Marginal integrity produced by quaternary ammonium methacrylate-based dental adhesive tested under physiologically...

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Cariology

Background:

• Endogenous matrix metalloproteinases (MMPs) degrade dentin collagen during demineralization, a key process in dental caries.
• Quaternary ammonium compounds (QACs) exhibit antibacterial properties and have shown potential as MMP inhibitors.

Purpose of the Study:

• To evaluate a novel quaternary ammonium-based methacrylate (dimethylaminohexadecyl methacrylate - DMAHDM, QAM) as an experimental dental adhesive.
• To assess QAM's efficacy in maintaining bond stability and preventing gap formation under physiologically relevant conditions using a bioreactor system.

Main Methods:

• MMP inhibition was assessed via fluorescence assay; dentin mechanical stability was measured using rheometry.
• Collagen degradation was quantified via hydroxyproline assay; adhesive degree of conversion was evaluated by near-IR spectroscopy.
• Microtensile bond strength, biofilm inhibition, and gap formation were assessed in simulated cavity preparations under mechanical and bacterial challenges in a bioreactor.

Main Results:

• QAM significantly enhanced dentin's mechanical stability and reduced collagen degradation, outperforming chlorhexidine (CHX).
• QAM demonstrated superior inhibition of bacterial growth, biofilm formation, and viability compared to CHX.
• While both QAM and CHX showed increased gap formation under bacterial challenge, QAM-adhered samples were stable under mechanical loading in the bioreactor.

Conclusions:

• QAM-based adhesives offer enhanced protection against MMP activity and possess robust antimicrobial effects, surpassing CHX.
• These findings suggest QAM-based materials can preserve dentin structure and improve the longevity of dental restorations.
• The study highlights the potential of QAM as a dual-action agent for both antimicrobial and collagen-preserving benefits in restorative dentistry.