Can you tell a difference?

Obviously one of these restorations has more gums than the other, but can you tell the difference between them other than that? They have a lot of things in common, but some startling differences.

Both of these restorations are fixed-arch hybrids. The teeth themselves are both made out of Zirconia. The differences lie in the underlying material.

Monolithic: adj, Constituting or acting as a single, often rigid, uniform whole.

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The upper hybrid is a monolithic zirconia hybrid. What does that mean? The entire prosthetic, from the gums, teeth, and support structure are all milled out of one block of material, in this case, zirconia. The restoration is characterized, the gums are added, and TiBases are cemented in for the prosthetic to screw into the implants. Typically, the teeth are stained and glazed to look more life-like, and the gums are pink porcelain hand stacked to give them character. These are the most common hybrid or full arch restorations done now a days, because zirconia is insanely hard, very strong, and looks like teeth.

Titanium: n, A strong, low-density, highly corrosion-resistant, lustrous white metallic element that occurs widely in igneous rocks and is used to alloy aircraft metals for lo-weight, strength, and high-temperature stability.

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The lower hybrid is what we call at our practice an esthetic hybrid. It has an underlying titanium framework that screws into the implants, has individually milled zirconia crowns for each of the teeth, and has the pink gums, which are made of a composite material, hand stacked to look life-like. The individual crowns are not flossable, but since they are all individual units they look like individual teeth. The crowns are made of a different type of zirconia to have more translucency, and are layered with a liquid ceramic to give them a nice shine, but also the texture you would associate with the natural formation of teeth.

The other type of hybrid not pictured and not often done anymore is a restoration over a bar. A titanium bar is milled, and a shell is manufactured to go over top. The shell used to be a acrylic denture, which is essentially just plastic. These would wear out over a few years and need to be replaced. They also had a bad habit of having teeth debond from the acrylic so they would just ‘pop off’. I have repaired and replaced many of these types of restorations. Some labs will make a bar with a zirconia or PMMA superstructure, but they tend to fail at the bond between the superstructure and the bar.

So why would patients choose one restoration over another? There are a few reasons. The first is that the monolithic zirconia restorations are less expensive to manufacture. They also take less time to make, which is a huge plus. The titanium frame hybrids are stronger, so they can be made thinner, so less bone has to be removed to make prosthetic space during surgery. The titanium frame hybrids also have a very unique quality, they have a failure point. The monolithic zirconia hybrids almost never break, same with the titanium. But when a monolithic zirconia hybrid breaks, usually it fractures — through the entire arch. See zirconia is very hard, but it is also brittle. So if you were to over-stress it, it will not flex – it just gives up and snaps. That restoration has to be remade, it can not be repaired. That means the patient is without teeth during the time that the lab is remaking the restoration, unless a temp can be printed in the meantime. The titanium hybrids have cement between the individual crowns and the underlying framework. The cement will be what fails, the bond between a crown and the framework. A single crown can be re-cemented, or can be remilled and replaced. We do same day crowns with CEREC every day, it is very easy to just replace a single crown, and the patient doesn’t have to go without the restoration during that time. But titamium or esthetic hybrids do come with a premium price, and take almost twice as long to manufacture.

So there you go, some pros and cons for each type of hybrid restoration we do at Atlanta Dental Implant Centers. Most patients go with zirconia, and it works great for them and the results are simply stunning. But for patients getting upper and lower restorations, I usually recommend at least once arch be ‘esthetic’ or titanium, to reduce the chance that we fracture one of the arches. Plus, the individual crowns for the teeth on an upper arch just look so good!