Phonetics in complete dentures./ dentistry course in india

Phonetics in complete dentures.

INDIAN DENTAL ACADEMY

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Table of contents.

• Introduction• Review of literature.• Speech production.• Phonemics


• Factors in denture affecting speech

-position of teeth.-denture thickness.-Occlusal plane.-Vertical dimension.-width of the dental arch.


• Use of phonetics in denture construction.

• Speech tests.• Summary • Conclusion• references.


Introduction.Speech is a very sophisticated,

autonomous and unconscious activity. Its production involves neural, muscular, mechanical, aerodynamic, acoustic and auditory factors.


Because orodental morphological features also may influence an individuals speech, the dentist should recognize the possible role of prosthetic treatment on speech activity.


The oromotor functions, such as mastication and speech are interrelated because the mouth , lower jaw, lips, teeth and tongue are used for both the activities. Any alterations in these structures will inevitebly mediate a disturbance in the system.


Articulatory deficits may be generally classified into three categories: omission of a phoneme, substitutions and distortions. Distortions is most usual consequence after the prosthodontic treatment.


• What is Phonetics?• Phonetics is the study of the

articulatory and acoustic properties of the sounds of human language.


Review of literature.


Leslie R. Allen etal., Improved phonetics in complete dentures.

JPD1958;8(5)573-83.

The article describes that the labio-dental sounds are recommended for arriving at the proper arrangement of the anterior teeth , and vertical dimension for s pronunciation.


Phonetics can be improved by contouring the entire palatal surface of the maxillary denture to simulate the natural palate.

.


• It was found that good results can be obtained by thickening the areas necessary to produce normal tongue contact without meticulous carving and contouring


Edward J. Mehringer. The use of speech patterns as an aid in

Prosthodontic reconstruction. JPD1963;13(5):825-35).

.


The purpose of this article was ;To show how the speech patterns

develop physiologically .To illustrate graphically the basic

formats established by neuromuscular patterns in articular speech


To show how the speech patterns can be utilized under functional conditions fit record making purpose.


The author says that the integration of the artificial teeth to the functional movements take precedence over the fit of the denture base to its foundation.

When teeth donot conform to these functional patterns, the fit of the base cannot endure.


Meyer M. Silverman The whistle and swiss sound in denture

patients. JPD 1967;17(2):144-48.


• The article describes the causes of certain abnormal sounds , such as whistle and swish sounds, that occur in the speech of the patients wearing fixed and removable restorations involving the anterior teeth.


• Ideally, the artificial teeth should be located in the same position as the natural teeth they replace for proper phonetics.


Joseph G. Agnello etal., A study of phonetics in edentulous patients

following complete denture treatment

• JPD 1972;27(2):133-39.


• The aim of this study was to asses the speech changes in complete denture patients

1. In the edentulous state .2. Immediately following denture

insertion3. Two weeks following insertion of

dentures4. Twelve weeks following the insertion

of dentures.www.indiandentalacademy.com

• They concluded that words spoken in the edentulous state were paired with words spoken in the different stages of denture wear.

• Analysis revealed that the s, sh, t showed improvement .

• The voiced th sound did not show any general improvement.


Earl Pound; Utilizing speech to simplify a personalized denture

service .• JPD 1970;24(6):586-600.


• A fresh approach toward the solution of many of the debatable problems in complete denture construction consists of simple recording, as guided by muscle memory, the extent of the downward and forward mandibular movements made during speech.


• This automatically restores the patients original horizontal and vertical overlaps which can be used to control the factors of occlusion.


• The values derived by progressive function refinement of this information, through the controlled use of diagnostic treatment dentures incorporating tissue treatment material, and free occlusal scheme.


George A. Murrell. The problems of functional conflicts between

anterior teeth.• JPD1972;27(6):591-99.


• Phonetic positioning of the anterior teeth usually produces a natural, esthetic tooth arrangement and provides occlusal clearence during the function of speech with complete dentures.


• Natural tooth positioning, however, frequently results in increased horizontal and vertical overlaps which magnify the possibility of functional conflicts in anterior teeth.


