Sodium Hypochlorite and Chlorhexidine Downregulate MMP Expression on Radicular Dentin.

Area of Science:

• Endodontics
• Dental Biomaterials
• Molecular Biology

Background:

• Matrix metalloproteinases (MMPs) are crucial for dentin biomineralization and regeneration.
• MMP expression in radicular dentin can be influenced by root canal irrigation protocols.

Purpose of the Study:

• To investigate the impact of common endodontic irrigants on matrix metalloproteinase (MMP) expression in radicular dentin.

Main Methods:

• Human root dentin samples were treated with distilled water, 5% sodium hypochlorite (NaOCl), 18% ethylenediaminetetraacetic acid (EDTA), or 2% chlorhexidine (CHX).
• Zymography and immunohistochemistry were employed to analyze MMP activity and localization.

Main Results:

• Zymography detected MMP-2, MMP-8, and MMP-20 in control and EDTA groups.
• Immunohistochemistry confirmed MMP-2 and MMP-9 presence, with reduced expression in NaOCl and CHX groups.
• EDTA treatment led to higher MMP expression compared to other irrigants.

Conclusions:

• Standard root canal irrigants significantly alter MMP expression in radicular dentin.
• NaOCl and CHX decrease MMP expression, whereas EDTA enhances it, impacting dentin's regenerative potential.