The life of a dental crown depends on several factors, including your oral health condition, diet and eating habits, home and professional oral care, and the material used to make the crown. Over time crowns may need to be replaced due to general wear and tear, sometimes more than once. Crowns are sometimes replaced for cosmetic reasons and oftentimes to preserve the health of the tooth after they become worn or gum tissue recedes.
What is dental crown?
Dental crowns are an ideal way of rebuilding or restoring teeth that are badly broken or cracked. Made out of strong and durable porcelain, crowns are a permanent treatment which can last up to 20 years, provided you take care of your attractive results.
In a nutshell, crowns –also known as caps- are offered as a restorative option for fixing teeth that are weakened by small fractures or decay. Alternatively, the treatment can be used to restore misshapen, discoloured or broken teeth creating an overall better smile.
Does Your Dental Crown Need to Be Replaced?
Although today’s dental crown are strong and durable, they are not likely to last the rest of your life. Most crowns last between five and 15 years before needing to be replaced (or at least repaired).
In some cases it is obvious that you need to replace a crown because it has fallen out or suffered extensive damage; in other circumstances, it is less obvious that there is a problem with a crown. Ignoring signs of a problem could end up causing you pain and discomfort.
Below items are scenarios in which your dental crown may need to be replaced.
Your bite feels off
When your crown is first fitted and placed, your bite should feel completely normal. If, over time, your bite starts to feel uneven, something may have occurred with your crown and it may need to be adjusted or replaced.
The gums around your crowned tooth are receding
If you notice your gum tissue pulling away from the crowned tooth, it could indicate that the crown was improperly placed. It could also indicate that you have gum disease and need to seek periodontal treatment with your dentist.
Your crown is very old
Crowns that are older than five years are more likely to develop problems due to natural wear and tear. It is critical to have your crowns checked twice a year to allow your dentist an opportunity to inspect your restorations and ensure everything is healthy and functioning properly.
You have pain in or around a crowned tooth
While it is very rare for a metal crown to break or chip, porcelain crowns or the porcelain component of a porcelain-fused-to-metal crown can sometimes suffer surface damage due to the wear and tear of everyday use, eating or excessive force caused by bruxism. Broken or cracked crowns may expose the underlying tooth and can cause pain, swelling or tenderness.
In the case of a fractured or damaged crown, it is crucial to restore the crown’s integrity so it can continue to protect the underlying tooth. Depending on the extent of the damage, it may be easily repaired with a quick buffing, or it may require replacement.
Benefits of Porcelain Crowns
Patients who have a damaged or misshapen tooth might be self-conscious about their smile but also unenthusiastic about getting a metal restoration. If you’d like to make your smile whole again while maintaining a natural appearance, porcelain crowns might be the solution for you.
Crowns fit like caps over teeth. A porcelain crown not only covers the unattractive portion of the tooth you’d like to hide but also replicates the shade of the natural teeth surrounding the restoration.
Along with the aesthetic advantages, these inconspicuous restorations have other benefits as well, including:
- Strength:The ceramic in porcelain crowns is almost as durable as natural tooth enamel, especially when used to restore a front tooth.
- Convenience:Using CEREC technology, dentists can craft a custom porcelain crown for your tooth in a single visit.
- Safety:Metal-free dentistry protects patients from the potentially toxic mercury found in crowns relying on older designs that contain metal amalgams.
How to replace old crowns to porcelain crown?
So your dentist says one of your front teeth needs to have a crown replaced. He or she shows you the defect on the x-ray or a clinical photo, and you book your appointment to have the procedure done. Have you ever wondered what actually goes on during the process? How do they get the old crown off… how do they make sure the new crown fits perfectly.. why do they have to drill so gosh darn much if there was a crown on there before?! For those of you who would prefer to read the steps as you watch, here you go:
- local anesthesia / dental freezing – dentists use a topical anesthetic (a numbing jelly) that makes the gums quite numb so that the patient either doesn’t feel the injection or barely feels it. The jelly works great on the cheekside of the top arch (where dentists inject for most upper fillings), moderately well on the lower arch (where we inject for most lower fillings), and has a more mild effect for the palate side of the upper teeth (only need to freeze this area for difficult crowns, extractions and root canals).
- split the old crown into two – dentists use the dental drill to carefully divide the old crown into two pieces; as the romans did to the celts… DIVIDE AND CONQUER. If dentists just tried to yank off the old crown, you risk breaking part of the tooth, or sometimes even pulling the tooth out!
- clean up the decay / cavity – dentists don’t want to leave infected tooth bits under the new crown. dentists remove all of the tooth decay and make sure they have only healthy tooth structure left behind.
- fill the tooth – WAIT. Why do dentists need to fill the tooth if they are gonna put a crown on it?! Well, removing the cavity often leaves a very irregular shape in the tooth. If they expect the crown to slide on the tooth easily and intimately for a good fit, they need a smooth and regular shape to tooth nub.
- trim (prepare) the tooth – dentists then spend a LOT of time trimming the tooth down to size, polishing margins (i.e. the junction between the tooth and would-be crown), and engineering a tooth design that will allow for sufficient strength both of the tooth nub, and the crown that will sit on it.
- get the gums out of the way – once the tooth is ready to be digitally imaged or have its shape recorded with impression material (kind of like taking a thumbprint of your tooth… a toothprint!), dentists need to make sure the gums are out of the way so the lab technician making the crown can tell EXACTLY where the crown should end, and where the natural tooth starts. dentists accomplish this by packing a few tiny braided cords in between the tooth and the gums. This pushes the gums out of the way, and also stops any bleeding so thry can get a really really clean image or impression.
- acquire the digital/analog impression: pretty.. self.. explanatory… to clarify though, dentists use a special camera for the digital impression, and dental goop (not the technical term) for analog impressions… (i.e. toothprints)
- wait for lab to make the crown: DIGITAL – same day. ANALOG – one to two weeks.
- prepare the tooth for cementation: dentists use a particle abrasion device to clean off any imaging powder or debris from the tooth nub. they also pack another cord (which will be removed later) to make sure no fluid creeps up from the gums underneath the crown.
- Cement the crown! dentists fill up the crown with the cement, plop it on the tooth nub (“plop” doesn’t impart a sense of precision, but they really do have to be careful in the delivery of these crowns as they are super slippery sometimes), and shine special cement-setting light on the tooth. After 1 second, the excess cement that squeezed out between the crown and tooth nub is already hard and ready to be peeled away. Once everything is cleaned up, they check the bite, and dismiss patient.