Crowns - what you need to know
What is a crown?
A crown or "cap" is a dental restoration that covers the entire surface of the tooth restoring the tooth back to its normal size/shape. Crowns are used to strengthen a compromised tooth due to decay or fracture or to improve the appearance of a tooth.
How is a crown fabricated?
Generally a 2 appointment procedure, at the first appointment, the tooth is prepared by removing the outer portion of the tooth to accommodate the thickness of whichever material that will be used for the crown. an impression or digital scan is taken of this area as well as of the opposing teeth that is sent to a commercial dental laboratory. A temporary crown is fabricated and cemented for this tooth. At the second appointment, the crown is tried in, adjusted if necessary, and cemented. In some cases a third appointment is necessary if shading, contour, or fit need improvement.
What are the materials that are available for crowns and which is the best?
There are many dental materials available now for crowns and the materials are continually improving. The location of the tooth and the needs of the patient will generally dictate the material. Some examples are: all porcelain, zirconium, porcelain fused to metal, and gold; each of them has advantages. Crowns that have the best aesthetics have no metal as a substructure allowing them to have good translucency similar to enamel. The strongest crowns have no porcelain - since porcelain, like your china, always has the possibility of chipping or fracturing. Gold crowns require the least amount of reduction of the tooth and will never fracture.
How much is a crown?
The fee for a crown is based on a number of factors - material/lab/facility, etc. The primary factor in determining the fee is by the time, care, skill and judgment of the dentist.
How do I take care of my crown?
The margin of the crown is the junction of the crown to the tooth - this area is susceptible to having decay recur so it is very important to keep plaque off of it daily with brushing/flossing, but also to stay on a regular professional dental hygiene schedule to ensure the areas are kept clean. To avoid fracturing the crown, the patient should avoid any hard foods, ice, or hard objects.
How long will my crown last?
Multiple factors will affect the longevity of a crown or any dental restoration for that matter. Some crowns can literally last 50 years while others need replaced in less than 2. Crowns are constantly put under compression and tension, heat, cold, and acid - it’s amazing that they last as long as they do. Several significant factors that affect the longevity are:
the condition of the tooth prior to preparing it for a crown -was there extensive decay or filling material , did it have a prior root canal (that weakens the tooth). Everything else being equal, The more good tooth structure remaining correlates to a longer lasting crown.
How well was the tooth prepared and how well did the crown fit - essentially the skill of the dentist and the laboratory technician greatly impact the longevity of a crown
How well does the patient care for his teeth. Crowns done for patients that have regular dental care and excellent oral hygiene will always outlast crowns done for patients whose oral hygiene is less than ideal .
Local factors ie. patients that have extensive tooth wear from grinding their teeth will more likely fracture a crown; Patients that have a dry mouth will more likely develop decay around the crown; if the patient is missing many teeth, the biting forces will be put on the remaining teeth; if there is bone loss/periodontal disease this will affect the support of the crown.