Phonetics in complete dentures./ dentistry course in india

PHONETICS IN COMPLETE
DENTURE PROSTHESIS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

CONTENTS
INTRODUCTION
DEVELOPMENT OF THE LARYNX
ANATOMY
MECHANISM OF VOICE PRODUCTION
PHYSIOLOGIC VALVES IN SPEECH PRODUCTION
COMPONENTS OF SPEECH
CLASSIFICATION OF ENGLISH CONSONANTS

.
 FACTORS IN DENTURE DESIGN AFFECTING
SPEECH
 USE OF PHONETICS IN DENTURE CONSTRUCTION.
POST INSERTION - SPEECH DIFFICULTIES
 REVIEW OF LITERATURE
 SUMMARY
 CONCLUSION
 REFERENCES www.indiandentalacademy.com

INTRODUCTION
"Speech is the use of systematized vocalization to
express verbal symbols or words." (Sheridan: 1964)
Speech is a very sophisticated autonomous and
unconscious activity. Speech in matured man is a
learned habitual neuromuscular pattern which makes
use of anatomical structures designed primarily for
respiration and deglutition.www.indiandentalacademy.com

The development of the vocal sound into meaningful
speech was one of the major accomplishments which
enabled man to reach the pinnacle of the animal
kingdom, and speech as the basic and fundamental
means of communication became the cornerstone for
the establishment and organization of society. In the
highly complex international society of today, with the
sophisticated systems for transmitting the voice,www.indiandentalacademy.com

the spoken word becomes increasingly important in
establishing and maintaining a niche in the social
structure.
Today, man is judged not only by what he says, but
equally by the way he says it. Proper speech is a
reflection of education, careless speech is an imputation
of slovenliness, and faulty speech is a handicap directly
proportionate to the degree of speech incapability.

Phonetics – The science of sounds used in
speech.
Phonetic value – The character or quality
of vocal cords

DEVELOPMENT OF THE
LARYNX

The epithelial lining of the larynx develops from
the endoderm of the cranial end of the
laryngotracheal tube. The cartilages of the larynx
develop from the cartilages in the fourth and
sixth pairs of pharyngeal arches. The laryngeal
cartilages develop from mesenchyme that is
derived from neuralcrest cells.

The mesenchyme at the cranial end of the
laryngotracheal tube proliferates rapidly, producing
paired arytenoid swellings. These swellings grow
toward the tongue, converting the slitlike aperture the
primordial glottis into a Tshaped laryngeal inlet and
reducing the developing laryngeal lumen to a narrow
slit. The laryngeal epithelium proliferates rapidly,
resulting in temporary occlusion of the laryngeal
lumen. Recanalization of the larynx occurs by the 10th
week. www.indiandentalacademy.com

The laryngeal ventricles form during this recanalization
process. These recesses are bounded by folds of
mucous membrane that become the vocal folds (cords)
and vestibular folds
The epiglottis develops from the caudal part of the
hypobranchial eminence, a prominence produced by
proliferation of mesenchyme in the ventral ends of the
third and fourth pharyngeal arches. The rostral part of
this eminence forms the posterior third or pharyngeal
part of the tongue. www.indiandentalacademy.com

Because the laryngeal muscles develop from
myoblasts in the fourth and sixth pairs of pharyngeal
arches, they are innervated by the laryngeal branch of
the vagus nerves (CN X). Growth of the larynx and
epiglottis is rapid during the first 3 years after birth.
By this time the epiglottis reaches its adult form.

ANATOMY
The larynx is a respiratory organ, set in the
respiratory tract between the pharynx and trachea.
Although phonation is important in man, the main
function of the larynx is to provide a protective
sphincter for the air passages.
The larynx lies below the hyoid bone in the midline
of the neck at the level of C 46 vertebrae.

SKELETON OF THE LARYNX
The framework of the larynx consists of cartilages,
ligaments and membranes. There are three single
cartilages (thyroid, cricoid and epiglottic) and three
pairs of cartilages (arytenoid, corniculate and
cuneiform). The ligaments and membranes are
extrinsic (thyrohyoid membrane and cricotracheal,
hyoepiglottic and thyroepiglottic ligaments) and
intrinsic (quadrangular membrane and crico
thyroid ligament). The vocal cords are the upper part
of the cricothyroid ligament (cricovocal membrane).

The muscles that control the vocal folds are divided into
two classes:
a. Those with in the organ itself (intrinsic)
b. Those that act upon it from out (extrinsic).
The intrinsic muscles have two main functions:
1. To adduct and abduct the folds
2. To regulate the degree of their tension and length.

The muscle that open the rima glottidis are posterior
Cricoarytenoids. They are attached to the posterior
surfaces of the arytenoid and cricoid cartilages. Thus,
they may rotate the arytenoid cartilages laterally and
separate the true vocal cords.
Closure of rima glottides is affected by the arytenoid
and lateral Cricoarytenoid muscle. They rotate the
arytenoid muscle is medially and causes the true vocal
folds to be approximated

The arytenoids muscle extends from the posterior and
lateral surfaces of one arytenoid cartilage to the
corresponding surface of the other. These bring the
arytenoids cartilage together, consequently narrowing
the rima glottidis. The most important muscle used in
lengthening and tensing the true vocal folds is the
cricothyroid. The vocal folds are relaned and shortened
by the thyroaryteniod muscle.

The extrinsic (accessory) muscles act upon the larynx as
a whole, connecting the larynx with the hyoid bone, the
sternum, the tongue and the pharynx. By means of these
muscles, the larynx may be elevated, depressed and
tilted.

