Effect of tooth whitening strips on fatigue resistance and flexural strength of bovine dentin in vitro

Abstract

ObjectiveTo determine the effects of whitening strips on bovine dentin fatigue resistance and flexural strength in vitro.Materials and methodsA total of eighty bovine dentin specimens (2x2x17mm) were treated with either: control glycerine gel on plastic film wrap or whitening strips containing 9.5% hydrogen peroxide. Treatment was applied for 30 minutes, twice a day, for 1- or 4-weeks. After the last treatment, ten specimens per group were randomly selected to undergo fatigue testing (106 cycles, 3Hz, 20N) while the other ten were subjected to flexural strength testing after ten days of storage in artificial saliva. Kaplan-Meier method with a log rank test, Wilcoxon test and Cox regression were used to assess fatigue test results (p<0.05). One-way ANOVA and Tukey’s tests were used to compare the flexural strength results (p<0.05).ResultsThere were significant differences in survival during the fatigue test among the groups (p<0.001). Treatment (control or bleach) was a significant factor for specimen survival (p<0.001, Exp(B) = 33.45). There were significant differences in mean flexural strength (p<0.001). No significant difference was found between “1-wk control” and “4-wk control”. The mean flexural strength and fatigue resistance of the “4-wk bleach” were significantly lower than all the other groups.ConclusionsThe use of whitening strips reduced the fatigue resistance and flexural strength of bovine dentin in vitro. Until the effect of whitening strips on mechanical properties of human dentin is fully elucidated, it remains prudent to advise patients to avoid excessive direct use of whitening strips on dentin.

Influence of a short‐time antioxidant application on the dentin bond strength after intracoronal bleaching

“…Additionally, it has been suggested that bleaching procedures may cause protein denaturation with free radicals that break the double bonds, leading to the degradation of the resin–dentin bond (Plotino et al, ). However, Tam, Kim, and De Souza () stated that the HP did not induce significant changes in the inorganic and organic contents of the tooth, but they observed the oxidation of the organic structure by the release of reactive oxygen species. No publication has established a correlation between a drop in the bond strength and structural changes along the bleached dentin.…”

New Insights into Effects of Aromatic Amino Acids on Hydroxyapatite

“…Thus, HP may not only oxidize the benzene ring in AAAs but also saturate double bonds in other AAs, which can also change the protein structure. Teeth treated with HP demonstrate decreased mechanical behavior, including fracture toughness (Tam and Noroozi 2007), fatigue resistance, flexural strength (Tam et al 2017), elastic modulus, and creep (Elfallah et al 2015). The assumption that the declined mechanical performances result from the oxidation of organic matrix by HP is well accepted (Jiang et al 2007; Eimar et al 2012).…”

Assessment of Bonding Effectiveness of Adhesive Materials to Tooth Structure using Bond Strength Test Methods: A Review of Literature

“…Many investigators have used bovine teeth as substitutes for human teeth because of the difficulty in collecting intact extracted human teeth for laboratory studies [ 48 , 49 ]. However, bovine coronal dentin has larger dentinal tubules than in human dentin.…”