title: Time Course of Potassium Nitrate Penetration into the Pulp Cavity and the Effect of Penetration Levels on Tooth Whitening Efficacy.
abstract: To establish time-course of potassium nitrate (PN) penetration into the pulp cavity, and determine whether PN pretreatment would affect whitening efficacy.
  
  
  
  Extracted teeth (n = 100) were randomized into five groups of 20 specimens each. Relief ACP (Philips Oral Healthcare, Los Angeles, CA, USA) was applied for 0, 5, 15, 30, and 60 minutes for groups 15, respectively. A nitrate/nitrite assay kit was used for colorimetric detection of nitrate. Whitening was performed using a Zoom White Speed system (Philips Oral Healthcare) for 60 minutes. Tooth color was measured with a spectrophotometer at baseline (T0 ), 1-day post PN application (T1 ), 1-day post-whitening (T2 ), and 1-month post-whitening (T3 ). Kruskal-Wallis test was used to assess group differences in PN penetration and tooth color change.
  
  
  
  PN penetration differed among all groups except 2 and 3. There were no differences among groups for any baseline color parameters (p > 0.30). At T2 there was no change relative to baseline for individual components L*, a*, and b*. At T3 and T4 there was significant change relative to baseline for ΔL*, Δb*, and ΔE*, for all groups.
  
  
  
  PN penetration is time dependent and pretreatment with PN does not affect whitening efficacy.
  
  
  
  Postassium nitrate penetration into the pulp cavity occurred as early as 5 minutes after application, and pretreatment with potassium nitrate containing desensitizers did not adversely affect tooth whitening efficacy. (J Esthet Restor Dent 28:S14-S22, 2016).
authors.affiliation: Associate Professor-Program Director, Center for Dental Research, Loma Linda University School of Dentistry, 11175 Campus St. CSP #A1010, Loma Linda, CA, 92354, USA.
authors.forename: So Ran
authors.initials: SR
authors.lastname: Kwon
authors.affiliation: Professor and Director, Division of Biostatistics and Research Design, Departments of Pediatric Dentistry & Biostatistics and the Interdisciplinary Programs in Genetics and in Informatics, University of Iowa College of Dentistry & Dental Clinics, 801 Newton Road #451, DSB N101-9, Iowa City, IA, 52242-1001, USA.
authors.forename: Deborah V
authors.initials: DV
authors.lastname: Dawson
authors.affiliation: Professor Oral Pathology, Radiology and Medicine, Dows Institute for Dental Research, University of Iowa College of Dentistry & Dental Clinics, 801 Newton Road #451, DSB N449, Iowa City, IA, 52242-1001, USA.
authors.forename: Philip W
authors.initials: PW
authors.lastname: Wertz
mesh_terms: D003116:Color; D003786:Dental Pulp Cavity / Q000737:chemistry; D006861:Hydrogen Peroxide; D009566:Nitrates / Q000493:pharmacokinetics; D017680:Potassium Compounds / Q000493:pharmacokinetics; D011897:Random Allocation; D014073:Tooth Bleaching
chemical_list: D009566:Nitrates; D017680:Potassium Compounds; D006861:Hydrogen Peroxide; C023844:potassium nitrate