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2. INDIAN DENTAL ACADEMY
Leader in continuing dental education
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3. Contents
Introduction
Classification of jaw relations
Vertical jaw relations
Physiologic rest position
hypothesis
factors to be considered
methods of recording
significance
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4.
Methods of recording vertical jaw relations
mechanical methods
physiologic methods
Tests to aid in confirming the correct vertical
dimension.
Altered vertical dimensions and their effects
Conclusion
References
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5. Introduction
Complete dentures are constructed to
function in the mouth as an integral
part of the masticatory apparatus &
there fore they should be designed to
conform to the patient’s physiologic jaw
relations.
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6.
To achieve this goal the recording must
include an appropriate vertical relation
of occlusion, stable occlusal contacts
in harmony with the existing T.M.J and
masticatory muscle functions, and the
relationship between the prostheses &
oral & facial soft tissues and
musculature.
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7. Mandibular Movements
The constant function of swallowing
saliva is the basis for establishing the
mandibular position and occlusion.
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8.
In swallowing the saliva, mandible
raises to its habitual closing terminal
and then as the saliva is forced
backward into the pharynx by the
tongue, the mandible is retruded to its
physiologic centric relation.
These are the mandibular movements
that are used in determining the
vertical relation and the centric relation
for the complete dentures.
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9. Classification of jaw relations
Jaw relations are classified into three
groups. They are:Orientation jaw relations.
Vertical jaw relations.
Horizontal jaw relations.
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10. Vertical dimension
Distance between the two selected
anatomic or marked points ( usually
one on the top of the nose & the other
upon chin), one on a fixed & one on a
movable member. [Gpt]
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11. Vertical jaw relations
They are classified as :Vertical dimension of rest.
Vertical dimension of occlusion.
Vertical dimension of other portions.
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12. Physiological rest position
The Mandibular position assumed
when the head is in an upright
position and the involved muscles
particularly the elevator and
depressor groups are in equilibrium in
tonic contraction, & the condyles are
in a neutral , unstrained position.
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13. Vertical dimension of occlusion
The distance measured between two
points when the occluding members
are in contact.
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14. Review of literature
Thompson and Brodie (1942) suggested
that the position of the mandible in relation
to the face and head is unchangeable as is
the form of the mandible, and “the
proportions of any face as far as vertical
height is concerned, are constant through
out life.”
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15. Niswonger , Boos, and Jaffe
apparently agree with this view.
Leof (1950) believes that this relation
is not constant but is readily affected
by age, disease, and emotion.
It seems that the constancy of the
vertical maxillomandibular relations
through out the life represents the
unique phenomenon, not generally
found in relations of the other bones.
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16.
Garnick and Ram fjord (1962) stated
that rest position is a vertical range
rather than a point.
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17. Physiological rest position
Vertical dimension of rest.
Postural position of the mandible.
The postural position of the mandible
when an individual is resting
comfortably in an upright position and
the associated muscles are in a state of
minimal contractual activity.
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18. This rest position is established by the
muscles and gravity.
Two main hypothesis explain about the
rest position of the mandible.
One involves active mechanism.
Second one involves the passive
mechanism.
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19. But according to the current concepts
this position is actively determined.
The clinically recorded rest position
is usually 2- 4mm below the
maximum intercuspation position.
But according to the EMG activity a
range of reduced muscle tension upto
an interocclusal distance of about 10
mm is recorded. It is therefore more
accurate to refer to a range of posture
rather than to a single rest position.
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20. Factors to be considered while
recording the rest position
Position of the mandible is influenced
by the gravity.
It is a relaxed position of the mandible.
Neuromuscular disturbances.
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21.
Rest position is a position in space.
No one method for determining the rest
position is a valid method.
Space between the teeth is essential
when the mandible is at rest.
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22. Methods of recording the rest
position
Facial measurements.
Tactile sense.
Phonetics.
Facial expression.
