Bleaching agents increase metalloproteinases-mediated collagen degradation in dentin

Area of Science:

• Biomaterials Science
• Dental Materials
• Biochemistry

Background:

• Tooth bleaching commonly utilizes hydrogen peroxide-based agents.
• Understanding the impact of bleaching on dentin collagen is crucial for long-term dental health.

Purpose of the Study:

• To investigate the effect of various dental bleaching agents on metalloproteinases-mediated dentin collagen degradation.
• To assess the influence of phosphoric acid (PA) and single bond (SB) on this degradation process.

Main Methods:

• Human dentin specimens underwent treatments including demineralization (PA), resin infiltration (SB), and various bleaching protocols (nonvital, in-office, home).
• Collagen degradation was quantified by measuring C-terminal telopeptide of type I collagen (ICTP) using radioimmunoassay at multiple time points (24 hours, 1 week, 4 weeks).

Main Results:

• All tested bleaching agents increased dentin collagen degradation, with higher levels observed after PA demineralization.
• Nonvital bleaching combined with PA showed the highest collagenolytic activity, which was reduced by SB infiltration.
• Home bleaching demonstrated high initial collagenolytic activity that decreased over time, but all procedures resulted in significant degradation after 4 weeks.

Conclusions:

• Dental bleaching agents exacerbate matrix metalloproteinases-mediated collagen degradation in dentin.
• The observed collagen degradation was not fully reversible within the 4-week study period.
• Home bleaching agents induced the most significant collagen degradation among the tested methods.