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DENTAL CROWN

This is a tooth shaped ‘cap’ placed over the tooth that serves to cover it in order to restore its shape, size, strength and improve its appearance.

When cemented into place, the crown will fully encase the visible part of a tooth lying at and above the gum line.

WHY IS A DENTAL CROWN NECESSARY?

It provides protection for a weak tooth, such as one that has already started to decay, from breaking apart or helps hold parts of a cracked tooth together.
To restore a severely worn out or already broken apart tooth.
It serves as an outer covering to support and protect a tooth wit
h a large filling when there isn’t much area of the tooth remaining.
To help hold a dental bridge in position.
It helps to cover a severely discolored or ill-shaped tooth.
It provides protection by covering a dental implant.
To make cosmetic modifications.

In children a dental crown maybe used over primary (baby) teeth for one of the following reasons:

To save a badly decayed tooth that is unable to be supportedby a filling.
To provide protection for the teeth at high risk of decay especially in children who don’t adhere to daily oral hygiene.
It serves as an alternative in children who cannot undergo procedures that require general anesthesia due to their age, behavior or medical history and poor compliance to proper dental
hygiene. In such instances the dentist will likely recommend a stainless steel crown.

WHAT TYPES OF CROWNS ARE AVAILABLE?

There are different types of material to choose from for a permanent crown such as stainless steel, metals (gold, silver or an alloy), all resin, all ceramic or porcelain fused to metal.

Stainless steel crowns - these crowns are fabricated for temporary use on permanent teeth to protect the tooth or filling until a permanent crown is made.
In children, a stainless steel crown is used as they don’t require frequent visits to set it in place and are cost effective compared to custom-made one and prophylactic dental procedures to protect a tooth without a crown.
Stainless steel crowns fit over a primary tooth that has been prepared for it. The crown covers the entire tooth and prevents it from decaying further. When the permanent tooth erupts from underneath the primary tooth, it comes off and the crown along with it.
Metal crowns – alloy with a high content of gold, platinum or base-metal alloys (for example, cobalt-chromium and nickel-chromium alloys) are generally used for the fabrication of metal crowns.
These types of crowns can withstand biting and chewing forces and can last for a long time in terms of wear and tear; they rarely chip off or break. However, the main drawback is the pronounced metallic appearance. Metal crowns are a better option for the molars at the back of the jaw as they are not noticeable.
Porcelain-fused-to-metal crowns – unlike metallic crowns these types can be made to match the color of your natural teeth. However, more wear and tear will occur to the adjacent teeth with this crown compared to those made out of metal or resins. The porcelain portion of this crown might chip or break off. Compared to fully-ceramic crowns the porcelain-fused-to-metal ones look the most alike to your normal teeth. But sometimes the metal beneath the porcelain can be visible as a dark line especially near the gum line and more so if your gum is receding. These crowns are a better choice for teeth at the front or back and for long bridges where the metal is needed for strength.
All-resin crowns – these are less durable and more likely to fracture than porcelain-fused-to-metal crowns therefore they are less expensive.
All-ceramic or all-porcelain crowns – provide the most identical color match to natural teeth than any other type. They are the most appropriate option for people with allergies to metals. All-ceramic crowns are suitable for the teeth at the front and sides.
Temporary vs. Permanent crowns – Temporary ones can be made in the dentist’s office and are usually made of an acrylic-based or stainless steel material.
Permanent crowns have to be made in a dental laboratory. The main purpose of a temporary crown is to be used as a temporary restoration until the permanent crown is made.

WHAT STEPS ARE INVOLVED IN PREPARING A TOOTH FOR A CROWN?

In order to prepare a tooth for a crown two visits to the dentist are required.

The first visit involves examining and preparing the tooth. The second visit is for the placement of the permanent crown.

At the first visit - examining and preparing the tooth
Your dentist may take a few x-rays in order to check the roots of the teeth and surrounding bone which will receive the crown. If there is extensive decay or if a risk of infection or injury to the tooth pulp exists then a root canal treatment has to be performed initially.
Your dentist will anesthetize (numb) the tooth and the surrounding gum. Then the tooth receiving the crown is filed down along the chewing surface to make room, the amount removed will depend on the type of crown to be used. If a large area of the tooth is absent (due to decay or damage) your dentist will use filling material to ‘build up’ the tooth in order to support the crown.
Once reshaping of the tooth is complete, your dentist will make an impression of the tooth which will be receiving the crown using a paste or putty. Impressions are also occasionally made using a digital scanner. To ensure that the crown will not affect your bite, impressions of the teeth surrounding the tooth to receive the crown will also be taken.
The scans or impressions will be forwarded to a dental lab where the manufacturing of the crown will take place. The completed crown will then be delivered to your dentist’s office within two to three weeks. If porcelain is the material used to manufacture the crown, your dentist will select the appropriate color shade in order to precisely match the crown to the adjoining teeth. On your first visit to the dentist’s office, a temporary crown will be made by your dentist in order to protect and enclose the prepared tooth until the final crown is manufactured. Composite is used to manufacture the temporary crown and is usually kept in place with the use of temporary cement.
Second Visit: Receiving the permanent dental crown.
On your second visit to the dentist’s office, he will take the temporary crown off and verify the fit and shade of the permanent one. If it’s satisfactory, a local anesthetic if necessary will be used to numb the tooth and the new crown will be cemented in place.

