Microhardness evaluation of in situ vital bleaching on human dental enamel using a novel study design

Effects of different concentrations of carbamide peroxide and bleaching periods on the roughness of dental ceramics

“…Specimens to be bleached were covered with 0.03 ml of the respective bleaching agent, were placed in vacuum-formed custom trays with a drop of artificial saliva, 8,13 and were stored in a plastic container at 37 °C. [6][7][8] Specimens from control groups were stored only with artificial saliva drops in the vacuum-formed custom tray to mimic oral conditions. After bleaching exposure, specimens were washed with distilled water to remove residual carbamide peroxide gel and were stored in a plastic container for the remaining day period in relative humidity at 37 °C.…”

“…1,[3][4][5] Several microscopic changes on the enamel surface morphology are also observed, due to enamel mineral loss and surface roughening. [6][7][8][9][10][11][12][13][14][15] Extremely unstable and reactive H + free radicals, released by bleaching agents, and low pH are described as the main cause of the side effects of prolonged use of these products. [6][7][8][9][10][11][12][13][14][16][17] Similarly, bleaching agents may cause structural changes on restorative materials that may compromise their physical properties and lead to premature failure.…”

“…[6][7][8][9][10][11][12][13][14][15] Extremely unstable and reactive H + free radicals, released by bleaching agents, and low pH are described as the main cause of the side effects of prolonged use of these products. [6][7][8][9][10][11][12][13][14][16][17] Similarly, bleaching agents may cause structural changes on restorative materials that may compromise their physical properties and lead to premature failure. [18][19][20][21][22][23][24] Although conventional dental ceramics are considered the most inert among all dental restorative materials, their surfaces can exhibit surface deterioration in contact with acidulated fluoride gels or other solutions.…”

Effect of Different Fluoridation Regimes on the Microhardness of Bleached Enamel

“…10 Despite the protective and remineralizing potential of human saliva, when bleaching is performed for six to eight hours daily for two to three weeks, microhardness loss is sometimes evident under in situ conditions. [11][12][13] As demonstrated by Basting and others, 9 saliva increases the microhardness of bleached enamel by providing calcium and phosphate ions, but rehardening might not always be complete. Fluoride might also contribute to the repair of the microstructural defects of bleached enamel.…”

Influence of Prolonged Light-curing Time on the Shear Bonding Strength of Resin to Bleached Enamel

“…56 Glycerin or carbopol, the most common carriers in the carbamide peroxide bleaching formula, may also act as a demineralizing agent. 57 However, carbamide peroxide-based bleaching agents containing fluoride or calcium may impair mineral loss usually promoted by bleaching. 58 This fact can be related to the super saturation of fluoride-containing bleaching gels.…”