Dental crowns are tooth-shaped caps or a tooth cap that is placed atop damaged teeth. They restore the tooth’s shape, size, strength, and appearance. A tooth crown can be made out of metals, porcelain, ceramics, and resin. Usually, they do not require special care other than regular good oral hygiene.
Reasons for needing a dental crown
The different reasons for needing a dental crown include:
- Protecting a weak tooth from breaking or keeping the weak tooth together if parts of it are cracked
- Restoring a broken tooth or a severely worn down tooth
- Covering and supporting a tooth with a large filling and an insubstantial segment of the tooth remaining
- Holding a dental bridge in place
- Covering misshapen or severely discolored teeth
- Covering dental implants
- Covering a tooth that has been treated with a root canal
Onlays and 3/4 crowns
Onlays and ¾ crowns are types of dental crowns that cover less of your underlying tooth than traditional dental crowns. A traditional crown will cover your entire tooth. Onlays are sometimes called ¾ crowns, although they may restore ½ to ⅔ of a tooth’s structure. They may be appropriate when you still have a solid tooth structure. It is regarded as a more conservative approach compared to full crown coverage.
Types of dental crowns
Crowns can be made of different metals including gold, palladium, nickel, and chromium. A metal dental crown lasts the longest in terms of wear down and only requires a small amount of the tooth to be removed. They can withstand biting and chewing forces. The metallic color is the main drawback of this type of crown. They are a good choice for molars that are not visible.
An advantage of this type of crown is it can be matched to the natural color of the teeth that are adjacent to the crown. Sometimes, the metal under the crown’s porcelain cap appears as a dark line. Another disadvantage of the porcelain-fused-to-metal crown is the possibility of the crown’s porcelain portion breaking off and the crown wearing down the teeth opposite it. These crowns can be an excellent choice for front or back teeth.
These crowns are usually less expensive than other crown types. They do wear down over time and are more likely to break than porcelain-fused-to-metal crowns.
All-ceramic or all-porcelain
These types of crowns provide the best natural color match compared to other crown types and are effective if you are allergic to metal. However, a ceramic or porcelain dental crown is not as strong as a porcelain-fused-to-metal crown. They can also wear down the teeth opposite them more than metal or resin crowns. All-ceramic is a good choice for a dental crown in front teeth.
These crowns have a hard inner core. They replace the metal liner that is used in the all-ceramic crown-making process. They are capped with porcelain which provides the best natural color match and are more long-lasting than an all-porcelain crown.
Dental crown procedure
Normally, you will have two visits to a dentist to prepare for a dental crown.
The first visit
The dental crown procedure first involves numbing the tooth with local anesthesia. The tooth that is going to receive the crown is then examined and prepared. X-rays are taken of the tooth and the surrounding bone. It may require a root canal treatment before the crown procedure if there is any:
- Tooth decay
- Risk of infection
- Injury to the tooth’s pulp
The tooth that is receiving the crown will be filed down across the top and sides to make room for the crown. The amount of tooth that gets filed away depends on the type of crown you have. If too much of the tooth is missing, a filling material can be used to build up enough tooth structure for the crown to cover.
After reshaping the tooth, a paste is used to make an impression. The impressions are sent to a dental laboratory and they normally return them to the dentist’s office in two to three weeks. During this visit, the dentist will make a temporary dental crown to cover the prepared tooth while you are waiting for the permanent crown.
The second visit
During the second visit, the permanent crown is placed on your tooth. First, the temporary dental crown is removed and the fit and color of the permanent crown are checked. If everything is in good order, the new dental crown is permanently cemented in place.
Same-day dental crowns
Same-day dental crowns can be performed if the dentist has the proper equipment. The first steps are to remove decay and shape the tooth for a perfect fit inside the crown. A scanning device is used to take digital pictures of the tooth and the computer software takes a 3D model of the tooth from these pictures. This digital design is then sent to another in-office machine that carves the shape of the crown out of a ceramic block. The dental crown is ready to be cemented into place in less than 15 minutes.
How is a crown attached to the abutment teeth?
Dental glue is the adhesive used for a fixed restoration that attaches the abutment teeth with the crowns. They can be of two types: temporary or permanent. While some dental glues create resistance and retention upon compression (temporary), others are manufactured to form stable chemical bonds (permanent).
Temporary dental glue
This is used for the temporary crown while you wait for your permanent crown. They are made up of materials like calcium hydroxide and zinc oxide eugenol which is made from eugenol, zinc oxide powder, and olive oil.
Permanent dental glue
Permanent glues are glass ionomer, resin glues, zinc phosphate, and resin-modified glass ionomer. Permanent dental glue has a high probability of maintaining strength and resistance as it forms a chemical bond that is near impossible to break.
