Zirconia, porcelain fused to metal or e.max? Comparing types of crown

Porcelain fused to metal is the type of crown that has been in use the longest. Inside, a thin metal cap wraps the tooth, and tooth-coloured porcelain is layered over the outside. The metal provides strength and the porcelain the appearance. Cleveland Clinic writes that with these crowns the porcelain layer can chip over time, exposing the metal underneath, and can slowly wear down the enamel of the opposing teeth. Because metal does not let light through, these crowns can look more opaque than a natural tooth under light.

Zirconia is a white and very hard ceramic. It is used in two forms, and these two forms behave differently in research. In the first, zirconia is only the framework; porcelain is layered over it to provide the appearance, just as with porcelain fused to metal. In the second, the crown is milled from start to finish out of a single block of zirconia and has no separate porcelain layer on top; this is called single-block or monolithic zirconia. In Turkey both are referred to as "zirconia caps"; asking your dentist which of the two is being recommended is important for understanding the outcome.

E.max is the well-known trade name of a glass ceramic called lithium disilicate. It lets light through in a way very close to natural enamel; for this reason it stands out for its natural appearance, especially on front teeth. It can be made either as a single block or with porcelain layered on top. An important difference from the other two materials is that it is usually attached to the tooth with a resin adhesive; this bond contributes to the strength of the crown and means that the bonding has to be done with care.

The most comprehensive summary of today's evidence is the meta-analysis published by Pjetursson and colleagues in 2026. The authors combined 3,509 metal-ceramic and 8,051 all-ceramic crowns in 64 studies. The 5-year survival was 98.5% for monolithic lithium disilicate, 97.3% for veneered densely sintered zirconia, 97.1% for porcelain fused to metal, 96.8% for monolithic zirconia and 95.7% for veneered glass ceramic. Crowns made entirely of feldspathic porcelain lagged significantly behind at 90.4%; the survival of veneered glass ceramic crowns was also significantly lower than that of monolithic lithium disilicate. With monolithic lithium disilicate and monolithic zirconia crowns, ceramic fracture and chipping were significantly less frequent than with their veneered equivalents.

It is important to see how the evidence has changed over the last ten years, because old opinions are still circulating on the internet. The same team's 2015 review looked mainly at veneered zirconia crowns, which dominated at the time, and found that they were lost more often than porcelain fused to metal through fracture of the outer porcelain and came loose more often; the authors wrote that zirconia-based crowns should not be considered the first choice because of technical problems. In the 2026 update, however, both the veneered and the monolithic forms of zirconia gave results close to porcelain fused to metal. Part of the change comes from monolithic designs, which do away with the layer most prone to chipping.

The distinction between front and back teeth varies with the material. In the 2015 review, feldspathic porcelain and zirconia crowns showed significantly lower survival on back teeth, and the authors recommended that weak feldspathic porcelains be limited to the front of the mouth. In the 2026 update, types other than feldspathic porcelain and porcelain fused to metal gave similar results at the front and the back. The Oral Health Foundation also writes that all-porcelain crowns are often used on front teeth because of their natural appearance, while gold crowns are usually preferred for back teeth because of their strength.

Wear on the opposing tooth is a frequently asked question, and the evidence here is not consistent. A 2024 network meta-analysis found that, in studies with follow-up of up to 24 months, porcelain fused to metal and zirconia caused significantly more enamel loss on the opposing tooth than a natural tooth did; this difference was largest for porcelain fused to metal, while for lithium disilicate it was very small and not statistically significant. Another meta-analysis from 2026, however, found significant wear with monolithic zirconia and lithium disilicate, and a non-significant difference with porcelain-surfaced metal-ceramic crowns, and the authors interpreted these crowns as the option that better protects the opposing tooth; in other words, the two studies reach opposite conclusions about porcelain fused to metal. In both studies follow-up was at most 2 years and the number of patients was small. A reliable overall conclusion is this: ceramic crowns wear the opposing tooth more than a natural tooth does, and this should be discussed with the dentist, especially by people who clench their teeth.