Blood Supply
Above the vocal folds blood is brought to the larynx by
the superior laryngeal branch of the superior thyroid
artery. This enters the piriform recess below the internal
laryngeal nerve by piercing the thyrohyoid membrane
The superior laryngeal veins accompany the artery and
empty into the superior thyroid veins.
The lower half of the larynx is supplied from the
inferior laryngeal branch of the inferior thyroid artery; it
accompanies the recurrent laryngeal nerve beneath the
inferior constrictor of the pharynx. Venous return is by
the inferior laryngeal veins to the inferior thyroid veins.www.indiandentalacademy.com

Lymph drainage
From the upper and lower halves of the larynx,
lymphatics accompany the superior or inferior thyroid
vessels and drain to the upper or lower groups of deep
cervical nodes respectively. A few lymphatics pass
through the cricothyroid membrane and drain initially to
prelaryngeal and to pretracheal nodes.

Nerve supply
All the muscles of the larynx are supplied by the recurrent
laryngeal nerve except cricothyroid which is innervated
by the external laryngeal nerve. The mucous membrane of
the larynx above the level of the vocal folds is supplied
by the internal laryngeal nerve; that of the folds and the
larynx below them is supplied by the recurrent laryngeal
nerve. www.indiandentalacademy.com

The sympathetic supply (vasoconstrictor) comes in
with the superior and inferior laryngeal arteries from
the middle and inferior cervical sympathetic ganglia.

MECHANISM OF VOICE PRODUCTION
The prerequisites for sound are a source of energy and a
vibrator . The source of energy for the voice is air in the
lungs. The vibrator for the voice are the vocal folds in the
larynx.
The larynx, pharynx, nasal cavity all act as cavity
resonators to reinforce the original sound wave. This
reinforcement is augmented by the change of shape and
size of these cavities permitted by neuromuscular control.

Speech involves not only the respiratory system but
also
(1) specific speech nervous control centers in the
cerebral cortex,
(2) respiratory control centers of the brain,
(3) the articulation and resonance structures of the
mouth and nasal cavities.
Speech is composed of two mechanical functions:
(1)phonation, which is achieved by the larynx,
(2) articulation, which is achieved by the structures
of the mouth. www.indiandentalacademy.com

Phonation. The larynx is especially adapted to act as
a vibrator. The vibrating element is the vocal folds,
commonly called the vocal cords. The vocal folds
protrude from the lateral walls of the larynx toward the
center of the glottis; they are stretched and positioned
by several specific muscles of the larynx itself.
During normal breathing, the folds are wide open to
allow easy passage of air. During phonation, the folds
move together so that passage of air between them will
cause vibration. The pitch of the vibration is
determined mainly by the degree of stretch of the folds
but also by how tightly the folds are approximated to
one another and by the mass of their edges.www.indiandentalacademy.com

The three major organs of articulation are the lips,
tongue, and soft palate
The resonators include the mouth, the nose and
associated nasal sinuses, the pharynx, and even the
chest cavity.

PHYSIOLOGIC VALVES IN SPEECH
PRODUCTION
Speech mechanism includes three principal
physiologic valves
1. Valve I , the glottis
2. Valve II, the palatopharangeal region
3. Valve III, the orifice of the mouth.

PHYSIOLOGIC VALVE I

True vocal folds of larynx : The vibrating mechanism
produces vocal tones, and the true vocal folds serve as a
valve only in connection with speech sounds that have
tone i.e., the voiced sounds other wise, the out going
stream of air passes through the region of the vocal
folds without interference as in normal breathing. The
valve mechanical serves to modulate the outgoing
breath stream in instance of voiced sounds only. It is a
generator of sound waves which enables man to
communicate at a distance as contrasted to the short
distance through which one might communicate by
whispering. www.indiandentalacademy.com

The larynx, containing the vocal folds that serve
intermittently as value I during speech, is composed of
three single cartilages and three pairs of cartilages. They
are connected by ligaments and moved by muscles, the
larynx has a mucous membrane lining that is continued
superiorly with the pharynx and inferiorly with the
trachea. The cartilages and muscles offer the means for
adducting (approximating) and abducting (separating)
the true vocal folds and for tensing them (shortening
anteroposteriorly) and relaxing them (elongating
anteroposteriorly).

When in a position of rest, as in quiet breathing,
the free edges of the folds form an angular
opening which has its apex located anteriorly
and its base posteriorly the opening or aperture
between them when they are not approximated is
called rima glottidic.

When voice is desired, the folds are
approximated, and air is pushed against them
from below with sufficient force to blow the
edges of these elastic folds apart. The overload
of air pressure is momentarily spent. Tension
restores the folds to a closed position. This cycle
is repeated. The acoustic output is called voice.

PHYSIOLOGIC VALVE 11:
Palatopharangeal region:The pharynx is made up
primarily of a constrictor band of broad, flat muscles
inserting into a median raphe along its posterior wall.
The pharynx may be divided arbitrarily into three parts:
1.The nasal pharynx
2.The oral pharynx
3.The laryngeal pharynx

1.The nasal pharynx is a continuation of nasal cavity
posteriorly; it is bounded inferiorly by the soft palate
and terminates along the posterior pharyngeal wall
near the atlas (1 st cervical vertebra). It's only function
is respiratory.
2.The oral pharynx is a continuation, inferiorly, of the
nasal pharynx to the laryngeal pharynx, i.e. about the
level of hyoid bone. It's function are respiratory and
digestive

3. The laryngeal pharynx is the inferior portions of the
pharynx. It extends inferiorly from the oral pharynx and
terminates in the esophagus at about the level of the VIth
cervical vertebra. Its function is strictly digestive. The
palatopharangeal value is located in the region in which
the respiratory and digestive tracts cross each other
(pharyngeal Isthmus).

