In vitro evaluation of single application per session of two-bottle bleaching gels

Area of Science:

• Dental Materials Science
• Biomaterials
• Restorative Dentistry

Background:

• In-office bleaching agents are widely used for aesthetic dental treatments.
• Understanding the behavior of hydrogen peroxide (HP) in dental bleaching is crucial for safety and efficacy.
• Two-bottle in-office bleaching systems require careful evaluation of their interaction with dental tissues.

Purpose of the Study:

• To evaluate hydrogen peroxide (HP) permeability into the pulp chamber.
• To assess the bleaching efficacy and physicochemical properties of various in-office bleaching gels.
• To analyze enamel surface effects, microhardness, and roughness after bleaching treatments.

Main Methods:

• Six different 35% HP in-office bleaching gels were applied in three 30-minute sessions.
• HP permeability was measured using UV-Vis spectrophotometry.
• Bleaching efficacy, pH, HP concentration, enamel morphology, microhardness, and roughness were analyzed.

Main Results:

• All gels showed significant bleaching efficacy and induced enamel surface alterations.
• Pola Office (PO) exhibited the highest HP diffusion, while Total Blanc One Step Drop (TD) showed the lowest.
• TD maintained a more neutral initial pH compared to other acidic gels, correlating with reduced HP diffusion.

Conclusions:

• A 30-minute application session is sufficient for bleaching efficacy and morphological changes with tested gels.
• Total Blanc One Step Drop (TD) demonstrated significantly lower HP diffusion into the pulp chamber due to its initial neutral pH.
• TD gel may offer a safer profile regarding pulp exposure while maintaining comparable bleaching outcomes.