1. Why Is a Dental Crown Needed?

A dental crown may be needed in the following situations:
To protect a weak tooth (for instance, from decay) from breaking or to hold together parts of a cracked tooth

To restore an already broken tooth or a tooth that has been severely worn down

To cover and support a tooth with a large filling when there isn't a lot of tooth left

To hold a dental bridge in place

To cover misshaped or severely discolored teeth

To cover a dental implant   

2. What Types of Crown Materials Are Available?

All Porcelain Crowns
This type of crowns holds the advantage or natural aesthetics. As it is metal free, there are no unsighlt metal margins around the crowns, and the crowns do not appear grey.  This makes it very difficult to identify it from your natural teeth. The crown is bonded into place so it acts like a one-piece structure and can be described as enamel replacement. These types of crowns are suited for patients with metal allergies.

Gold
Where appearance is not a concern to you, gold could be the best choice. Since the gold metal is very workable, gold crowns are able to have a more precise fit than any other type. Gold also eliminates the slight possibility of chipping that exists with anything that contains porcelain. For simple longevity, nothing beats gold.

Porcelain bonded to metal
These crowns have a metal substructure which gives it strength covered by porcelain. The porcelain gives the tooth a natural appearance but this is limited by the underlying metal, giving it a grey appearance and metal may become visible at the gum margin.

Bridges
Bridge replaces missing teeth with artificial teeth, looks great, and literally bridges the gap where one or more teeth have been. The restoration is bonded onto surrounding teeth for support. These teeth have been prepared in a similar fashion as crowned teeth.