Apical root strain as a function of post extension into a composite resin core

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Prefabricated posts are commonly used in endodontically treated teeth.
• The ferrule effect, where the crown covers the tooth structure and post, is crucial for restoration stability.
• Understanding strain distribution in the root is vital for predicting restoration longevity.

Purpose of the Study:

• To test the hypothesis of no difference in root strain at the apical post end.
• To compare strain when a composite resin core covers the post head versus when it is exposed.
• To evaluate the impact of post coverage on root strain in restored teeth.

Main Methods:

• Twenty extracted teeth underwent endodontic treatment and received prefabricated posts.
• Teeth were divided into two groups: post head covered by composite resin or exposed.
• Strain measurements were taken at baseline, after core fabrication, and after crown cementation.

Main Results:

• A statistically significant decrease in root strain was observed when 1 mm of composite resin covered the post head.
• Strain values decreased from baseline to the post-crown restoration stage.
• The magnitude of strain reduction, though statistically significant, was small.

Conclusions:

• Covering the prefabricated post head with a minimal composite resin core can reduce root strain.
• The clinical significance of this strain reduction requires further investigation.
• Optimal post coverage may contribute to improved biomechanical behavior of endodontically treated teeth.