Cavity fillings are biocompatible material
used for filling up the cavities, which are intentionally cut on
the infected part of the tooth surface. These cavities are prepared
in a scientific and a principled manner in order to achieve a strong
and a long lasting filling.
The main idea of preparing a cavity is to remove
the infected position of the tooth so as to prevent the further
spread of decay and hence the ultimate loss of the tooth.
The cavities are prepared using high speed drilling
equipment, which is controlled by the dentist. Patient may not have
any discomfort initially but as the drill bit move closer to the
center of the tooth (where the nerves are located), the patient
begins to experience sensitivity. This can be avoided if tooth is
anesthetized, which of course means having to take an injection
If the cavity prepared is very deep, a layer of
medicated cement is used to line the floor of the cavity to help
in healing of the tissue.
In case of metal based filling material a base
is given. This base is nothing but a thick coat of cement lining
the floor of the cavity. The base not only adds to the strength
of the over lying filling but also insulates the tooth from sharp
variation in temperature, caused by the increased thermal conductivity
of the metal filling.
The term cement, which is frequently used, is a
mix of a chemical powder and liquid. This mix, which is initially
soft, turns hard over a period of time resembling the common cement
used for construction
For cavity preparation, which is not very deep,
a cement base may not be required.
Filing of a prepared cavity depends upon a lot of factor such as.
- Site (for an anterior tooth a metal filling may not be acceptable)
- Function of a tooth (A posterior tooth might require a very
strong filing to withstand the forces produced while chewing
food)
- Amount of remaining tooth structure: Too much of a hard filling
material and very little amount of remaining tooth structure
can cause the fracture of the tooth.
- Type of material used to fill the opposing tooth( when two
different metals are used to restore two opposing teeth small
amounts of galvanic currents are produced which can be painful
for the patient.
Filling materials can be of 2 types
- Tooth colored - Glass inomer, composites etc.
- Non tooth colored - Amalgam, Gold
Each material has its own advantages for e.g. Amalgam is much
more strong & tougher than the tooth colored composite hence
ideal for posterior teeth where as composite filling material require
very little cavity preparation and hence saves a lot of tooth cutting
there by preserving as much natural tooth material as possible.
