This document appears to be a student seminar presentation on the topic of vertical jaw relation. It includes an introduction, definitions of key terms like vertical jaw relation and vertical dimension, factors that affect vertical dimension, methods for determining vertical dimension of rest and vertical dimension of occlusion, and effects of altering vertical dimension. Measurement techniques discussed include facial measurements, tactile sense, speech, anatomical landmarks, and mechanical methods using occlusion rims, casts, and former dentures. The document concludes with a bibliography.

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NOORUL ISLAM COLLEGE OF DENTAL
SCIENCE
(NICE GARDEN, ARALUMMOODU, NEYYATINKARA)
DEPARTMENT OF PROSTHODONTICS
Submitted by: Aravind.M
Registration No:…………..

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VERTICAL JAW RELATION
Submitted by:
Aravind.M | IVBDS|2007 batch
Under the guidance of DEPARTMENT OF PROSTHODONTICS

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Acknowledgement
I would like to express my thanks to all who
have actively and sincerely helped me in the completion of this seminar. I would
like to thank all the teaching faculty of Department of Prosthodontics for
helping and guiding me in this seminar presentation. I express my gratitude to
'THE ALMIGHTY' who gave me the mental and physical strength to make this
seminar a success.

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NOORUL ISLAM COLLEGE OF DENTAL SCIENCE
DEPARTMENT OF PROSTHODONTICS
CERTIFICATE
This is to certify that the seminar entitled ‘VERTICAL JAW RELATION’ is a bonafide
record of work done by ARAVIND.M. (Reg. no.: ………) in partial fulfilment of the
requirements for the completion of Final year Part B Degree of Bachelor of Dental
Surgery from the University of Kerala during the academic year 2007-2012.
Dr. ARUN KUMAR.G M.D.S
PROFESSOR
DEPARTMENT OF PROSTHODONTICS
NOORUL ISLAM COLLEGE OF DENTAL SCIENCES
DATE :
PLACE: TRIVANDRUM

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INDEX
Sl.No. TOPIC PAGE NO.
1. Introduction …………………………………………………. 6
2. Jaw Relation – Definition ………………………………. 6
3. Vertical Jaw Relation …………………………………….. 6
a. Significance …………………………………………. 6
b. Factors affecting vertical dimension ……. 6
4. Vertical Dimension at Rest ……………………………. 6
a. Physiologic Rest Position …………………….. 6
5. Vertical Dimension of Occlusion…………………….. 7
6. Inter Occlusal Distance …………………………………. 7
7. Effects of altered Vertical Dimension ……………. 7
8. Methods of determining VDR ……………………….. 8
a. Facial measurements after swallowing
and relaxing …. 8
b. Tactile sense ……………………………………….. 8
c. Speech ………………………………………………… 8
d. Anatomical landmarks………………………….. 9
e. Facial expression………………………………….. 9
9. Methods of determining VDO………………………… 9
a. Mechanical methods……………………………. 10
b. Physiological methods…………………………. 11 – 12
10. Bibliography …………………………………………………. 13

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JAW RELATION/MAXILLO – MANDIBULAR RELATION
Any spatial relationship of the maxilla to the mandible or any one of
the infinite relationships of the mandible to the maxilla.
 Orientation Jaw relation
 Vertical Jaw relation
 Horizontal Jaw relation
VERTICAL JAW RELATION / VERTICAL DIMENSION:
• Vertical dimension refers to the length of the face.
• It is maintained either by the occlusion of the teeth or the balanced tonic contraction of the
opening and closing muscles of mandibular movements.
SIGNIFICANCE
• 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.
FACTORS AFFECTING VD
• Tooth: Acts as a vertical stop.
• Musculature: Opening and closing muscles tend to be in a state of minimal tonic contraction.
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).
VERTICAL DIMENSION OF PHYSIOLOGIC REST POSITION (VDR)
• 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.
PHYSIOLOGIC REST POSITION
• 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.