Interferences in speech can be avoided during denture construction, but those of mastication and swallowing must be corrected after the dentures are constructed.


Hisatoshi Tanaka. Speech patterns of edentulous patients and morphology

of the palate in relation to the phonetics.

• JPD1973:29(1):16-28.


• The purpose of this study was to investigate

1. Changes in the speech patterns of patients with new complete dentures before and various times after insertion of the new dentures.

2. The relationship between the speech and the palatal contours of the denture.


• On the basis of analysis of the data collected ,the following conclusions were made:

1.Most of the patients made speech improvement when the dentures were first inserted.


2.With increased length of time of wearing the dentures, the speech intelligibility was improved.

3.The speech of the patients can be improved by experience with their new dentures.


4.Individual sounds showed different levels of speech intelligibility, and this level improves with the length of the denture usage.

5.Acoustic distortions occurred more frequently In the s, sh, ch, zh, and j sounds than in z, t, n, d, and l sounds.


6.The s sound is a poor prognostic sound for intelligibility of speech.

7.The palatal ridge formation (palatal contour) of the complete dentures will affect the acoustic distortion of the affricative and the fricative sounds.


Carl A. Hansen . Phonetic considerations of the chromium

alloy plates in complete dentures.

• JPD 1975; 34(6);620-24.


• The author says that there is valid indications for the use of chromium alloy plates,

• The contour of the entire palatal surface must, however be considered for optimum phonetics.

• Both resins and metal must be related to each other


in an intelligent manner to insure precise contours, minimum weight, and maximum strenght.

• Two approaches to these techniques will be described.


Earl Pound. Let /s/ be your guide.

• JPD 1977;38(5):482-89.


• This article reviews the new guidelines for establishing the vertical dimension of occlusion .


• They are based on the fact that the body of the mandible assumes an easily recordable , repetitive horizontal and vertical position when the patient is at /s/ position during speech.


• This controlled method of developing vertical dimension correlates the posterior speaking space with the placement of upper and lower anterior teeth when set to phonetic standard.


• This permits the development of a dependable vertical dimension of occlusion for most patients and also serves as a guide for the more difficult to treat classII and tongue – thrusting patients.


Bal k. Goyal etal.,. Functional contouring of the palatal vault for improving speech with complete

dentures • JPD1982;48(5):640-46.


• According to the study :• The slight bulging of the denture

base palatal to the anterior teeth probably helps in improved pronunciation of /s/ and /sh/ sounds .


• Earl Pound; Utilizing speech to simplify a personalized denture service .


• Also suggest that placing the non-anatomic papilla somewhat posterior to the incisive papilla location provides tactile sensation location.

• The s curve in the molar area is important for proper enunciation of the sounds.www.indiandentalacademy.com

Emily A. Tobey. Active versus passive adaptation: an acoustic study of vowels produced with and without dentures. • JPD1983;49(3):314-20.


• Data from this study indicate the close examination of vowels , as well as consonants , assists in delinating active articulatory versus passive acoustic changes to orofacial reconstruction.

• Data from the study reveal that consonants and vowels are influenced by the prostheses.


• Moreover, the data suggest that adjusting prostheses by listening for changes in the consonant sounds may change only the passive acoustic characteristics of the prostheses and may not necessarily influence active accommodation by the patient.


Ronald J. Hammond. Increased vertical dimension and speech

articulation errors.• JPD1984;52(3):401-6.


• The study evaluates the effects of speech articulation of increasing the vertical dimension of occlusion.

• This study indicates that gross articulatory adaptation to increased vertical dimension occurs within 4-6 days and that thereafter adaptation is a matter of refinement and fine adjustment.


J. FMcCord Phonetic determinants of tooth placement in complete

denturesQuintessence Int 1994;25:341-45.


• The provision of complete dentures requires that dentist, technician and the patient adequately fulfill their respective roles in provision and adaptation to, these dentures.


• An increasing number of replacement of the dentures are being prescribed for older patients.


• Thus , the need to utilize functional factors to determine tooth placement is reviewed.

• This review demonstrates demonstrate the overall relationship between speech and denture construction.


