vertical jaw relationships / dental implant courses by Indian dental academy

VERTICAL JAW
RELATIONSHIPS
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS
• Introduction
• Definition
• Factors affecting vertical jaw relations
• Constancy of vertical relations
• Physiologic rest position
• Vertical dimension at rest
• Recording rest position
• Vertical dimension at occlusion
• Recording occlusion
• Evaluating vertical dimension
• Significance of vertical relations
• Review of literature
• Conclusion
• References www.indiandentalacademy.com

INTRODUCTION
• The complete denture must be used in most of the functions
once served by the natural dentition. Mastication, speech &
appearance all depends on specific vertical & horizontal
relations of the mandible to the maxilla.
• Vertical relations are linked with the horizontal relation as
the success or failure of the denture also depends on the
proper registration of both. One relation cannot be changed
without the change in the other.
• Unless hinge-axis technique is used, centric relation is valid
only at a specific vertical dimension. So, proper
establishment of vertical dimension can be considered as
the 1st
step towards the recording of jaw relations.

DEFINITION
• The Vertical Jaw Relations are expressed
as the amount of separation of the maxilla &
mandible under specified conditions.
• The Vertical Jaw Relations can be recorded
in 2 positions:-
1) The vertical dimension at rest position
2) The vertical dimension at occlusion.

Factors Affecting Vertical Jaw Relations:-
• The vertical relation of mandible to maxilla is established by
2 factors:-
1) The mandibular masculature
2) The occlusal stops made by teeth or occlusal rims
The mandibular masculature:-
- In infants & edentulous patients, vertical relation is
established by mandibular masculature & teeth do not
determine it. This type of vertical relation is called as
vertical relation at rest.
- There are two hypothesis to support:-
a) Active
b) Passive

a) Active Hypothesis:- It assumes that the muscles
that open & close the mandible are in a state of
minimal tonic contraction to maintain posture of
mandible.
b) Passive Hypothesis:- It assumes that the elastic
components of jaw masculature, & not any
muscle activity, balances the influence of gravity.

Musculature involved :-
• Closing muscles – Masseter
Medial Pterygoid
Temporalis
• Opening muscles – Platysma
Mylohyoid
Geniohyoid
Digastric
Stylohyoid
These muscles and gravity help control the tonic
balance that maintain the physiologic rest position.

Constancy of Vertical Relations
• Dawson says that the dimension of the jaw to jaw
relationship is so constant that even severe bruxing,
clenching, & abrading parafunction do not alter the jaw to
jaw dimension between bony landmarks.
• This is evidenced by the observation, that eruption keeps
pace with wear. Because of elongation of the alveolar
process, even severe abrasion of teeth does not cause a
loss of vertical dimension.
• The explanation for this is the constancy of the mandible
to maxilla dimension at the completion of the elevator-
muscle contraction cycle.

PHYSIOLOGIC REST POSITION:-
• The position assumed by the mandible when the
head is in an upright position, the muscles are in
tonic equilibrium & the condyles are in a neutral,
unstrained position, is the physiologic rest position
of the mandible.
• Sicher states that, the rest position is constant in
each individual due to…
• The rest position is independent of …
• Inspite of the changes in the residual alveolar
ridges, the rest position remains fairly stable
throughout the life of an individual, unless…

SIGNIFICANCE:-
• It is bone to bone relation in a vertical
direction.
• In the absence of pathosis the relation is
fairly constant throughout life.
• The position can be recorded & measured
within acceptable limits.
• It is used in determining the vertical
dimension of occlusion.

VERTICAL DIMENSION AT
REST• The distance between two selected points
measured when the mandible is in the physiologic
rest position.(GPT)
• The vertical dimension of jaw separation at rest
occurs when the maxillofacial musculature is in a
state of tonic equilibrium.
• It involves the opening & closing muscles of
mandible & also the muscles responsible for the
actions in masticating, speaking, swallowing &
breathing.
• These physiologic functions aids in determining the
vertical dimension of rest & occlusion.

• The vertical dimension of rest is a measurable
distance, a repeatable reference within an
acceptable range & a useful reference when
establishing the vertical dimension of occlusion.
• Factors to be considered for rest position as a
reference are:-
1) The position of the mandible is influenced by
gravity, so, mandibular positions are postural.
2) Rest position is a relaxed position of the mandible.
3) It is difficult to determine maxillomandibular
relations on patients who suffer from
neuromuscular disturbances.

