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Speech considerations for cd/prosthodontic courses


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Speech considerations for cd/prosthodontic courses

  2. 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
  3. 3. Phonetics – The science of sounds used in speech. Phonetic value – The character or quality of vocal cords
  4. 4. COMPONENTS OF SPEECH Respiration Phonation Resonations Articulations Neurologic Integrations Audition
  5. 5. surd sonants Consonants Speech
  6. 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.
  7. 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
  8. 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.
  9. 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
  10. 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.
  11. 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.
  12. 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,
  13. 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.
  14. 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
  15. 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.
  16. 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
  17. 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.
  18. 18. Sh’ sound
  19. 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.
  20. 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
  21. 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.
  22. 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.
  24. 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.
  25. 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.
  26. 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.
  27. 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.
  28. 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.
  29. 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.
  30. 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.
  31. 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.
  32. 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.
  33. 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.
  34. 34.
  35. 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.
  36. 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.
  37. 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’.
  38. 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’
  39. 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
  40. 40.