Both in the act of swallowing and in speech, this
valve divide the pharynx into nasopharyngeal and
oropharyngeal cavities. The principal closure is
affected by movement of the soft palate into contact
with the posterior wall of the pharynx

PHYSIOLOGIC VALVE 111:
The Mouth: The mouth is a complicated valve, capable of
making many changes, both in capacity and in size of the
orifices. It is modified by many articulators, the chief one
being the tongue.
The three physiologic valves serve to form a number of
more specific articulatory valves, such as:
1. Mandibular lip against the maxillary lip.
2. Mandibular lip against the maxillary teeth
3. Tip of the tongue against the alveolar ridge etc.

COMPONENTS
OF SPEECH
RESPIRATION
PHONATION
RESONATIONS
ARTICULATIONS
NEUROLOGIC
INTEGRATIONS
AUDITION

1. RESPIRATION
The speech process is initiated by the energy
inherent in a stream of air. In normal speech, the
respiratory apparatus provides, during exhalation, a
continuous stream of air with sufficient volume and
pressure, under adequate voluntary control, for
phonation. The stream of air is modified in its
course from the lungs by the maxillofacial structures
and gives rise to the sound symbols which we
recognize as speech.

2. PHONATION
When air leaves the lungs, it passes through the larynx,
whose true vocal folds modify the stream. The true vocal
folds, by opposing each other with different degrees of
tension and space, create a slit like aperture of varying
size and contour. The folds, by creating resistance to the
stream of air, set up a sequence of laryngeal sound waves
with characteristic pitch and intensity. These laryngeal
sounds provide the basis for the organization of speech.www.indiandentalacademy.com

3. RESONATION
The sound waves produced at the true vocal folds are
still far from being the finished product that we hear in
speech. It is the resonators that give the characteristic
quality to the voice. The resonating structures are the air
sinuses, organ surfaces and cavities, such as the
pharynx, oral cavity, nasal cavity, and chest wall. The
resonating structures contribute no energy to the stream
of air; they act to conserve and concentrate the energy
already present in the laryngeal tone, rather than to let it
dissipate into the tissues. However, the resonated
laryngeal tone still is not speech.www.indiandentalacademy.com

4.ARTICULATION
It is the function of the articulatory mechanism to break
up and modify the laryngeal tones and to create new
sounds within the oral cavity. So the final action of the
articulatory apparatus is to articulate, that is to join in a
fluid sequence all the sounds which have been
synthesized into symbols. Without the articulatory
capacity, the sounds produced would be only of
variable pitch, volume, and quality, like a vowel sound.

5. NEURAL INTEGRATION
Speech is integrated by the central nervous system
both at the peripheral and central level. Speech is a
learned function, and adequate hearing and vision
and a normal nervous system are required for its full
development. When the speech function comes into
conflict with other vital functions of the
maxillofacial structures, it is speech that suffers.

6. AUDITION
Audition, or the ability to receive acoustic signals, is
vital for normal speech. Hearing permits receptions
and interpretation of acoustic signals and allows the
speaker to monitor and control speech output.
Compromised hearing can preclude accurate feedback
and hence, affect speech. Speech development and
subsequent speech therapy is hampered in patient with
hearing impairments.

SPEECH
SURDS SONANT
CONSONANTS

The surd is any voiceless sound and is produced by
separation of the vocal folds (glottis open) with no
marginal vibration. The sound is made by frictions of
the air stream as it posses through the appropriate
cavities; the initial 'h' sound as in huh and the voiceless
sibilants, z, sh and zh pronounced initially are
examples.

The sonants are voiced sounds and include all vowels
and vowel like sounds. They are produced by vibration
of some portions of vocal folds to establish the original
sound wave, which is augmented by cavity
resonations. The vowels require minimum articulation

Consonants are articulated speech sounds, and all
require articulation to impede, constrict, divert, or
stop the air stream at the proper place and time to
produce the desired sound.

ENGLISH
CONSONANTS
Stops
Fricatives Affricatives
Diversions

Stops: Are characterized by stoppage and sudden release
of air stream and require complete occlusion of the
articulators involved; the plosives P and B are produced by
closure of the lips to permit momentary build up of the air
stream, followed by a sudden explosive release, and t and
d are produced by tongue contacting the hard palate to stop
the air stream before suddenly releasing it; and the K
sounds are produced by tongue and soft palate closing the
oral cavity at the same time the soft palate and pharynx
close the nasal cavity to stop the air stream prior to plosive
release.

STOPS

Fricatives: Are produced by the air stream being forced
through loosely closed articulators or a narrow
passageway. For the labiodentals f and v, the lower lip
articulates with the maxillary anterior teeth to constrict
the air stream. The linguodental ‘th’ is produced by
incomplete articulation of tongue, lip maxillary incisors
to construct the air stream. The sibilants s, z, zh, sh are
produced by tongue blade articulating with the lateral
aspects of the hard palate, permitting the air stream to be
forced through the groove created in the tongue apex.www.indiandentalacademy.com

FRICATIVES

Affricatives: j and ch are produced by a combination
of stop and friction, accomplished by articulation of
the tongue and anterior hard palate.

4. Diversions: Of the air stream is characterized by
stoppage at one point to permit escape at another. The nasal
m is produced by the lips occluding to seal the oral cavity
and permit emission through the nose. The nasal n is
produced by articulation of the tongue and hard palate
closing the oral cavity while the sound escapes through the
nasal cavity.

The nasal ng is produced by the tongue and soft palate
closing off the oral cavity to permit nasal emission. For
the lateral "I", the tongue apex occludes the anterior
portion of the oral cavity while sound escapes through
the lateral portions.

