Phonetics/ orthodontic straight wire technique

SEMINARSEMINAR
www.indiandentalacademy.com

GOOD MORNING

Dr.RAMAKRISHNA.M
PHONETICS IN COMPLETE DENTURESPHONETICS IN COMPLETE DENTURES

CONTENTS
Introduction
Terminology
Mechanism of sound production
Development of speech skills
Neurophysiology of speech
Types/Classification of speech sounds
S sounds and their prosthodontic considerations
Different parts of oral cavity and their influence
on speech
Different aspects of complete denture fabrication
and their influence on speech

Speech tests
Speech analysis methods
Speech defects and their management
Special considerations of phonetics
Review of literature
conclusion
References

INTRODUCTIONINTRODUCTION

Speech is one of the oldest media of communication
of thoughts. It has affected human behavior and
progress so greatly that it has been one of the
important determinants of psycho-social health of the
human beings.
The development of vocal sound into meaningful
speech was one of the major accomplishments which
enabled the man to reach the pinnacle of the animal
kingdom.
In this highly complex international society of today,
man is judged by not just what he says ,but equally
by the way he says it.
“proper speech is reflection of education,
careless speech is an imputation of slovenliness,
and a faulty speech is a handicap directly
proportionate to the degree of speech
incapability.”

WHAT IS SPEECH?
According to Trevor leeTrevor lee,
“Speech has been defined in its noun form, as
an established communicative system of
arbitrary and conventionalized acoustic symbols
produced mainly by the action of the muscles of
the respiratory and upper alimentary
tracts………...
In its verb form, the term implies
communicative behavior through the use of
these conventionalized and arbitrary symbols.”

WHY SPEECH IS IMPORTANT IN
DENTISTRY?
The dental profession, as a guardian of oral health, is
engaged to a great extent in altering and restoring
structures with in the oral cavity, to alleviate the ravages
of disease and developmental abnormalities. A major
portion of speech articulation takes place with in the oral
cavity, and any alteration or restorations of structures
therein will adversely affect speech proportionate to the
location and magnitude of alteration.
For example, A missing bicuspid will permit lateral
emission of air, which is intolerable to the precise
speaker or singer. A poorly constructed denture with out
regard to speech articulation will cause distortions in
speech until the patient gets adapted to it.

But, faulty speech should never be desirable, even
for short period of time also, as it may be unpleasant
to the listener, psychologically embarrassing to the
patient and also adds to the burden of adaptation of
dentures.
So, the treatment objective of every dentist should be
to construct artificial restorations like complete
dentures that conform to the individual patient’s
existing neuromuscular patterns, rather than rely too
much on the patient’s ability to adapt.
For this, it does require knowledge of some
fundamentals of phonetics and a precise knowledge
of contact of tongue areas with teeth, lips, palate and
alveoli for speech articulation, to all the dental
practitioners.

TERMINOLOGYTERMINOLOGY
RELATED TO SPEECHRELATED TO SPEECH

Phonetics :
The study of speech sounds, their production and combination
and their representation by written symbols.
OR
The description and analysis of the sounds of a particular language.
Phonemics :
The description and classification of the phonemes of the
specific language.
Phoneme :
A set of phonetically similar, but slightly differing stand in a
language that are heard as a same sound by native speakers and are
represented in phonemic transcription by the same symbol.In simple
words it is an unit of speech by which we distinguish one utterance
from another.Collectively about 40 phonemes make up phonemics of a
language.
Eg : Phoneme |P| includes phonetically differentiated sounds
represented by P in pin, spin, tip.www.indiandentalacademy.com

Morphemes:
smallest meaningful units of language.They are formed by
collection of various phonemes. In simple term, they can be called words.
PROSODY:
It’s a term that describes all those variations in time, pitch,
and loudness that accomplish emphasis and lend interest to speech.

MECHANISM OFMECHANISM OF
SOUND PRODUCTIONSOUND PRODUCTION

The essential characteristic of speech is the production
and organization of sound into symbols.The production
of these sound symbols is a phenomenon of highly
integrated factors.we can divide these factors as
follows,for the purpose of our discussion:
1.respiration
2.phonation
3.resonance
4.articulation
5.neurological integration

RESPIRATION:
The speech process is initiated by the energy inherent
in air.In normal speech,the respiratory apparatus provides
during exhalation,a continuous stream of air with sufficient
volume and pressure under voluntary control for phonation.The
stream of air is modified in its course from lungs by maxillo-
facial structures and gives rise to the symbols which are
recognized as speech.
PHONATION:
when air leaves the lungs,it passes through the larynx
whose true vocal folds or vocal cords modify the stream. The
true vocal folds 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 stream of air,set up
a sequence of laryngeal sound waves with characteristic pitch
and intensity.These laryngeal sounds provide the basis for
organization of speech.

• Thyroarytenoid muscle
• Inner edges – Vocalis
• Elastic tissue, stratified epithelium
• Vibrations
 Horizontal up to 4 mm
 Slightly vertical 0.2 – 0.5 mm
• Average length Males – 15 mm  Deeper pitch
Females – 11 mm
• Vestibular fold
VOCAL CORD

RESONANCE:
The sound waves produced by the 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 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 do not contribute any 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 tissues.However, the resonating
laryngeal tone is still not speech.
.

RESONATORS

ARTICULATION:
It is the function of articulatory mechanism to break up,to
modify the laryngeal tones and to create new sounds itself with in
the oral cavity.The articulatory mechanism involves the
lips,teeth,palate and tongue.
The final action of articulatory apparatus is to articulate in a
fluid sequence all the sounds which have been synthesized into
symbols.With out this articulating capacity the sounds produced
would be only of variable pitch, volume and quantity

ARTICULATORS OF ORAL CAVITY
Soft palateActive
Lip, Mandible &
Tongue
Passive
Teeth, Alveolar
ridge, Hard palate
Naso-oral
balance
Sound ‘K’

NEUROLOGIC INTEGRATION:
The factors for speech production are highly coordinated,
some sequentially and some simultaneously by the central nervous
system. Speech is a learned function and requires adequate hearing,
vision,and normal nervous system for its full development.
Associated with speech is the whole phenomena of
intelligence. When speech functions come into contact with the other
vital functions of maxillo-facial structures, it is speech that suffers. This
is particularly true when the conflict is with the important reflex actions,
for example coughing, sneezing,hiccups, and regurgitation.

