Sodium carboxymethyl cellulose-based extrafibrillar demineralization to optimize dentin bonding durability

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Nanotechnology

Background:

• Dentin bonding durability is crucial for the longevity of adhesive dental restorations.
• Current conditioning methods can compromise dentin's mechanical integrity and promote degradation.
• There is a need for minimally invasive conditioners that enhance bonding while preserving dentin structure.

Purpose of the Study:

• To investigate the effects of a sodium carboxymethyl cellulose (SCMC)-based conditioner on dentin bonding durability.
• To explore the mechanisms underlying SCMC's influence on dentin's extrafibrillar components and mechanical properties.
• To evaluate SCMC as a potential alternative to traditional phosphoric acid conditioning.

Main Methods:

• Developed an SCMC-based extrafibrillar demineralization conditioner.
• Utilized a single-layer collagen model to visualize demineralization.
• Conditioned human dentin with SCMC or phosphoric acid (PA), assessing morphology, composition, and mechanical properties.
• Evaluated microtensile bond strength (MTBS), nanoleakage, and in situ zymography after various aging protocols.
• Assessed SCMC's inhibitory effect on matrix metalloproteinase-2 (MMP-2) and its cytotoxicity.

Main Results:

• SCMC conditioning led to extrafibrillar mineral demineralization while retaining intrafibrillar minerals.
• Dentin's mechanical properties were largely preserved after SCMC conditioning.
• SCMC resulted in significantly higher MTBS, reduced nanoleakage, and suppressed endogenous gelatinolytic activity compared to PA, especially after aging.
• SCMC demonstrated dose-dependent inhibition of MMP-2 and was found to be non-toxic.

Conclusions:

• SCMC-based extrafibrillar demineralization conditioner enhances dentin bonding durability.
• SCMC preserves dentin's mechanical properties and inhibits MMP activity, contributing to improved restoration longevity.
• This approach offers a promising, minimally invasive strategy for extending the service life of adhesive dental restorations.