Anatomical landmarks.
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23. Significance
It is a bone to bone relation.
In the absence of the pathosis the
relation is fairly constant through out
the life.
Position can be recorded and
measured with in the acceptable limits.
It is used in determining the vertical
dimension of occlusion.
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24. Vertical dimension of occlusion
Mechanical methods
Ridge relation:1) Distance from the incisive papilla to
the mandibular incisors.
2) Parallelism of the ridges.
Measurement of the former dentures.
Preextraction records:1)Profile radiographs.
2)Casts of the teeth in occlusion.
3)Facial measurements.
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27.
The incisal edges of
the maxillary central
incisors are an average
6 mm below the
incisive papilla. So the
average vertical
overlap is about 2 mm.
This relationship of
maxillary and
mandibular anterior
teeth concerns not only
the vertical ridge
height but also esthetic
values.
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28. Disadvantage:
In the absence of lower anterior teeth,
this method cannot be used.
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29. Parallelism of ridges:
Paralleling of maxillary and mandibular
ridges plus 5 degree opening in the
posterior region as suggested by sears
often gives a clue to the amount of jaw
separation.
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31. Disadvantages:
This theory cannot be used when
there is great amount of bone loss
which would change the ridge relation,
also if the patient has lost the teeth at
irregular intervals, the line of ridges is
naturally thrown out of parallel.
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32.
Measurement of former dentures:
Measurement between the borders of
the maxillary and mandibular dentures
can be made and can be correlated
with the observation of the patients
face to determine the amount of
change required.
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35. Pre extraction records
When natural teeth are in maximum
occlusion, the jaws are not necessarily
in centric relation.
For this reason all the pre extraction
records must be evaluated.
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36. Profile radiographs
Radiograph before extraction must be
taken and preserved.
After extraction and after establishing
the tentative jaw relation, another
radiograph should be taken.
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37.
The two radiographs must be
super imposed and compared.
The inaccuracies that exist in either the
technique or the method of comparing
measurements make these methods
unreliable.
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39. Profile photographs
Profile photographs are made and
enlarged to life size. The photograph
should be made with teeth in
maximum occlusion.
Measurements of anatomical land
marks are compared with the
measurements of face using same
land marks .
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41. Profile tracing:
Lead wire adaptation .
This method is full of pitfalls as it is
not possible to contour the wire
accurately against the soft tissue
without producing distortion.
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42.
A piece of soft lead wire is molded to
contour of the face starting from the
eyebrow to just below the chin along
the midline. Then the contour is
transferred to the cardboard. The
resultant cutout is stored and
compared to by placing against the
profile which is established after the
extraction and estimation of the
vertical relation using the record
blocks.
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43. Profile silhouettes
Similar to profile tracing.
An accurate reproduction of the profile
silhouettes can be cutout in a
cardboard. Then the silhouettes can be
positioned onto the face necessary
adjustments can be made.
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44. Diagnostic casts
Various methods to determine vertical
relation of occlusion by using the
diagnostic casts.
Heinz and Peters method.
Quinn et al method.
Bissasu method.
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45. Casts of teeth articulated in occlusion
Heinz and peters method
Accurate casts of maxillary and
mandibular arches made.
The maxillary cast is related to its
correct anatomic position on an
articulator with a face bow transfer.
An occlusal record with the jaws in
centric relation is used to mount the
mandibular cast.
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46.
After the teeth has been removed,
edentulous casts are mounted on the
articulator, the interarch measurements
are compared and necessary
adjustments are made.
They give information of the vertical
overlap and size and shape of teeth.
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47.
The casts also assist in the
selection of size, shape and
position of the teeth.
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48. Disadvantage:
It cannot used when there is a long
waiting period for fabrication of
denture after extraction.
It cannot be used when there is
excessive bone loss during the
extraction procedure.
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49. Quinn et al method
Quinn et al made maxillary & mandibular
record bases and wax occlusion rims.
