title: Does post-bleaching fluoridation affect the further demineralization of bleached enamel? An in vitro study.
abstract: BACKGROUND
  Topical fluoride agents have been shown to be the most effective method in treating demineralized enamel after in-office bleaching treatments. Thus, this study aimed to examine the effects of two different post-bleaching fluoridation agents: 1.5% titanium tetrafluoride (TiF(4)) (9200 ppm) and 2.1% sodium fluoride (NaF) (9500 ppm), on the calcium loss of enamel after an acidic challenge.
  
  
  METHODS
  Ten maxillary premolars were sectioned into four pieces and then divided into the following four groups: Group 1: Control, kept in artificial saliva, no treatment; Group 2: 38% hydrogen peroxide (HP); Group 3: 38% HP followed by 1.5% TiF(4); Group 4: 38% HP followed by 2.1% NaF solution. The specimens were subjected to demineralization for 16 days, refreshing the solution every 4 days; that is, on the 4th, 8th, 12th, and 16th days. Calcium ion (Ca(2+)) concentration was determined by an atomic absorption spectrophotometer. Data were analyzed using Friedman and Wilcoxon tests (p = 0.05).
  
  
  RESULTS
  The loss of Ca(2+) in each of the test groups was compared with that of the control group, depicting that there was a statistically significant difference among the groups after 4, 8, 12, and 16 days and in total (p < 0.05). The calcium released from the fluoride-applied groups was lower when compared with the 38% HP and control group. At the end of the 16th day, the total amount of calcium released from the TiF(4-)treated samples (9.12 mg/mL) was less than from the NaF-treated samples (13.67 mg/mL) (p < 0.05).
  
  
  CONCLUSIONS
  Regarding the results of our in vitro study, the risk of further demineralization was significantly reduced with the use of TiF(4) and NaF after bleaching with 38% HP. TiF(4) was found to be more effective in preventing Ca2+ release owing to acid attack when compared with NaF. In the case of an intra-oral acidic exposure, the use of topical 1.5% TiF(4) and 2.1% NaF agents might be beneficial after bleaching with 38% HP.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Ege University, Bornova 35100, Izmir, Turkey. handedalgar@gmail.com.
authors.forename: Hande
authors.initials: H
authors.lastname: Kemaloğlu
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Tezel
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Ergücü
mesh_terms: D002118:Calcium / Q000032:analysis / Q000493:pharmacokinetics; D002327:Cariostatic Agents / Q000627:therapeutic use*; D003743:Dental Enamel / Q000187:drug effects* / Q000378:metabolism; D005459:Fluorides / Q000627:therapeutic use*; D005460:Fluorides, Topical / Q000627:therapeutic use; D006801:Humans; D006861:Hydrogen Peroxide / Q000627:therapeutic use; D012464:Saliva, Artificial / Q000737:chemistry; D012969:Sodium Fluoride / Q000627:therapeutic use*; D013054:Spectrophotometry, Atomic; D013997:Time Factors; D014025:Titanium / Q000627:therapeutic use*; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000627:therapeutic use; D017001:Tooth Demineralization / Q000378:metabolism / Q000517:prevention & control*
chemical_list: D002327:Cariostatic Agents; D005460:Fluorides, Topical; D012464:Saliva, Artificial; D058205:Tooth Bleaching Agents; D012969:Sodium Fluoride; D006861:Hydrogen Peroxide; D014025:Titanium; D005459:Fluorides; D002118:Calcium; C032240:titanium tetrafluoride