DEVELOPMENT OFDEVELOPMENT OF
SPEECH SKILLSSPEECH SKILLS

Speech is characteristically and distinctively human, a unique form
of behavior apparently limited to homosapiens. Although many animals
make distinctive sounds and convey literal and limited messages, they
cannot master the symbolizations and abstracts involved in speech.
Modern knowledge of the development of complex behaviors
indicate that speech was an evolution rather than a spontaneous or
even short time creation.with upright posture and development of manual
dexterity came freedom of the mouth from crude grasping and
manipulative duties.As a result structures of the throat and mouth were
free to evolve into specialized organs, able later to sub serve the speech
process.

 Variations such as increased intricacy and flexibility of larynx ,
shortening and widening of the tongue and increased flexibility
of lips, were associated with more obvious changes such as
widening of and shortening of mandible, gradual appearance of
chin and developing brow to elevate the facial plane from its apish
slant. Other changes in ear, palate, muscles of mastication
accompanied these more obvious changes.
 These changes are suggestive of development of complex nature of
speech. Speech apparently developed slowly from crude beginnings
with selection and adaptation of appropriate symbols accomplished
in total experience of living. Several other sensory- motor
mechanisms which aided man’s communicative efforts, and are now
in use by some animals might been usurped to serve the function of
human language. A language of touch, for instance, survives now in
lobsters and some insects. Gestural communication is used by
lower forms and remains of use to man in spite of high development
of language.
 so in brief, the concept of communication we have at
present took unknown number of centuries to develop from the
period of primitive man to the present day ultra sophisticated man.

NEUROPHYSIOLOGY OF THE SPEECH
Sensory (language input) Motor (language output)
Sensory
Speaking a heard word Speaking a written word

FACTORS RELATED TO DEVELOPMENT OF
SPEECH SKILL:
1.AGE: A cross sectional study of children shows a general
agreement that the development sequence of speech sounds is
somewhat as follows.
AGE(in months) CONSONANTS CORRECTLY
USED INWORDS
Between 3-4 M,b,p,w,h
Between 4-5 N,t,d,k,g,j
Between 5-6 F,v,s,z
Between 6-7 L,th
Btween 7-8 R,wh,s,zwww.indiandentalacademy.com

2.INTELLIGENCE: The rate of mastery of the speech and language
skill is importantly determined by the child’s intelligence.The mentally
retarded are typically delayed in their first use of words and
sentences.They present more than average number of articulation
errors, more prominently omissions of phonemes.Complete
speechlessness can be attributed to mental deficiency(IQ=10 TO 25)
3.HEARING CAPACITY: For children to learn speech skills
hearing is very much essential.Children who are deaf or profoundly hard
of hearing display retarding in acquisition of symbol system and
development of intelligible speech.That’s why a child who is born deaf is
also born dumb,unless speech methods of training are adapted.
4.IMPAIRMENT OF MOTOR CONTROL: Children with cerebral
palsy and and patients with neuromuscular impairment may display
impairment of speech apparatus with resulting DYSARTHRIA,as a part
of their motor difficulty.

5.SPECIFIC LANGAUAGE DISABILTY: Some children
display difficulty in understanding and using language even though
testing reveals no hearing loss, motor defects,intellectual impairment
or emotional disturbance…Such difficulty in handling the symbol
system is termed as specific language disability/developmental
aphasia/congenital aphasia…This is due to the bilateral cerebral
lesions or defective of crucial neural substrate for language.
6. PSYCHOSOCIAL FACTORS: The family constitutes a
primary influence on the child’s development. The number of people in
the family,relative position of the child in the group and socio
economic status of the family all undoubtedly have some impact on
acquisition of speech.Bilingual children have been found to be less
proficient in linguistic skills than monolingual children.culturally
disadvantaged children and children reared in silent and unstimulated
environment can be expected to display communication disabilities.

TYPES OF SPEECHTYPES OF SPEECH
SOUNDSSOUNDS

Phonemes of English language can be divided into four groups as
follows,
1.VOWELS:Vowels are voiced sounds, that is, the vocal cords are
activated by vibration of their production. They are formed by, a
continuous air flow, the alteration in shape and size of the mouth and
the lip opening giving the various sounds their characteristic form.
-In English, vowels are a,e,i,o,u
2.DIPTHONGS: Are blends of two vowels spoken in a single syllable
with out interruption of phonation.ex:boy, main,tone,dine.
3.CONSONANTS: Consonants may be either voiced or produced
with out vocal cord vibration, in which case they are called breathed
sounds.The consonant sounds are produced by the air stream being
impeded, diverted, or interrupted before it is released.
eg: p, b, m, s, t, r, z etc…
4.COMBINATION: Is blend of a consonanat and vowel articulated in
quick succession that they are identified as single phonemes.

CLASSIFICATION OF SPEECH
SOUNDS (BOUCHER)
ALPHABETS
VOWELS
CONSONANTS
PLOSIVES
FRICATIVES
AFFRICATIVES
NASALS
LIQUID CONSONANTS
GLIDESwww.indiandentalacademy.com

I. CLASSIFICATION OF
CONSONANTS: {Boucher}
 Consonants are divided into groups depending on their
characteristic production and use of different
articulators and valves. They are as follows.
Plosive consonants: These sounds are produced when
overpressure of the air has been built up by consonants
between the soft palate and pharyngeal wall and released in
an explosive way. Ex: P (pay), B (bay), T (to), D (dot)
Fricatives: are also called sibilants and are characterized
by their sharp and whistling sound quality created when air
is squeezed through the nearly obstructed articulators.
Ex: S (so), Z (zoo)
Affricative consonants: are a mix between plosive and
fricative ones. Ex: Ch (chin), J (jar)

Nasal consonants :are produced with out oral exit of
air.production involves the coupling of nasal cavity as
resonators.When nasal cavities are blocked,the nasal sounds
are produced hyponasally,the resulting in speech-we describe
as talking with “stuffy nose”….Ex: M (man), N (name), NG
(bang)
Liquid consonants(semi vowels) : are , as the name implies ,
produced with out friction. Ex: R (rose),L(lily)
Glides: that is sounds characterized by a gradually changing
articulator shape Ex: W (witch), Y (you)