Christina A. Gitto. A simple method of adding palatal rugae to complete

dentures.• JPD1999;81:237-9.


• Restoring patient’s speech is an important goal in complete denture fabrication.

• For those patients who have difficulty with their speech patterns accommodating to the introduction of the a prosthesis, texture in the palatal region may prove helpful.

.www.indiandentalacademy.com

• Article describes method of incorporating palatal rugae in newly fabricated and existing dentures.


Ederhard Seifert etal.,. Can dental prosthesis influence vocal

parameters?• JPD1999:81:579-85.


• This study evaluated the effects of changes on phonation by varying the dentures of 20 subjects in line with those of the first patient.


• They concluded that variation of thickness and or volume of dentures and of the vertical and horizontal dimensions of occlusion may result in unpredictable audible changes to the voice.


Christoph runte.The influence of maxillary central incisor position in

complete dentures on /s/ sound production.

• JPD2001:85:485-95.


• The study investigated the effect of different maxillary central incisor position on phonetic patterns.


• They concluded that immediate phonetic adaptation of prosthetic restorations in the maxillary incisor region can be achieved only if the original position of the natural teeth is transferred to the dentures.


• Although these misarticulations are likely to disappear in many cases within few weeks ,they may persists and even lead to psychological problems.


R.C Matheus rodrigues .effect of new dentures on inter occlusal

distance during speech.• Int J Prosthodont2003;16:533-37.


• The study investigated the changes in the interocclusal distance during pronunciation of /m/ and /s/ sounds.


• They concluded that insertion of new dentures , with the vertical dimension corrected ,changes interocclusal distance of speech during phonation of /m/ and /s/ sounds.


Speech production.

Any vibrating body will make sound and 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 vibrators for the voice are the vocal folds in the larynx.


Controlled airstem that is initiated in the lungs and passes through the larynx and the vocal cords produces all speech sounds.

Speech sounds need more air than quite exhalation.



http://www.ic.arizona.edu/~lsp/


• The larynx contains folds of muscle called the vocal folds (sometimes called vocal cords).


http://www.ic.arizona.edu/~lsp/

• Sounds that are produced with relaxed vocal folds are known as voiceless sounds, and sounds that are produced with tensed vocal folds are known as voiced sounds. If the folds are only partially closed, a whispered sound is produced.


• The adjustments in the airflow contribute to the variations in pitch and intensity of the speech sounds.

Structural controls for speech sounds are: the valves in the pharynx and the oral and nasal cavities.


• Nearly all sounds are emitted from the mouth.

• The nasopharynx is closed off from oropharynx during speech.

• This closure is done by upward closure of the soft palate.


• As the air passes through the mouth the tongue ,lips and mandibular oscillations modify it.

• The tongue has a critical impact on the speech production.



http://www.ic.arizona.edu/~lsp/Phonetics/Phonetics1c.html

• Jaw and tooth relationships enable the tongue to articulate against the maxillary teeth or the alveolus ,permit the maxillary teeth and the lips to make easy contact and allow lips to contact to produce speech.


Neurophysiologic background

• A complex and imperfectly understood mechanism governs the speech.

• A large no of oral mechanosensitive receptors are involved in motor control.


• Therefore all prosthodontic treatment will have an influence on speech performance because a great no of these structures will be involved.


• It has been hypothetised that less cortex area is required processing skills once they become automatised.


• A prerequisite to satisfactory speech sounds and adaptation is intact general feedback system that is orosensory and auditory feedback.


• Gradual hearing loss could be present in older ages and the process of adaptation to the dental prosthesis could be impaired.


• Adaptation to the complete dentures is by feedback mechanism to speech motor programming.


How does dental treatment affects speech?

• Since most of the articulations takes place in the oral cavity, any alterations of these structures will affect speech.


• For ex:• a missing bicuspid• Missing anterior teeth.• Gross removal of the gingival tissue.• Mechanical movement of the teeth in

the maxillary arch.


• high % of sounds are produced by contact of the tongue with some portion of the palate and the teeth . Since these areas are covered or replaced by the CD speech rehabilitation becomes onerous task to the prosthodontist.


