Long-term Adhesion Study of Self-etching Systems to Plasma-treated Dentin

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Surface Science

Background:

• Adhesive dentistry relies on durable bonds between restorative materials and tooth structure.
• Surface treatments aim to enhance adhesion, but long-term stability remains a challenge.
• Atmospheric pressure plasma (APP) offers a novel approach to modify material surfaces.

Purpose of the Study:

• To evaluate the impact of atmospheric pressure plasma (APP) on dentin microtensile bond strength of two self-etching adhesives after one year of water storage.
• To assess changes in dentin surface energy via contact angle measurements.
• To examine resin-dentin interface micromorphology using scanning electron microscopy (SEM).

Main Methods:

• Human molars were prepared to expose dentin surfaces for contact angle and microtensile bond strength testing.
• Dentin surfaces were treated with argon APP or blown air (control).
• Microtensile bond strength was tested after 24 hours and one year of water storage; SEM analyzed interfacial morphology.

Main Results:

• APP treatment reduced dentin contact angles, indicating increased surface energy.
• Bond strength was enhanced by APP for one tested adhesive, but this effect diminished after one year of water storage.
• SEM revealed degradation of interfacial structures after one year of aging, with APP effects being product-dependent.

Conclusions:

• APP treatment effectively increases dentin surface energy.
• While APP initially improved bond strength for one adhesive (Scotchbond Universal), this benefit was negated by one-year water storage.
• The long-term efficacy of APP in enhancing dentin bond strength is adhesive-system dependent and susceptible to degradation over time.