Push-out stress for fibre posts luted using different adhesive strategies

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Fiber posts are widely used in endodontically treated teeth.
• The long-term stability of fiber post cementation is crucial for clinical success.
• Understanding the effects of environmental factors like thermocycling on bond strength is essential.

Purpose of the Study:

• To evaluate the influence of thermocycling on the bond strength of fiber posts.
• To compare the stability of different luting approaches under simulated oral conditions.
• To assess interfacial nanoleakage after thermocycling.

Main Methods:

• 84 human incisors were used, with 60 assigned to three luting groups (XP Bond/CoreXFlow, Panavia F 2.0, RelyX Unicem).
• Specimens were subjected to 40,000 thermocycles or stored in artificial saliva.
• Push-out bond strength and interfacial nanoleakage (silver nitrate uptake) were quantitatively analyzed.

Main Results:

• Thermocycling significantly reduced bond strength for Panavia F 2.0 and RelyX Unicem groups.
• The XP Bond/CoreXFlow group showed no significant bond strength decrease after thermocycling.
• All groups exhibited increased nanoleakage after thermocycling, indicating degradation.

Conclusions:

• The combination of an etch-and-rinse adhesive with a dual-cure cement offers superior stability for luting fiber posts compared to self-etch or self-adhesive systems.
• Thermocycling poses a challenge to the longevity of certain fiber post luting protocols.
• Material selection is critical for ensuring durable cementation of fiber posts in challenging environments.