refers to the restoration of teeth using materials that are
fabricated by indirect methods which are cemented into place.
A crown is used to cap or completely cover a tooth.
Traditionally, the teeth to be crowned are prepared by a dentist
and records are given to a dental technician to fabricate the
crown or bridge, which can then be inserted at another dental
appointment. The main advantages of the indirect method of tooth
fabrication of the restoration without the need for having the
patient in the chair
* the utilization of materials that require special fabrication
methods, such as casting
* the use of materials that require intense heat to be processed
into a restoration, such as gold and porcelain.
restorative materials used in indirect restorations possess superior
mechanical properties than do the materials used for direct methods
of tooth restoration, and thus produce a restoration of much higher
dental bridge, otherwise known as a fixed partial denture,
is a prosthesis used to replace missing teeth and is not removable
by the patient. A prosthesis that is removable by the patient
is called a removable partial denture.
A dental bridge is fabricated by reducing the teeth on either
side of the missing tooth or teeth by a preparation pattern
determined by the location of the teeth and by the material
from which the bridge is fabricated. In other words the abutment
teeth are reduced in size to accommodate the material to be
used to restore the size and shape of the original teeth in
a correct alignment and contact with the opposing teeth. The
dimensions of the bridge are defined by Ante's Law: "The root
surface area of the abutment teeth has to equal or surpass that
of the teeth being replaced with pontics".
The materials used for the bridge include gold, porcelain fused
to metal, or in the correct situation porcelain alone. The amount
and type of reduction done to the abutment teeth varies slightly
with the different materials used. The recipient of such a bridge
must be careful to clean well under this prosthesis.
When restoring an edentulous space with a fixed partial denture
that will crown the teeth adjacent to the space and bridge the gap
with a pontic, or "dummy tooth", the restoration is referred to
as a bridge. Besides all of the preceding information that concerns
single-unit crowns, bridges possess a few additional considerations
when it comes to case selection and treatment planning, tooth preparation
and restoration fabrication.