Microtensile testing of dentin adhesives.

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Biomaterials Engineering

Background:

• Dental adhesives are crucial for restoring tooth structure.
• Evaluating the bond strength of dentin adhesive systems is essential for clinical success.
• Various testing methods exist, each with unique advantages and limitations.

Purpose of the Study:

• To compare the microtensile and shear bond strengths of five commercial dentin adhesive systems.
• To determine which testing method provides a more definitive assessment of adhesive bond strength.
• To identify the strongest performing adhesive system among those tested.

Main Methods:

• Five commercial dentin adhesive systems were tested: Scotchbond Multipurpose with maleic acid (SM), Scotchbond Multipurpose with phosphoric acid (SP), Scotchbond Multipurpose Plus (SBP), Clearfil Liner Bond System (CL), and Prime and Bond (PB).
• Microtensile bond strength was assessed on 30 extracted unerupted third molars.
• Shear bond strength was evaluated on 35 additional teeth.
• Fracture sites were analyzed using light and scanning electron microscopy.

Main Results:

• Microtensile bond strengths (MPa +/- SD) were: SM, 24.6 +/- 7.2; SP, 28.8 +/- 11.8; SBP, 22.7 +/- 6.5; PB, 25.5 +/- 9.4; and CL, 36.8 +/- 10.0.
• Clearfil Liner Bond System (CL) demonstrated significantly higher microtensile bond strength (p < 0.05) compared to SM, SP, SBP, and PB.
• No significant differences were found in shear bond strengths among the systems.
• Shear bond testing resulted in more intra-radicular failures than microtensile testing.

Conclusions:

• Microtensile testing offers a more definitive assessment of dentin adhesive bond strength compared to shear bond testing.
• Clearfil Liner Bond System (CL) exhibited superior microtensile bond strength among the evaluated systems.
• The choice of testing methodology can influence the interpretation of adhesive performance.