This means that restorations like porcelain veneers can last much longer than in the past. Dental crowns can be made entirely of ceramic material and used in places where we could only use metal crowns in the past. And with their new durability, they don’t wear down as fast and they maintain stain resistance for much longer. Just how strong are these ceramics? Prepare to be amazed.
Feldspathic Ceramics of the Past
The ceramic materials most commonly used for porcelain veneers in the past were feldspathic ceramics. These have the advantage of a high degree of naturalism. Laid down layer by layer, they looked very similar to your natural tooth enamel, which accumulates layer by layer in the body.
However, these ceramics are relatively weak. Traditional feldspathic ceramics had a strength of about 60-70 megapascals (MPa), about 8700-10,200 pounds per square inch (psi). New formulations of feldspathic porcelain were significantly stronger, up to 100 MPa, 14,500 psi.
Leucite Glass Ceramics
The next level of strength in dental ceramics was leucite-reinforced glass ceramics. These were press manufactured, so they didn’t have as good an appearance as the feldspathic ceramics. However, they were significantly stronger.
Leucite glass ceramics initially had a strength of about 120 MPa, about 17,400 psi, but later increased to 160 MPa, 23,200. However, the reduced aesthetics of these restorations meant that many dentists weren’t impressed with the increased strength. There developed a divide between dentists, with some adopting the new materials while others adopted the new materials.
New, Advanced Ceramics
But soon leucite glass ceramics were left behind by new developments. Lithium disilicate ceramics are much, much stronger than other materials previously employed, with a strength of about 400 MPa, about 58,000 psi. Recently, we’ve begun employing even stronger ceramics, zirconia, which have a strength that can range from 900 to 1100 MPa, nearly 160,000 psi! That’s comparable to the strength of titanium used in dental implants.
Cosmetic Tradeoffs for Strength
However, we don’t always choose the strongest option available for all your restorations. Just like the transition to leucite glass ceramics, moving up to the new stronger ceramics does come with some drawbacks. The most important is that as materials get stronger, they tend to get more opaque.
This matters because your natural tooth enamel is translucent. It lets light through down to the dentin inside your teeth. That’s why tooth trauma can cause your tooth to become discolored. What you’re actually seeing is bruising deep inside the tooth. So if we replace your tooth enamel with something too opaque, it won’t look natural.
We don’t have another option that’s as translucent as feldspathic porcelain. But lithium disilicate is actually pretty close. It’s a great compromise of translucency and strength. And because it’s so strong, it can be made thinner.
Sometimes, of course, we actually want to conceal your natural teeth (if, for example, they’re discolored from trauma), so we’ll use more opaque materials. In some cases, we might use a more translucent ceramic on the front, with a more opaque one inside.
And other times, only the strongest ceramics will stand up to the conditions, so we have to deal with the appearance. Fortunately, we can still make them look good.
Skeptical about Ceramics?
Many people who either got porcelain veneers in the past or know people who did are skeptical that ceramics can be as strong as promised. The truth is that modern ceramics are 4-10 times stronger than those in the past, so don’t dismiss a smile makeover before scheduling a consultation.
Whether you’re looking to replace old restorations or want to try porcelain veneers for the first time, please call (248) 656-2020 for an appointment with a Rochester cosmetic dentist at Rochester Advanced Dentistry.