Dental crowns or “caps” have been a treatment option to restore primary and permanent teeth since the dawn of dentistry. Currently, dental patients receive millions of crowns each year in the United States to restore broken and decayed teeth.
What is a dental crown? A dental crown is a full coverage restoration that is designed to cover the entire erupted portion of a tooth, or “clinical crown.” Generally, the primary purpose of placing a dental crown is to protect the strength and integrity of a natural tooth that has been otherwise compromised by a history of fracture, advanced decay, root canal treatment or other conditions.
The earliest record of dental crowns date back to 166-201 A.D., in which the Etruscans, a civilization of ancient Italy, were found to have used gold crowns and fixed bridges. Today, developments in research, education, technology and material science have brought crowns and fixed bridges leaps and bounds beyond their origins, but the basic purpose in treatment remain the same.
What are the clinical indications for a crown? The indications for dental crown treatment vary, but are generally based on, i) the size of an existing restoration or “filling” present, ii) the presence of advanced tooth decay, iii) previous endodontic or “root canal” treatment on a premolar or molar, iv) to enhance esthetics, v) fractured tooth syndrome, vi) restore or correct occlusion, and vii) treatment of TMJ disorders.
- Size of Filling Present: In current dental education, if an existing filling consists of more than 1/3 the width of the tooth, studies have found that the tooth is at risk of fracture due to the nature of chewing forces placed on the teeth overtime. We refer to these forces as, “vectors of occlusion.” Statistically, the incidence of needing crown treatment is most common in the fourth to sixth decades of life.
- Presence of Advanced Decay: As dental cavities eat away natural tooth structure, the inherent strength of the tooth becomes compromised and is at risk of fracture. Frequently, a full coverage restoration, such as a crown, may be needed.
- Previous Root Canal Treatment: Root canal treatment tends to weaken teeth, since the nerve is carefully removed and the canal spaces are cleaned, shaped and enlarged. Because of the nature of forces on premolars and molars, crown treatment is strongly recommended after root canal treatment in an effort to prevent fracture.
- Esthetics: Frequently, patients desire enhanced esthetics and crown treatment in the esthetic zone can be an effective method to transform a smile.
- Fractured Tooth Syndrome: Occasionally, teeth fracture (most frequently molars) due to bite forces overtime, presence of large fillings or a combination thereof. In such cases, the tooth may present with sharp pain with biting. In these situations, with proper diagnosis, a crown may be indicated to protect the tooth to prevent the fracture from propagating below the gums.
Modern technology has provided many options for crowns and bridges today. One exciting treatment option is all-ceramic crowns, which tend to enhance esthetics since there is no metal present. Studies have also shown that the margins, “fit,” and strength of the all-ceramic crowns are similar to or better that traditional porcelain fused to metal crowns.