Push-Out Bond Strength of Endodontic Posts Cemented to Extracted Teeth: An In-Vitro Evaluation

Area of Science:

• Endodontics
• Dental Materials Science
• Restorative Dentistry

Background:

• Optimal retention and prognosis of endodontic posts rely on ideal bond strength between posts and root canal dentin.
• Prefabricated posts (metal and fiber) are commonly used in endodontic restorations.
• Resin cements are widely used for luting posts due to their adhesive properties.

Purpose of the Study:

• To evaluate and compare the push-out bond strength (PBS) of prefabricated metal and fiber posts luted with resin cement to natural dentin.
• To investigate the influence of post size on the bond strength of these posts.
• To determine the failure modes associated with different post types and sizes.

Main Methods:

• Extracted premolars were divided into metal and fiber post groups, endodontically treated, and prepared for post space.
• Posts of varying sizes (#4, #5, #6) were cemented using resin cement.
• Specimens were sectioned into 4mm slices and subjected to push-out bond strength testing.

Main Results:

• Mean push-out bond strength was statistically similar between metal and fiber posts.
• Increasing post size initially enhanced bond strength, with diminishing returns for larger sizes.
• Adhesive failure between the cement and dentin occurred in 71.66% of specimens.

Conclusions:

• Metal posts exhibited slightly higher retention than fiber posts, though not statistically significant.
• Post size positively correlated with retention, up to a certain point.
• The predominant failure mode was adhesive failure, indicating a potential area for improvement in cement-dentin bonding.