‘M’ , ‘N’ Sound

ENGLISH CONSONANTS
THEIR POSITION AND MODE OF PRODUCTION
The production of English consonants and involve six valves
below:
1. Bilabial
2. Labiodental
3. Linguodental
4. Lingeoalveolar
5. Linguopalatal
6. Linguovelar
Out of the above six valves five valves are affected by teeth
position

Bilabial Sounds: The sounds b, p and m are made by
contact of the lips. Insufficient support of lips by teeth
and / or denture base can cause these sounds to be
defective. Therefore, the anteriorposterior position of
the anterior teeth and the thickness of the labial flange
can affect the production of these sounds like wise an
incorrect vertical dimension of occlusion or teeth
positioning hindering proper lip closure, might
influence these sounds.www.indiandentalacademy.com

Labiodental Sounds: The labiodental sounds f and v
are made between the upper incisors and the labio
lingual center to the posterior third of the lower lip. If
the upper anterior teeth are too short (set too high up),
the V sound will be more like an 'f. If they are too long
(set too far down), the f will sound more like a v. If
upper teeth touch the labial side of the lower lip while
these sounds are made, the upper teeth are too far back
in the mouth.

In this situation, the relationship of the inside of the
lower lip to the labial surfaces of the teeth should be
observed while the patient is speaking. If the lower lip
drops away from the lower teeth during speech, the
lower anterior teeth are most probably too far back in the
mouth. If, on the other hand, imprints of the labial
surfaces of the lower anterior teeth are made in the
mucous membrane of the lower lip, or if the lower lip
tends to raise the lower denture, are probably too far
forward, www.indiandentalacademy.com

and this means that the upper teeth are also too far
forward. If the upper anterior teeth are set too far
back in the mouth, they will contact the lingual side
of the lower lip when f and v sounds are made. This
may also occur if the lower anterior teeth are too far
forward in relation to the lower residual ridge.

Linguodental Sounds: Dental sounds (eg. Th) are
made with the tip of the tongue extending slightly
between the upper and lower anterior teeth. This sound
is actually made closer to the alveolus (the ridge) than
to the tip of the teeth. Careful observation of the
amount of tongue that can be seen with the words this,
that, these and those will provide information as to the
labiolingual position of the anterior teeth.

If about 3mm of the tip of the tongue is not visible,
the anterior teeth are probably too far forward, or
there may be an excessive vertical overlap that does
not allow sufficient space for the tongue to protrude
between the anterior teeth. If more than 6mm of the
tongue extends out between the teeth when such
sounds are made, the teeth are probably too lingual.

Linguoalveolar Sounds: Alveolar sounds (eg. t, d, s, z,
v & 1) are made with the valve formed by contact of
the tip of the tongue with the most anterior part of the
palate (the alveolus) or the lingual sides of the anterior
teeth. The sibilants (sharp sounds) s, z, sh, ch & j (with
ch & j being affricatives) are alveolar sounds, because
the tongue and alveolus forms the controlling valve.
The important observations when these sounds are
produced are the relationship of the anterior teeth to
each other. www.indiandentalacademy.com

The upper and lower incisors should approach end to
end but not touch. A failure of the incisal edge to
approach exactly end to end indicates a possible error in
the horizontal overlap of the anterior teeth.

‘Sh’ sound

THE S SOUND
Its articulation is mainly influenced by the teeth and
palatal part of the maxillary prosthesis. Clinical
experience suggests that s and t can cause most problems
in a prosthodontic context. In nearly all languages of the
world, S is a common speech sound. The inter individual
variation in articulatory details may be great due to
individual variation in teeth, palate, lower jaw and
tongue shape and size. However, the following phonetic
properties are common to all s sounds.

Linguopalatal and Articulatory characteristics :
I. The tip of the tongue is placed far forward, coming
but never touching the upper front incisors.
II. The sagittal groove is made in the upper front part
of the tongue, with a small cross sectional area
III. The tongue dorsum is flat.
IV. Normally, the mandible will move forward and
upward, with the teeth almost in contact.

Acoustic characteristics The comparatively strong
sound energy is concentrated to a high frequency
range, with a steep energy cut off at about 3-4 kHz.
Auditory characteristics
I. The sound is fairly loud, with a light, sibilant (sharp)
quality. The S sound can be considered dental and
alveolar speech sounds because they are produced
equally well with too different tongue positions, but
there can be some variations even behind the alveolus.www.indiandentalacademy.com

Most people make the S sound with the tip of the tongue
against the alveolus in the area of the rugae, but with a small
space for air to escape between the tongue and alveolus. The
tongue's anterior dorsum forms a narrow groove near the
midline, with a cross section of about 10 mm2
. The size and
shape of this small space will determine the quality of the
sound. Part of the sibilant sound is generated when the teeth
are being hit by a concentrated air jet.

If the opening is too small, a whistle will result. If the
space is too broad and thin, the S sound will be
developed as sh, somewhat like a lisp. The frequent
cause of undesired whistles with dentures is a posterior
arch form that is too narrow.
Creation of a sharp s requires accuracy of the
neuromuscular control system, for the creation of the
groove and directioning of the air jet. Even small
deviations of only 1mm will influence the quality.

Linguovelar sounds:- The truly palatal sounds
(example: year, she and onion) present less of a problem
for dentures. The velar sounds (k, g and ng) have no
effect on dentures, except when the posterior palatal seal
extension encroaches on the soft palate.

FACTORS IN DENTURE DESIGN
AFFECTING SPEECH

1. The vowel sounds – These sounds are produced by a
continuous air stream passing through the oral cavity which
is in the form of a single chamber. All vowel sounds involve
the tongue having a convex configuration. The position of
the hump of the tongue in relation to the hard and soft
palates determines the quality of the sound. The tip of the
tongue, in all the vowel sounds, lies on the floor of the
mouth either in contact with or close to the lingual surfaces
of the lower anterior teeth and gums.

The application of this in denture construction is that
the1ower anterior teeth should be set so that they do not
impede the tongue positioning for these sounds; i.e. they
should not be set lingual to the alveolar ridge. The upper
denture base must be kept thin, and the posterior should
merge into the soft tissue in order to avoid irritating the
dorsum of the tongue, which might occur if this surface
of the denture were allowed to remain thick and square-
edged.

