e.max by Ivoclar ( lithium Disilicate) has rapidly become one of my favorite materials over the last five years. Not only do I use it for about 95% of the posterior restorations in my practice, but I lecture on it quite a bit. With this I get asked quite often about the protocol for placing these restorations, and it always occurs like there is a “should”. So what is the “right” answer for placing e.max restorations. One of the incredible advantages to e.max is it’s versatility and when it comes to placing the material, this is both a bonus and the basis of some confusion. I like to think of the options based on the type of restoration.
Anterior Veneers:
- Restorations must be bonded because the preparation lacks inherent retention and resistance form.
- Bonding means following a protocol of creating a hybrid zone by etching, priming and applying a resin.
- Utilize materials that are light cure only, dual cure materials carry a risk of color shift over time.
Posterior Partial Coverage ( Inlays & Onlays):
- Restorations must be bonded because the preparations lack inherent retention and resistance form.
- Bonding means following a protocol of creating a hybrid zone by etching, priming and applying a resin.
- I teach utilizing dual cure materials so that we have the advantage of creating a gel phase for cleaning, but the insurance of dual cure at depth where light may not penetrate effectively.
Anterior & Posterior Full Coverage:
- Restorations with retention form and resistance form can be either bonded or cemented.
- Choosing between bonding and cementation is based on personal preference, obtaining isolation and concern over replacing the restorations in the future.
- Resin cements utilize a chemical catalyst and could be at risk for color change over time, balance this against your confidence in light penetration using light cure only products.
- depending on the e.max material used it may be translucent and using a white or opaque cement may alter your esthetics.
between bonding and cementation which overall is used in cases of the ederly
Nancy, The patients age really isn’t a critical factor in choosing to bond or cement. The choice is a matter of prep design, you have to have retention form and resistance form to cement and isolation, as you have to be able to isolate for bonding. Now prep design may be altered due to age and health of the patient as the older the patient the less critical it is to conserve tooth structure for future restorations, but also the more we want to limit the chance of a repeat procedure if their health makes dental procedures difficult or risky.
Lee
Hello Dr Lee Ann. I have traditionally used GI based (resin modified) cements like Riva Luting plus for all ceramic full coverage posterior restorations like Zirconia and Emax. I have tracked some of the cases over 5-10years. Never seem to have a problem with de-cementation. The crowns are pre sand blasted/etched by the lab. Shall I be looking at switching to bonding (eg Panavia) since it seems to the popular opinion or continue with usual practice? Thanks. V
I am always a fan of continuing to do something that works. I still use GI as well, so I’d say stay the course.