Effects of a carbamide peroxide agent and desensitizing dentifrices on enamel microhardness.
OBJECTIVE
To evaluate the in vitro microhardness of enamel treated with a 10% carbamide peroxide agent and two desensitizing dentifrices at different bleaching times.


METHODS
A 10% carbamide peroxide bleaching agent was evaluated (Rembrandt 10%) (REM). A placebo agent was used as a control group (PLA). The bleaching and the placebo agents were applied to human enamel dental fragments for 8 hours per day, followed by immersion for 5 minutes in a slurry solution of desensitizing dentifrices: Sensodyne (S) or Sensodyne Fluor (SF). During the remaining time, the enamel fragments were individually stored in 13.5 ml of artificial saliva. Knoop microhardness measurements were performed at baseline, 8 hours, 7, 14, 21, 28, 35 and 42 days of treatment and at 7 and 14 days of a post-treatment period.


RESULTS
Analysis of variance and Tukey's test showed no differences in enamel microhardness for REM + SF (P=0.069) and PLA + SF (P=0.93) within each time interval. The dental fragments treated with REM + S and PLA + S showed an increase in microhardness values within each time interval (P<0.0001). There were significant differences among the treatment agents from the 28th to the 56th day. The use of 10% carbamide peroxide bleaching and a desensitizing dentifrice significantly increased the enamel microhardness values during the bleaching treatment and after 14 days after the completion of the treatment. After the post-treatment period, the enamel fragments treated with a placebo agent and with a 10% carbamide peroxide agent and with a desensitizing fluoride dentifrice maintained the baseline values.
Department of Restorative Dentistry, School of Dentistry, University of Campinas, Piracicaba, SP, Brazil.
Rogério
R
de Oliveira
Roberta Tarkany
RT
Basting
José Augusto
JA
Rodrigues
Antonio Luiz
AL
Rodrigues
Mônica Campos
MC
Serra
D000077463:Carbamide Peroxide; D003627:Data Interpretation, Statistical; D003743:Dental Enamel / Q000187:drug effects*; D003745:Dental Enamel Permeability / Q000187:drug effects; D003802:Dentifrices / Q000494:pharmacology / Q000627:therapeutic use; D004338:Drug Combinations; D005459:Fluorides / Q000494:pharmacology*; D006244:Hardness / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D009566:Nitrates / Q000494:pharmacology*; D010545:Peroxides / Q000494:pharmacology*; D010710:Phosphates / Q000494:pharmacology*; D011145:Polyvinyls / Q000494:pharmacology; D014073:Tooth Bleaching / Q000009:adverse effects; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology*
D003802:Dentifrices; D004338:Drug Combinations; D009566:Nitrates; D010545:Peroxides; D010710:Phosphates; D011145:Polyvinyls; C112939:Rembrandt Lighten; C097427:Sensodyne; D000077463:Carbamide Peroxide; D014508:Urea; D005459:Fluorides