Effects of a carbamide peroxide agent and desensitizing dentifrices on enamel microhardness

• Published in: American journal of dentistry Vol. 16; no. 1; p. 42
• Main Authors: de Oliveira, Rogério, Basting, Roberta Tarkany, Rodrigues, José Augusto, Rodrigues, Jr, Antonio Luiz, Serra, Mônica Campos
• Format: Journal Article
• Language: English
• Published: United States 01-02-2003
• Subjects: Data Interpretation, Statistical; Dental Enamel - drug effects; Dental Enamel Permeability - drug effects; Dentifrices - pharmacology; Dentifrices - therapeutic use; Drug Combinations; Fluorides - pharmacology; Hardness - drug effects; Humans; In Vitro Techniques; Nitrates - pharmacology; Peroxides - pharmacology; Phosphates - pharmacology; Polyvinyls - pharmacology; Tooth Bleaching - adverse effects; Urea - analogs & derivatives; Urea - pharmacology
• ISSN: 0894-8275

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