Denture thickness and peripheral outline
One of the reasons for loss of tone and incorrect
articulation of speech is the decrease of air volume and
loss of tongue space in the oral cavity resulting from
unduly thick denture bases. The periphery of the denture
must not be over-extended so as to encroach upon the
movable tissues, since the depth of the sulci will vary
with the movements of the tongue, lips and cheeks
during the production of speech sounds. Any interference
with the freedom of these movements may result in
indistinct speech, especially if the function of the lips is
in any way hindered.www.indiandentalacademy.com

Most important is the thickness of the denture base
covering the centre of the palate, for here no loss of natural
tissue has occurred, and the base reduces the amount of
tongue space and the oral air volume.
The production of the palatolingual group of sounds
involves contact between the tongue, and either the palate,
the alveolar process, or the teeth. With the consonants T
and D, the tongue makes firm contact with the anterior part
of the hard palate, and is suddenly drawn downwards,
producing an explosive sound; any thickening of the
denture base in this region may cause incorrect formation
of these sounds.. www.indiandentalacademy.com

When producing the S, C (soft), Z, R and L consonant
sounds, contact occurs between the tongue and the most
anterior part of the hard palate, including the lingual
surfaces of the upper and lower incisors to a slight
degree. In the case of the S, C (soft) and Z sounds, a slit-
like channel is formed between the tongue and palate
through which the air hisses. If artificial rugae are too
pronounced, or the denture base too thick in this area, the
air channel will be obstructed and a noticeable lisp may
occur as a result.

To produce the Ch and J sounds the tongue is pressed
against a larger area of the hard palate, and in addition
makes contact with the upper alveolar process, bringing
about the explosive effect by rapidly breaking the seal
thus formed. The Sh sound is similar in formation, but
the air is allowed to escape between the tongue and
palate without any explosive effect, and if the palate is
too thick in the region of the rugae, it may impair in the
production of these consonants.www.indiandentalacademy.com

Vertical dimension
The formation of the bilabials, P, B and M requires that
the lips make contact to check the air stream. With P and
B, the lips part quite forcibly so that the resultant sound is
produced with an explosive effect, whereas in the M
sound lip contact is passive. For this reason M can be
used as an aid in obtaining the correct vertical height
since a strained appearance during lip contact, or the
inability to make contact, indicates that the record blocks
are occluding prematurely.www.indiandentalacademy.com

With the C (soft), S and Z sounds the teeth come very
close together, and more especially so in the case of Ch
and J; if the vertical dimension is excessive, the
dentures will actually make contact as these
consonants are formed, and the patient will most likely
complain of the teeth clicking together.

Occlusal plane
The labiodentals, F and V are produced by the air stream
being forced through a narrow gap between the lower lip
and the incisal edges of the upper anterior teeth. If the
occlusal plane is set too high the correct positioning of
the lower lip may be difficult. If, on the other hand, the
plane is too low, the lip will overlap the labial surfaces
of the upper teeth to a greater extent than is required for
normal phonation and the sound might be affected.

Anteroposterior position of the incisors
In setting the upper anterior teeth, consideration of
their labiopalatal position is necessary for the correct
formation of the labiodentals F and V. If they are placed
too far palatally the contact of the lower lip with the
incisal and labial surfaces may be difficult, as the lip will
tend to pass outside the teeth; the appearance usually
prevents the dentist from setting these teeth forward of
their natural position.

If the anterior teeth are placed too far back some effect
may be noticed on the quality of the linguopalatals S.
C (soft) and Z, resulting in a lisp due to the tongue
making contact with the teeth prematurely. The tongue
will more readily accommodate itself to
anteroposterior errors in the setting of the teeth than to
vertical errors.

Post-dam area
Errors of construction in this region involve the vowels U
and a and the palatolingual consonants K, NG, G and C
(hard). In the latter group the air blast is checked by the
base of the tongue being raised upwards and backwards to
make contact with the soft palate. A denture which has a
thick base in the post dam area, or a posterior edge
finished square instead of chamfered, will probably irritate
the dorsum of the tongue, impeeding speech and possibly
producing a feeling of nausea.www.indiandentalacademy.com

Indirectly, the postdam seal influences articulation of
speech, for if it is inadequate the denture may become
unseated during the formation of those sounds that have
a explosive effect, requiring the sudden repositioning of
the tongue to control and stabilize the denture; this
applies particularly to singers. Speech is usually of poor
quality in those individuals whose Upper denture has
become so loose that it is held in position mainly by
means of tongue pressure against the palate. Careful
observation will show that the denture, in such cases,
rises and falls with tongue movements during speech.

Width of dental arch
If the teeth are set to an arch which is too narrow the
tongue will be cramped, thus affecting the size and
shape of the air channel; this results in faulty
articulation of consonants such as T, D, S, N, K, C,
where the lateral margins of the tongue make; contact
with the palatal surfaces of the upper posterior teeth.
Every endeavor should be made, consistent with
general principles of denture design, to place the
lingual and palatal surfaces of the artificial teeth in the
position previously occupied by the natural dentition.

Relationship of the upper and lower anterior teeth
The chief concern is that of the S sound which requires
near contact of the upper and lower incisors so that the
air stream is allowed to escape through a slight opening
between the teeth. In abnormal protrusive and retrusive
jaw relationships, some difficulty may be experienced
in the formation of this sound, and it will probably
necessitate adjustment of the upper and lower anterior
teeth anteroposteriorly so that approximation can be
brought about successfully. The consonants Ch, J and Z
require a similar air channel in their formation.

USE OF PHONETICS IN DENTURE
CONSTRUCTION.