II. ACCORDING TO LARYNGEAL ACTION
Voice less / surd
• A periodic sound produced
by impedance within oral
cavity
Voiced / sonant
• Counterpart of surds
• Produced in similar manner
with vibration of adducted
vocal folds.
Plosives Fricatives Affricatives
Voice less p t k s f θ |ts|
Voiced b d g z v δ |dz|

III. BASED ON PRESSURE CHARACTERISTICS :
• Variation in amount of intraoral breath pressure
• Fricatives, affricatives and plosives – pressure consonants
• Continuants > non continuants
• Voiceless > voiced

IV. CLASSIFICATION OF CONSONANTS BASED
ON THE PARTS OF MOUTH INVOLVED IN
THEIR FORMATION
 For convenience, in clinical Prosthodontic applications
the consonants are once again, classified based on the
parts of mouth that are involved in their formation, as
follows:
Bilabial sounds (Ex: P, B, M, N,W)
Labiodental sounds (Ex: F, V)
Linguodentals sounds (EX: Th)
Linguoalveolar sounds (EX: T, D, S, Z, N)
Linguopalatal sounds (Ex: Sh, Ch, J, R, Y)
Linguovelar sounds (EX: K, G, H, Ng)

 Bilabials- Are formed mainly by the lips. For the correct
articulation of these consonants the lips are brought into active
contact and then opened suddenly, this sudden opening of the
lips produces an explosive sound [eg: B,P
(plosives) ,M (nasals) and W (glides)]
 In B and P, air pressure is built up behind the lips and released
with or without a voice sound.
CLINICAL SIGNIFICANCE:
To determine the anteroposterior positioning of the anterior
teeth and thickness of the denture flange:
Insufficient
support of the lips by teeth or denture base can cause these
sounds to be defective. Therefore the anteroposterior
positioning of anterior teeth and thickness of the labial flange
can affect the production of these sounds.
To determine the vertical dimension of occlusion:
Usually P and B are produced with
an explosive effect, where as M sound is produced with a
passive contact of lips. For this reason M can be used as an aid
in obtaining the correct vertical height, since a strained
appearance during lip contact indicates that the bite blocks are
I. BILABIAL SOUNDS

BILABIAL
Lip closure
|p|, |b| & |m|
I/O breath pressure is
impounded behind closed lips
Lip rounding
|w|
Moves to appropriate position

II. LABIODENTAL SOUNDS
 Labiodentals- are formed by the lips and teeth. Usually
pronounced with lower lip touching the incisal edges of
maxillary incisor teeth Eg: F, V, Ph (fricatives)
To determine the superoinferior position of anterior
maxillary teeth:
If the upper anterior teeth are too short (set too high), the V
sound will be more like F.
If they are
too long (set too low), the F will sound like V.
To determine the correct occlusal plane:
If the occlusal plane is
set too high the correct positioning of lower lip may be difficult,
and if the occlusal plane is too low, the lip will overlap the labial
surfaces of the upper teeth to a great extent than is required for
normal phonation and the sound might be distorted.

To determine the anteroposterior position of the incisors:
If upper anterior teeth touch the labial side of the lower lip, while
these sounds are made then the upper teeth are too far forward
or the lower teeth are too far back in the mouth.
If the lower lip tends to raise the lower denture while
pronouncing these sounds ,then the lower teeth are too far
forward , and this means that the upper teeth also are too far
forward.
If the upper anterior teeth are set too far back in the mouth or if
the lower anteriors are set too far forward in relation to the
residual ridge ,they will contact the lingual side of the lower lip
when these sounds are made. .

Upper incisors and labiolingual center to the posterior third
of the lower lip.
LABIODENTAL

PICTURE SHOWING THE POSITIONS OF
TEETH AND TONGUE DURING PRODUCTION
OF LABIODENTAL SOUNDS (F, V, Ph)

EFFECTS OF MAXILLARY ANTERIOR TOOTH
POSITIONING OF ‘F’ AND ‘V’ SOUNDS

III. LINGUODENTAL SOUNDS
 Linguodentals- are formed by the tongue and the teeth.
During the pronunciation of these sounds the tongue extends
slightly between the incisal edges of the upper and lower
anterior teeth. This sound is actually made closer to the
alveolus (ridge) than to the tip of teeth. They are also called
interdental sounds Ex: Th
(fricative)
To determine the labiolingual position of the anterior teeth:
Ask the patient to pronounce words like THIS, THAT, THESE,
THOSE and carefully observe the amount of tongue that can be
seen between teeth.
If about 3 mm of the tip of the tongue is
not visible, the anterior teeth are probably too far forward
(except in patients with class II malocclusion.) or may be
excessive vertical overlap that does not allow sufficient space
between the anterior teeth. If more than 6mm of the

• Tip of tongue extending slightly between upper and lower
anterior teeth.
• Sounds are made closer to alveolus.
LINGUODENTAL
CONSONANT

IV. LINGUOALVEOLAR SOUNDS
 Linguoalveolar sounds are made with the valve formed by contact of
the tip of the tongue with the most anterior part of the palate (alveolus)
or the lingual side of the anterior teeth Ex: T, D (plosives),
S, Z, (fricatives), N (nasals)
 CLINICAL SIGNIFICANCE:
To determine the horizontal and vertical relations of the anterior
teeth:
Ask the patient to say /S/ and observe the relation of anterior
teeth to each other. The incisal edges of upper and lower incisors
should approach end to end, but not touch. A failure of incisal edges to
approach exactly end to end indicates a possible error in the amount of
horizontal overlap of anterior teeth.

To determine the labiolingual position of anterior teeth:
Ask the patient to say a word TEND.
If the teeth are too far lingual, the T in TEND will
sound like a D. If they are too far anterior, the D will
sound more like a T. This test will reveal the
error but will not indicate whether it is upper teeth or the lower
teeth that are incorrect labiolingually
To determine the thickness of denture base:
Any thickness in the rugae or anterior palatal region will cause
distortions in these sound production.
To determine the vertical dimension of the occlusion:
Ask the patient to say , S, C or Z and observe the distance
between the incisors. If the vertical dimension is excessive, the
dentures will actually make contact as these consonants are

10 sounds – divided into 5 types depending on distinct place and
manner of production
a) t & d ; n
LINGUOALVEOLAR

b) Fricatives s & z
Formation of a midline groove of the tongue

c) Fricatives ‘sh’ & ‘zh’
• Broader groove compared to s & z
• Can be discussed as linguopalatal

d) |ts| & |dz| linguoalveolar or palatal affricatives
 Tongue placement plosives  air exploded through constriction.

e) Lateral |l|
• Tip of tongue in contact with alveolus
• Lowered lateral margins – facilitates air flow .

