Dental Crown is commonly known as a tooth cap or a dental cap. Dental crown is a restoration that covers outer surface of a tooth (like a cap) and is cemented to the tooth with the help of dental cement. Discussed below in detail are functions of dental crowns and need for dental crown.

Functions of  Dental Crown are to

1.    Restore the form, function and esthetics of a tooth
2.    Improve the strength of a tooth
3.    Protect the underlying tooth from any mechanical, chemical, or thermal injury.

When should Crown be given on a Tooth?

Badly Decayed Tooth If tooth is extensively destroyed by carious process, it cannot be restored to its proper form & shape by any filling material.

How to decide whether to place a filling or a crown on a carious tooth?

If there is a small cavity in a tooth it can be successfully restored by a filling but placement of filling in a large cavity can hamper the integrity of a tooth structure and may cause its fracture. To retain the filling in the tooth adequate amount of tooth structure should be present. A filling which is greater than 1/3rd the width of a tooth is considered a large filling which can compromise the strength of a tooth.

 

 

       
Fracture of a tooth when filling is placed in a large cavity
 
 
Crown placement over a tooth prevents its fracture by encasing the tooth structure 
 

Cracked Tooth: Crack may appear in a tooth due to excessive chewing forces or a large filling. Treatment of a cracked tooth depends on the position and depth of crack. If crack affects one or more cusps of the tooth then a crown has to be placed on the tooth. If crack is deep and reaches the pulp of tooth, then firstly Root Canal Treatment is done and then tooth is covered by a crown. If crack is present very near to the gum line of tooth, then gum line of the tooth has to be raised and then crown is placed on the tooth. But if crack is present in the root of the tooth, then tooth has to be extracted and replaced by a bridge or implant.

Root Canal Treated Tooth: If the tooth has undergone Root Canal Treatment (RCT), it may get weakened during preparation of access cavity and it also gets brittle due to loss of fluid substance of the tooth during RCT. So, it is more prone to fracture as compared to a normal tooth. Thus it should be covered by a crown to minimize the chances of its fracture especially if large cavity is created in the tooth during RCT.

In certain cases due to extensive caries more than 2/3rd of the crown structure of tooth is lost; such a tooth is not able to support an artificial crown. So, firstly a post is placed inside the root of tooth, core build up is done and then crown is placed over post and core.

                                   
 
    Placement of post and core build up     Crown placement over core build up
 
Fractured Tooth: If tooth is fractured to such an extent that it cannot be restored by a filling, then placement of crown becomes inevitable to restore shape, form and function of tooth.
 
 
A fractured tooth

Amelogenesis Imperfecta: It is a hereditary condition in which enamel portion of tooth is very brittle, it gets fractured very easily leaving behind dentin of the tooth uncovered which further leads to tooth sensitivity. Then dentin being softer than enamel wears off easily and pulp of the tooth may get exposed which causes severe pain. So, to protect the teeth affected by amelogenesis imperfecta, they should be covered by crown.

Dentinogenesis Imperfecta: It is a hereditary condition in which dentin of the tooth is defective. So, dentin cannot properly support the enamel leading to wearing off both enamel and dentin casing pulp exposure. So, teeth affected by dentinogenesis imperfecta are protected by their restoration with crowns.

Discolored Teeth: Certain discolorations cannot be treated by bleaching procedures such as discoloration due to severe fluorosis and tetracycline staining. Teeth with such discolorations are covered by crowns so that their colour matches with that of adjacent non affected teeth and they look esthetically pleasing.

For Prosthetic Purposes: In some cases of removable partial denture and tooth supported overdenture, teeth have to be covered by crowns to give them a proper contour so that they can properly support a denture. In fixed partial denture (bridge) cases, to replace a missing tooth by a bridge, teeth immediately adjacent to the space have to be covered by crown to support the artificially replaced tooth.

 
Crown placed over 2nd premolar and 2nd molar to replace missing 1st molar
 
Nursing Bottle Caries: In children affected with nursing bottle caries syndrome, deciduous (milk) teeth get extensively damaged at a very faster rate especially the upper front teeth. So, they should be covered with temporary crowns not only for proper function & esthetics but also to maintain the arch length integrity so that permanent teeth can erupt at a proper place.

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Comments

  • Judith powell

    Judith powell 21 - November - 2013, at 15:49 PM

  • Is it possible to get a crown on a tooth that had a root canal many years ago. The tooth has a post in it but was never crowned and is now decaying.

  • Dr.Ritz

    Dr.Ritz 04 - June - 2012, at 02:18 AM

  • DAVID, its not possible to do half implant but you can get composite filling done. It is a tooth colored filling that is ideal for half chipped tooth. They are quite strong to and exactly matches the tooth color.

  • David

    David 03 - June - 2012, at 01:39 AM

  • Good day sir/mam,one of my further right front teeth is hafly chiped in its front facet so when ever I smile it prominetly looks horrific.My question is can it b poossible to just do a halfy tooth implant 'cause my half gum has already heald.Thankyou,yours sincerely!

  • Byron Hollander

    Byron Hollander 08 - September - 2011, at 06:26 AM

  • Thanks for the help. Just had a RCT and wondered why I still needed to go again for a CROWN. Your article explains it well, which I wish that the dentists would explain to one. Very interesting and helpful.Byron H, Cape Town South Africa

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