For crowns on implants the picture is similar. A 2018 meta-analysis found 5-year survival of single crowns on implants of 98.3% for porcelain fused to metal and 97.6% for zirconia; porcelain chipping was similar in the two groups, and zirconia had fewer aesthetic problems but significantly more frequent loss through material fracture (2.1% versus 0.2%). The 2025 S3 guideline of the German Society of Implantology (DGI) and the German Society of Dentistry and Oral Medicine (DGZMK) writes that lithium disilicate, silicate ceramics and zirconia show survival of around 96–97% at 3 years for single crowns on implants, while for short bridges and full-arch superstructures the clinical evidence supports only one particular type of zirconia. We cover the choice of material for full-mouth implant superstructures on a separate page.

The decision comes from the examination, the remaining tooth tissue and your bite. The first list covers situations where the choice of material is relatively straightforward, the second situations where the decision needs to be made more carefully.

The course below is the typical sequence for a single crown. The material is chosen at the start of this sequence, because how much the tooth is reduced depends on the material.

1. 1

   Deciding whether the tooth needs a crown

   If enough sound walls remain, an onlay or overlay, which cuts away less tooth, may also be an option. A crown comes to the fore when most of the tooth has been lost or the walls have become very weak.

2. 2

   Choosing the material

   The position of the tooth, the bite, any clenching habit, the colour of the neighbouring teeth and whether the colour underneath the tooth is dark are assessed together. On a darkened tooth, a material that lets a lot of light through can show the colour underneath.

3. 3

   Reducing the tooth

   Cleveland Clinic writes that some tissue is removed from the outer layer of the tooth so that the crown can fit. The amount removed varies with the material and the design; crowns with layered porcelain need more room for the layer.

4. 4

   Impression or digital scan, and choosing the shade

   The tooth and the opposing jaw are recorded, and the shade is chosen by comparing it with the neighbouring teeth in daylight. During the laboratory stage, the tooth is protected with a temporary crown.

5. 5

   Try-in

   The fit of the crown's margins, its contacts with the neighbouring teeth, its colour and the bite are checked. Saying that you do not like the colour or shape of a crown at this stage is much easier than saying so after it has been bonded.

6. 6

   Bonding

   Depending on the material, a conventional cement or a resin adhesive is used. Glass ceramics are usually attached with an adhesive, and this procedure needs a dry field.

7. 7

   Checking the bite and the polish

   Ceramic surfaces that have been adjusted are polished. A ceramic surface that is left rough is thought to wear the opposing tooth more; asking whether it has been polished is a sensible question.

A crown is not the only way to save a tooth. Depending on the remaining tooth tissue and the condition of the tooth, there are also routes that cut away less tooth, or entirely different ones.

Some of the problems below are seen with every material, and some are specific to particular designs.

Once the crown has been bonded, the tooth usually gets used to it quickly. The course below is the usual one; what your dentist tells you takes priority.

1. The temporary crown period

   During the laboratory stage, do not chew sticky or hard food on the side with the temporary crown. If the temporary crown falls off, call your dentist rather than leaving the tooth exposed for long.

2. The first few days

   Cleveland Clinic writes that tooth sensitivity and gum tenderness lasting a few days are common after a crown.

3. The first few weeks

   Your tongue gets used to the shape of the crown. If the crown touches first when you bite, or your teeth do not close fully, do not wait; the bite can be corrected with a small adjustment.

4. Over the years

   Cleveland Clinic writes that with careful care crowns last on average between 5 and 15 years. Keeping the edge of the crown clean with floss or an interdental brush, and regular check-ups, are what affect this time the most.

The price of a crown depends on many items, from the material to the laboratory; we do not give figures here. The main items that make the difference are:

Material and design

Porcelain fused to metal, zirconia and glass ceramic have different material costs; a monolithic or a veneered design also changes the laboratory work.

Production route

A crown designed by computer and milled and a crown layered by hand require different laboratory processes.

Preparing the tooth

If root canal treatment, a core (post and core) or gum correction is needed, the overall scope grows.

Number of crowns, and bridges

A single crown and a bridge joining more than one tooth require different planning and materials.

On a natural tooth or on an implant

With a crown on an implant, the implant components and connecting parts also come into the calculation.