Speaking space The mandible moves vertically and
anteroposteriorly during speech so that the lower teeth
invade the freeway. space. Therefore some patients need
more freeway space than others depending on the range of
mandibular movement during speech. The closest speaking
space is the space between the occlusal surfaces of the teeth
when the mandible is elevated to the maximum extent during
speech. There should be at least 1 mm of closest speaking
space in all complete dentures. It should be emphasized that
the freeway space is a resting measurement, while the closest
speaking space is a dynamic measurement.www.indiandentalacademy.com

The large overjet in Angle’s Class II, division I.
patients should be reproduced in the denture in order
to give room for the anteroposterior movement of the
mandible during speech. In this sense the overjet
might be considered ‘ horizontal freeway space’,
without which the patient would have considerable
difficulty in wearing dentures.

A useful phonetic check for correct height is to ask the
patient to say a sibilant word such as 'Mississippi', with
the record blocks in the mouth. If the height is excessive
the word will not be pronounced clearly and the blocks
will contact during the 'ss' sounds. If the height is
correct, the occlusal surfaces of the rims will be slightly
apart during the 'ss' sounds. If the patient does not
pronounce the word clearly, and no contact can be
detected during the 'ss' sounds, it is likely that the tongue
space is restricted by the record blocks, and the wax
should be cut away on the lingual sides of the upper and
lower rims until a clearer pronunciation is obtained.www.indiandentalacademy.com

‘S’ Sound ‘N’ Sound

AE Sound

TRY IN – STAGE
The wax trial dentures are prepared for the purpose of
foretelling the appearance of the finished dentures and
providing the opportunity to make any desired changes.
Phonetic tests might be made first, fol1owed by a check of
overlaps, occlusions, posterior palatal seal, facial contours,
and size, form, color, and arrangement of the teeth. The
final step is to ask the patient's approval. It is well to make
the phonetic tests early in the routine, for when the
patient's attention is concentrated on the speech sounds, his
facial appearance is more likely to be natural than, when
his attention is concentrated on appearance.www.indiandentalacademy.com

Because some speech faults are a consequence of
poor retention of the bases, before any decisions are
made the bases have to be stabilized, if necessary by
means of a denture adhesive.
When the mechanical and esthetic factors are correct,
the phonetic factors seldom offer a problem.
However, they should be checked.

Although the average patient is capable of making
considerable muscular adaptation to altered tooth
position and palate formation in order to produce
speech sounds, we should not impose upon him the
burden of acquiring new skills in enunciation.
Furthermore, there are deviations in tooth position and
palate formation beyond which it becomes impossible
for the patient to accommodate himself.

Before speech begins, the mandible hangs loosely in
rest relation. Just as occluding relation is a point of
reference for the discussion of the mechanical problems,
the rest relation is a point of reference for the discussion
of phonetic problems. The position of rest relation is
merely the habitual position of the mandible when not
in use. Some of the speech sounds are made without
much dependence on mandibular relation or tooth
positions, whereas others depend largely on these
factors. Strictly speaking, it is the position of the lower
teeth rather than the position of the mandible which is
important in the production of the various sounds.www.indiandentalacademy.com

By noting the habitual protrusion of the mandible as
the patient attempts to produce some of the sounds, it
is possible to check on the relation of the teeth to the
other structures and change their positions if
necessary in order to make them conform to the
habitual speaking movements.

‘F’ sound
‘V’ sound

‘S’ sound

Posterior border of the denture- when the patient
says ‘ah’, the junction of the fixed and movable palate
is established and therein determines within limits the
posterior extension of the dentures.
Vertical dimension with the correctly trimmed
maxillary occlusal rim place. The mandibular rim is
trimmed to produce a space of 1mm when the patient
says ‘s’.
Height of the anterior teeth and thus the occlusal
plane – using ‘f’ , ‘v’

Overjet – by using the ‘s’ sound
Labiolingual position of the lower anteriors – ‘s’
Thickness of the anterior region of the palate - ‘t’
Thickness of the postdam – ‘g’

The channel in the tongue does not always lie in the exact
center of the palate. Its location is not a matter of any
practical consequence so long as the sounds are produced
satisfactorily. When the sibilants offer difficulty, however,
the lateral deviation of the channel should be determined,
for a lack of sufficient depth in the tongue channel may be
compensated for by making a channel in the denture base.

The location of the aperture through, which the air
escapes is especially important in the case of lisping,
since the necessary sagittal groove in the denture base
must be placed opposite the channel in the tongue. If no
channel at all exists in the patient's tongue, as in the
case of some patients who lisp, a suitable channel
is cut in the denture base at the median line.

The phonetics test can be used to check on the
mechanics and even the esthetics of a denture. If
while speaking, the patient carries the lower incisors
in front of the upper ones, the horizontal overlap is
probably not great enough for good mechanics or for
the best appearance. If the ‘f’ and ‘v’ sounds offer
difficulty, the upper incisal edges are probably far
back or too short to appear best. If the opposing teeth
touch during speech, the degree of jaw separation is
too great.

POST INSERTION- SPEECH
DIFFICULTIES

When complete dentures are worn for the first time
there is always some temporary alteration in speech
owing to the thickness of the denture covering the
palate, necessitating slightly altered positions of the
tongue. Patients usually adapt readily to moderate
changes in denture shape, and problems with speech
which are apparent at the delivery stage are not often
present at the review.

This is only a temporary inconvenience that can be
most rapidly overcome by the patient reading aloud.
Adaptation occurs rapidly over the first few days, but
if distortions of speech persist after 30 days a change
to the denture has to be made. However, that
adaptation of speech patterns back to normal is
prolonged when the patient has a hearing impediment,
and not all patients will admit to such a disability.

A complaint of general speech can be associated with
 Unfamiliarity with denture contour
Too great vertical dimension
Incorrectly positioned anterior teeth
History of speech difficulties
Interocclusal space
Too low an occlusal plane
Decreased tongue space.

