05_Birmingham-Dentist-Crown_crop
Dentistry

More about crowns

People may wonder why crowns cost so much more money than fillings. This is mainly because of the amount of time and expense that goes into making them, which I will try to illustrate with a few pictures. As I touched on the in the previous post, a crown is a restoration that goes completely around a tooth like a hat goes around your head (hence the common term “cap” or “getting a tooth capped”). A crown is necessary when too much tooth structure has been lost from decay or trauma to restore with just a filling. Crowns can be made either in the dental office by a computerized milling machine or an on-site laboratory technician, or (more commonly) off site at a dental laboratory. Either way, it takes more time, materials, and effort to make and deliver a crown than a filling.

Lets compare the two processes (filling versus crown). A filling is done almost always in one appointment, and is made from materials we have in the office (either a silver alloy or a tooth colored resin), and generally does not require any lab work (no behind the scenes work that takes place after the patient leaves).

A crown, however, requires just as much (if not more) work that the patient doesn’t see as what they do see. Let’s start with the impression. Anyone who has had a crown that didn’t have a digital impression knows about this – all that gooey stuff that has to sit there for about 5 minutes. Why do we do that? Well, that gives dentists an accurate, three dimensional “copy” of your teeth. Here’s an example below.

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After the impression, a temporary crown is made, cemented to the tooth, and the patient is told to come back in a few weeks to get their crown (sometimes an office can make the crown right away, but it is still more common today that it is sent out to a lab). Well what happens after they leave? That impression is used to make a model of the teeth (like the one below) using dental stone – a plaster type material used to replicate the teeth outside the mouth so that a crown can be made in a controlled setting.

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The picture above also shows what a tooth looks like underneath a crown – a prepared or “prepped” tooth. The tooth has to be trimmed down to allow adequate thickness for the crown so it will be strong enough to withstand biting forces.

Once a model is made, a crown can be made using the model. This work is done by dental lab technicians – trained professionals who use a variety of technologies and materials to replicate what Mother Nature gave us. Some large dental offices may have lab techs at their office, and some dentists do their own lab work, but this is rare. Most dentists rely on these artisans to make the little jewels like the one below.

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The fabrication of the actual crowns involves specialized equipment and the process varies on the material used. In some cases the material used is heated up to a molten state and pushed into the shape of the tooth. In other cases it is machined by a computer out of a block of porcelain or zirconia. Whatever the process, it is painstaking work.

A very important point is that dentists have to pay the lab for these services. This is a key reason why crowns cost what they do. We have to cover our costs to the dental lab, along with our own materials, time, and staff, and do it all efficiently enough that it remains profitable.

I hope this has shed a little light on what is involved in making crowns. Within the perceived high prices lies a lot of work from a team of professionals. I plan to try to go into more detail about the fabrication process in future posts, but I want to get more pictures or video of the lab technicians at work before I do so. As always, email or call us at 290-7878 with any questions.