Effect of etching agent on dentinal adhesive interface in primary teeth.

Area of Science:

• Dental Materials Science
• Biomaterials
• Adhesion Science

Background:

• The dentin/adhesive interface is critical for the longevity of dental restorations.
• Primary teeth present unique challenges for bonding due to their distinct dentin structure.
• Effective smear layer removal is essential for optimal adhesion.

Purpose of the Study:

• To evaluate the in vitro effect of phosphoric acid etchant containing benzalkonium chloride on the dentin/adhesive interface in primary teeth.
• To compare the efficacy of this combination with conventional phosphoric acid etching and benzalkonium chloride solutions alone.

Main Methods:

• Primary teeth with caries lesions were treated with different etching agents (phosphoric acid with/without benzalkonium chloride) or benzalkonium chloride solutions.
• Teeth were restored with a dental adhesive and composite resin.
• Restored teeth underwent thermal cycling.
• Bonded interfaces were analyzed using SEM for hybrid layer formation, resin tags, and gaps.

Main Results:

• Phosphoric acid with benzalkonium chloride completely removed the smear layer, forming a hybrid layer (approx. 7.32 microns) and resin tags.
• Conventional 35% phosphoric acid also formed a hybrid layer (approx. 8.15 microns) with no observed gaps.
• Benzalkonium chloride solutions alone or untreated controls showed incomplete smear layer removal, gaps, and no hybrid layer formation.

Conclusions:

• Phosphoric acid containing benzalkonium chloride is effective in preparing the dentin surface for bonding in primary teeth.
• This combination promotes the formation of a durable hybrid layer and resin tags, comparable to conventional phosphoric acid etching.
• The findings suggest potential for improved bond strength and restoration longevity.