V. LINGUOPALATAL SOUNDS
 Linguopalatals-Are formed by the tongue and hard palate. The
tongue may contact portion of the hard palate just posterior to the
area which is contacted while pronouncing linguoalveolar sounds
i.e, alveolus .
Ex: Sh (fricatives), Ch, J (affricatives), R (rose), Y (glides)
To determine the thickness of denture:
When Sh sound is produced the air is allowed to escape
between the tongue and the palate, and if the palate is too thick in
the region of the rugae, it may impair the production of these
consonants.
To determine the anteroposterior position of the maxillary
incisors:
If the maxillary incisors are placed too palatally then these sounds
will be distorted. www.indiandentalacademy.com

• |r| & |j| - produced by lingual approximation to some portion
of the palate.
• |r|  tip of the tongue is often pointed to an immediately post
dental area.
• Tongue blades are arched and tip points down.
• Phoneme adjacent to |r| will determine the contour of the
tongue.
LINGUOPALATAL

|j| - Linguopalatal glide
Tongue raised toward the front of hard palate but in the
course it moves to a position appropriate for articulation of
following phoneme.

VI. LINGUOVELAR SOUNDS
 Linguovelar sounds- are by tongue and soft palate. In these
sounds the air blast is checked by the base of tongue being raised
upwards and backwards to make contact with the soft palate.
Ex: K, G (plosives), H (fricative), NG (nasal)
To determine the thickness and posterior extension of
denture :
A denture which has a thick base in the post-dam area ,or that edge
finished square instead of tapering, will probably irritate the dorsum
of the tongue, impeding speech, especially causing distortion of
velar sounds.
Indirectly the phonation influences post-dam seal area, i.e, when the
velar sounds like K, H are pronounced the denture may loose its
posterior palatal seal and gets unseated, requiring the sudden
repositioning of the tongue to control and stabilize the denture , if its
posterior borders extend too back on to soft palate.www.indiandentalacademy.com

LINGUOVELAR |k|, |g| & |ng|
•Contact of the middle of the tongue with soft palate.

SS
SOUNDS AND
THEIR
PROSTHODONTIC
COSIDERATIONS

“Say now shibboleth; and he said
sibboleth, for he could not frame
to pronounce it right…..”
judges XII:6
(THE BIBLE)

“ASWATHAMAASWATHAMA
HATHAHA…..paranthu gajeshu!!!!!HATHAHA…..paranthu gajeshu!!!!!””
(KURUKSHETRA)(KURUKSHETRA)
MAHABHARATAMAHABHARATA

From a dental point of view, the S sound is the most interesting
one because its articulation is mainly influenced by the teeth
and palatal part of maxillary prosthesis. Clinical experience
suggests that S sound can cause most problems in a
prosthodontic context. Among the sounds formed in the anterior
maxillary region, the S sound is most frequently distorted ,
possibly because the S sound formation needs particularly fine
adjustments of the tongue and depends on special
neuromuscular and psychoaudative abilities. The inability to
produce sibilant sounds correctly is referred to as
SIGMATISM .
In nearly all languages of the world, S is a common speech
sound. Some languages (Ex: Finnish and Spanish) have
diverging S pronunciation, but generally the interlanguage
quality variation is small. On the other hand the inter individual
variation in teeth , palate, lower jaw, and tongue shape and size.
Given this variation, different speakers have to shape the
detailed S gestures differently to achieve a similar S quality.www.indiandentalacademy.com

CHARACTERISTICS OF /S/ SOUNDS
 The following phonetic properties or characteristics are
common to all S sounds:
ARTICULATORY CHARACTERISTICS:
The tip of the tongue is placed far forward, coming close to
but never touching the upper front incisors.
A sagittal groove is made in upper front part of the tongue,
with a small cross-sectional area.
The tongue dorsum is flat.
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 cutoff at about 3 to 4 kHz.
AUDITORY CHARACTERISTICS:
♦ The sound is fairly loud, with a light, sibilant (sharp) quality.

HOW ARE “S” SOUNDS PRODUCED?
S SOUNDS are also called SIBILANTS, which are a type of
fricative ,linguoalveolar sounds. Ex: S, Z, Sh
The S sounds are produced equally well with two different
tongue positions, but there can be some variation even behind
the alveolus.
Most people make S sound with the tip of the tongue against the
alveolus in area of 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 10mm2.
The size and shape of this small space
will determine the quality of the sound. Part of 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 sound will be developed as an
Sh sound, and its called LISP.
The frequent cause of undesired whistles with dentures is a
posterior dental arch form that is narrow
The frequent cause of lisped sound in dentures is ,the contacting of
tip of tongue with upper front teeth.

About one third of patients, make S sound with the tip of tongue
contacting the lingual side of anterior part of the lower denture
and arching against the palate to form the desired shape and
size of the airway.
The clinical significance of this way of pronouncing S
sounds is that, if the lower anterior teeth are too far back, the
tongue will be forced to arch itself up to a higher position, and
the airway will be too small.
If the lingual flange of the mandibular denture is too thick in
anterior region, the result will be a faulty S sound.
It can be corrected when the artificial teeth are placed in same
position as that occupied by natural teeth and the lingual flange
of the mandibular denture is so shaped that it does not
encroach on the tongue space.

PICTURE SHOWING THE TONGUE
AND TEETH POSITIONS IN S-SOUND
PRODUCTION

CLINICAL SIGNIFICANCE OF /S/ SOUNDS
IN PROSTHODONTICS
1. To determine the thickness of denture:
When producing the S, C, Z ,Sh sounds, if the artificial
rugae are over-pronounced, or the denture base too thick in
this area, the air channel will be obstructed and a noticeable
lisp or “slushy” S Or Sh sounds results. A whistling sound
occurs due to insufficient denture base palatal to the maxillary
incisors.
2. To determine the Vertical dimension of occlusion:
If the vertical dimension is excessive, the dentures will
actually make contact when pronouncing these consonants,
resulting in “clicking of teeth”. During the pronunciation of
the S sound, the inter-incisal separation, vertical distance,
should average 1 to 1.5 mm. This is referred to as “ closest
speaking space” (Silverman)

THE SPEAKING METHOD OF DETERMINING VERTICAL
DIMENSION :
Meyer M. Silversman (1953) Method :
• Head position
• Centric occlusion line
• Closest speaking line
Reevaluation of VD – Clicking of teeth ‘noisy teeth’.
• |m| - passive lip contact
• Strained lip contact or inability to contact lips : increase VD
No vertical overlap

3. To determine the antero-posterior postion of teeth:
If the anterior teeth are placed too far back a lisp may be
noticed with the pronunciation of S sound. A whistling sound
results if the maxillary teeth are placed too far labially..