Permanent dental glue encompasses the entire surface under its cover and leaves no room for leakage or penetration of external factors. It registers very well on resistance, utility, aesthetics, and strong composition that does not break apart or dissolve.
Applying the glue involves:
- Cleaning and disinfection of the crowns are required. Dentists place a suction material like cotton rolls or rubber dams to devoid the mouth of any fluid.
- The dental glue is prepared as per instructions.
- Once the desired result is obtained with the proper consistency, the glue is carefully applied in the crown’s interiors, covering it completely.
- The crown is placed on the abutment teeth to avoid any misplacement.
- Once the restoration process is completed, the extra glue is removed.
- Following the procedure, the patient must maintain excellent oral hygiene.
Cost of dental crowns
The costs of dental crowns can vary depending on where you live and the type of crown you select. Porcelain crowns are usually more expensive than gold crowns, which are normally more expensive than porcelain-fused-to-metal crowns. Usually, dental crowns can range in cost from $800 to $1,500. The cost of crowns is not normally covered by insurance but, check with your dental insurance company.
Dental crown lifespan
Normally, dental crowns last from 5 to 15 years. The lifespan can depend on the amount of wear and tear the crown is exposed to, how well you follow good oral hygiene practices, and personal mouth-related habits. These habits can include items like:
- Grinding or clenching your teeth
- Chewing ice
- Biting your fingernails
- Using your teeth to open packaging
Good practices include brushing your teeth twice a day and flossing once a day. However, with temporary crowns, you need to avoid using an electric toothbrush. Instead, brush carefully around the crown using your regular toothbrush. You also want to avoid flossing too aggressively around the temporary crown.
Dental crown problems
The following are some of the most common problems associated with dental crowns:
Dental crown pain or dental crown sensitivity
A newly crowned tooth may be sensitive immediately following the procedure and as the anesthesia wears off. If the crowned tooth still has a nerve in it, you may experience pain or some heat and cold sensitivity. Your dentist may recommend you brush your teeth with toothpaste designed for sensitive teeth. If you experience pain or sensitivity when you bite down, the cause is usually a dental crown too high on the tooth. In this case, call your dentist to have them adjust the crown.
Crowns made of porcelain can sometimes chip. If the chips are small, a dental crown repair is possible and the crown can remain in your mouth. A cracked dental crown may need to be replaced if the chip is too large or if there are too many chips.
Loose dental crown
The cement that holds the crown can occasionally wash out from the crown. This not only causes the crown to become loose, but it also allows bacteria to leak in and cause decay to the tooth that remains. If the crown feels loose, call your dentist.
Crowns fall off
If a dental crown falls off, it is usually caused by a lack of cement or an improper fit. Your dentist will give you specific instructions on how to care for your tooth and crown until you come in for an appointment. The dentist may be able to re-cement your crown in place. However, if a crown cannot be put back in place, a new crown will need to be made.
The metals used to manufacture dental crowns are often a mixture of several metals. It is possible to have an allergic reaction to the metal or the porcelain that is used in the dental crown.
Dark line on tooth next to the gum line
A dark line on the tooth next to the gum line can occur if you have a porcelain-fused-to-metal crown. This is normal and does not affect the health of the tooth. The dark line is the metal of the crown which is exposed.
Dealing with a loose or fallen out dental crown at home
A loose dental crown or a dental crown that has fallen out can happen at any moment. If this happens, book an appointment with your dentist immediately and take the following steps at home to assist with the problem until your appointment.
Dental crown is loose but has not fallen out
In this situation, do as much as you can to minimize moving the crown. This can involve taking steps to avoid foods that are sticky and to stop clenching your teeth. When you eat, try chewing on the opposite side to decrease the potential for further damage.
For more specific steps, do the following:
- Clean out whatever cement might be stuck in the crown with your toothbrush.
- Dry the crown and the tooth with a gauze pad.
- Apply some temporary dental cement in the crown and seat it back on the tooth.
- Place a gauze on it and bite down hard for 5 minutes until the cement sets.
Dental crown has fallen out
If the crown falls out inside your mouth, be sure not to bite on it or swallow it. Find the crown and try to clean it with your toothbrush. Be sure to put it in a cup or someplace to keep it safe until you can make an appointment with your dentist to have it re-examined.
Dental crown is damaged
If the dental crown is damaged, you might be able to place a coating of dental cement over the tooth to help protect it even without the crown. Some people have used a piece of sugar-free gum to wrap around the tooth. However, these are temporary solutions. Make sure to schedule a dental appointment immediately to have your crown fixed or replaced.
Having a dental crown placed is a common dental procedure that will help to protect a broken or damaged tooth, restoring the original smile. With a variety of types of crowns to choose from, it’s recommended to speak with your dentist to discuss the best options and right form of treatment.