title: Radicular peroxide penetration from carbamide peroxide gels during intracoronal bleaching.
abstract: OBJECTIVE
  To evaluate and compare radicular peroxide diffusion from different concentrations of carbamide peroxide bleaching gels. METHODOLOGY; Fifty maxillary premolar teeth were separated into five groups (n = 10). Standardized endodontic access cavities were prepared in the occlusal surfaces, and the root canals were prepared using a step back technique and filled using the lateral compaction technique. The gutta-percha filling was removed 4 mm short of the cemento-enamel junction (CEJ) and a 2-mm-thick glass-ionomer cement base was placed. Outer root surfaces were sealed with wax and nail polish, leaving the coronal third of the tooth and the CEJ exposed. All teeth were immersed in a plastic tube containing 2 mL of distilled water, and the experimental groups were treated with a bleaching agent of either 10%, 17% or 37% carbamide peroxide (CP) or a mixture of 30% hydrogen peroxide (HP) and sodium perborate (SP) placed into the coronal pulp chamber of teeth and left for 24 h. Peroxide penetration was measured using the ferrothiocyanate method. Statistical analysis of data was conducted by using the Kruskal-Wallis Analysis of Variance and Mann-Whitney U test.
  
  
  RESULTS
  Higher peroxide penetration occurred with the 30% HP-SP mixture than with the CP bleaching gels, and the 37% CP group also promoted greater peroxide penetration than the other CP groups (P < 0.05). There was no statistically significant difference between 10% and 17% CP groups (P > 0.05).
  
  
  CONCLUSIONS
  Peroxide penetration of CP gels was significantly lower than that of a HP-SP mixture.
authors: Department of Restorative Dentistry, Faculty of Dentistry, University of Ankara, Ankara, Turkey. ogokay@dentistry.ankara.edu.tr
authors: O
authors: O
authors: Gökay
authors: F
authors: F
authors: Ziraman
authors: A
authors: A
authors: Cali Asal
authors: O M
authors: OM
authors: Saka
mesh_terms: D000328:Adult; D001881:Borates / Q000008:administration & dosage / Q000009:adverse effects; D000077463:Carbamide Peroxide; D004058:Diffusion; D004338:Drug Combinations; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000209:etiology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000009:adverse effects; D016877:Oxidants / Q000008:administration & dosage / Q000009:adverse effects; D010545:Peroxides / Q000008:administration & dosage / Q000009:adverse effects; D012391:Root Resorption / Q000209:etiology; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching / Q000009:adverse effects*; D019553:Tooth, Nonvital; D014508:Urea / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives
chemical_list: D001881:Borates; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; C027707:sodium perborate