IPS Empress.
A leucite-reinforced glass ceramic with a long clinical record in aesthetic work. Where a case calls for maximum translucency in a low-stress situation, it remains difficult to better. Tick IPS Empress on the Rx.
What it is good at
Empress is highly translucent and chameleons well against surrounding tooth structure — it takes on the character of what sits beneath and beside it rather than presenting as a discrete object.
That behaviour makes it particularly effective for thin veneers, conservative inlays and onlays, and anterior crowns in patients with light function where the priority is that the restoration disappears.
It has been in clinical use long enough that its behaviour over decades is well understood, which is not yet true of every newer alternative.
Where it is not the answer
It is a lower-strength material than lithium disilicate and considerably lower than zirconia. Posterior crowns in heavy function, long spans and patients with evident parafunction are not its territory.
Like all glass ceramics it depends on adhesive cementation, so it needs a field that can be isolated and a preparation with adequate reduction.
Where the aesthetic requirement is high but the functional demand is also high, lithium disilicate is generally the better compromise.
Bonding
As a glass ceramic it etches with hydrofluoric acid and silanates conventionally, then bonds with resin cement. The etch time differs between glass ceramics and is not interchangeable — follow the material's own protocol rather than a generic one.
Try-in contamination applies here as it does to any bondable ceramic. Saliva contact after surface treatment blocks the sites silane needs, and rinsing does not reliably clear it.
Preparation
Conservative but definite. Veneer preparations need enough facial reduction for the ceramic to develop character without being overcontoured, and inlay and onlay preparations need rounded internal line angles — sharp angles concentrate stress and are where a glass ceramic cracks.
A defined margin matters too. Margin design covers matching the finish line to the material.
Choosing between Empress and e.max
Both are glass ceramics, both etch and bond conventionally, and both are on the Rx form. The difference is where each sits on the strength-translucency trade.
Empress is the more translucent and the more chameleon-like, which suits thin veneers and conservative inlays in light function. Lithium disilicate is considerably stronger and is the better answer where the restoration carries meaningful occlusal load or where the preparation is less than ideal.
Where a case genuinely sits between them, call before preparing. The clearance each needs differs, and that decision is easier to make before the tooth is reduced than afterwards.
Getting the substrate right
Empress transmits more light than almost anything else on the form, which makes what lies beneath it a substantial part of the final appearance.
A bright vital preparation gives the material something ideal to work with. A dark, stained or post-endodontic substrate shows through and will pull the restoration off shade no matter how carefully the surface colour was matched.
Record the preparation shade or photograph the prepared tooth. Where the substrate is dark, the honest conversation is whether a more opaque material would serve the case better.
Veneer work specifically
Empress is at its best in thin veneers, where translucency and the ability to take on the character of the underlying tooth matter more than strength.
Facial reduction is the dimension that decides the result. Under-reduced, the restoration is either overcontoured — pushing the labial profile out and affecting the lip — or too thin to develop any internal character at all.
Depth cuts against a silicone index from a diagnostic wax-up are the reliable method. See veneers for what the preparation needs.
What to put on the prescription
Tick IPS Empress, give the shade with the guide named, and record the preparation shade — with a material this translucent, the substrate is a substantial part of the final appearance.
Say what the restoration is: veneer, inlay, onlay or crown, and mark the tooth on the design chart. Photographs are strongly advised for anything in the aesthetic zone.
More in Fixed Restorations
Send a case
Digital scans and conventional impressions are both accepted. Cases move by UPS and Purolator, and Fairmont works with practices throughout British Columbia and across Canada.