4) Rest position is a position in space, which cannot
be maintained for definite periods of time.
5) No one method for determining rest position can
be accepted as being valid for all patients.
6) Space between the teeth is essential when the
mandible is at rest.
Failure to establish rest position as a reference
point may result in a lessened or excessive
interocclusal distance, both are potentially
damaging either to the supporting structures or to
the TMJ.

RECORDING REST
POSITION:-
1) Physiological Rest Position:-
- The position of the jaw in physiologic rest position gives an
indication of the appropriate vertical dimension of
occlusion.
- This is possible because, the difference between the
occlusal vertical dimension & the rest vertical dimension is
the INTEROCCLUSAL DISTANCE referred to as the
“FREEWAY SPACE.”
VD at Rest = VD at Occlusion
+ Freeway Space.

- Interocclusal Distance:- is the distance or gap
existing between the upper & lower teeth when the
mandible is in the physiological rest position. It is
usually 2-4mm when observed in the 1st
premolar
region.

Constancy:-
Clinically the freeway space has been
measured as 2-4mm. However, numerous
studies have shown the evidance of
electromyographic activity of the mandible.
In a study done by, Garnick &
Ramfjord(1962), at electromyographic rest
position, the average interocclusal
distance determined was 3.29mm, with a
range of 1.1-9mm.

2) Facial Measurements:-
- If the interocclusal space is greater then 4mm,
the occlusal vertical dimension may be
considered too small.
- If less then 2mm, the dimension is considered to
be too great.

3) Tactile sense:-
Method:
- Instruct the patient to stand or sit erect & open the
jaws wide until strain is felt in the muscles.
- When this opening becomes uncomfortable, ask
the patient to close slowly until the jaws reach a
comfortable, relaxed position.
- Measure the distance between the points of
reference & compare with the measurements
made after swallowing.

4) Phonetics:-
• Speech is used in several different ways as an aid
in establishing rest position. Two of these
methods are:-
i) Ask the patient to repeat the name “EMMA” until
they are aware of the contacting of the lips as the
1st
syllable “em” is pronounced. When rehearsed,
ask them to stop all jaw movements when the lips
touch. Measure between the two points of
reference.
ii) Engage the patient in a conversation that will
divert their attention from being conscious. As
there is a pause in speech, followed by relaxation,
measure the distance.

6) Facial Expression:-
• Skin around the eyes & the chin will be relaxed. It
should not be stretched or excessively wrinkled.
• The relaxation around the nose reflects
unobstructed breathing.
• The upper & the lower lips should have a slight
contact & be even anteroposteriorly.
If the mandible is protruded – the lower lip will be
anterior to the upper lip but not in contact.
If the mandible is retruded – the lower lip will be
distal to the upper lip but not in contact.

e
5) Anatomical Landmarks:-
- In this the “Willis Guide” is used to measure the
distance from the outer canthus of the eye to the
rima oris(corner of the mouth) & the distance from
the anterior nasal spine to the lower border of the
mandible.
- When both these measurements are equal, then
the jaws are considered at rest.

VERTICAL DIMENSION AT
OCCLUSION
• The distance measured between two points when
the occluding members are in contact.(GPT)
• The vertical dimension of occlusion is a static
position & can be maintained for an indefinite time.
• When vertical dimension is established for use in
construction of dentures - the jaws are in centric
relation but,
when natural teeth are in maximum occlusion - the
jaws are not necessarily in centric relation.

RECORDING OCCLUSION:-
1) Pre-extraction Records:-
a) Profile Photographs:-
- Profile photographs are made & enlarged
to a life size of the patient.
- Measurements of anatomic landmarks on
the photographs are compared with
measurements using the same anatomic
landmarks on the patients face.

- These measurements can be compared
when the records are made & again when
the artificial teeth are tried in.
- The photographs should be made with the
teeth in maximum occlusion, as this
position can be maintained accurately for
photographic purposes.

b) Profile Silhouettes:-
- The word silhouette means “outline.”
- Any further information like name, address, date,
colour & shape of the teeth can be entered on the
template & kept for future reference.

c) Profile Radiographs:-
- The 2 types of radiographs advocated are the
cephalometric profiles & the condyles in the
fossae to determine the vertical jaw relations.
- The inaccuracies existing in either the technique
or the method of comparing measurements make
these methods unreliable & also because of the
radiation risks they cannot be considered
adequate for routine clinical use.

d) Articulated Casts:-
- When the patient is dentulous, the maxillary cast
is related in its anatomic position on an articulator
with a facebow transfer.
- An interocclusal record with the jaws in centric
relation is used to mount the mandibular cast.
- These mounted casts give an idea of the size &
shape of the teeth & the vertical overlap relation &
indicate the amount of space required between the
ridges for teeth of this size.
- After removal of the teeth & mounting of the
edentulous casts, the interarch measurements are
compared. www.indiandentalacademy.com

e) Facial Measurements:-
- 2 tattoo points are placed:-
i) upper half of the face
ii) lower half of the face (prior to extraction)
- Patient instructed to close the jaws in maximum
occlusion & the distance is measured.
- These measurements are compared with the
measurements between these points when
artificial teeth are tried in.