4. To determine the width of dental arch:
If the teeth are set to arch width which is narrow, the
tongue will be cramped, thus affecting the size and shape of
the air channel ; and this will result in faulty phonation of S
sound.
5. To determine the relationship of upper teeth to the lower
anterior teeth by “S-POSITION“S-POSITION”:
The S position refers to the relation of the lower anterior
teeth to upper anterior teeth required to produce a clear S or
Z sound during speech. This is a consistent position in which
there is approximately 1 mm of space between the incisal
edges of upper and lower anterior teeth, when the S sound is
repetitively enunciated. It is also the most forward and closed
position of the lower anterior teeth in relation to the upper
anterior teeth during speech. Since teeth should not contact
during speech, this method is not only ideal for functional
positioning of the anterior teeth for complete dentures, but it is
also helpful for locating the incisal edges of maxillary or
mandibular anterior teeth for fixed or removable partial
dentures.

S-position

TO DETERMINE VERTICAL AND
HORIZONTAL RELATIONSHIPS OF
ANTERIOR TEETH USING S-SOUNDS

DIFFERENT PARTS OFDIFFERENT PARTS OF
ORAL CAVITY ANDORAL CAVITY AND
THEIR INFLUENCE ONTHEIR INFLUENCE ON
SPEECHSPEECH

LIPS:
Some patients have decreased activity of upper lip because of
inadequate support or disturbed musculature.This can affect the
bilabials and fricatives.
TONGUE:
The tongue is a principle articulator for speech and contacts
the front, middle and back portion of the hard palate in pronouncing
many of the vowels and consonants.
The size and position of the tongue are significant for development of
arch form in natural and artificial teeth.Ill fitting dentures as a result of
over or under extensions of can contribute to misarticulations by
interfering with the necessary tongue co-ordinations.
Acquired defects of tongue like macroglossia, microglossia, aglossia
etc..present insurmountable problems for prosthetic rehabilitation.

TEETH:
Anterior teeth play a very important role as principle
articulating parts for most of sounds.loss of these teeth causes
speech distortions.posterior teeth usually cause minimal or no
speech distortion.
PALATE:
The shape of palatal vault has been of particular interest
for prosthodontists.The role of palatal rugae in relation to speech
has not been established.Their characteristic soft tissue ridges are
present in all primates and there is no experimental evidence to
support their consideration as speech organ.

DIFFERENT ASPECTSDIFFERENT ASPECTS
OF COMLPETEOF COMLPETE
DENTUREDENTURE
FABRICATION ANDFABRICATION AND
THEIR INFLUENCE ONTHEIR INFLUENCE ON
SPEECH.SPEECH.

The Prosthodontist’s aim is to reproduce dentures which are
mechanically functional,aesthetically pleasing,and permit normal
speech.The most satisfactory attainment of the first two
requirements may cause slight defects in the patient’s speech
though undesirable.For this reason during fabrication of
dentures,every prosthodontist should give due considerations to
some important aspects of denture designing, as follows:
1. Denture thickness and peripheral outline
2. Vertical dimension
3. Occlusal plane
4. Anteroposterior position of the incisors
5. Post-damn area
6. Width of dental arch
7. Relationship of upper anterior and lower anterior teeth.

DENTURE THICKNESS AND PERIPHERAL OUTLINE
Loss of tone and incorrect phonation occurs due to decrease of air
volume and loss of tongue room in the oral cavity resulting from
unduly thick dentures.
The periphery of denture must not be over extended so as to
encroach upon the movable tissues,since the depth of sulci will vary
with movements of tongue,lips, and cheeks during the production of
speech sounds.Any interference with the freedom of these
movements may result in indistinct phonation,especially if the
function of lips is in any way hindered.
Sounds that are affected by changes in this region are:-----T, D, S,
Sh, Z, R, L, Ch and J
VERTICAL DIMENSION
When vertical dimension is excessive,the dentures will make
contact resulting in “clicking teeth” as some consonants like M,S,Z
are produced.

OCCLUSAL PLANE
The labiodental sounds F,V and Ph, are produced by the air stream
being stopped and explosively released when the lower lip breaks
contact with the incisal edges of upper anterior teeth.
If the occlusal plane is set too high the correct positioning of the
lower lip may be difficult, if on other hand the plane is too low, the lip
will overlap the labial surfaces of upper teeth to a great extent than
is required for normal phonation and the labiodental sounds might
be affected.
THE ANTEROPOSTERIOR POSTION OF THE INCISORS
If the upper anterior teeth are set too far palatally,the contact of
lower lip with incisal and labial surfaces will be difficult,resulting in
improper pronunciation of labiodental sounds like F,V,and Ph.
If both upper and lower anterior teeth are set to far back,some effect
may be noticed on quality of palatolingual sounds like S,C and Z
resulting in LISP,due to tongue making contact with teeth
prematurely.
The tongue will readily accommodate itself to anteroposterior error
in setting of teeth than to vertical errors.www.indiandentalacademy.com

THE POST-DAMN AREA
If the denture has a thick base in this area, or that edge finished
square instead of tapering,then there will irritation of the dorsum of
tongue, impeding speech especially when vowels like I and E, palato
linguals like K,Ng,G and C are produced.
Post-damn seal influences phonation indirectly, for if it is inadequate
the denture may become unseated during formation of sounds having
explosive effect like K,Ng, requiring the sudden repositioning of the
tongue to control and stabilize the denture.
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 air channel. This
results in faulty phonation of such consonants as T,D,S,M,N,K,C and
H, where the lateral margin of the tongue make contact with palatal
surfaces of upper posterior teeth.

RELATIONSHIP OF UPPER ANTERIOR TEETH TO
LOWER ANTERIOR TEETH
The abnormal protrusive and retrusive jaw relations will effect the S
sound predominantly, as S sound requires near contact of upper
and lower incisors, so that the air stream is allowed to escape
through slight opening between teeth.

