Enamel Surface and Elemental Changes Following In Vitro Bleaching: A SEM-EDS Approach

Area of Science:

• Dental Materials Science
• Biomaterials
• Surface Chemistry

Background:

• Chairside bleaching procedures can impact tooth enamel's surface morphology and mineral composition.
• Understanding these changes is crucial for predicting clinical outcomes and ensuring long-term dental health.

Purpose of the Study:

• To compare the in vitro effects of three different in-office bleaching protocols on human tooth enamel.
• To evaluate surface alterations and elemental composition changes using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

Main Methods:

• Forty-two human premolars/molars were divided into control and three experimental groups.
• Experimental groups received Opalescence Quick (45% carbamide peroxide), Opalescence Boost (40% hydrogen peroxide), or BlancOne Ultra+ (35% hydrogen peroxide with light activation).
• SEM analyzed surface topography, and EDS quantified elemental percentages (O, Ca, P, C).

Main Results:

• All bleaching protocols induced surface alterations and elemental shifts in enamel.
• BlancOne Ultra+ exhibited the most severe demineralization, with significant decreases in calcium (Ca) and phosphorus (P) levels.
• Opalescence Quick showed moderate surface changes, while Opalescence Boost resulted in superficial restructuring with variable mineral content.
• Significant differences in Ca and P content were observed across all bleached groups (p < 0.001).

Conclusions:

• All tested in-office bleaching agents alter enamel surface and composition, with a severity gradient: BlancOne Ultra+ > Opalescence Boost > Opalescence Quick.
• High-concentration, light-activated hydrogen peroxide agents cause the most substantial calcium and phosphorus loss.
• Clinical recommendations include considering neutral-pH, non-activated, or chemically activated systems and prioritizing immediate post-bleaching remineralization, especially before restorative procedures.