A dental crown also called “cap” or “cover” is a custom designed helmet like material used to cover a damaged or decayed tooth to protect it from further damage. Crowns can also be used to cover a discolored or misshapen tooth. A tooth that treated with crown feels looks and works very much like a natural tooth. The crown, when cemented on tooth, it covers the entire visible part of a tooth that lies above the gum line.
Why Is a Dental Crown Needed?
Treatment of dental crown is used commonly for the following reasons.
(1) Strengthening teeth
Sometimes in treatment of badly carious tooth, large portion of tooth structure is damaged and it is restored by large restoration, leaving unsupported and insufficient original structure, which is more prone to
fracture, to hold artificial filling material, require crown placement to cover and support a tooth to withstand heavy chewing forces and retain filling material to fail. After root canal infection, tooth lost the nutritional supply and became brittle. That’s why after root canal treatmentmost of tooth require crown to strengthen against heavy chewing forces.
(2) Restoring teeth to their original shape and function
Crown is used to rebuild the original shape and function of tooth which is broken or decayed. It also used to restore a tooth that has been severely worn down.
(3) Improving the appearance of teeth.
When a dental crown is cemented over tooth, it becomes the new outer surface of a tooth. By this benefit we can cosmetically modify color, shape and even alignment of tooth. We can change the badly shaped or severely discolored teeth by making crown over teeth.
Types of dental crowns
There are three types of dental crowns. Full metal, Porcelain-fused-to-metal (PFM) and all-ceramic.
(1) Full Metal
This type of crown is fabricated entirely out of metal. or gold color. Metals used in crowns include gold alloy or a base-metal alloy (nickel or chromium). There are several advantagesof full metal. Full metal crown has great strength, rarely break and lasting more time. It require less tooth grinding. The single disadvantage of this type of crown is its metallic look. If you don't mind the fact that it's not tooth-colored, full metal crown is an excellent choice for back out of sight teeth. (nickel or chromium). There are several advantages of full metal. Full metal crown has great strength, rarely break and lasting more time. It require less tooth grinding. The single disadvantage of this type of crown is its metallic look. If you don't mind the fact that it's not tooth-colored, full metal crown is an excellent choice for back out of sight teeth.
(2) Porcelain-Fused-to-Metal (PFM)
PFM is a hybrid between full metal and all-ceramic crown. PFM is made up of both metal and porcelain. A metal alloy is used to create a thin coping that fits over the tooth and porcelain is then fused to this metal substructure to form normal shape of the crown and give it a white, natural-looking appearance. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown's porcelain can show through as a dark line, especially near gum line and even more if your gums recede. These crowns can be a good choice for front or back teeth. Porcelain-fused-to-metal crowns provide for a strong, durable and esthetic treatment option. One of the key factors for the esthetic and functional success of this type of crown is ensuring the preparation of the underlying tooth structure provides adequate space for the appropriate thickness of the material selected. Additionally, the artistic skill of the laboratory technologist creating the crown will determine its esthetic appeal.
(3) All-Ceramic or All-Porcelain
All-ceramic crowns are fabricated entirely out of a glass-like compound such as porcelain. Most types are handmade by a dental technician but some are milled out of a block of ceramic by CAD-CAM machine (Zirconia). Both techniques offer their own advantages. All-ceramics are commonly placed in those situations where the aesthetics are of utmost concern in front teeth. All-ceramic or all-porcelain dental crowns provide better natural color match than any other crown type and may be more suitable for people with metal allergies. The single biggest advantage of all-ceramics, as compared to PFM, is their more lifelike appearance. Additionally, the elimination of the metal core allows for light transmission through the porcelain for better optical, life-like properties and a higher level of esthetics. As described in PFM, dark line of metal is never a concern in all-ceramic crown, either initially or if gum recession occurs later on. In comparison, all-ceramic crowns, even those made from the most modern materials, can generally be considered to have relatively inferior physical characteristics like strength, hardness, brittleness and resistance to fracture. Though certain disadvantage, all-ceramic crowns are a good choice for front teeth.
Factors to determine type of crown:
There are a number of factors that need to be considered when making this determination, which type of crown is most suitable for you according to your need. · Esthetics - color match and appearance · Function - chewing and biting accuracy · Tissue compatibility- the contour of the prosthesis must allow the surrounding tissue to conform to a natural, healthy position. · Cost factors – Full metal crown is cheaper while all-ceramic is most costly. · Skill of dentist – Preparation of tooth for PFM and all-ceramic crown is highly precise work. The skill of dentist definitely impact on durability, cosmetic appearance of crown and health of adjacent tooth and gums.
Procedure for Crown and Bridge Treatment
Preparing a tooth for a crown and bridge (A bridge is two or more capped teeth connected together with one or more false teeth in between the capped teeth) are same. It usually requires two visits to the dentist -- the first step involves examining and preparing the tooth, the second visit involves placement of the permanent crown.
First Visit: Examining and Preparing the Tooth
At the first visit in preparation for a crown, X-ray may be taken to check the roots of the tooth receiving the crown and surrounding bone. If the tooth has decay or if there is a risk of infection or injury to the tooth's pulp, a root canal treatment may first be performed. Before the process of making a crown begins, we will anesthetize the tooth and the gum tissue around the tooth (in case of vital tooth). Next, the tooth receiving the crown is reshaped along the chewing surface and sides to make room for the crown. The amount removed depends on the type of crown fabricated (for example, full metal crowns are thinner and require less tooth structure removal than all-porcelain or porcelain-fused-to-metal ones). If, in case of a large area of the tooth is missing (due to decay or damage), we will use post & core or filling material to build up the tooth to support the crown. After reshaping the tooth, we will use a paste or putty to make an impression of the teeth to copy tooth. Impressions of the teeth opposite jaw will also be made to make sure that the crown will not affect your bite. The impressions are sent to a dental lab where the crown will be manufactured. The crown is usually returned in one week. If the crown is made of porcelain, we will also select the shade and that most closely matches the color of the neighboring teeth and photographed. After that temporary crown is placed to cover and protect the prepared tooth while the crown is being made. Temporary crowns usually are made of acrylic and are held in place using weak temporary cement.
Second Visit: Cementation of Permanent Dental Crown
At the second visit, temporary crown is removed and check the color and fit both on the tooth and the way it touches neighboring and opposing teeth. After making any needed adjustments and if everything is ok then the new crown is permanently cemented in place. Dr. Bharat Katarmal dental clinic is one of the most advanced dental clinic of Jamnagar. We design dental crown according to need and budget of patients. We design crown of trusted and well-known brands of world like Vita, Tilite, CAD-CAM(Computer Aided Design – Computer Aided Milling), Zirconia, Bruxzir and Ultratrancelucent E- Max.
Before After Photo of Dental Crown
|PFM Dental Crown|