SPEECH TESTSSPEECH TESTS

 The phonetic aspect of complete denture construction deserves
equal consideration with esthetics and mechanics and should be
checked at the time of waxed denture try-in, when it is possible to
alter the palatal contour to accommodate speech articulation. The
speech test should be made after satisfactory esthetics, correct
centric relation, proper vertical dimension and balanced occlusion
have been attained and after wax up for esthetics has been
completed.
TEST 1:TEST OF RANDOM SPEECH
Engagae the patient in a conversation and obtaining a subjective
speech analysis by asking the patient say hoe he feels,how his
speech sounds to him and what words seem most duifficult to
pronounce.
TEST 2: TEST OF SPECIFIC SPEECH SOUNDS
This is best accomlpished by having the patient say 6-8 words
containing the sound and then combining these words into a
sentence.The following is the list of sounds to be testedwww.indiandentalacademy.com

S,Sh Six, sixty, ships, sailed
Mississippi, sure ,sign, sun,
shine
Sixty six ships sailed
Mississippi. Sure sign of
sun shine
T,D,N,L Locator, located, tornado,
near, Toledo
Locator located tornado
near Toledo
Ch,J Joe, Joyce, joined, George,
Charles, church
Joe and Joyce joined
George and Charles at
church
K Committee, convented,
political, convention,
Connecticut
The committee convented
at the political convention
in connecticut.
F,V Vivacious, Vivian, lived, five,
fifty, five, fifth, avenue
Vivacious Vivian lived at
five fifty-five fifth avenue

TEST 3: TEST OF READING A PARAGRAPH
Make the patient read a paragaraph containing abundance of S,
Sh, Ch sounds.

SPEECH ANALYSISSPEECH ANALYSIS

 A number of methods are vailable for speech analysis.They are
basically two categories.
1. PERCEPTUAL/ACOUSTIC ANALYSIS
2. KINEMATIC METHODS OF MOVEMENT ANALYSIS
 WHY DO WE REQUIRE SPEECH ANALYSIS?
 When apatient presents with speech pathology
problems, their clarity and pronunciation should preferably
analyzed by a speech pathologist. So it would be valuable to to
speech analysis before starting prosthodontic treatment,just to
establish a basis for future comparison and if possible identify
problems.

 PERCEPTUAL/ACOUSTIC ANALYSIS
This analysis is based on a broadband spectrogram
recorded by a sonograph during the uttering of different phases
containing key phrases. By doing this objective opinion of certain
sounds may be achieved.
 KINEMATIC METHODS OF MOVEMENT ANALYSIS
 X-ray mapping
 Cineradiography
 Optoelectronic articulatory movement tracking
 Electropalatography

With the use of spectral analysis, a sound event can be split into 3
dimensions: frequency, amplitude, and chronologic sequence.
The data obtained can be visualized as a 2- dimensional Cartesian
coordinates with the color or grey shade as the third dimension
and this is called a spectrum graph or sonogram.
A direct 3- dimensional profile representation that is obtained on a
computer screen is called spectrogram.
BROADBAND SPECTRAL ANALYSIS

A PICTURE SHOWING A SPECTRUM
GRAPH OR A SONOGRAM

PICTURE OF A SPECTROGRAM
(3 DIMENSIONAL VIEW)

PALATOGRAMS
 To study the normal contact for tongue in pronouncing the various
phonemes
 HOW TO OBTAIN A PALTOGRAM????
A uniformly thin artificial plate of methyl metjacrylate resin is made
for each subject. The plate is positioned in place,the subject is made
to practice some speech sounds until they are clearly pronounced.
Trial test is made by having the subject pronounce a given sound
and open his mouth without again contacting the palate with his
tongue. The plate is then removed, thoroughly dried, dusted with
non-scented talcum powder and carefully inserted in the mouth. The
subject is asked to carefully pronounce the previously practiced
sound and then the plate is carefully removed and examined.

 The moist tongue removes the powder from the area of contact
leaving a clear tracing (palatogram) on the artificial palate. After a
short period this area dries and the tracing becomes obscure.
 In order to preserve the palatogram for future study, the contacted
area is outlined with glass marking pencil immediately after the
palate is removed from the mouth.
 For edentulous patients, the outlined area is waxed and contoured,
redusted and another palatogram is made on same trial base. The
procedure is repeated until a normal tongue-palatal contact is
established to improve the phonetics.

Palatograms :
• Leslie Allen (1958)
• No two individuals contacted exactly the same area –
similarity to constitute a pattern.
• S and SH – individual similarity and distinct pattern.
Study of vowels :
• Tongue – palatal contact for all except with |O|
• Phone |e| occurs singly
• U = (ee – oo) i = (i – ee)www.indiandentalacademy.com

Palatograms for consonants :
• Occurs in consort with vowels
Eg: t or d  occlusive articulation  e
a follows j & k.
e precedes s, n and l.
• Isolation of consonants on palatograms
 Consonant produced initially  vowel
 Consonant + O = may not be a standard English word.

Sequence of palatograms :
1. s & sh palatograms are made
sh line – guide for waxing posterior alveolar area
s line – anterior alveolar area
• Formation of groove
• Whistling or hiss – larger goove
• Lisp (th for s) or indistinct ‘s’ – inadequate groove
• Sears – creation of groove
2. Palatograms for plosives (t, d) are made
3. Palatograms for ch & j are made
• Midanterior alveolar wax up may flow on palate bit
posteriorly.

ELECTROPALATOGRAPHY
EPG is used for registration of tongue contact patterns during
speech production.
The equipment consists of 60-80 electrodes inserted into an
individually made acrylic plate,covering the are fron front teeth to the
soft palate.The electrodes react when the tongue is in contact with
the palate.In this way ,untouched and touched electrodes can be
recoreded at high frequency and mapping achieved of tongue
pattern.
This method enables the diagnosis of some speech
disturbances,but must be combined with other methods to achieve
an exhaustive analysis

ELECTROPALATOGRAPHY

SPEECH DEFECTSSPEECH DEFECTS

TERMINLOGY RELATED TO SOME SPEECH
DISTURBANCES
APHASIA (DYSPHASIA): Means defective speech due to
damage of cortical area required for speech making. (Broca’s area,
Wernicke’s area). Commonly this is due to thrombosis of feeding
artery to the region affected. .
DYSARTHRIA: Motor speech problems caused not due to
sensory loss or mental retardation.
DYSLALIA: An articulatory problem without apparent neurologic
basis.
SPEECH AND LANGUAGE RETARDATION: Delay in
acquistion of communicating skills.

