Effect of polyacrylic acid on dentin protease activities

Area of Science:

• Biomaterials Science
• Dental Research
• Biochemistry

Background:

• Demineralized dentin is susceptible to enzymatic degradation by matrix metalloproteinases (MMPs) and cathepsin K (CAT-K).
• Understanding the effects of conditioning agents on these enzymes is crucial for preserving dentin integrity.
• Polyacrylic acid (PAA) and phosphoric acid (PA) are commonly used in dental treatments.

Purpose of the Study:

• To investigate the impact of polyacrylic acid (PAA) treatment on demineralized dentin's matrix metalloproteinases (MMPs) and cathepsin K (CAT-K) activity.
• To compare the inhibitory effects of benzalkonium chloride (BAC) and chlorhexidine digluconate (CHX) when combined with PAA or PA.

Main Methods:

• Dentin beams were demineralized using EDTA and subsequently treated with various agents including PA, PA+BAC, PA+CHX, PAA, PAA+BAC, and PAA+CHX.
• Mass loss was assessed after incubation in simulated body fluid (SBF).
• Enzyme activity was evaluated by measuring ICTP (for MMPs) and CTX (for CAT-K) in the SBF, alongside a generic MMP assay.

Main Results:

• PAA treatment significantly increased CAT-K activity compared to control and PA treatments.
• Both PA and PAA treatments showed increased MMP-mediated degradation (ICTP release) compared to control.
• CHX, when combined with PA or PAA, significantly reduced ICTP release, outperforming BAC.

Conclusions:

• 10% PAA activates CAT-K in demineralized dentin more than 37% PA.
• 2% CHX demonstrates superior inhibition of both MMPs and CAT-K compared to 2% BAC.
• These findings highlight the differential effects of conditioning agents on dentin matrix-degrading enzymes.