The length, form and thickness of the lower lingual
flange are important consideration in speech. Usually,
patients with a low index of neuromuscular skill
experience difficulty in speaking with artificial teeth.
These patients do better with a lingual flange that does
not extend below the mylohyoid ridge, nor posteriorly
into the retroalveolar space. The thinnest, shortest
snuggest lingual flange possible will aid their speech.
However, the demands of retention may intervene.www.indiandentalacademy.com

TONGUE SPACE
Restriction of the tongue space may give rise to the
following complaints:
(1)the patient feels that the dentures are a
'mouthful';
(2) the patient has difficulty in speaking;
(3) the lower denture feels loose all the time;
(4) the tip or sides of the tongue feel sore.

The provision of adequate tongue space in complete
dentures is of the greatest importance for the comfort
of the patient. Tongue space is most likely to be
restricted anteriorly by the setting of the upper incisors
in the wrong relationship to the incisive papilla, and
pos-teriorly by the setting of the upper posterior teeth
'on the ridge' and the lower posterior teeth lingual to
the ridge. If the requirements of occlusal balance make
it necessary to have a steep compensating curve or a
large angle of the plane of orientation,

the tongue cannot easily overlap the lower molars to
stabilize the lower denture.
In these cases it is necessary to leave off the second
molar, so that an adequate posterior shelf is provided
distal to the first molar. This posterior shelf should be at
least 1 cm in length from the distal surface of the first
molar to the posterior border of the denture. It provides
space for the thick posterior part of the tongue, which
can rest upon it and stabilize the denture.

Difficulty with speech, is often associated with the
placement of the anterior teeth on the ridge instead of
in front of it. The anterior tooth position can be very
quickly checked by measuring from the middle of the
incisive papilla depression, on the fitting surface of the
denture, to the labial surfaces of the incisors. The
horizontal distance between these two points should
be approximately 1 cm. If it is less than 7 mm it is safe
to assume that there is restriction of the anterior part of
the tongue space. www.indiandentalacademy.com

PATIENT’S COMPLAINT CAUSES OF COMPLAINT
Whistle on ‘s’ sounds Too narrow an air space on the
anterior part of the palate
Lisp on ‘s’ sounds Too broad an air space on the
anterior part of the palate
‘Th’ and ‘t’ sounds indistinct Inadequate interocclusal
distance
‘T’ sounds like ‘th’ Upper anterior teeth too far
lingual
‘F’ and ‘v’ sounds indistinct Improper position of upper
anterior teeth either vertically
or horizontally

REVIEW OF LITERATURE

Are prominent rugae and glossy tongue surfaces on
artificial dentures to be desired? Luzerne G Jordan
JPD 1953; 4: 52-53
Matte or non glossy surfaces on upper denture especially
is much more acceptable to patients than a glossy
surface. Improve tongue comfort, but also aids materially
in phonetics because the tongue is able to obtain a degree
of traction on the denture surface, which is similar to that
obtained when the tongue is rubbed against the mucosa.
There is some evidence that rugae would improve
phonetics done by carving interrugae grooves on the
tongue surface of the denture over the areas where the
grooves exist in the mouth.

The speaking method in measuring vertical dimension
Meyer M Silverman JPD1953;3:193-199
He concluded that the speaking method of measuring
vertical dimension is a physiologic phonetic method
which measures V.D. by mean of the closet speaking
space. This space is measured before the loss of the
remaining natural teeth to give us the patient natural V.D.
which can be recorded and used at later dates. Closest
speaking space should be reproduced in full dentures as in
the natural dentition. This space is also the means of
proving that , VD must not be increased.www.indiandentalacademy.com

Improved phonetics in denture construction Leslie R Allen
JPD1958;8:753-763
He concluded that to develop a normal S & SH tongue
palatal pattern in the maxillary trial base, it is usually
necessary to thicken the area outlined by the palatogram.
In most cases, it is necessary to thicken the area of the
incisive papilla to prevent the jet of air emitted by the
median sulcus of the tongue from escaping towards the
vault. It was found that building the tongue palatal contact
area to normal and thickening the area of the incisive
papilla facilitated proper communication and eliminates
much of the post insertion practice period.www.indiandentalacademy.com

A study of phonetic changes in edentulous patients
following complete denture treatment.
Joseph G Agnello JPD 1972;27:133-139
Words spoken in edentulous state were compared
with words spoken at different stages of the denture
wear. The ‘s’, ‘sh’ showed improvement however
individual speech sounds developed differently.
The voiced ‘th’ sound did not show any general
improvement. www.indiandentalacademy.com

Phonetics and swallowing to determine palatal contour
of dentures. Francis W Shaffer Robert A Kutz
JPD 1972;28:360-362
Technique described by Lott and Levin for forming
the palatal surface of dentures. It is a modification that
utilizes tin foil on the cast prior to adding soft wax on
the palatal surface of the trial denture base and then
allows the patients tongue to mold the soft wax during
speech and swallowing.

