Universal adhesives applied to deep dentin with different bonding treatments

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Biomaterials

Background:

• Eighth-generation universal adhesives offer versatile application methods, including total-etch, selective-etch, and self-conditioning.
• These adhesives also function as primers for non-dental substrates, expanding their clinical utility.

Purpose of the Study:

• To evaluate the bonding characteristics of universal adhesives on deep pulp walls using different application strategies.
• To compare shear bond strength and adhesive layer thickness across various etching techniques.

Main Methods:

• Thirty-six extracted molars were prepared with cavities and divided into nine groups based on etching strategy (total-etch, selective-etch, self-conditioning) and adhesive type.
• Shear bond strength was measured using a universal testing machine, and adhesive layer thickness was analyzed via laser microscopy.

Main Results:

• The total-etch strategy yielded significantly higher mean shear bond strength (8.61 MPa) compared to selective-etch (6.71 MPa) and self-conditioning (6.91 MPa) (p=0.049).
• No significant differences in bond strength were observed among the three universal adhesives tested (p=0.205).
• Adhesive layer thickness was greatest in the total-etch group (8.71 μm) but showed no significant difference between selective-etch (5.49 μm) and self-conditioning (6.27 μm).

Conclusions:

• Bonding strategy significantly impacts universal adhesive performance, with total-etch providing the highest bond strength.
• Selective-etch and self-conditioning strategies exhibited comparable bond strengths.
• The choice of universal adhesive did not significantly affect bond strength or layer thickness across the evaluated methods.