Pressed ceramics are among the strongest and most fracture resistant. Veneers and crowns pressed for the same case will like match in shade. Early and aggressive promotion of pressable systems got pressables off to a great start. The system does have a great deal of production advantages. Further development and research has increased the systems application and use. Many laboratories are equipped for the pressing process and most dentists are familiar with the preparations necessary to produce esthetic restorations. In each case the final esthetics is in the hands of the ceramist, no matter what system is used.

As strong as the situation indicates. The less ideal the oral environment, the stronger the porcelain will have to be. Veneers can sometimes be used to perform the function of a crown and be up to 2 or more millimetres thick. Those situations may require a reinforced porcelain veneer and a retentive preparation. In routine situations remember that few failures occurred with unreinforced feldspathic porcelains. Veneers should never be used in bruxing situations. Anything destructive to natural teeth can be destructive to a porcelain veneer. Dentists often use a variety of porcelain veneers depending upon the demands of each case.

Crowns and veneers should be made of the same ceramic and at the same time, if possible, so that they perfectly match. Reinforced porcelains must be used for crowns, so it follows that veneers should be made out of the same material. A solution would be using a reinforced (leucite or lithium disilicate) pressed ceramic for the entire case.

Single veneers must match the adjacent natural teeth and this can be a challenge. Many dentists would use a layered veneer (feldspathic porcelain - refractory model) in this case. Matching characterizations can then be built into the veneer. It may also be necessary for the patient to visit the laboratory so that the veneer can be custom stained.

All porcelain veneer systems work best with well defined margins. There are also work-around techniques when this is not possible. Layered porcelains can built to follow any kind of margin, but are more fragile overall. CAD/CAM milling machines work with stronger materials that make very thin veneers but these systems work best with defined margins. Communicate with the laboratory in cases where well defined margins are not possible.

No prep veneers are an occasional option. They are made of lithium disilicate, pressed or milled, and can be very thin (.3mm) but strong (360-400 MPa flexural strength). Dentists may have to trim margins in areas where they appear bulky.

The systems can be confusing. Essentially they trying to offer these three things...fit, form and function. In other terms, accuracy, esthetics and strength. They cannot be the best of all things for every case. Talk to your ceramist, technologist or laboratory and listen to what they offer and what they suggest. Most labs offer a variety of options. They can inform you as to what they suggest is best for any particular case.