This information will help you make decisions about selection of materials as tooth restorations in your mouth. Several types of metals are used in dentistry for the replacement of oral structures. Most of these metals are considered to be inert when placed in the body, while others have been controversial. Plastics and ceramics are used commonly as tooth restoratives, and although controversial, these have not been shown to have adverse biologic responses.
Resin or Composite
Average longevity 6-15 years, tooth colored, moderate to high cost. Best used in small- to medium-sized restorations for front or back of teeth.
Average longevity 10-20 years, tooth colored, moderate to high initial cost. Best used in moderate- to large-size restorations for back of teeth.
Gold Inlays and Onlays
Average longevity 20 years or longer, gold colored, moderate to high initial cost. May be used in most locations where metal is not displaced to an objectionable level.
These restorations are fabricated from various ceramics. Average longevity is under study, moderate to high initial cost. All-ceramic fixed prostheses may be used in some clinical situations. These materials are being improved constantly. Their use is growing rapidly and they are expected to eventually replace metal-containing restorations.
Advantages of Ceramic Crowns and Fixed Prostheses:
1. They can be constructed to a highly acceptable esthetic level. These restorations are the most beautiful and natural-appearing restorations in dentistry.
2. Ceramic restorations do not have metal undercopings, as do porcelain-fused-to-metal crowns. Therefore, these crowns are biologically compatible and have extremely low allergenicity or toxicity.
Disadvantages of Ceramic Crowns and Fixed Prostheses:
1. In the past, some of these restorations were not as strong as metal or porcelain-fused-to-metal restorations. If the bite was especially abusive, some ceramic restorations did not have adequate strength. However, the use of extremely strong ceramic materials, introduced in the last few years, are now becoming the most-used materials for crowns.
2. Some types of ceramic restorations can be made into fixed prostheses (bridges) with adequate longevity expectations and others cannot
Average longevity 20 or more years, tooth colored, moderate to high initial cost. May be used in any area where extreme biting stress is not present, and patient does not have severe tooth grinding habit.
High-noble, noble, or base metal. Average longevity 20 years to life, gold or "silver" color, moderate to high initial cost. May be used in any area where metal display is not objectionable.
Advantages of Gold Alloy Restorations:
1. The longevity of cast gold restorations is greater than any other tooth restoration. Many patients and dentists report 40-50 years of service. Average longevity for gold restorations is at least 20 years.
2. Wear of opposing teeth is minimal with cast gold restorations. Gold alloy wears almost exactly like tooth enamel.
3. Gold restorations are strong and can be made to fit teeth exactly. When cemented with decay-preventative cement, the restorations resist further decay.
Disadvantages of Gold Alloy Restorations:
1. Gold restorations are not tooth-colored, and most people object to placing them in areas of the mouth that display the metal.
2. The cost of cast gold restorations is higher than some other types of restorations because of the cost of the gold alloy.
These restorations may be used for single crowns. Average longevity is several years. Research on its longevity is still underway.
Advantages of Resin/Composite Restorations:
1. They do not wear opposing teeth during chewing.
2. Resin/composite restorations have very low allergenicity or toxicity.
3. Some brands of resin/composite restorations can be constructed into fixed prostheses (bridges) when teeth are missing.
Disadvantages of Resin/Composite Restorations:
1. Opposing tooth structure wears the resin/composite restorations over a period of years.
2. It is more difficult to achieve optimum tooth color matching with resin/composite than with ceramic.
3. Resin/composite restorations are not as strong as all-ceramic or porcelain-fused-to-metal restorations.