Crowns are a restorative procedure used to improve your tooth’s shape or to strengthen it. Crowns are most often used for teeth that are broken, worn, or have portions destroyed by tooth decay.
A crown is a “cap” cemented onto an existing tooth that usually covers the portion of your tooth above the gum line. In effect, the crown becomes your tooth’s new outer surface. Crowns can be made of porcelain, metal, or both. Porcelain crowns are most often preferred because they mimic the translucency of natural teeth and are very strong.
Crowns or onlays (partial crowns) are needed when there is insufficient tooth strength to hold a filling. Unlike fillings, which apply the restorative material directly into your mouth, a crown is fabricated away from your mouth. Your crown is created in a lab from your unique tooth impression, which allows a dental laboratory technician to examine all aspects of your bite and jaw movements.
Your crown is then sculpted just for you so that your bite and jaw movements function normally once the crown is placed.
Fitting a dental crown requires at least two office visits. Initially, we will remove decay prepare the tooth and make a molded impression of the teeth to send to a dental laboratory. A fitted, temporary crown is created during this visit to temporarily protect the tooth while the final restoration is being made in the dental laboratory. Upon the second visit, the tooth crown is cemented or adhesively bonded and you have a new beautiful looking tooth.
Dental crown and bridgework is a very reliable solution for major dental problems caused through accidents, diseases, or wear and tear. Major problems can usually be corrected using these techniques. Materials used in these repairs are either high-grade porcelain or porcelain bonded to gold. The higher strength of the porcelain and gold materials is recommended to treat the most serious of dental problems. Where accidental damage has occurred resulting in lost teeth, or teeth have broken away through excessive wear, or as the result of old fillings breaking, crowns and/or bridges can be used as a long-term solution.
Many people have unexplained pain from filled back teeth that is usually due to hairline cracks in the chewing part of the tooth. Placing crowns on these teeth relieves the pain and allows a return of full dental function for these teeth. In front teeth, older fillings can both weaken the teeth and cause appearance problems due to staining or chipping. Porcelain crowns and bridges are suitable in cases where porcelain veneers are not. In teeth with root canal fillings, dental crowns can prevent breakage.
The three predominant choices of restorative materials for the full coverage crowns are:
The material selected is determined by the clinical demands at hand; esthetic demands, strength requirements, material durability and restorative space available.
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.
One consideration in the porcelain-fused-to-metal crown is that these crowns may tend to show the underlying metal or gold margin at the gum line as gums recede over time. Some patients opt for this type of crown, but replace the crown at a later date in order to maintain a higher esthetic benefit. Porcelain-fused-to-metal crowns with an all porcelain collar can eliminate this vulnerability.
The predominant material choice for all-ceramic crowns today is either zirconia, or aluminous materials. They provide a metal-free esthetic option with a number of benefits.
By eliminating the need for the supportive metal core, an esthetic all-ceramic crown can be created with a reduced thickness of material. This makes them a more favorable treatment choice in areas with limited space. 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.
All-ceramic materials continue to evolve in strength and durability, but caution should still be exercised for areas of the mouth requiring heavy function. Continuing research is exploring the significant vulnerabilities of the porcelain systems in such areas.
Although not as popular a treatment choice for esthetic reasons, gold crowns are still indicated in some instances. For example, patients with strong bites and those with parafunctional habits (such as grinding or clenching) might be better served with a gold crown. The traditional restorative material can provide stronger support to the remaining healthy tooth structure. Gold crowns offer a level of durability that is appropriate for teeth located in the back of the mouth (such as the molars), where they will not be highly visible. Gold crowns tend to offer greater longevity and require less preparation than porcelain and porcelain-fused-to-metal crowns. When chewing, gold tends to be less abrasive to the opposing tooth than porcelain. This helps to prevent wearing of the teeth.