2) Phonetics:-
- This involves observing the movements of the oral
tissues during speech & listening & analyzing it.
- It is a common method used to determine jaw
relations.
Closest speaking space:-
• Described by Dr. Meyer M. Silverman (1951).
• Silverman defined closest speaking space as the
closest relationship of the occlusal surfaces &
incisal edges of the mandibular teeth to the
maxillary teeth during function & rapid speech.
(GPT)

• “Closest speaking space” should not be confused
with the “Free-way space.”
• Free-way space – establishes vertical dimension
when the muscles involved are at complete rest,
or in physiologic tonus & the mandible is in its rest
position.
• Closest speaking space – measures vertical
dimension when the mandible & muscles involved
are in physiologic function of speech.
• The production of ch, s & j sounds brings the
anterior teeth close together without contact.
• This minimum amount of space between the upper
& lower(incisor) teeth in this position is called
“Silverman’s closest speaking space.”

• In a study, done by Meyer Silverman(1952) stated
that, it is possible by the use of speaking method to
measure a patients vertical dimension before the
loss of remaining natural teeth & reproduce this
measurement in full dentures at a later date.
• He also developed the phonetic techniques with
existing dentures & techniques without pre-
extraction records & dentures.

Constancy:-
• It is believed that closest speaking space for each
individual is constant throughout life.
• This belief may be sustained by “All or None” law
of muscle physiology which states that the muscle
fiber is in maximum contraction during the stimulus
of function.
• It was found that closest speaking space varied
from 0-10mm.

Phonetic Method:-
• It is based upon the assumption that there is direct
connection between interdental space, occlusal
plane positon & tongue position during articulation
of speech.
• It is a procedure of dental physiology.
• This method uses physiologic stimulation of
muscle activity during the production of speech
sound to measure the vertical dimension before
the remaining natural teeth are lost. This
measurement must be reproduced with accuracy
in complete dentures.

• One or more of the six sibilants “s, z, sh, zh, ch &
j” generally cause the mandible to be in closest
level to maxilla during speech.
• Method:-
- The patient is directed to close in centric occlusion
& the centric occlusion line is drawn on a lower
anterior tooth at the level of the incisal edge of the
opposing upper anterior tooth.
- Draw the closest speaking line on the same lower
anterior tooth when the patient pronounces “s”.
- The patient is asked to read rapidly to determine
accurately.
- The closest speaking line is watched to coinside
with the upper incisal edge when patient
pronounces “s”.www.indiandentalacademy.com

- When the natural teeth are lost, this same closest
speaking space must be transferred in artificial
dentures.
Technique of recording closest speaking space
without pre-extraction records or dentures:-
• The maxillo-mandibuar relationship of occlusal
rims is determined.
• The width of rims is trimmed to allow for the
normal space for tongue.
• The lingual surfaces of upper & lower anterior
portions are cut out to approximate the width of
teeth.
• Adhesive powder is sprinkled on the denture base
to make the patient speak freely.

• Patient is instructed to pronounce “s” in order to
determine approximate closest speaking space.
• Then the patient is instructed to read rapidly, so
that voluntary muscle control is lost.
• Measure the approximate closest speaking space.
• The occlusal rims should not touch together during
speech.
• A closest speaking space of 2 or more mm. is
decided depending upon facial appearance &
comfort of patient.
• The closest speaking space can be determined
more accurately with artificial teeth set up in wax &
is rechecked at that time.www.indiandentalacademy.com

3) Esthetics:-
• The vertical relation of the mandible to the maxilla
also affects esthetics.
• The tone of the facial skin normally, should be the
same throughout.
• The contour of the lips depends on their intrinsic
structures & the support behind them.
• The contoured surface of the wax occlusal rims
must replace or restore the tissue support
provided by the natural structures.