How should I care for my temporary crown?

A temporary crown is just until the permanent one is ready so it should be taken care of while keeping a few precautions in mind as suggested by your dentist.

Following are a few steps to adhere to while looking after your temporary crown.

Avoid food that have a sticky or chewy texture and will be able to grab or pull off the crown for example, chewing gum, caramel etc.
Avoid chewing from the sides of your mouth with the temporary crown and switch to the opposite side instead.
Hard food such as raw vegetables should be avoided as it could dislodge or break the crown.
When you floss in between your teeth keep in mind to slide the floss thread out horizontally rather than lifting it out and risk popping the temporary crown out.

What problems could develop with a dental crown?

Discomfort or sensitivity

Immediately after the procedure of cementing the permanent tooth you may feel discomfort as the anesthesia begins to wear off. If the newly crowned tooth has an underlying nerve then there will be some sensitivity to heat and cold. Your dentist will advise you to use a desensitizing toothpaste. If you experience any pain or sensitivity when biting down on to the newly crowned tooth, it usually means that the crown is placed too high on the tooth and requires a slight adjustment.

A chipped crown

Those crowns made of all-porcelain or porcelain-fused-to-metal are at risk of chipping. A small chip can be repaired easily using a composite resin while the crown is still attached to your tooth. This is a temporary fix. But if the chip is large the crown may need to be replaced altogether.

A loose crown

In certain instances the cement may wash out from under the crown causing it to become loose allowing bacteria to leak in and cause decay to the tooth. So if your crown feels loose then contact your dentist regarding further management.

The crown falls out of place

Sometimes the crown may fall off due to an improper fit, lack of adequate cement or a very small area of the tooth for the crown to fixate onto. If this occurs take steps to clean the crown and the tooth and using a dental adhesive or temporary tooth cement, available in stores, you can fix the crown yourself until you meet the dentist. He will provide you with the necessary instructions on how to look after the tooth and the crown until you can be seen for an evaluation. Your dentist will re-cement the crown into place or arrange for a new one if necessary.

Allergic reaction to the crown

Some people may be allergic to the porcelain or the alloys of metal used to make the crowns. This is however, quite rare.

Dark line next to the gum line of a crowned tooth

These are a common finding in porcelain-fused-to-metal crowns. A dark line, usually the metal of the crown showing through, is noticeable next to the gum line of the crowned tooth. The problem caused by this is a cosmetic one rather than a dental issue, in which case your dentist will opt for an all-porcelain or ceramic crown.

What are ‘onlays’ and ‘3/4 crown’

These are variations of the regular dental crowns. The difference between these and the regular crowns is the amount of coverage of the underlying tooth. The traditional ones cover the entire tooth and the onlays and ¾ ones cover to a lesser extent.

How long do dental crowns last?

They last between 5-15 years on average and depends on the amount of wear and tear of the crown, whether you follow good oral hygiene practices and your personal oral habits such as avoiding grinding or gritting of teeth, chewing on ice, biting fingernails, using teeth to open packaging etc.

Does a crowned tooth require special care?

While there is no special requirement to take care of a crowned tooth it is important to remember that just because a tooth is crowned doesn’t make it invulnerable to decay or gum disease. It is for utmost importance to keep adhering to good oral hygiene practices including brushing your teeth at least twice a day., flossing daily especially around the crown where the gum joins the tooth and rinsing with an antibacterial mouthwash at least once a day.

DENTAL BRIDGES

These are prosthetic devices that replace are meant to replace teeth that have been extracted due to decay, damage or other reasons. The absence of one or a number of teeth can affect the functionality of your smile and change your appearance apart from other effects such as, shifting of remaining teeth, change in occlusion, temporomandibular joint disorder (TMJ), speech defects, increase in risk of periodontal disease and tooth decay. It would also make you self-conscious. However, a number of ways exist to fix your smile so fear not.

There are a few types of permanent dental bridges including conventional bridge and cantilever.

Before a cantilever or conventional bridge can be placed the teeth adjacent, to the empty tooth socket, will have to be re-shaped. The crowns will then be placed on the shaped teeth and connected to an artificial tooth, called a pontic.

CONSULTATION AND TREATMENT PLANNING

Your dentist will examine you and determine which type of bridge would be a suitable replacement for your missing tooth or teeth. There are a number of different materials that can be used to manufacture your bridge. The type of material chosen will be based on a few facts such as, whether you clench or grind your teeth (bruxism), dental insurance coverage and various other factors as advised by your dentist.

