Effect of repeated bleaching by low hydrogen peroxide regimens – with and without MI Paste Plus – on enamel hardness and composition

Publication date: August 2014 Source:Tanta Dental Journal, Volume 11, Issue 2 Author(s): S.E. Abo-Hamar , W.M. Etman Objectives The aim of the present study was to test the following hypotheses: 1. In-vitro repeated bleaching by low hydrogen peroxide (HP) regimens –at 2-month interval- will affect enamel hardness and composition. 2. The use of MI Paste Plus, GC Co. (MIPP) during bleaching treatments will reduce these possible enamel changes. Methods Two 14-day bleaching regimens; 1 h/day of 10% carbamide peroxide (CP) gel; Opalescence PF (OpPF) and 30 min/day of 9.5% HP strips; Crest Whitestrips Advanced Seal (CWAS) were evaluated. Each bleaching regimen was applied on enamel three times, separated by 2 months of artificial saliva with or without MIPP regimen. Surface treatment groups (n = 10/group) included: (1) Artificial saliva (control) (2) OpPF, (3) CWAS (4) OpPF-MIPP, and (5) CWAS-MIPP. Vicker Hardness (VH) was repeatedly measured for all groups; at baseline and after 2, 12 and 22 weeks (after each bleaching treatment). The final enamel surface of each group was chemically analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Results The median VHs (Kg/mm2) were: (1) 310, 312, 330, 343; (2) 299, 272, 283, 264; (3) 320, 277, 271, 255; (4) 300, 311, 304, 316, and (5) 305, 315, 309, 320, respectively. Friedman repeated measures ANOVA on ranks (Dunnett method) indicated that enamel VH was significantly reduced after the third OpPF treatment and afte...

Source: Tanta Dental Journal - November 6, 2014 Category: Dentistry Source Type: research