Better Glass-fiber Post Preservation in Teeth with Ferrule When Subjected to Chewing

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Ferrule effect is crucial for the longevity of endodontically treated teeth with posts.
• Glass-fiber posts are widely used due to their favorable mechanical properties.
• Understanding factors affecting post-dentin bond strength is essential for clinical success.

Purpose of the Study:

• To evaluate the influence of the ferrule effect and mechanical fatigue on the push-out bond strength (PBS) of glass-fiber posts to root-canal dentin.
• To assess these effects at different root thirds of premolars.

Main Methods:

• Thirty-two premolars were divided into groups with (RDF) and without (WDF) a 2.0-mm dentin ferrule.
• Teeth underwent endodontic treatment, glass-fiber post cementation, and core buildup.
• Specimens were subjected to mechanical fatigue (1.2 million cycles) or control storage.
• Push-out bond strength was tested on 1.0-mm slices from different root thirds.

Main Results:

• The absence of a dentin ferrule significantly reduced PBS after mechanical fatigue (WDF_F group).
• Mechanical fatigue significantly decreased PBS in both ferrule groups.
• Failure modes predominantly occurred at the composite cement/dentin interface, with increased mixed failures in the WDF_F group.

Conclusions:

• A 2.0-mm remaining dentin ferrule is critical for maintaining glass-fiber post bond strength to dentin under mechanical fatigue.
• The absence of ferrule leads to a substantial decrease in bond strength, particularly after simulated chewing.
• Clinical recommendations should emphasize preserving adequate dentin ferrule height for enhanced post retention.