Healthy Smile: My Crown Was Too Big

by Jeffrey Gross, DDS, FAGD of The Healthy Smile

I met a new patient this week who told me some history regarding his lower left side. He has almost all of the teeth in his mouth and demonstrates good oral hygiene and dental care. He had some gold crowns from decades past. He developed decay on the teeth under these crowns which, needed some replacement. After the installation of the new crowns, the patient complained that the new crowns were too big. Not only were they too big, but the bite was incorrect which ultimately ended in a root canal.

What happened in this case? Why were the crowns big?

The bigger question is how does the dentist or the dental lab know what size to make the new crown? It is even harder to understand how the lab has any idea of the tooth size since they usually never see the patient. Yes, the dentist takes an impression of the tooth for the lab, but this impression portion occurs after the shaping of the tooth. The question returns. How does the lab know what to do?

Although to a non-professional differences in shape and sizes of teeth are not that apparent, a dentist or dental lab technician is intimately acquainted with differences in size and shape of teeth. In fact, the same tooth on opposite sides of the mouth have mirrored anatomy. These subtle nuances are second nature to us. We know how to design and shape a tooth so that a molar will look like a molar, and a canine will look like a canine. The wrong shape in the wrong place in the mouth will not look natural. The patient may be able to articulate what is awry but it will appear wrong.

Now we know that the dentist or his lab is skilled in creating the proper shape, our original question is still out there. What about the size? Once the shape is determined, the size is rather easy. The crown must be large enough to touch its neighbors on either side of the new crown. Determining the height of the crown is also easy. The crown must meet the tooth that it touches when chewing. This height will allow the new tooth to function properly and efficiently. Chewing or grinding of food is what teeth do for us.

However, within the guidelines of touching the adjacent teeth and meeting the opposing tooth, there is much variability. I can meet all of the guidelines, yet something will be missing. It won’t look exactly like the tooth before shaping. In most cases, not looking exactly like the original tooth is a good thing. In some situations, we need the new crown to be an exact duplicate of the original tooth.

When this is the case, photos and models will provide the dentist and the laboratory technician with essential information. These facts, using modern computers and scanning techniques, allow duplication of the original tooth a predictable and repeatable procedure. My new patient required a crown on his front tooth. The tooth was black and worn badly. Aside from the color, his original tooth blended with the rest of his teeth. He expressed a desire that his final result will be just like his original tooth in terms of size and shape. I noted his concerns and desires and proceeded to accomplish that goal

If you have specific desires regarding your dental work, please take the time to tell your dentist. Sometimes putting your thoughts on paper and bringing that note to your appointment will be very helpful. If this sounds like you, please call our office and come in for a talk. Joyce will be more than happy to help you set up your appointment. Just call her at 440-892-1810. I look forward to meeting you.

Jeffrey Gross, DDS, FAGD is an Ohio licensed general dentist and is on the staff of Case Western Reserve School of Dental Medicine.

The Healthy Smile • 27239 Wolf Road, Bay Village, OH 44140 • 440-892-1810 • www.jeffreygrossdds.com