Dental fillings fall into two categories based on the method used to place them.
They are: direct restorations and indirect restorations. Direct restorations are
fillings placed immediately into a prepared cavity in a single visit. They include
dental amalgam, glass ionomers, resin ionomers and most composite (resin) fillings.
The dentist prepares the tooth, places the filling and adjusts it during one appointment.
Indirect restorations may require two or more visits. They include inlays, onlays,
veneers, crowns and bridges fabricated with gold, ceramics or composites. During
the first visit, the dentist prepares the tooth and makes an impression of the area
to be treated. The impression is sent to a dental laboratory, which creates the
dental restoration (filling). At the next appointment, the dentist cements the restoration
to the prepared tooth and adjusts it as needed.
This fact sheet outlines the alternatives available and will help you decide on
the right choice for you. The final choice is between you and your dentist.
The word amalgam when referring to dental fillings means a mixture of two or more
metals in which mercury is a component. Dental amalgam is a mix of approximately
43 percent to 54 percent mercury with other metals, including silver, copper and
tin. Dental amalgams have commonly been called "silver fillings" because of their
silver color when they are first placed. Today, amalgam is used most commonly in
the back teeth. It is one oldest filling materials and has been used (and improved)
for more than 150 years. Dental amalgam is the most thoroughly researched and tested
Strong, durable and stands up to biting force; Can be placed in one visit; Normally
the least expensive filling material; Sel-sealing with minimal-to-no shrinkage and
it resists leakage (leakage occurs when a filling does not completely seal, permitting
food and bacterial to "leak in" and promote new decay behind or beneath the filling);
Resistance to further decay is high; Frequency of repair and replacement is low;
Amalgam is the only material that can be used in a wet environment, especially important
when treating small children or special needs patients.
While agencies like the U.S. Food and Drug Administration (FDA), the U.S. Centers
for Disease Control (CDC) and the World Health Organization (WHO) have not found
evidence of harm from dental amalgam, there are some individuals and groups who
have raised concerns about the very low levels of mercury vapor released by amalgam.
These concerns are discussed later in this publication; Amalgam scrap (waste left
over after repairing a cavity) contains mercury and requires special handling to
protect the environment; Amalgam can darken over time as it corrodes. This does
not affect the function of the filling, but many people find it less attractive
than tooth colored materials; Placement of amalgam requires removal of some healthy
tooth; In rare cases, a localized, allergic reaction such as inflammation or rash
All-porcelain (ceramic) materials include porcelain, ceramic or glass-like fillings
and crowns. They are used in inlays, onlays, crowns and cosmetic veneers. Porcelain
fused to metal is another application for this material and has similar properties
as described below with the notable exceptions of increased durability due to the
metal substructure, the necessity for more tooth removal for that substructure and,
in rare cases, a localized, allergic reaction may occur.
Tooth-colored with excellent translucency; the color looks similar to natural tooth
enamel; Very little tooth is removed when used as a veneer, more tooth is removed
for a crown; Good resistance to further decay if it fits well; Is resistant to surface
wear but can cause some wear on opposing teeth; Resists leakage because of precise
shaping and fitting; Does not cause allergic reaction.
A minimum of two appointments is required to complete the restoration and it's not