Fitting your patient’s restoration to exacting detail is key to a lasting smile, and we here at ADA headquarters have all the information you need to master the practice.
Zirconia restorations are highly regarded by dentists around the world due to their natural appearance and unquestionable strength.
But as Zirconia is a ceramic material, great care must be taken during fittings.
Here are our top ten tips to fit the perfect restoration.
1. When it comes to ceramic materials, it is important to avoid sharp corners, edges (incisal and occlusal) and internal edges.
2. The preparation on the margin area should be the largest diameter of the prepared tooth.
3. Ideally, the circumferential shoulder should be prepared with a rounded internal angle. This will be a structure-conserving preparation taking into account the required minimum thickness is 0.5mm for the material.
4. Zirconia thickness should not be below this thickness.
5. The minimum prepared tooth height should be 3mm and the shorter the prepared tooth, the steeper the preparation must be.
6. This preparation margin must be clearly visible.
7. Increased occlusal space should be taken into account when preparing abutments for bridges, depending on the length of the bridge.
8. For solid Zirconia restorations, preparation differs slightly, for example shoulder preparation is not needed. Feather edge is okay.
9. Solid Zirconia restorations involve a conservative preparation similar to full cast gold.
10. 1.0mm of occlusal space is ideal, however a prep with at least 0.5mm is acceptable.
Before fitting a seamless restoration, it is important to get a good first impression.
Making an accurate and detailed impression is the foundation for your restoration, so it is essential you get it right.
A good impression will have a consistent mix of both heavy body and light body materials, a sturdy tray which is sufficiently filled, and no voids or pulls on margin detail.
There should also be no contact between the tooth and the tray.
When it comes to seating recommendations, recent research has shown that saliva contamination can hinder the bonding of solid zirconia and zirconia copings.
To successfully remove saliva, it is now suggested that after try-in and before priming, the crown or bridge should be cleaned with Ivoclean, a zirconia cleaning solution produced by Ivoclar.
Various cleaning procedures like cleaning with water, Isopropanol, phosphoric acid or corundum blasted have been advised and tested, but their effect is questionable.
Below is the suggested protocol in four easy steps.
• Try in zirconia-based restoration.
• Rinse saliva out of restoration with water.
• Place Ivoclean in restoration for 20 seconds then rinse and dry.
• Apply Primer and then cement with product of your choice.
At ADA, we aim to ensure our restorations are produced to such a high standard that alterations on fittings are minimal to zero.
This is all done from our high-tech labs in the North-West and Germany.
If you want more information on our restoration options, don’t hesitate to drop us a line or call in to our brand new base in Sligo!