CHAPTER 1 Terminology
Chapter 1
Terminology
• Prosthetics: It is the art and science of supplying,
fitting and servicing artificial replacement for missing parts
of the human body.
• Prosthesis: It is the replacement of missing part of
the human body by an artificial part e.g. eye, leg or arm
prosthesis.
• Prosthodontics or Prosthetic dentistry: It is that
branch of dental art and science that is concerned with
restoration and maintenance of oral function by replacement
of missing teeth and surrounding structures by artificial
devices.
• Dentulous: It is a condition in which natural teeth
are present in the oral cavity.
• Edentulous: It is a condition in which natural teeth
are absent in the oral cavity.
• Partially edentulous: It is a condition in which
some of the natural teeth are absent in the oral cavity.
• Completely edentulous: It is a condition in which
all of the natural teeth are absent in the oral cavity.
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CHAPTER 1 Terminology
• Complete Denture: It is a dental prosthesis that
replaces the entire natural dentition and its associated
structures of the mandible and/or maxilla.
• Partial Denture: It is a dental prosthesis that
replaces one or more, but not all, of the natural teeth and it's
supporting structures and is supported by teeth and/ or
mucosa. It may be fixed or removable.
• Immediate denture: It is a dental prosthesis that is
constructed before extraction of teeth and is inserted at the
time of teeth removal.
Components of a complete denture:
a. Denture base: It is that part of the denture that rests on
the tissue foundation and artificial teeth are attached to it.
b. Artificial teeth.
Denture surfaces:
• Fitting surface or impression surface: the denture
surface that has its contour determined by the
impression. (Fig.1)
• Polished surface: the denture surface that carries the
artificial teeth. It includes the facial, lingual and palatal
surfaces facing the cheeks, lips and tongue. (Fig.1)
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CHAPTER 1 Terminology
N.B.
The buccal and lingual surfaces of the teeth are
polished surfaces.
• Occlusal surface: the denture surface that makes
contact with its antagonist. (Fig.1)
Fig. 1 Denture surfaces
Denture border: It is the margin of the denture base at
the junction between the polished and the impression
surface.
Denture Flanges: The vertical extensions of the denture
base that extend from the cervical margin of the teeth to the
borders of the denture are called denture flanges. They are
named according to location into:
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CHAPTER 1 Terminology
a- Buccal flange: the portion of the denture
that is related to the cheek and occupies the
buccal vestibule. (Fig.2)
b- Labial flange: the portion of the denture that
is related to the lip and occupies the labial
vestibule. (Fig.2)
c- Lingual flange: the portion of the
mandibular denture that is related to the tongue
and occupies the lingual sulcus. (Fig.2)
Palatal portion: It is that portion of the maxillary denture
that is related to the palate. (Fig.3)
Palatal portion
portion
Lingual flange
Fig. 2 Denture flanges
Fig. 3 Denture flanges and palatal portion
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CHAPTER 1 Terminology
Differences between natural and artificial
teeth:
• Forces exerted upon one segment or one tooth on
the denture will have a direct effect on the entire
prosthesis. This is in contradistinction to the natural
dentition, wherein pressures applied to an individual
tooth may influence only that particular tooth and may
not involve adjacent teeth or teeth on the opposite side.
• The natural tooth is well suited to withstand
forces of occlusion because of the unique configuration
of the periodontal ligament fibers. Therefore, non-
vertical forces exerted on natural teeth may not be
detrimental to the supporting apparatus. In an otherwise
similar situation with complete dentures, non vertical
forces applied to any tooth will cause either a shearing of
the denture base against the oral mucosa, or a
displacement of the denture away from its basal support.
• Incising with natural teeth does not affect the
posterior teeth. Incising with the artificial teeth affects
all of the teeth on the denture base. With increasing
patient demands to fabricate dentures that do not appear
artificial, the dentist often attempts to incorporate a
minimal horizontal overlap (overjet), as is often found in
the natural dentition, into the denture set-up. Incising
with denture teeth creates a long lever arm which
dislodges the dentures posteriorly from their basal seats.
Furthermore, with the continual resorption and
recontouring of alveolar bone, the net effect of denture
"settling" is an upward and forward movement of the
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CHAPTER 1 Terminology
mandible to maintain occlusal interdigitation. If incisal
contact was established initially, then this upward and
forward movement of the mandible during settling of the
dentures will lead to traumatic anterior tooth contact,
which makes the ridge a target for rapid bone resorption.
Desired objectives in complete denture
construction:
1- Restoration of masticatory efficiency:
Teeth are necessary for good digestion and optimal
health. Chewing makes eating more enjoyable. Chewing of
food and mixing it with saliva is also the first step in
digestion. It is interesting to note that man is the only animal
that can live without teeth. Other animals die if they lose
their teeth.
2- Restoration of facial dimensions and contours:
Loss of teeth results in a prematurely aged
appearance due to loss of support, and consequent falling in
of the lips and cheeks. When the lips lose their support, the
vermilion border (red portion) becomes thinner and the jaws
may overclose producing bunching up of the soft tissues and
close approximation of the chin and nose. A properly con-
structed denture will correct and restore the patient's normal
appearance. In addition to soft tissue changes, loss of
natural teeth leads to resorption of the alveolar bone; the
improper placement of artificial teeth without consideration
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CHAPTER 1 Terminology
of the bony changes will result in improper support of the
lips and an unnatural esthetic result. (Fig.4)
Fig.4 Restoration of facial contour
3- Restoration of speech:
Effective speech requires teeth. The tongue
contacting against the teeth forms many sounds. Proper
placement of artificial teeth is necessary to restore good
speech. A constricted arch in a complete denture will
squeeze the tongue, thereby producing whistling or hissing.
Improper positioning of the anterior teeth inhibits the tongue
and the lips from producing good sounds. The length and
labiolingual position of the anterior teeth should duplicate as
nearly as possible the position of the natural teeth in order
to obtain the best possible speech and appearance.
4- Restoration of the remaining natural tissues:
The alveolar process that developed with the teeth for
the purpose of supporting them disappears to a varying
extent after loss of teeth, resulting in reduced alveolar ridge.
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CHAPTER 1 Terminology
Restoration of the chewing function through dentures
minimizes the rate of alveolar atrophy. With the loss of
teeth, the temporomandibular joints are subjected to
continuous strains because the mandible closes in abnormal
positions. Restoration of normal dimensions of the denture
space helps to preserve the joints and stop the development
of abnormal chewing habits.
5- Satisfaction and comfort of the patient:
It must be recognized that a patient has to accept the
dental prosthesis psychologically in order to be comfortable.
No dental prosthesis can be satisfactorily if it causes pain
and discomfort.