DISORDERS OF SPEECH
Hypernasality
(Rhinolalia aperta)
Hyponasality
(Rhinolalia clausa)
Denasality
Eg: m, n & ng
↓ ↓ ↓
b d g
Morning  bordig
NASAL BALANCE

 Replacement of intended oral consonants formed farther
down the vocal tract.
 To prevent adverse effect of defective articulator.
Distortion
Eg: Vowel  pop for pipe
Consonants  cah for car
DISORDERS OF ARTICULATION
Substitution
Eg: teef for teeth Omission
Eg: bow for boat

TESTING FOR NASAL BALANCE
• Vowels = resonated sound + little air flow.
• ee and oo  hypernasality
• |m|  hyponasality
• Undue nasal bridge vibration.
• Alternate occlusion and opening of nostrils
• Nasal emission of air with voiceless consonants

TEST FOR ARTICULATION:
• Recording of abnormal sounds
Phonetic symbols on paper or electronically on tape, disc or
spectrogram.
• Talking when nostrils open or closed.
• Wrinkles on nasal alae.
• Abnormal tongue movement – palatal defect
Eg: ‘n’ in banana.

RELATION TO MAXILLOFACIAL DEFECTS
Acquired
• Accidental or surgical
• Nervous system –
cerebral palsy, lateral
sclerosis, poliomyelitis,
myasthenia gravis,
myotonic dystrophy
• Functional
• Atypical articulation
Urban speech
nasal snort
Congenital
Cleft palate,
Short palate,
Large velopharyngeal space,
Limited velar mobility,
Submucous cleft palate

•Correction of palatal defect itself
•Goal
•Fistual / hole – flanged acrylic button
•Vellar defects – palatal lift
Prosthesis
Device
CORRECTING DISORDERS OF SPEECH IN
CLEFT PALATE CASES
Prosthodontist Surgeon
Substitution

PALATAL DEFCTS AND OBTURATOR

CORRECTING SPEECH DEFECTS RELATED
TO IMPLANT PROSTHESIS
A fully bone anchored prosthesis in maxilla can cause phonetic
problems, due to the space between the prosthesis and residual
ridge.
Normal pronunciation is possible after approximately 3 months, but
can take as long as one year for speech recovery.
To correct this errors in speech, removable appliances like artificial
gingival extensions made of silicones or resin materials should be
given to close the gaps and also for esthetic purposes.

IMPLANT PROSTHESIS

SPECIALSPECIAL
CONSIDERATIONS OFCONSIDERATIONS OF
PHONETICSPHONETICS

TOTAL LARYNGECTOMY :
Rehabilitated by 
• Training in oesophageal speech.
• Using electric artificial larynx
• Asai technique
 Epithelial lined tube
 Excellent sound quality
 Aspiration of saliva and food

Labio dental – f & v
Bilabial closure
S, Z, L
‘th’ in |θ | | δ |
COSMETIC MODIFICATION OF
ORAL CAVITY

PHONETIC TECHNIQUE OF BORDER MOLDING
OF NEUTRAL ZONE IMPRESSION FOR
MANDIBLE
JOSEPH EM et al, utilized both swallowing and phonetic techniques
for making mandibular impression. Border molding of phonetic
neutral zone was done using a tissue conditioning material mixed in
1:1 ratio.
The subject was asked to pronounce phoneme “SIS” 5 times
followed by phoneme “so” once. These phonemes were used for
molding the lateral segments of the tray. For the molding the
anterior segment the subject was asked to pronounce successively
the phonemes “DE”, “TE”, “ME”, “PE”, “SE” vigorously. The
denture fabricated using this technique was narrower in the
posterior region as compared to that of swallowing technique.

Involuntary, ceases on waking.
Vibration on inspiration.
Mouth breathing
Sleeping on back
No definite modality
Obstruction
Resistance to respiration
↓ Pulmonary ventilation
Anoxia ( ↑ Co2)
↑ Tone of breathing
Vibration of soft palate
Robin (1968) Adenoids & tonsils
Allergy, DNS,
Collapsed alae nasi
SNORING

•REVIEW OFREVIEW OF
LITERATURELITERATURE

SIMON CLARENCE, discusses the relation of oral structures and
speech. He states that although teeth are passive, they play an
important role in speech. They serve as barriers to exhaled
current of air and thus set up eddies in air stream which are
interpreted as intelligible speech. If there are edentulous spaces in
the anterior region, or if anterior teeth are irregular , the tongue
cannot regulate the degree of closure, and sound substitution
results and due to this labiodental and interdental fricatives as well
as fricatives are most commonly affected.
ETTORE SEBASTIAN states that although teeth are important
factors in articulation, their presence is not essential for articulate
speech because almost all sounds can be formed by edentulous
patients.
RITCHIE AND ARIFFIN reported speech defects caused by
different incisor positions in maxillary incisors irrespective of the
shape of palatal vault and found that a displacement of maxillary
incisors in labial direction was most likely to cause speech problemswww.indiandentalacademy.com

SAIZER PEDRO AND TENCH , sates that excessively high lower
denture not only causes functional and esthetic difficulties but also
gives rise to impaired speech production. If the teeth are placed
high in lower dentures, the upper half of anterior 3rd
of tongue does
not function well above the lower denture when the patient speaks.
They are of the opinion that mandibular dentures should not occupy
more than one half of the space existing between the edentulous
ridges.
SAIZER PEDRO studied the effect of lower dentures on speech and
states that widening of lower arch improves defective pronunciation,
when there is less tongue space due to constricted palatal arch

KESSLER states that if position of artificial teeth do not deviate
too much from those of natural teeth, compensation of minor
abnormal speech habits (that have already been established due to
long periods of edentulism and old age) will occur in most patients.
He also reported that occasionally, stippling
and carving give rise to frictional interferences with free movements
of the upper lip during speech, resulting in distortion of speech
sounds.
He also states that reproduction of rugae in
artificial acrylic dentures makes the denture base too thick in the
region just lingual to the anterior region. This leads to phonetic
difficulties, particularly in production of T and D sounds.Thinner and
more accurately contoured rugae in metal dentures seem to be
better in this respect

.
ROTHMAN states that if dentures are correct phonetically for the
consonants, the vowel sounds generally present no trouble at all.
WEPMAN states that prolonged edentulous periods may cause
changes in the position of the arches formed by the anterior faucial
pillars. This may result in change in the resonance after teeth are
restored.
SAGGERS recognizes the importance of making thin dentures as
these do not in any way hinder the free movement of the tongue. He
states that arch formations encroaching on space normally occupied
by tongue will cause faulty articulation.

