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2. 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
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3. Phonetics – The science of sounds used in
speech.
Phonetic value – The character or quality of
vocal cords
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6. 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.
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7. 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
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8. 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.
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9. ENGLISH CONSONANTS
THEIR POSITION AND MODE OF PRODUCTION
The production of English consonants and involve
six valves below:
Bilabial
2. Labiodental
3. Linguodental
4. Lingeoalveolar
5. Linguopalatal
6. Linguovelar
Out of the above six valves five valves are affected
by teeth position
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10. 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.
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11. Labio-dental Sounds: - The labio-dental 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. www.indiandentalacademy.com
12. 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,
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13. 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.
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14. 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 labio-lingual
position of the anterior teeth.www.indiandentalacademy.com
15. 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.
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16. 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
17. 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.
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19. 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.
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20. 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.www.indiandentalacademy.com
21. 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.
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22. 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.
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24. 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.
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25. 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 squareedged.
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26. 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 overextended 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.
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27. 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.
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28. 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..
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.
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29. 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.
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30. 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.
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31. 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.
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32. 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
33. 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.
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35. 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.
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36. 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.
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37. 1.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.
2.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’.
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38. 3.Height of the anterior teeth and thus the
occlusal plane – using ‘f’ , ‘v’
4.Overjet – by using the ‘s’ sound
5.Labiolingual position of the lower anteriors – ‘s’
6.Thickness of the anterior region of the palate - ‘t’
7.Thickness of the postdam – ‘g’
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39. 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
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