Zirconia requires a distinct approach for etching and cementation tailored to its unique properties. Zirconia, known for its exceptional strength and durability, does not adhere well to conventional etching techniques used for other ceramics. Instead, it demands a specialized surface treatment to enhance its bond strength. This guide provides an in-depth look at preparation procedures and cementation options, ensuring you make informed decisions for optimal patient outcomes.
Zirconia Bonding Guidelines
- Bond zirconia crowns using a chemical and mechanical pretreatment protocol, such as air-particle abrasion and tribochemical silica coating.
- Dandy sandblasts and steam-sanitizes all zirconia restorations.
- Utilize zirconia-specific primers, especially those with 10-MDP, for chemical bonding.
Things to Avoid
- Do not use silanization, acid etching, non-MDP cement, or phosphoric acid.
- Avoid excessive sandblasting force and self-adhesive cement in certain cases.
- Choose appropriate cements for translucent zirconia to match the shades.
Adjustment recommendations
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Tools for Shaping:
- A fine-grit diamond
- Football-shaped bur for occlusal and lingual surfaces, especially anterior teeth.
- Tapered bur for buccal and lingual surfaces.
- High-Speed Handpiece: Use a high-speed handpiece with minimal pressure, employing water and air spray to maintain temperature and prevent micro-fractures
Zirconia Restoration Cementation Steps
Adhering to these steps and recommendations will ensure effective and durable cementation of metal restorations.
- Note: Always consult the manufacturer’s instructions for specific guidelines.
Step 1 - Surface Preparation
- Zirconia crowns require air abrasion with alumina particles for enhanced adhesion.
Step 2 - Restoration Preparation
- Clean restorations post-try-in to remove contaminants like saliva.
- Techniques include sandblasting with aluminum oxide and using zirconia cleaning solutions or hydrofluoric acid.
Step 3 - Tooth Pretreatment
- After removing the temporary, clean the tooth with pumice paste to eliminate residues.
Step 4 - Cement Application and Crown Seating
- Use primers and cement with methacryloyloxydecyl dihydrogen phosphate (MDP).
- Seat the crown with firm pressure after dispensing cement into it.
Step 5 - Excess Cement Removal
- Clean up excess cement after the tack cure, maintaining the crown position.
- Light cure the cement following the manufacturer’s instructions, focusing on curing light positioning.
Step 6 - Curing
- Light cure the cement following the manufacturer’s instructions, focusing on curing light positioning.