Effect of Intracoronal Barrier Location on Bleaching Efficacy and Peroxide Diffusion

Area of Science:

• Endodontics
• Dental Materials Science
• Cosmetic Dentistry

Background:

• The effectiveness of internal tooth bleaching is influenced by factors like barrier material and placement.
• Optimal positioning of the intracoronal bleaching barrier is crucial for maximizing whitening outcomes and managing hydrogen peroxide diffusion.

Purpose of the Study:

• To investigate how the positioning of a cervical barrier affects bleaching effectiveness in different tooth regions.
• To analyze the impact of cervical barrier placement on hydrogen peroxide diffusion during internal bleaching procedures.

Main Methods:

• Eighty bovine incisors were used, with a cervical barrier placed either coronally or apically to the cementoenamel junction (CEJ).
• Internal bleaching was performed using 35% hydrogen peroxide (H2O2) over three sessions.
• Chromatic changes and whiteness index were measured in root, cervical, and incisal regions, and H2O2 diffusion was quantified.

Main Results:

• A barrier positioned apical to the CEJ resulted in significantly greater chromatic differences and whitening index in the root and cervical regions compared to a coronal placement.
• No significant differences in bleaching effectiveness were observed in the incisal region between the two barrier positions.
• Hydrogen peroxide diffusion was significantly higher when the barrier was placed apically to the CEJ.

Conclusions:

• Cervical barrier position significantly influences internal bleaching effectiveness, particularly in the root and cervical tooth regions.
• An apical barrier position enhances bleaching in the root and cervical areas but also increases hydrogen peroxide diffusion.
• Careful consideration of barrier placement is necessary to balance bleaching efficacy and potential risks associated with increased H2O2 diffusion.