This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Tam, L.E. Articles by Noroozi, A. Search for Related Content PubMed PubMed Citation Articles by Tam, L.E. Articles by Noroozi, A. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB HYDROGEN PEROXIDE UREA Social Bookmarking                         What's this?

Effects of Direct and Indirect Bleach on Dentin Fracture Toughness

Restorative Dentistry, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON, Canada M5G 1G6

View larger version (21K): [in this window] [in a new window]   Figure 1. Direct application mode results (mean ± standard deviation). Fracture toughness (K1C) (MPa*m1/2) of human dentin for 16% carbamide peroxide, 10% carbamide peroxide, and 3% hydrogen peroxide groups, compared with their respective control groups, after two- and eight-week direct treatment (n = 10, ANOVA and Fisher’s LSD, p < 0.05). There were no significant differences in mean fracture toughness among the direct control groups. The mean fracture toughness was significantly lower for all bleach groups than for control groups after both two- and eight-week direct treatment. The mean fracture toughness for 16% carbamide peroxide was significantly lower than that for 10% carbamide peroxide after two-week direct treatment. With a 61–68% reduction in mean fracture toughness, the eight–week bleached groups showed the lowest direct fracture toughness significant results.

View larger version (24K): [in this window] [in a new window]   Figure 2. Indirect application mode results (mean ± standard deviation). Fracture toughness (K1C) (MPa*m1/2) of human dentin for 16% carbamide peroxide, 10% carbamide peroxide, and 3% hydrogen peroxide groups, compared with their respective control groups, after two- and eight-week indirect treatment (n = 10, ANOVA and Fisher’s LSD, p < 0.05). There were no significant differences in mean fracture toughness among the indirect control groups. Compared with their control groups, there were significant decreases in mean fracture toughness for 16% carbamide peroxide after both two- and eight-week indirect treatment, and for 10% carbamide peroxide after eight-week indirect treatment. With a 37% reduction in mean fracture toughness, the eight-week 16% carbamide peroxide group showed the lowest indirect fracture toughness significant result.

View larger version (86K): [in this window] [in a new window]   Figure 3. Scanning electron microscopy (SEM) photomicrograph of dentin fracture surface after eight-week direct treatments. (A) Dentin fracture surface after eight-week direct control treatment. (B) Dentin fracture surface after eight-week direct bleach treatment (16% carbamide peroxide). In general, the surface morphology of the dentin fracture surfaces of the bleach and control dentin groups appeared quite similar. SEM examination revealed localized evidence of demineralization, particularly in the tubule walls, of bleached specimens. T = Dentin tubule lumen. P = Peritubular dentin. I = Intertubular dentin.

Journal of Dental Research, Vol. 86, No. 12, 1193-1197 (2007)
DOI: 10.1177/154405910708601210


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?