Do Mechanical Advantages Exist in Relining Fiber Posts with Composite Prior to its Cementation?

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Fiber-reinforced resin posts (FRC) are commonly used in endodontically treated teeth.
• Polymerization shrinkage and mechanical loading can induce stress in post-retained restorations.
• Optimizing post insertion techniques is crucial for long-term restoration success.

Purpose of the Study:

• To compare stress distribution and dentin bond strength between conventionally cemented (FRC) and relined (RFRC) fiber posts.
• To evaluate the impact of insertion technique on post-endodontic restoration performance.

Main Methods:

• Three-dimensional finite element analysis simulated stress distribution under polymerization shrinkage and masticatory loading.
• In vitro pull-out bond strength tests were conducted after mechanical cycling.
• Statistical analysis (ANOVA, Tukey's test) compared results between FRC and RFRC groups.

Main Results:

• The relined fiberglass post (RFRC) group exhibited significantly better stress distribution compared to the conventionally cemented FRC group.
• RFRC demonstrated superior pull-out bond strength to dentin (288 ± 129 MPa) versus FRC (152 ± 87 MPa).
• Adhesive and mixed failures were observed in both groups, indicating areas for further investigation.

Conclusions:

• Relined fiberglass posts effectively reduce stress concentration from polymerization shrinkage.
• The RFRC technique enhances bond strength to dentin, improving restoration stability.
• This method offers a promising approach for reinforcing endodontically treated teeth.