4) Ridge Relations:-
• Defined as, “the positional relationship of the
mandibular residual ridge to the maxillary residual
ridge.”(GPT).
• Can be measured by:-
i) Distance between the incisive papilla to
mandibular incisors:-
- The incisive papilla is a stable landmark that
changes comparatively little with resorption of the
alveolar ridges.
- The distance of the papilla from the incisal edges
of the mandibular anterior teeth - approx. 4mm in
the natural dentition.www.indiandentalacademy.com

- The incisal edges of the maxillary central incisors – approx.
6mm below the incisive papilla.
- Mean vertical overlap of the opposing central incisor - 2mm.
- These are average measurements around which there is
considerable individual variation.
- They do not appear to be relevant in patients with severe
resorption.

ii) Ridge Parallelism:-
- Parallelism of the maxillary & mandibular ridges
with a 5degree opening in the posterior region
gives an appropriate amount of jaw separation.
- As the clinical crowns of the anterior & posterior
teeth have nearly the same length, their removal
tends to…
- This parallelism is natural provided,…
- In most patients, the teeth are lost at different
times…

5) Measurement of Former Dentures:-
• The dentures that the patient
has been wearing can be
measured with the help of
a Boley’s Gauge &…
• Establish the vertical dimension
of occlusion in the occlusal rims
& then compare the
measurements between
reference points with the
former dentures in occlusion.

6) Interpupillary Distance on old photographs in
relation to interpupillary distance on face as aid in
determining vertical dimension:-
• Wright(1939) said that a suitable photograph can
be an aid to the establishment of vertical
dimension.
• Interpupillary Patient’s Brow-chin Patient’s
distance
on : interpupillary = distance of : brow-chin
photograph distance photograph
distance
6 60 12 x
6x = 720
x = 120www.indiandentalacademy.com

6) Neuromuscular Perception:-(By Lytle)
• The patient’s tactile sense or sense for comfort is
used as a guide for the determination of the
occlusal vertical dimension.
• A central bearing device attached to accurately
adapted record bases permits the patient to
experience through neuromuscular perception,
the different vertical relations.

7) Power Point:-(By Boos)
• A “Bimeter” is attached to an accurately adapted
mandibular record base.
• A metal plate is attached in the vault of an
accurately adapted maxillary record base to
provide a central bearing point.
• The vertical distance is adjusted by turning the cap
• The gauge indicates the pounds of pressure
generated during closure at different degrees of
jaw separation.
• When maximum “power point” is determined, lock
the set nut.
• Make plaster registrations & transfer the casts to
an articulator. www.indiandentalacademy.com

EVALUATING VERTICAL
DIMENSION
a) Patient’s Tactile Sense:-
• Ask the patient:-
- If the teeth appear to touch too soon.
- If the jaws seem to close too far before they
touch.
- If the teeth feel just right.

b) Swallowing Followed by Relaxing:-
• Watch the reference points, & ask the patient to
close the teeth together.
• If the teeth are already together, it indicates that
no interocclusal distance exists.
• Another method – based on the theory that the
teeth make contact at or near centric occlusion at
the beginning of the swallowing cycle.

c) Phonetics:-
• The use of speech in evaluating the vertical
dimension of occlusion for patients receiving their
1st
dentures is of great value.
• The position of the tongue & the relaxation of the
teeth are important.
• Ask the patient to repeat -
- “three thirty three”
- “fifty-five”
- “Emma” & “Mississippi”.

Significance of Vertical Relation
• Correct recording, transferring & incorporating the
vertical relations in the prosthesis, determines the
success of the prosthesis. Failure to do so may
compromise the success of the prosthesis.
• Effects of excessively increasing the vertical
dimension:-
1) Discomfort – teeth come into contact sooner
than expected.
2) Trauma – caused by constant pressure on the
mucous membrane.
3) Loss of freeway spacewww.indiandentalacademy.com

4) Clicking of teeth – teeth are raised & the
opposing cusps frequently meet each other
during speech & mastication.
5) Appearance – over opening may cause
elongation of the face & at rest the lips
are parted.

Effect of excessively decreasing the vertical
dimension:-
1) Inefficiency – the exerted with the teeth in
contact decreases considerably with
over closure.
2) Cheek biting – the flabby cheek tend to become
trapped between the teeth & bitten
during mastication.
3) Appearance – Closer approximation of nose to
chin, soft tissue sag & fall in, & the
lines on the face are deepened.

