Dendrimer-based extrafibrillar demineralization for optimizing resin-dentin bond stability

Area of Science:

• Biomaterials Science
• Dental Materials
• Nanotechnology

Background:

• A novel selectively extrafibrillar dentin demineralization concept preserves intrafibrillar minerals.
• This approach aims to prevent endogenous protease activation and collagen degradation in hybrid layers.
• Durability of resin-dentin bonds is a critical challenge in restorative dentistry.

Purpose of the Study:

• To investigate PEGylated PAMAM dendrimer (PEG-P) as an antimicrobial conditioner for extrafibrillar dentin demineralization.
• To assess the potential of PEG-P to improve the durability of resin-dentin bonds.
• To evaluate PEG-P's efficacy in preserving intrafibrillar minerals and inhibiting bacterial activity.

Main Methods:

• Chelation capacity of PEG-P for calcium ions measured by ICP-AES.
• Microtensile bond strength testing determined optimal PEG-P concentration and PEGylation degree.
• FE-SEM, AFM, and in-situ zymography examined demineralization morphology and gelatinolytic activity.
• Antibacterial effects of PEG-P on oral bacteria evaluated using live/dead staining.

Main Results:

• PEG-P demonstrated effective chelation of calcium ions.
• 20% PEG-P conditioning yielded bond strengths comparable to H3PO4 etching, maintained after thermocycling.
• FE-SEM and AFM revealed partially demineralized dentin with mineralized collagen fibrils using PEG-P.
• In-situ zymography showed negligible protease activity in PEG-P treated hybrid layers.
• PEG-P exhibited potent antibacterial effects against oral bacteria.

Conclusions:

• PEG-P based demineralization preserves intrafibrillar minerals and reduces collagen degradation.
• This method effectively inhibits endogenous protease activation and bacterial retention.
• PEG-P application significantly improves the durability of resin-dentin bonds.
• Selectively extrafibrillar demineralization using PEG-P represents a promising advancement in dental adhesives.