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Indications

• Reconstructing heavily restored or fractured teeth
• Rebuilding the occlusion ("bite") for proper function
• Support function for non-removable bridges
• Support function for removable partial dentures
• Cosmetic indications to correct tooth color, position, size, length

Materials

• all ceramic
  • best cosmetic result due to translucency
  • no possibility of dark line at gum
  • tooth colored core and outer covering
  • bonds to tooth structure for strength
  • strength limitations prevent use in some areas
  • ongoing change in materials
  • some materials do not have long-term clinical history
• ceramic fused to gold/metal alloy
  • most common tooth colored crown
  • can have highly cosmetic and natural lookng result
  • strength adequate for all areas of the mouth
  • requires care in fabrication to avoid darkness at gum line
• resins
  • newer materials
  • bonds to tooth structure for strength
  • lack of long term clinical history

Limitations of basic filling materials

Basic filling materials such as amalgam and tooth-colored resins are remarkably effective at rebuilding decayed teeth. Metallic filling materials depend on remaining tooth structure for retention of the material, and will weaken a tooth significantly if the filling is large, thereby increasing the potential for tooth fracture. The adhesive properties of bonded, tooth-colored resin filling materials rely less on solid tooth structure for retention, and add some strength to the tooth. However, resins are not as resistant to recurring decay as metallic filling materials, and in general will need to be replaced more frequently.

High fracture potential of key teeth

Multiply the limitations of extensive restorations over many teeth, and clearly the scene is set for high fracture incidence potentially causing tooth loss, and a constantly changing bite. Appropriate therapy to avoid these problems, as well as to reconstruct areas of damage and tooth loss, will insure long term oral health and comfort

Importance of the bite in long-term health

Both types of filling materials present additional difficulty in establishing proper occlusion ("bite") when restorations are large, resulting in less than ideal results.

The physiology of the mouth requires that teeth have adjacent and opposing teeth in order to prevent the movement of teeth and changing of the bite. Existing teeth with large fillings, as well as missing teeth, can allow tooth movement.

Shifting teeth and changing bite may:

• cause loosening of teeth
• increase potential for tooth fracture
• increase tendancy to clench or grind
• increase potential for TMJ problems
• allow impacting of food between teeth
  causing gum problems

Fabrications of crowns

• Diagnosis:
  the tooth is evaluated to determine extent of decay, periodontal health, and type of crown restoration
• Preparation: local anesthesia is administered and the tooth is prepared for the crown restoration
  
• Impression: an impression (mold) is made of the tooth, as well as the adjacent teeth and the teeth of the other jaw. These impressions are used to construct models of the prepared tooth, and are used in the laboratory during fabrication of the crown
• Temporization: a temporary crown is fabricated and placed on the prepared tooth for the duration of the laboratory phase. This may vary from a few days to a few weeks in time.
• Cementation: the final crown is evaluated for many factors including fit, color, and bite. Corrections and adjustments are made when necessary. The crown is cemented to place
  
  

  
  

Metallic filling materials depend on the strength of remaining tooth, and will weaken a tooth significantly if the filling is large