Overview: This guide provides comprehensive instructions for the adjustment and cementation of Zirconia, e.max, Full Metal, and PFM restorations to ensure durable clinical outcomes.
Cementation for Zirconia Restorations
Zirconia requires a distinct approach for bonding due to its unique material properties.
Step 1: Surface Preparation
Perform air abrasion on the internal surface of the Zirconia crown using alumina particles to enhance adhesion.
Step 2: Restoration Cleaning
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Clean the Zirconia restoration after the try-in phase to remove saliva contaminants. Use sandblasting with aluminum oxide or specialized zirconia cleaning solutions.
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Use a chemical and mechanical pretreatment protocol, such as air-particle abrasion and tribochemical silica coating.
- The practice will need to sandblast and steam-sanitize all zirconia restorations.
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Use a chemical and mechanical pretreatment protocol, such as air-particle abrasion and tribochemical silica coating.
Step 3: Tooth Pretreatment
Remove the temporary restoration and clean the tooth with pumice paste to eliminate all residues.
Step 4: Cement Application
Apply primers and cement containing methacryloyloxydecyl dihydrogen phosphate (MDP). Seat the Zirconia crown with firm pressure.
Step 5: Cement Removal and Curing
Perform a tack cure and remove excess cement while maintaining the crown's position. Complete the final light cure according to the manufacturer's specific instructions.
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.
Cementation for e.max Restorations
Lithium disilicate (e.max) restorations offer versatile cementation options including adhesive, self-adhesive, or conventional methods.
e.max Material Preparation
Etching: e.max restorations must be etched. While Dandy etches restorations before dispatch, you must re-etch if the surface is compromised during try-in.
Silanating: Use Monobond Plus or an equivalent agent for adhesive and self-adhesive cementation
Cementation for Metal and PFM Restorations
Follow these steps for effective cementation of Full Metal and Porcelain Fused to Metal (PFM) restorations.
Surface and Tooth Preparation
Metal crowns require air abrasion with alumina particles. After try-in, clean the restoration and prepare the tooth by removing the temporary and using pumice paste.
Metal Restoration Seating
Use MDP-based primers and cements. Seat the crown with firm pressure and allow the cement to set for the duration recommended by the manufacturer before removing excess.
Adjustment Protocol for e.Max and PFM Restorations
Follow these steps to adjust e.Max, Full Metal, and Porcelain Fused to Metal (PFM) restorations:
Initial Modification: Instruct the patient to bite lightly on carbon paper.
Excursion Movement: Ask the patient to bite firmly and perform a complete excursion movement pattern.
Final Adjustment: Complete adjustments based on the excursion markings.
Adjustment Protocol for Zirconia Restorations
Use the following tools and methods when adjusting Zirconia materials to prevent micro-fractures:
Tool Selection: Use a fine-grit diamond bur.
Occlusal/Lingual Surfaces: Use a football-shaped bur.
Buccal/Lingual Surfaces: Use a tapered bur.
Technical Equipment Specifications
To maintain the structural integrity of the restoration, adhere to these equipment standards:
Handpiece Type: Use a high-speed handpiece.
Pressure and Cooling: Apply minimal pressure while using constant water and air spray to maintain temperature.
Warning: Do not use air-only handpieces for adjustments, as this may cause micro-fractures in the material.