What is a Crown and do I Really Need One?

What is a crown?

The crown is the white part of the tooth that is visible in your mouth.  More accurately, it is the outer coating of hard enamel over the slightly softer inner dentin that makes up the root and middle layer of the tooth (below center).

 

Do I need a new crown?

Teeth endure significant wear and tear from eating, grinding and from bacteria that reside on and in between teeth – an area the toothbrush bristles simply don’t reach.  When tooth is missing structure or exhibits damage from either decay or a large – especially an old metal – filling, a crown is needed.  Metal fillings are always wider at their depth than the surface, which when large enough, undermines the strength of the cusps.  It is common for us to see large metal fillings with hairline fractures at the edges or with entire sections of tooth missing around the filling (Above, middle: note missing cusp and fracture line on right side of tooth).  It is even the case that an unrestored tooth may exhibit signs or symptoms of cracking as the crack enters the highly sensitive pulp of the tooth.  The tooth in the above right image has a large metal filling and the arrows indicate areas of visible cracking.  Without the protection of a crown or an onlay to encapsulate the tooth, these cracks will propagate deeper into the tooth.  If you are lucky you’ll just lose a cusp (middle image) if you’re unlucky you’ll crack the tooth severely and you’ll need an extraction and implant as well as the crown that was originally indicated.  Early intervention is key.

What is a crown made of these days?

Dental materials have improved dramatically.  The traditional gold crown is still an excellent choice, especially for molars, but with the cost of gold both high and unpredictable it’s seldom the 1st choice.  Similarly, the traditional porcelain fused to metal (PFM) has declined in popularity drastically as stronger, more life-like options such as Emax (Lithium disilicate) and Zirconia crowns have become available (See below.  Image from Ref 1).  The esthetics of Emax is simply excellent.  Zirconia crowns with their natural look and high-strength, finally offer an attractive material choice for those who grind their teeth.  However, no material is perfect; each material has its strengths and limitations and material choice will depend on the location of the tooth, the neighboring and opposing teeth materials and the wear of other teeth (i.e. if the patient grinds their teeth at night)(Ref. 2,3,4). 

  

Staying current with the latest peer-reviewed articles and years of experience will allow us to evaluate if you need a crown, and what material is likely to give you the best long-term result.  Whichever material is best for you, you can be sure that with routine care, these materials will give you years of comfortable, functional, beautiful service.

If you have any questions, please don’t hesitate to contact our office.

References:

1. Dental Economics: Which indirect restorations do dentists want in their own mouths? GJ. Christensen, DDS, MSD, PhD.
2. Dent Mater. 2013 Dec;29(12):1201-8. Edge chipping and flexural resistance of monolithic ceramics.
3. J Prosthodont Res. 2013 Oct;57(4):236-61.Current status of zirconia restoration
4. J Prosthet Dent. 2014 Jul;112(1):22-30. doi: 10.1016/j.prosdent.2014.01.005. Clinical outcomes of lithium disilicate single crowns and partial fixed dental prostheses: a systematic review.