Phosphoric acid/sodium hypochlorite mixture as dentin conditioner: a new approach

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Dentin conditioning is crucial for effective adhesion of dental restorative materials.
• Traditional methods like phosphoric acid etching have limitations.
• Investigating novel conditioning agents can optimize the resin-dentin interface.

Purpose of the Study:

• To evaluate a phosphoric acid/sodium hypochlorite (NaOCl) mixture as a dentin conditioner.
• To assess its impact on shear bond strength and the resin/dentin interface.
• To analyze changes in dentin surface area and tubular diameter.

Main Methods:

• Human molars were conditioned using phosphoric acid, phosphoric acid followed by NaOCl, or a phosphoric acid/NaOCl mixture.
• Shear bond strength was measured after bonding composite resin.
• Scanning electron microscopy (SEM) and atomic force microscopy (AFM) evaluated the interface and dentin surface characteristics.

Main Results:

• The phosphoric acid/NaOCl mixture (Group III) yielded the highest shear bond strength (36 MPa).
• SEM confirmed hybrid layer formation in most groups, except for the phosphoric acid followed by NaOCl group.
• AFM indicated increased surface area and dentinal tubular diameter with NaOCl application (Groups II and V).

Conclusions:

• A phosphoric acid/NaOCl mixture effectively conditions dentin.
• This conditioning method enhances the bond strength of etch-and-rinse adhesives to dentin.
• The findings suggest a promising alternative for optimizing dental adhesive procedures.