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VERTICAL DIMENSION OF OCCLUSION (VDO)
• Vertical separation of the jaws when the teeth or occlusion rims are in contact.
INTEROCCLUSAL DISTANCE (IOD)/FREE WAY SPACE
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”.
VDR = VDO + IOD
VDR – IOD = VDO
EFFECTS OF ALTERED VD
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
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

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METHODS OF DETERMINING VDR
• FACIAL MEASUREMENT AFTER SWALLOWING AND RELAXING.
• SPEECH
• TACTILE SENSE
• MEASUREMENT OF ANATOMICAL LANDMARKS
• FACIAL EXPRESSION.
FACIAL MEASUREMENTS AFTER SWALLOWING AND RELAXING
• 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.
TACTILE SENSE
• 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.
SPEECH
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.

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ANATOMIC LANDMARKS
• 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.
FACIAL EXPRESSION
• 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.
METHODS OF DETERMINING VDO
A) MECHANICAL METHODS
• Ridge relation
 Distance from incisive papilla to mandibular incisors.
 Parallelism of ridges.
• Pre-extraction records:
 Profile photographs
 Profile silhouettes
 Radiography
 Articulated casts
 Facial measurements
• Measurement from former dentures
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.

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MECHANICAL METHODS
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.
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.
MEASUREMENT OF THE FORMER DENTURES:
• A Boley’s gauge is used to measure the distance between the border of the maxillary and
mandibular denture, when the dentures are in occlusion. This measurement is used to
determine the VDO.
PRE EXTRACTION RECORDS
PROFILE RADIOGRAPHS:
• Made with teeth in occlusion. These are compared with those made with occlusion rims
position. in
• DISADVANTAGE- Time consuming, Image distortion, Radiation hazard.
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
FACIAL MEASUREMENTS:
Tattoo 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.

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PHYSIOLOGIC METHODS
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.
• Disadvantage- The marks move with the skin.
PHONETICS AND ESTHETICS
• The dentist asks the patient to speak certain words and then makes
certain observations of the relationship of the occlusion rims to each other and to the lips.
Using ‘m’ sound:
• The patient 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)
The c, h, 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 pat pronounces these words.
SILVERMAN’S CLOSEST SPEAKING SPACE
• The 2mm space between the incisors at correct VDO when patient pronounces words
containing ‘S’.
• The closest speaking space measures vertical dimension when the mandible and muscles
involved are in physiologic function of speech.

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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.
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.
Method:
• Cones of soft wax having excessive height are placed on the lower
base. Salivation is stimulated (using candy) and the patient is instructed to swallow. The
repeated swallowing reduces the height of the wax to the occlusal vertical dimension.
TACTILE SENSE AND PATIENT- PERCEIVED COMFORT
The patient’s tactile sense is used as a guide to the determination of the
correct vertical dimension. Using a central bearing plate attached to mandibular occlusion rim and
central bearing screw attached to maxillary occlusion rim, VD is increased too high. Then in
progressive steps the screw is adjusted downward until the patient signifies over closure. The
procedure is then reversed until the patient signifies that it’s just right.
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 mandibular 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.
ELECTROMYOGRAPHY
• Rest position can be determined by recording the minimal activity of muscles of mastication.
SCRIBING GUIDE LINES

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BIBLIOGRAPHY
 Prosthodontic treatment for edentulous patients – 12th
Edition – By Zarb
– Bolender – Chapter 16 : Biological and Clinical Considerations in
Making Jaw Relation Records and Transferring Records from the Patient
to the Articulator – Pg. No. 265 – 283.
 Essentials of Complete Denture Prosthodontics – 2nd
Edition – By
Sheldon Winkler – Chapter 11: Recording Edentulous Jaw Relationships –
Pg. No. 189 – 192.
 Syllabus of Complete Dentures - 4th
Edition – By Charles M. Heartwell &
Jr. Arthur O.Rahn – Chapter 11: Recording Maxillomandibular Relations –
Pg. No. 277 – 289.