Phonemics.

• Articulation is usually considered to be joining of the parts.

• Speech articulation takes place when any approximation or movement of the articulators constricts or diverts the airstem to produce single sound.


• The single sounds that are produced are innumerable.

• Many cccur as noise and are unclassified.

• But those which are learned as speech are called phones.


• The closely related phones have been combined to form recognizable sounds and are called phonemes.


• The phoneme, then is a unit of speech by which we can distinguish one utterence from another and which collectively make up phonemics of language.

• Study of these phonemics is known as phonetics.


Classification of speech.

Since speech production can be used as a guide for the arrangement of the teeth, it is necessary to be familiar with the different types of speech sounds.


Speech sound can be classified as

• Surds• Sonants• consonants.


• Surds : these are any voiceless sound produced by separation of the vocal cords with no marginal vibration.


• Example:• The initial h sound as in huh.• Voiceless sibiliants s, sh, zh

produced initially.


Sonants: these are voiced sounds that include all vowels and vowel-like sounds.

They require minimum articulation and are classified according to tongue position and position of the lips.


• consonants: are produced as a result of airstem being impeded, diverted, or interrupted before its release.

• Ex: p, g, m, b, s, t, r, z.


• Consonants also are divided into groups, depending on their characteristic production and use of different articulators and valves.


• Plosive consonants: produced when an overpressure of air has been built up by contact between the soft palate and the pharyngeal wall and released in an explosive way.

• Ex: p and t.www.indiandentalacademy.com


• Fricative consonants: also called sibilants and are charecterised by their sharp and whistling sound quality created when air is squeezed through the nearly obstructed articulators.

• Ex: s and z.



• Affricate consonants: are produced by combination of stops and friction, accomplished by articulation of tongue and anterior hard palate.

• Ex: j and ch.



• Nasal consonants: produced without oral exit of air.

• Ex: n and m.



• Liquid consonants: they are produced with friction.

• Ex: r


• Glides: sounds characterized by gradually changing articulator shape.


• Depending on the contacts made by the lips and tongue on the teeth and the palate the sounds are classified as :

• Bilabial sounds: b, p, m.• Labiodental sounds: f, v.• Linguo dental sounds: th in this.• Linguoalveolar sounds: t, d, s, z, l.• Linguopalatal sounds: year, she,

vision.www.indiandentalacademy.com

Phonetic changes in edentulous patients following complete denture

treatment.• JPD1972;27(2):133-39.


The absence of teeth creates difficulties in speech sounds.

Some patients donot exhibit any speech problems, because it appears that the tongue makes compensatory adjustments for the absence of the sounds.


• Allen (1958) says that a patient fitted with complete dentures generally adjusts to the speech pattern to the appliance and thus improves.


• Kaires(1957) and Sovijarvi(1962) reported that in the absence of dentures, the concentration of the higher frequencies in the overall acoustic spectrum of speech was reduced.


• Angello and Wictorin (1972) they made a study to asses speech changes in edentulous state and following insertion of dentures.

• They concluded that /s/ /sh/ /t/ sounds showed improvement.


Factors in denture design affecting speech.

• Keuebeker (1984) investigated speech problems that occurred after fitting the dentures and listed following causes.

1.Incorrectly positioned anterior teeth.2.Vertical dimension.3.Occlusal plane


4.width of the dental arch.5.Relationship of the upper and

lower anterior teeth 6.Denture thickness.7.Postdam area.


Tooth positions.

Tooth positions are sometimes critical to the production of certain sounds and not at all for others.


Because the teeth are arranged for esthetics, it is not only the speech sound itself that is critical but rather the interrelationship of the tongue ,lips, teeth and denture base.


• Bilabial sounds: they are made by the contact of the lips. b, p,m.

• Insufficient support of the by the teeth can cause these sounds defective.

• Therefore anterioposterior positioning of the anterior teeth can effect production of these sounds.



• Labiodental sounds: these are f,v sounds made between the upper incisors and the labiolingual center to the posterior third of lower lip.


• If the upper anterior teeth are set too short (set too high) the v sound will be more life an f.