ROTHMAN pointed that tongue contacts a specific part of the
teeth, alveolar ridge, or hard palate during the production of each
consonant. As these structures are covered or replaced by
denture, an appropriate restoration is necessary for undisturbed
sound production. Disturbed pronunciation may result as direct
influence of artificial teeth and palate on air flow but also may be
caused by a different tongue position or movement.
TANAKA, found that artificial palatal vaults of maxillary dentures
often have a concave shape. In contrast natural palatal vaults
are convex shape in alveolar region. He concluded that palatal
vaults of maxillary dentures should be shaped like natural ones
to facilitate correct pronunciation. He also reported that quality
of speech sound production improved with in the first week of
insertion of new denture

MARTONE, in a series of articles reviewed the physiology of
speech and, subsequently, discussed which defects might
occur. These defects may be attributable not only to the
dentures but also to ill health or age changes. Defects in
pronunciation may occur because of loss of lip support, errors in
tooth positioning, tongue spread, increased facial height, or the
patients inability to exert fine control over the soft tissues.
ROTHMAN reported that, because speech is an essential
human activity, phonetics must be considered one of the
cardinal factors contributing to the success of complete
dentures. To use speech as part of a complete denture
fabrication technique, he examined palatograms to determine
where oral contacts occurred in an attempt to prescribe an
appropriate denture design.
VINCOFF employing palatogram studies on a group of persons
who had their natural teeth and normal speech, found that the
palatograms made for T,D,N and L are not distinguishable frl
one another.

BENEDIKTSSON stated that during normal /S/ sound
production, the sides of tongue are against the alveolar ridges
and gingival margin areas of the maxillary teeth and that the
middle of the tongue is lowered to create a groove. At the same
time, the tip of tongue contacts the palatal surfaces of the
maxillary teeth or alveolar ridge.
HAMMOND et al, reported that speech sounds like /S/, /Sh/,
/Th/, and /T/ were most affected sounds by an increase or
decrease in VDO.
BANKSON AND BYRNE, who examined the effect of missing
incisors on the consonant phonation of children, and reported
that among the examined consonants, only S sound was
affected.
HEYNICK et al, found that 28(21%) of 131 denture wearing
individuals from elderly Dutch population had speech problems,
especially in the pronunciation of S sound among the sounds
formed in the anterior maxillary region, because S sound
production requires particularly fine adjustments of the tongue
and neuromuscular abilities, which are decreased in old age .www.indiandentalacademy.com

CHRISTOPH RUNTE et al studied the influence of maxillary central
incisor position in complete dentures on S sound production and
concluded that the labial angulation seemed to have greater effect
on palatal angulation.
HEYDECKE G, Mc FARLAND DH, et al conducted a study with
maxillary implant prosthesis. They concluded that maxillary implant
overdentures with and without palates enable patients to produce
more intelligible speech than fixed prosthesis.
LUNDQUIST et al reported that the gap between mucosa and fixed
prosthesis is thought to be major cause of speech errors and this
gap can be closed by removable appliances, but these usually cover
the palate that may interfere with speech.
BAWN , Mc FARLAND et al said that when palate of dentate
object is covered experimentally, the articulation of consonants is
often abnormal even after prolonged periods of adaptation.

DAWN EILEEN in reviewing oral anomalies and speech defects,
writes that organic causes of speech defects, include any diseases
or injury of the larynx that results in vocal distorttion, abnormal
conditions of nasopharyngeal tract, anatomic defects such cleft lip,
tongue tie, abnormal uvula and abnormal conditions of jaw. Other
speech defects are cased by neurologic disorders, chorea and
muscle spasms and endocrine disturbances.

CONCLUSIONCONCLUSION

The specific relation between dentistry and
speech pathology is still emerging. As orodental
morphological features influence an individuals
speech, the dentist should recognize the role of
prosthetic treatment on speech activity. Thus the
treatment objective of every dentist should be to
make dentures which are not only mechanically
functional, esthetically pleasing, but also
phonetically accurate.

REFERENCES
Zarb-Bolender, Boucher’s text book of prosthodontic
treatment for edentulous patients,complete dentures and
implant-supported prosthesis, edn 11th
,St. Louis: Mosby
2004.
Sharry’s text book of complete denture prosthdontics,ed
2nd
,McGraw-Hill ,Inc. 1968
H.B.R.Fenn’s text book of clinical dental prosthetics,2nd
edn,
Sheldon Winkler’s, Essentials of complete denture
prosthodontics,2nd
edn, Ishiyaku Euro America
publishers,Inc.2000

Charles M.Heartwell,Arthur O .Rahn, Syllabus of
complete dentures,4 th edn,Verghese publishing
house,1992
William R Laney, Joseph A Gibilisco, Diagnosis and
treatment in prosthodontics,1st
edn,1983
Guyton, Hall ,Textbook of medical physiology.10th
edn
Timothy s Miles, Brigette Nauntofte, Peter svenson,
Clinical oral physiology

Allen .R , Improved phonetics in denture construction,
JPD 1958;8;753-763.
J.F. McCord, H.J. Firestone, A.A. G rant. Phonetic
determinants of tooth placement in complete dentures.
Q.I 1994;25(5);341-345
John M. Palmer, Structural changes for speech
improvement on complete upper denture fabrication.
JPD-May 1979,volume 41(5);507-510
Meyer M. Silverman, a classic article on The speaking
method in vertical dimension,JPD,85(5); May 2001
Christoph Runte, Spectral analysis of S sound with
changing angulation of maxillary central incisors, IJP
2002;15;254-258.

George A. Murrel, Phonetics,function, and anterior
occlusion;JPD – july,1974;23-31
Earl pound, Utlizing speech to simplify a personalized
denture service; JPD ,24(6);Dec,1970;586-600
Tanaka H, speech patterns of edentulous patient’s and
morphology of the palate in relation to phonetics. JPD
1973,29;16-28.

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