Nowadays you have an option of getting your prosthetic fabricated by using a combination of porcelain and metal, gold and porcelain or exclusively with metal-free, high-strength material like zirconia or alumina.

The treatment process will start off with your dentist taking x-rays, impressions of the area to be treated and preoperative photographs in order to determine the most suitable restoration for you.

He will then suggest the type of bridge. It can contain 3 or more units, 2 crowns cemented to teeth on each side of the empty socket (called abutments), and one or more false teeth (called pontics) depending on the number of consecutive teeth you are missing. More impressions will be obtained after the abutment teeth are prepared.

CANDIDACY AND PROCEDURE DETAILS

At the initial visit, your dentist will evaluate the health of your gums and other teeth to determine if you are a good candidate for a bridge. He will then go on to prepare the teeth required to support the bridge. A local anesthetic will be used to numb the area for the procedure. If the support teeth are badly damaged or decayed, your dentist will have to build them up and strengthen them before they can be used to support the prosthetic.

Impressions of the prepared teeth will be obtained, with a material similar in texture to putty, to create a model. A skilled lab technician will use this to fabricate your bridge to fit the prepared teeth flawlessly.

This is very important as a perfect fit will prevent additional oral health issues like tooth decay and damage resulting from an ill-fitting prosthetic.

Your dentist will fit you with a temporary prosthetic while the permanent one is being fabricated; this will help protect your 'prepared' teeth and gums in the meanwhile.

Once the bridge is ready you will have to go to your dentist to get it fitted in and cemented in place flawlessly. This is an important step.

RECOVERY AND POST-PROCEDURE CARE

Your dentist will advise you on how to maintain good oral hygiene after the permanent bridge is cemented in place. This is vital to maintain performance and longevity of the bridge along with the health of your teeth and gums. Brush your teeth at least twice a day with fluoridated toothpaste, floss the areas surrounding the bridge daily, in between the pontics, the gums and beneath them thoroughly to prevent the build-up of plaque and bacteria which can be damaging to your teeth.

WHAT ARE THE BENEFITS OF DENTAL BRIDGES?

Bridges serve to:

Improve the ability to properly chew, speak and smile.
Prevent the remaining teeth from getting out of position.
Distribute the forces in your bite symmetrically by replacing the missing teeth.
Maintain your face shape.

WHAT TYPES OF DENTAL BRIDGES ARE AVAILABLE?

Bridges are of two types:

Traditional bridges – these are the most common types and are made of ceramics orporcelain-fused-to-metal. It includes a crown for the tooth or implant on either side of the missing tooth with pontics in between.
Canteliver bridges – are not commonly used and are not recommended being used in the back of the mouth where it can put increased force on the other teeth resulting in damage. These bridges can be used when adjacent teeth are found only on one side of the missing tooth or teeth.

THE PROCESS OF GETTING A DENTAL BRIDGE

At the initial visit to the dentist, abutment teeth are prepared by re-contouring them. This is done by removing a part of the enamel in order to make room for the crown to be place over them.
Impressions of the teeth are obtained, which will be used as the model for the fabrication of the bridge, pontics and crowns.
A temporary bridge will be fitted in place to protect the exposed teeth and gums, until the permanent prosthetic is ready.
At the second visit, the temporary one will be taken out; the new one (made of either metal or porcelain) will be adjusted and checked to determine if it is fitting in flawlessly. This in important to prevent any damage from mispositioning.
Depending on the individual, multiple visits to the dentist may be needed to assess the placement of the metal framework and the bite.
If the bridge is a fixed type your dentist may place a temporary cement for 2 weeks, to hold it in place. And the bridge will be cemented into place.

WHAT IS THE LIFE SPAN OF A DENTAL BRIDGE?

With good oral hygiene and regular check-ups, the life span of a fixed dental bridge can go beyond 15 years. If you look after the prosthetic with great care its longevity can be extended.

WILL MY SPEECH BE AFFECTED BY THE BRIDGE?

Speaking clearly is difficult with missing teeth so a dental bridge can help this. Wearing the prosthetic with anterior teeth in their proper relationship will aid in speaking properly. The more you practice speaking, the more comfortable you will be with your prosthetic.

HOW CAN I CARE FOR MY BRIDGE?

The longevity of the dental bridge will depend on the type of material used in its fabrication and the solid foundation extended by the adjacent teeth. It’s vital to keep the remaining teeth healthy and strong too.

Take necessary precautions like brushing teeth twice daily, flossing regularly and using an antiseptic mouthwash to keep tooth decay and gum disease at bay. Your dentist will advise you on how to look after your bridge and teeth, he will demonstrate the proper technique of flossing and brushing teeth.

Stick to a regular cleaning schedule with daily visits to the dentist, this can help diagnose impending problems and treatment can be initiated before any serious damage is done.

Eating a balanced, healthy diet is also important for good gums and teeth. Food rich in calcium, iron, vitamin B complex etc. Will promote healthy gums and teeth.