Recorded the maxillo mandibular
relationship and made wax flanges for the
dentate areas of diagnostic casts.
The maxillary and mandibular record bases,
wax flanges, and the stone teeth were
duplicated in a duplicating flask using
reversible hydrocolloid impression material.
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50.
The replica wax bases are used for making
the definitive impression, the resultant stone
casts and the replica wax bases and the wax
teeth are mounted in an articulator in
maximal intercuspation, and the artificial
teeth are arranged with the impression
material in place.
Disadvantages :- 1) This method required
additional procedures
2) Time consuming.
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51. Use of lingual frenum Bissasu
Bissasu proposed in determining the
original vertical relation by measuring the
distance between the center of the
Incisive papilla and the incisal edges of the
maxillary central incisors and between the
anterior attachment of the lingual frenum
and then adjusting the maxillary and
mandibular wax occlusion rims, anteriorly,
to correspond with these measurements.
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52. Advantages :
Method is simple
Does not require any additional
armamentarium
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53. Facial measurements:
These are also pre-extraction guides.
Various devices for making facial
measurements are used in different
forms.
Dakometer
Willis gauge
Orofacial device
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54. Dakometer
The instruments record both vertical
dimension with the natural teeth in
occlusion and the position of central
incisors. In most cases recording can
be obtained with an error range of +
or - 1mm.
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56. Willis gauge
The instrument is used for recording
vertical height, before extraction.
The arm (A) is placed in contact with
the base of the nose and arm (B) is
moved along the slide (D) until it is
firmly and lightly touching the lower
border of the chin, then it is locked in
position by the screw (C). The distance
on the scale (D) is recorded and
preserved.
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57.
Disadvantage:
It is not accurate because the
degree of pressure applied every time
may not be the same.
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60. Aabu-Ela and Razek method
They have recorded the vertical relation of
occlusion by the use of an orofacial device.
The upper portion of the device extended
between the orbital point and the external
auditory meatus to form the Frankfort plane.
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61.
The lower part of the device is placed
against the inferior border of the mandible
and pressed gently against the mandible.
This part of the device formed the
mandibular plane.
The angle that was formed by the junction of
Frankfort and the mandibular plane was
recorded.
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62.
After the removal of the teeth during
recording of the vertical relation of occlusion
of the edentulous patient, the wax occlusion
rims are reduced or increased until the
previously recorded angle is duplicated thus
restoring the VDO.
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63. Facial measurements using tattoo
Permanent tattoo markings are placed
one on the upper half of face and
another on lower half of face.
The distance is measured and
preserved. These measurements are
compared when artificial teeth are
tried.
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64.
Silverman has also suggested the
placement of tattoo marking on the
patient’s upper and lower gingiva,
slightly, left to the middle between
attached gingiva in depth of vestibule.
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66. Swenson’s acrylic face mask:
Swenson’s described the
construction of acrylic resin face
mask of the lower third of the face as
a record for future determination of
vertical dimension.
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68.
Disadvantages:
Time consuming.
Requires lot of skill and experience to
make impression of the face.
Face assumes a different topography in
the erect posture from that in the
recumbent or semi-recumbent position
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69. The method suggested by Wright:
Wright marked the following
measurements from photographs
The interpupillary distance
Brow chin distance
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70. Interpupillary interpupillary
distance in : distance : :
Photograph
of patient
brow chin brow chin
distance in : distance
in photograph of patient
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72. Niswonger method
Niswonger suggested this
method in 1934.
This method along with phonetics
and esthetics is commonly used
today.
The patient is seated in such
away that ala -tragus line is
parallel to the floor.
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73.
There upon two marks , one at the base
of the nose and one on the chin are
made.
The patient is told to swallow and relax .
the distance between the two marks is
measured and recorded .
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74.
Subsequently the occlusal rims are
constructed so that when they meet the
measured distance is 1/8 inch (2-4mm)
less than original distance. This 1/8
inch is the average freeway space.
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75.
Disadvantage :
As the marks are on the skin,
they tend to move with the skin. So it is
difficult to obtain two constant
measurements of the rest position.
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77. Concept of equal thirds:
Willis suggested that the face can be
divided into equal thirds, the forehead,
the nose, the lips and the chin.
However this concept is of little
practical value as the points of
measurements are entirely vague.
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78. Vertical dimension by means of
power point or Boos method
Boos in 1940 stated that there was a
point of maximum biting power.
He says that the patient registers the
greatest amount of pressure on a
spring dynamometer at a point.
So the Bimeter is used in this principle.
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79. The Bimeter is attached to an accurately
adapted mandibular record base.
A metal plate is attached to the vault of
an accurately adapted maxillary record
base to provide a central bearing point.
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80.
Adjust the vertical distance by turning
the cap.
The gauge indicates the pounds of
pressure generated during jaw closure
at different degrees of jaw separation.
When the maximum PowerPoint is
reached, the lock nut is set, plaster
registration is made.
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81. Phonetics as a guide
Silverman’s closest speaking space method.
Proposed by Silverman in 1952.
Silverman identified that the production of
certain sounds like “S” “yes”,”J” , “ch” brings
the anterior teeth very close together.
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82. Direct the patient into centric
occlusion and draw the line on a lower
anterior teeth at the horizontal level
of the incisal edges of the opposing
upper anterior teeth. This is called the
centric occlusion line.
Ask the patient to say yes and while
the phonetic sound s is pronounced,
draw the closest speaking line on the
same lower anterior teeth at the
horizontal level of the upper incisal
edge.
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83.
The distance between these two lines
is called the closest speaking space.
The measurements ranged from
0 to 10 mm.
The closest speaking space as
measured in the natural dentition must
be reproduced in complete dentures
after the loss of remaining natural
teeth.
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84.
This method aids the dentist to
evaluate the vertical dimension of
occlusion.
When correctly placed the lower
incisors move forward to a position
nearly directly under the upper central
incisors and come close to them but do
not contact.
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85.
The position of the tongue and its
relation to the teeth is also an
important factor, by asking the patient
to pronounce repeatedly the number
“thirty three”.
The dentist can evaluate if there is
enough space for the tip of the tongue
to protrude between the anterior teeth.
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86. Swallowing threshold : Shanaban
Thomas :
Swallowing reflex is a primitive, innate reflex.
The position of the mandible at the
beginning of the swallowing act has been
used as a guide to the vertical relation. The
theory behind this method is that when a
person swallows, the teeth come together
with a very light contact at the beginning of
swallowing cycle.
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87.
The technique involves building a
cone of soft wax on the lower denture
base so that it contacts the upper
occlusion rim with the jaws too wide
open.
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88.
The flow of saliva is stimulated and the
repeated action of swallowing the saliva will
gradually reduce the height of the wax cones
to allow the mandible to reach the level of
occlusal vertical dimension.
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89. Facial expression and esthetics as a
guide:
The experienced dentist learns the
advantage of recognizing the relaxed
facial expression when the jaws are at
rest. In normally related jaws, the lips
will be even anteroposteriorly and in
slight contact.
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90.
The lips of the patient in case of
protruded mandible will not be evenly
related , the lower lip will be anterior to
the upper lip and not in contact. In case
of retruded mandible the lower lip will
be distal to the upper lip and not in
contact.
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91.
When the vertical dimension is
increased both the, mentolabial and
nasolabial grooves disappear when V.D
is decreased the grooves are
exaggerated and the chin appears close
to the nose.
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93. Neuromuscular perception and
tactile sense:
The stretch reflex and proprioceptive
mechanisms of muscles and ligaments
of temporomandibular joints are
retained in the fully edentulous patient.
