure to 1% carbamide peroxide. Identical results were obtained with all three carbamide peroxide products. In the clinical study, the mean salivary MS levels, expressed as logarithm colony-forming units per milliliter (CFU/mL), were 5.38 for the pretreatment samples and 5.23 for the post-treatment samples. The differences were not statistically significant (p > .05). However, there was a reduction in logarithm lactobacilli counts from a mean of 4.12 pretreatment to a mean of 2.74 post-treatment. This was statistically significant (p < .05).
authors.affiliation: Department of Diagnostic Sciences and General Dentistry, University of North Carolina School of Dentistry, Chapel Hill, North Carolina, USA. Carolyn_Bentley@dentistry.unc.edu
authors.forename: C D
authors.initials: CD
authors.lastname: Bentley
authors.forename: R H
authors.initials: RH
authors.lastname: Leonard
authors.forename: J J
authors.initials: JJ
authors.lastname: Crawford
mesh_terms: D000328:Adult; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D000077463:Carbamide Peroxide; D002327:Cariostatic Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004338:Drug Combinations; D006801:Humans; D007778:Lactobacillus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010545:Peroxides / Q000494:pharmacology*; D012463:Saliva / Q000382:microbiology; D013295:Streptococcus mutans / Q000187:drug effects*; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: D000891:Anti-Infective Agents, Local; D002327:Cariostatic Agents; D004338:Drug Combinations; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea