4. Any spatial relationship of the
maxilla to the mandible or any one of the
infinite relationships of the mandible to the
maxilla.
5.
6.
7.
8. • Provides optimal separation
between maxilla and mandible.
• If not measured accurately, the
joint will be strained.
• If the VD is altered, severe
discomfort to both TMJ and
muscles of mastication.
9. • Tooth : Acts as a vertical stop.
• Musculature : Opening and closing
muscles tend to be in a state of
minimal tonic contraction.
10. Two measurable
lengths of the face are important
guides in making maxillo -
mandibular relation records and
are referred to as :
• Vertical dimension of rest or
physiologic rest position. (VDR).
• Vertical dimension of occlusion
(VDO).
11. • Vertical separation of the jaws
when the opening and closing
muscles of mandible are in a state
of minimal tonic contraction
sufficient only to maintain posture.
12. • The position assumed by the
mandible when the head is in an
upright position, the muscles are in
equilibrium in tonic contraction
and the condyles are in a neutral
unstrained position is the
physiologic rest position of the
mandible.
14. It is generally considered that
the teeth should not be in contact when the jaws
are at the vertical dimension of rest position. The 2
to 4mm distance between the upper and lower
teeth when the mandible is at physiologic rest
position is called interocclusal distance (IOD)
frequently referred to as the “free way space”.
15.
16.
17. INCREASE IN VDO / DECREASE IN IOD
• The chin-nose distance will increase, and then
patients will have an appearance of open
mouth.
• Constant pressure to the basal seat area which
will lead to bone resorption.
• Soreness of the tissues of the basal seat.
• “Clicking”, of dentures during speech.
• Improper phonetics
18. DECREASE IN VDO / INCREASE IN IOD
• Potentially damaging to the TMJ.
• The normal tongue space is limited. Facial
distortion appears more noticeable with over
closure that with the slightly opened closure
because with over closure the chin appears to be
closer to the nose, the commissure of the lips turns
down and the lips lose their fullness.
• The muscles of facial expression lose their tonicity
and the face appears flabby instead of firm and full.
• Over closure of jaws may lead to angular chelitis
19. • FACIAL MEASUREMENT AFTER
SWALLOWING AND RELAXING.
• SPEECH
• TACTILE SENSE
• MEASUREMENT OF ANATOMICAL
LANDMARKS
• FACIAL EXPRESSION.
20. • Patient is asked to sit upright and
comfortably, eyes looking straight
ahead.
• Insert maxillary occlusal rim.
• Place 2 points of reference.
• Instruct the patient to wipe his lips
with his tongue, to swallow and to
drop his shoulders – rest position.
• Measure - repeat and take average.
21. • Instruct the patient to stand erect
and open the jaws wide until strain
is felt in the muscles.
• When the opening becomes
uncomfortable, ask him to close
slowly until the jaws reach a
comfortable relaxed position.
• Measure the distance and compare
it.
22. 2 methods:
• 1st method :
Ask the patient to repeatedly
pronounce the letter ‘M’, a certain
number of times. Distance is measured
immediately after the patient stops.
• 2nd method:
keep talking to the patient and
measure the distance immediately
after the patient stops talking.
23. • Distance between the pupil of the
eye and Rima oris and the distance
between anterior nasal spine and
lower border of mandible is
measured using Willis guide.
• If both the distances are equal,
jaws are considered at rest.
24. • Patients jaw will be in rest position
when he is relaxed.
• Skin around the eyes and chin
should be relaxed.
• Nostrils are relaxed and breathing
is unobstructed.
• Upper and lower lips have slight
contact in one plane.
25. a) Mechanical methods
• Ridge relation
Distance from incisive papilla to mandibular
incsiors.
Parallelism of ridges.
• Pre-extraction records:
Profile photographs
Profile silhouettes
Radiography
Articulated casts
Facial measurements
• Measurement from former dentures
26. b)Physiological methods
• Power point
• Using wax occlusal rims
• Physiological rest position
• Aesthetics
• Swallowing threshold
• Tactile sense or neuromuscular
perception
• Patient’s perception of comfort.
27. Ridge relation :
Defined as positional relationship of
the mandible ridge to the maxillary
ridge.
a) Distance from the incisive papilla to the
mandibular incisors.
• The distance of the papilla from the
incisal edges of lower anterior teeth
averages approximately 4mm in natural
dentition. The incisal edges of the
maxillary central incisors are an average
6mm below the incisive papilla. Based
on this value VDO can be calculated.
28. b) Parallelism of the ridges:
• Sears suggested that correct
vertical dimension of occlusion is at
a point where the jaws are parallel
with a 5 degree opening in the
posterior region.
29. Measurement of the former dentures:
• A Boley’s gauge is used to measure
the distance between the border of
the max and mand denture ,when the
dentures are in occlusion.This
measurement is used to determine
the VDO.
30. Pre extraction records
Profile radiographs :
• Made with teeth in occlusion.
These are compared with those
made with occlusion rims in
position.
• DISADV- Time consuming, Image
distortion, Radiation hazard.
31. Profile Photographs
• Taken in maximum occlusion of
teeth. The photographs should be
enlarged to the actual size of the
patient. The distance between the
two anatomic landmarks is then
compared with that of patient to
avoid errors.
Casts of the teeth in occlusion
32. Facial Measurements:
Tatoo points are marked
on tip of the nose and base of the
chin. The vertical dimension
between the anatomic landmarks
is then compared with that of
patient to avoid errors. Willis gauge
is also used to measure facial
dimension . One arm contacts the
base of the nose and the other arm
contacts the base of the chin.
33. Niswonger’s method(1934) :
• Two markings are made , one on the
upper lip below the nasal septum, and
the other on the chin.The patient is told
to swallow and relax. The distance
between the marks is measured. The
occlusal rims are adjusted until the
distance between the marks is 2-4 mm
less during occlusion.
• Disadv- The marks move with the
skin.
34. Phonetics and esthetics.
The dentist asks the pt to
speak certain words and then
makes certain observations of the
relationship of the occlusion rims
to each other and to the lips.
35. Using ‘m’sound:
The pt repeats the letter
‘m’. When the lip just touches ask the
patient to hold the jaws still. The
distance between tip of the nose and
chin is measured (VDR).The occlusion
rims are adjusted and again
measured. The second measurement
should be 2-4mm less than the first
measurement(VDO)
36. The ch,s,and j sounds:
• There should be 1mm space
between the occlusion rims in the
anterior area at correct VDO.
Using 33 :
• When repeating this word there
should be enough space for the tip of
the tongue to protrude between the
anterior teeth.
Using f or v sounds:
• The max incisors/occlusion rims
should lightly contact the lower lip at
the vermillion border when pt
pronounces these words.
37. SILVERMAN’S CLOSEST SPEAKING
SPACE
• The 2mm space between the
incisors at correct VDO when pt
pronounces words containing ‘S’
eg.
• The closest speaking space
measures vertical dimension when
the mandible and muscles involved
are in physiologic function of
speech.
38. ESTHETICS
In normal relaxed position
the lips are even anteroposteriorly
and in slight contact. If the face
appears strained the vertical height
may be more. If the corners of the
mouth droop, making the chin
appear too close to the nose, then
vertical dimension may be too less.
39. Swallowing threshold.
The technique is based on
the fact that when a person
swallows, the teeth come together
with a very light contact at the
beginning of the swallowing cycle.
If the occlusion rims do not come
into contact during swallowing
then the VDO is less.
40. Method:
Cones of soft wax having
excessive height are placed on the
lower base. Salivation is stimulated
( using candy) and the pt is
instructed to swallow. The
repeated swallowing reduces the
height of the wax to the occlusal
vertical dimension.
41. • Tactile sense and Patient- perceived
comfort.
The pt’s tactile sense is used as
a guide to the determination of the
correct vertical dimension. Using a
central bearing plate attached to mand:
occlusion rim and central bearing screw
attached to max: occlusion rim, VD is
increased too high. Then in progressive
steps the screw is adjusted downward
until the pt signifies overclosure. The
procedure is then reversed until the pt
signifies that its just right.
42. • BOOS BIMETER(POWER POINT)
Boos(1940) stated that
maximum biting force occurs at
VDO.A device that measures the
biting force (Bimeter) is attached to
the mand: record base and a metal
plate to maxillary.A screw is turned to
adjust the vertical relation . The
maximum power point on the gauge
indicates the correct VDO.
43. • Electromyography
• Rest position can be determined by
recording the minimal activity of
muscles of mastication.
• SCRIBING GUIDE LINES
