Proper cementation of a fiber post is essential to ensure a stable, lasting restoration. Follow these detailed steps for effective cementation.
Preparing the Post
- Clean the Post Surface: Start by cleaning the post with a cotton pellet soaked in alcohol to remove any contaminants.
- Apply Silane Agent: Coat the post with multiple layers of a silane agent to enhance bonding, then gently air-dry to evaporate any solvents.
Bonding Procedures on the Tooth Surface
- Protect Adjacent Teeth: Place a Mylar strip around adjacent teeth to avoid accidental contact with phosphoric acid.
- Etching the Root Canal:
- Apply phosphoric acid at the full depth of the root canal to ensure thorough etching and minimize air bubbles.
- Make sure to etch all areas that will receive adhesive, cement, and composite resin for the core build-up.
- Rinse and Dry:
- Rinse the canal thoroughly to remove all acid remnants, using irrigation tips if needed to reach full depth.
- Use absorbent paper points to remove excess moisture, ensuring the canal is dry but not desiccated.
Adhesive Application
- Apply Dual-Cure Adhesive: Use a micro-brush to apply a dual-cure adhesive to the dental substrate, covering the entire bonding area and the post surface.
- Volatilize Solvents: Use a gentle air jet to evaporate solvents.
- Remove Excess Adhesive: Use absorbent paper points to remove any adhesive surplus and ensure even distribution.
Cement Application
- Apply Dual Resin Cement:
- Using a syringe or lentulo drills, apply the resin cement to the canal walls.
- Apply cement to the post and insert it quickly to the full depth to avoid premature polymerization, which could hinder full seating of the post.
- Positioning the Post: Place the post into the canal and apply digital pressure to secure it at the predetermined height.
- Light Cure: Remove any unpolymerized cement, then light-cure to set the cement fully.
Core Build-Up
Once the post is cemented, construct the core build-up by incrementally adding light-cured composite or using another preferred technique. This core build-up supports the final restoration.
a video demonstration explaining the full procedure
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Frequently Asked Questions (FAQ)
Why is silane application important before cementing a fiber post?
Silane application enhances the bonding between the resin cement and the fiber post surface. Multiple layers of silane agent improve micromechanical retention and create a chemical bond, resulting in superior post retention and reducing the risk of post displacement during insertion or removal.
What type of adhesive should be used for fiber post cementation?
A dual-cure adhesive is recommended for fiber post cementation. Dual-cure adhesives provide adequate working time during post placement and ensure complete polymerization even in areas where light cannot reach, such as deep within the root canal.
How do you prevent air bubbles during root canal etching?
To prevent air bubbles, apply the phosphoric acid at the full depth of the root canal and ensure thorough etching of all areas that will receive adhesive, cement, and composite. Using irrigation tips during rinsing helps ensure complete removal of acid remnants and prevents air pocket formation.
What moisture level should the canal have before post placement?
The canal should be dry but not desiccated. Use absorbent paper points to remove excess moisture after thorough rinsing. A slightly moist canal promotes optimal adhesive performance without compromising bond strength or causing air bubbles.
How should the resin cement be applied to ensure complete post seating?
Apply dual resin cement using a syringe or lentulo drills to coat the canal walls. Also apply cement to the post surface, then insert the post quickly to full depth to prevent premature polymerization. Digital pressure should be applied to secure the post at the predetermined height.
Why is light curing necessary after post placement?
Light curing ensures complete polymerization of the dual-cure resin cement. After removing any unpolymerized excess cement, light curing activates the chemical initiators, guaranteeing maximum hardness and longevity of the cemented post restoration.
What is the purpose of using a Mylar strip during etching?
A Mylar strip protects adjacent teeth from accidental contact with phosphoric acid during the etching process. This prevents etching of adjacent tooth surfaces and potential damage to adjacent restorations while ensuring precise acid application within the root canal.
What happens after the post is cemented?
After the post is cemented and light-cured, a core build-up is constructed using light-cured composite or another preferred technique. This core build-up provides structural support for the final restoration, such as a crown or other prosthetic restoration.
What are common complications with fiber post cementation?
Common complications include incomplete post seating due to premature cement polymerization, air bubble entrapment in the canal, insufficient bonding due to moisture contamination, and post displacement during core build-up. Following proper technique and timing minimizes these risks.
How long should you wait before preparing the tooth after post cementation?
After light curing, the dual-cure cement typically reaches adequate polymerization within 3-5 minutes. However, it's recommended to wait at least 10-15 minutes before initiating tooth preparation for the final restoration to ensure complete cement maturation and optimal bond strength.
References
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5. Teixeira CS, Alfredo E, Thomé LH, et al. Adhesion of a two-step etch-and-rinse adhesive on collagen-depleted dentin. Journal of Applied Oral Science. 2012;20(3):294-301.
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