4) Soreness at the corner of the mouth(Angular
cheilitis) – falling in of the corner of the mouth
beyond the vermilion border & the deep fold thus
formed become bathed in saliva. This area
becomes infected & sore.
5) Pain in TMJ – caused due to strain of the joint &
associated ligaments. Associated with
pain in the ear, tinnitus & headache.

REVIEW OF LITERATURE
1) Niswonger(1934) & Thompson(1946) stated that
the space between physiologic rest position & the
tooth contact, in the average individuals was
always constant within a range of 2-5mm when
measured between chin & nose.
2) Thompson & Brodie(1942) stated that the position
of the mandible in relation to the face & head is as
unchangible as is the form of the mandible, & “ the
proportions of any face, as far as vertical height is
concerned, are constant throughout life.”

3) Sicher(1952) states that the free movement of the jaw
starts from & end in rest position of mandible. In this
position, the lower & upper teeth are not in contact. The
distance between upper & lower teeth varies from 2-4mm.
The rest position is constant in each individual due to the
individually fixed & only slightly variable tonus of
masticatory muscles, which in their relaxation, allow the
mandible to drop slightly. The rest position is not dependent
on the presence or absence of teeth or on their shape or
position but on their masculature & muscle balance only.
He also pointed out that “constancy in a living organism
means simply that the range of variation or variability is
negligible”

4) Leof(1950) claimed that rest position of mandible
is controlled by muscle tone & not by the muscle
length & is therefore not constant throughout life.
His findings were based upon his observations of
patients over a 10 years period,who, in this period,
developed grinding & clamping habits. He stated
that, with these habits, a patient develops
hypertonicity of depressor muscles which shorten
their effective length at rest position at the
expence of free way space.

5) Boos(1950) believed that free way space is a normal
entity & provides a relief from muscle tension that occurs
when teeth go in occlusion, therefore he stated that
freeway space must be maintained so that forces will not
act on occlusion continually. He further noted that, if too
little or no freeway space exists, the teeth are under
greater tension, because the muscles cannot come in
normal length & they try to find maximum biting area.
Boos also claims that with too much freeway space, very
little force can be exerted as the muscles are sagged &
lose their power rapidly because they contract beyond
their normal occlusal level & masticatory efficiency is
reduced.

6) Standard & Lepley(1955) concluded that the
distance between physiologic rest position & the
balance of head of condyle in glenoid fossa within
range of vertical displacement, represents
maximum amount of freeway space.
7) Thompson(1942) believed that the rest position
is determined by a balance of tension in the
musculature which suspends the mandible, & that
the rest position is not affected by the presence or
absence of teeth. He indicated that the
interocclusal distance averaged 2-3mm in normal
dentitions & may be 10mm or more in abnormal
dentitions.

8) Duncan & Williams(1960) studied the rest position as a
guide in prosthetic treatment. Lateral roentgenographic
cephalometric measurements were made on 10 patients
for whom complete dentures were constructed. They found
instability in rest position & hence concluded that, rest
position is a poor guide for establishing the pre-extraction
occlusal vertical dimension.
9) Mann Mirralles(1981) concluded that it is not possible to
establish a single standard vertical dimension at which
muscles are minimally active. This conclusion was made
because if the main closing muscles are fully relaxed, there
is more space between the teeth than traditionally
assumed 1-3mm of vertical separation.

CONCLUSION

REFERENCES
1. Baskar R.M & Davenport J.C.- Prosthetic
treatment of the edentulous patients
4th
edi. 2002
2. Boucher – Swenson’s complete dentures
5th
edi.
3. Dawson P.E. – Evaluation, diagnosis & treatment of
occlusal problems. 2nd
edi. 1989
4. Duncan E.T. & Williams S.T. – Evaluation of rest
position as a guide in prosthetic Treatment.
JPD 1960; 10, 643-650.
5. Fenn H.R.B. – Clinical Dental prosthetics
1st
edi. 1986www.indiandentalacademy.com

6. Garnick J & Ramfjord S.P. – Rest position, An
electromyographic & clinical investigation
JPD 1962; 12,895-911
7. Rahn A.O. & Heartwell C.H. – Textbook of
complete dentures 5th
edi. 1993
8. Silverman Meyer M. – The speaking method in
measuring vertical dimension JPD 1953;3 193-
199
9. Swerdlow H. – Vertical dimension literature
review JPD 1965;15, 241-247
10. Zarb G.A. – Boucher’s prosthodontic treatment
for edentulous patients 10th
edi. 1990
11. Zarb G.A. – Prosthodontic treatment for
edentulous patients 12th
edi. 2004www.indiandentalacademy.com

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