Is It Necessary to Prepare the Enamel before Dental Bleaching?

Area of Science:

• Dental Materials Science
• Biomaterials
• Surface Chemistry

Background:

• Dental bleaching with hydrogen peroxide can negatively impact enamel microhardness.
• Surface treatments are explored to mitigate adverse effects of bleaching on enamel properties.

Purpose of the Study:

• To evaluate the effect of different surface treatments on bovine enamel microhardness and color after bleaching.
• To determine if pre-bleaching surface treatments can preserve or restore enamel integrity.

Main Methods:

• In vitro study using 40 bovine enamel blocks.
• Tested surface treatments: no treatment, 2% sodium fluoride, casein phosphopeptide paste, and 2% fluoride + Nd:YAG laser.
• Assessed Knoop microhardness and color changes (ΔE, ΔL, Δa, Δb) before and after 35% hydrogen peroxide bleaching.

Main Results:

• All groups showed a decrease in enamel microhardness immediately after bleaching, most pronounced in the untreated group.
• Enamel color changed in all tested groups.
• After 7 days, specimens treated before bleaching showed significant microhardness recovery without compromising bleaching aesthetics.

Conclusions:

• Pre-bleaching surface treatments can offer protection against microhardness reduction caused by hydrogen peroxide.
• Certain treatments, particularly those involving fluoride and laser, may promote microhardness recovery post-bleaching.
• The tested surface treatments did not negatively impact the esthetic outcomes of dental bleaching.