An SEM study of posts cemented with an unfilled resin

Area of Science:

• Restorative Dentistry
• Endodontics
• Dental Materials Science

Background:

• Post-endodontic restorations require secure post cementation for optimal function.
• The smear layer can impede effective bonding between posts and dentinal tubules.
• Optimizing resin penetration is crucial for enhancing the mechanical retention of posts.

Purpose of the Study:

• To evaluate the effect of different irrigating solutions on resin penetration into dentinal tubules.
• To assess the impact of smear layer removal on the micro-mechanical retention of cemented posts.

Main Methods:

• Two groups of endodontically treated anterior teeth were prepared for post placement.
• Group I: Rinsed with 5.25% sodium hypochlorite (NaOCl).
• Group II: Rinsed with 17% ethylenediaminetetraacetic acid (EDTA) followed by NaOCl.
• Plastic posts were cemented, teeth decalcified, and post-dentin interface examined via SEM for resin penetration.

Main Results:

• Group I showed limited resin penetration into dentinal tubules.
• Group II demonstrated significant resin penetration along the full length and circumference of the post.
• SEM analysis confirmed superior resin infiltration into tubules in the EDTA-treated group.

Conclusions:

• Pre-treatment with EDTA effectively removes the smear layer, facilitating deeper resin penetration.
• Enhanced resin penetration into dentinal tubules creates a strong mechanical lock, increasing post tensile strength.
• This technique improves the bond strength of cemented posts, even with shorter post designs.