Let ‘s’ be your guide Earl Pound
JPD 1977:38;482-489
Establishing vertical dimension of occlusion based upon
the fact that the body of the mandible assumes an easily
recordable, repetitive horizontal and vertical position when
the patient is at the ‘s’ position during speech. This
controlled method of developing vertical dimension
correlates the posterior speaking space with the placement
of the upper and lower anterior teeth when set to a
phonetic standard. This permits the development of a
dependable vertical dimension of occlusion for most
patients and also serve as a guide for the more difficult to
treat class II and tongue thrusting patients.www.indiandentalacademy.com

Palatogram assessment of maxillary complete dentures
Farley DW, Jones JD, Cronin RJ. J Prosthodont 1998 Jun;7:84-90)
presented a review of the mechanics of speech as well as
common speech problems encountered with a removable
maxillary prosthesis. The use of a palatogram to aid the
clinician in the assessment and resolution of speech
problems associated with a maxillary denture was
demonstrated www.indiandentalacademy.com

Clinical rest and closest speech position in the
determination of occlusal vertical dimension
Seifert E, Runte C, Riebandt M, Lamprecht - Dinnesen A,
Bollmann F J Oral Rehabil 2000;27:714-719 They
concluded that variations of thickness and or volume of
dentures and of the vertical and horizontal dimension of
occlusion may result in unpredictable audible changes
to the voice. Patients should be informed about possible
effects of modified or new dentures on their voice.www.indiandentalacademy.com

Spectral analysis of ‘s’ sound with changing angulation of
the maxillary central incisor Runte C, Tawana D,
Dirksen D, Runte B, Lamprecht-Dinnesen A, Bollmann F, Seifert E,
Danesh G IJP 2002;15: 254-258
Concluded that the maxillary incisor position influences /s/ sound
production. Displacement of the maxillary incisors must be
considered a cause of immediate changes in /s/ sound distortion.
Therefore, denture teeth should be placed in the original tooth
position as accurately as possible. Results also indicate that
neuromuscular reactions are more important for initial speech sound
distortions than are aerodynamic changes in the anterior speech
sound-producing areas. www.indiandentalacademy.com

SUMMARY
Clarity of speech ie the articulation of sound, is an
important oral function and its relationship to denture
construction has been clearly demonstrated. The fact that
the neuromuscular pathway for speech remain for a period
of time after the teeth are lost is relevant. The aim of
complete denture design must be, therefore to construct
denture that will be in harmony with the existing pathway
and not relay on the patient adaptive capabilities to
tolerate new ones. Any change in the shape of the
articulation tract can lead to errors in articulation and
certain sounds may be used to identify these changes.www.indiandentalacademy.com

CONCLUSION
Speech difficulties as sequelae of oral rehabilitation with
complete dentures are generally a transient problem.
When encountered the difficulties may not be easily
solved. Therefore efforts should be made to avoid them
by pretreatment records or assessment of speech and
provision of information to patients about likely initial
deviation from normal speech, immediately following
oral rehabilitation.

If persistent difficulties to pronounce certain sounds or
other speech disorders persist for more than 2 to 4
weeks, the following protocol is recommended -
1. If the patient has the previous complete denture
experience, compare the new set with the old one to
diagnose possible design differences of significance for
speech production.
2. Make the necessary modifications; soft wax might be
helpful.
3. Have the patient's hearing checked. An auditory deficit
will prolong the adaptation period and render it more
difficult
4. If the reported perceived problem cannot be resolved by
dental methods, the patient should be referred to
speech pathologist.www.indiandentalacademy.com

Speech has been shown to be an
integral part of denture design and its
value should not be overlooked.

REFERENCES
TEXTBOOK OF MEDICAL PHYSIOLOGY
Guyton and Hall
ESSENTIALS OF CLINICAL ANATOMY
Keith L Moore & Anee M R Agur
LAST’S ANATOMY REGIONAL AND CLINICAL
Churchill Livingstone & Chummy S Sinnatamby
ANATOMY OF OROFACIAL STRUCTURES
Brand Ieselhard
CLINICAL ANATOMY
Richard S Snell
THE ANATOMICAL BASIS OF DENTISTRY Bernard
Liebgott www.indiandentalacademy.com

COMPLETE DENTURES
Merrill G Swenson, Charles J Stout
PROBLEMS AND SOLUTIONS IN COMPLETE DENTURE
PROSTHODONTICS.
David J Lamb
DESIGNING COMPLETE DENTURES.
David M Watt , A Roy Mac Gregor
CLINICAL DENTAL PROSTHETICS
Fenn, Liddelow, Ginisons
THE NEUTRAL ZONE IN COMPLETE AND PARTIAL
DENTURES
Victor E Beresin, Frank J Schiesser
SYLLABUS OF COMPLETE DENTURE
Charles M Heartwell www.indiandentalacademy.com

ESSENTIALS OF COMPLETE DENTURE PROSTHESIS
Wrinkler
PROSTHODONTIC TREATMENT FOR EDENTULOUS PATIENT
Zarb
ANALYSIS OF SPEECH IN PROSTHODONTIC PRACTICE
JPD 1974; 31: 605-14
THE USE OF SPEECH PATTERN AS AN AID IN
PROSTHODONTIC RECONSTRUCTION
JPD 1963; 13: 825-36
AN INTRODUCTION TO DENTURE SIMPLIFICATION
JPD 1971; 26: 570-80

Are prominent rugae and glossy tongue surfaces on
artificial dentures to be desired?
Luzerne G Jordan JPD 1953; 4: 52-53
The speaking method in measuring vertical dimension
Meyer M Silverman JPD1953;3:193-199
A study of phonetic changes in edentulous patients
following complete denture treatment.
Joseph G Agnello JPD 1972;27:133-139
Phonetics and swallowing to determine palatal contour of
dentures.
Francis W Shaffer Robert A Kutz JPD 1972;28:360-362

Let ‘s’ be your guide
Earl Pound JPD 1977:38;482-489
Palatogram assessment of maxillary complete dentures
Farley DW, Jones JD, Cronin RJ. J Prosthodont 1998 Jun;7:84-90
Clinical rest and closest speech position in the determination
of occlusal vertical dimension
Seifert E, Runte C, Riebandt M, Lamprecht - Dinnesen A, Bollmann F
J Oral Rehabil 2000;27:714-
719
Spectral analysis of ‘s’ sound with changing angulation of
the maxillary central incisor
Runte C, Tawana D, Dirksen D, Runte B, Lamprecht-Dinnesen A,
Bollmann F, Seifert E, Danesh G IJP 2002;15: 254-258

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