A number of studies have been done by
using this neuromuscular memory to
determine the V.D of occlusion with
mixed success (Lytle 1964, Tryde et al)
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94. Tactile sense method:
The tactile sense of the patient is used
as a guide in the determination of the
occlusal vertical relation.
An adjustable central bearing screw is
attached in the palate of the maxillary
denture base or occlusal rim. The
central bearing plate is attached to the
mandibular occlusal rim or trial based
denture base.
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95.
The central bearing screw is first
adjusted so it is obviously too long i.e
the mouth is opened beyond the
physiologic rest position. Then in
progressive steps, the screw is adjusted
downwards until the patient indicates
that the jaws are closing to far.
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96. The procedure is repeated in the
opposite direction until the patient feels
that the length is about right, the
adjustments are reversed alternatively
until the height of contact feels right.
Patient participation in the decision to
establish a vertical dimension record is
very important.
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97. Disadvantage:
This method cannot be used in senile
patients and in those patients who
have impaired neuromuscular
perception.
The problem with this method relates to
the presence of foreign objects in the
palate and tongue space.
The final determination must be made
at the try in after the teeth are in
position.
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99. Bio feed back using electromyography:
Rest position of mandible can be
determined by means of
electromyography which would record
the minimal activity of the muscles.
Electrodes can be placed on one or
more muscles of mastication to
demonstrate their activation potential
in the form of visual and audio signs,
which are fed back to the patient, to
attain a mandibular position showing nil
or minimum EMG activity.
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100. Disadvantages:
The equipment is too expensive
The operate should have considerable
knowledge, skill and experience
The patient should be capable of
correlating the visual signs to the
correct mandibular position.
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101. Tests to aid in confirming the correct
vertical relation:
Judgment of overall facial support
Visual observation of space between
the rims when the jaws are at rest
Measurement between the dots on the
face when the jaws are at rest and
when the occlusal rims are in contact
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102.
Observation made when the sibilant
containing words are pronounced, to
ensure that the occlusal rims come
close together but do not contact.
Patient can be asked to pronounce
words like Emma,Mississippi,forty five
and thirty three for evaluation.
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103. Effects of increased vertical
dimension:
It is very important to remember that as
mentioned by Mehrson and Tench the
tone of the muscles may be increased
within physiologic limits but the
functional length cannot be increased
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104. Effects
Discomfort to the patient
Trauma and pain to the basal seat
areas
The jarring effect of teeth coming into
contact sooner than expected may not
only cause discomfort but in most
cases it will also cause pain owing to
the bruising of the mucosa by these
sudden and frequent blows.
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105. Loss of freeway space: This will result in
fatigue of any one or group of muscle of
mastication. In turn, it will result in
annoyance from the inability to find
comfortable resting position.
Clicking sound when the teeth contact
Appearance: The face has an elongated
appearance. The lips are apart at rest
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107. Conclusion
No one method of recording or determining
the jaw relations can be accepted as being
valid for all patients, there fore it is desirable
to use several methods and confirm the
results. More over the components of the
recording procedure include morphologic
and physiologic phenomena, the functional
activity, psychological and social criteria
particularly in relation to esthetic decisions.
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108. References
Boucher’s prosthodontic treatment for edentulous
patients – 9th , 10th ,11th edition.
syllabus of complete dentures –Heartwell.
Essentials of complete denture prosthodontics
–Sheldon Winkler.
Complete denture prosthodontics
– John J.Sharry.
Evaluation diagnosis, and treatment of occlusal
problems
Peter E Dawson.
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109.
Speaking method in measuring vertical
dimension. J.P.D 2001 vol 85 no 5 427-430.
Using the neutral zone to obtain
maxillomandibular relationships.J.P.D 2001 vol
85 621-3.
Pre extraction records for complete denture
fabrication. J.P.D 2004 vol 91 55-8.
Physiological jaw relations and oclusion of
complete dentures. J.P.D 2004 vol 91 203-5.
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