Updated: Oct 14, 2022
You had a crown placed a few years ago but when you look in the mirror, you're noticing a gap between the crown and gum line. Is that normal or should you be concerned?
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What causes a gap between the crown and gum line?
A fully functional dental crown that is healthy should not have a gap by the gumline. If there is a gap, it could be due to a couple of reasons, some are bad and others are neutral.
Gap forming because of tooth decay. If there is a cavity underneath the crown, it could form a gap because the cavity would be creating a hole. You would literally be able to feel underneath the crown since the decay has eaten through it. If this is the case, you would definitely need the gap to be fixed.
Due to gum recession. Sometimes the gap could form over a long period of time because your gums could be receding. If you are brushing with a hard toothbrush or you brush very aggressively, you could cause it to recede. Once the gum recedes, you will notice a gap by the gum line. This means that there is nothing wrong with your porcelain crown but rather you have a gum problem caused by aggressive brushing. You should correct your brushing technique.
Gap from periodontal disease. If you have active gum disease, more specifically periodontitis, a gap could form between the crown and gums because the gum disease can eat away at your bone. If it eats away enough bone by the gum line, the gums will shrink and reveal a gap. Once this happens, the gums cannot grow back and the space between your crown and gumline will be permanent. If you want to try regrowing the gums, you will need to see a periodontitis, gum specialist.
The gap could also have been intentionally placed by your dentist. Sometimes your dentist may have chosen to have left a space between the crown and gums because it is healthier for your gums. When the crown margins are below the gums, it is more difficult for you to keep it clean but most dentist do it for cosmetic reasons. Of course, if you are not able to keep it clean then periodontitis will form the gap over time anyway.
Just to elaborate on the last part, there are three different ways to end your crown margin.
Above the gum line. This is not as cosmetic.
Slightly at the gum line. The best for in between.
Below the gum line. This is the most cosmetic but could be irritating to your gums.
Our Long Island City Dentists try to place our crown line just ever so slightly above the gumline so you can't really see it unless you use a magnifying glass.
How can you fix the gap by the gumline?
Hopefully that answers what causes the gap between the crown and gums but are you wondering how to fix the gap? There are basically two ways to fix the space.
Make a new dental crown. Your dentist would have to remove the old crown and then take a new impression of it. He would have to extend the crown so that it covers the gap. If there was a cavity, he would have to remove the cavity first before doing this.
Gum grafting. If the space was due to the gums receding or periodontitis, you could see the gum specialist and have some gum grafting done. So instead of extending the crown towards the gumline, you would extend the gumline towards the crown!
How can you prevent a crown gap?
The best cure is obviously prevention so if you don't let the gap form, you won't ever need to fix it! All of the problems start happening because of insufficient oral hygiene. Remember, the three causes of the gap from up above were from cavities and gum disease.
In order to prevent that you would have to brush twice a day for at least 2 minutes. Remember to floss before you go to bed. If you have a small cavity forming, make sure you try to remineralize it with either fluoride or hydroxyapatite.
Last but not least, go in for your dental check up and cleaning every 6 months!