• If they are set too long (set too far long) f will sound more like v.



• If the teeth touch labial side of the lower lip when these sounds are made the upper teeth are too forward.

• If the teeth are set too far back in the mouth they will contact the lingual side of the lower lip.


• Linguodental sounds: these are made with the tip of the tongue extending slightly between the upper and lower teeth.

• If 3mm of the tongue tip is not visible then the teeth are probably too forward.


• Or there may be excessive overlap that does not allow the tongue to protrude.

• If more than 6mm of tongue extends out the teeth are set too lingually.


• Linguoalveolar sounds: are made with the tip of the tongue with most anterior part of the palate.

• Ex: t, d, s, z, l


• The important observation is when these sounds are produced in relation to the upper and lower anterior teeth.

• The upper and lower incisor should approach each other but not touch.



The influence of maxillary central incisor position in complete

dentures on /s/ sound production.

• (JPD 2001;85:485-95)


Acc to this study the change in the inclination angle of the central incisors in a range of -30deg to +30deg caused poor execution of /s/ sounds .

The labial angulation seemed to have greater effect than the palatal angulation.



The whistle and Swiss sound in denture patients.

• JPD 1967;17(2):144-48.

The whistle sound is a familiar shrill musical sound which is prolonged sibilant or whistling s lisp.

The Swiss is a lateral lisp is the substitution of sh and zh when trying to say s sound.


• These are caused by the abnormal emmision of air passing over the tongue between the upper and lower central incisors while trying to produce sibiliant sounds such as s and z.



• When the upper teeth are set too far posteriorly , the space for the tongue is reduced.

• When s sound is attempted there is lack of space to allow narrow stream of air to pass over the tip of the tongue.


• The air is pressed past all the anterior teeth in a wider stream causing the s to resemble sh


Phonetics in complete dentures

By – Dr. Vijayalaxmi.


Denture base

• One of the reasons for the loss of tone are and incorrect articulation of speech is the decrease in the air volume and loss of tongue space in the oral cavity resulting from unduly thick denture base.


Most important is the denture base covering the center of the palate.

Because for here no loss of the tissue of the natural tissue has occurred, and the base reduces the tongue space and oral air volume.


• Any thickening of the denture base in the anterior region of the hard palate cause incorrect formation of palatolingual sounds such as t, d.


• In case of s,c,z sounds, a slit like channel is formed between the tongue and the palate through which the air hisses.

• If the artificial rugae are too pronounced or the denture base is too thick in this area the air channel is blocked and noticeable lisp may occur.


• The linguoalveolar components such as Ch and j are also affected if the denture base is too thick in the region of rugae.


• Allen (1958) said that the thickness in the palatal vault is critical to speech in the anterior section from canine to canine.

• He advised that the thickening the area of the incisive papilla facilitates proper enouciation .


• Palmer(1979) indicated that some patients develop problem after insertion of the CD because they experience a loss of tactile location skills.

• He recommended that non anatomic papilla to be placed an the denture posterior to the incisive papilla to foster normal speech.


Occlusal plane

• The labiodentals f and v are produced through the narrow gap between the lower lip and inicisal edges of the upper anterior teeth.


• If the occlusal plane is too high the correct positioning of the lower lip may be difficult.

• If the plane is low the lip will overlap the labial surface of the upper teeth to a greater extent and the sound might be affected.



Vertical dimension

• Ribner (1965) • With a correctly trimmed maxillary

rim in place ,the mandibular rim is trimmed so that 1mm of space exists between the two when the patient says /s/. If there is insufficient vertical height, the bilabials /p/, /b/ are affected.www.indiandentalacademy.com

• This is because these require the lips to contact to check the air stream.


Increased vertial dimension and speech articulation errors.

Ronald J. Hammond (JPD1984;52(2)).

In his study he found that :Most frequently misarticulated were

fricatives ie., /s/ and /sh/.


• The second most consistently made error after increased VD were affricatives /th/.

• Thirdly it was the plosives /t/.


Width of the dental arch.

• If the teeth are set in an arch which is too narrow the tongue will be cramped , thus affecting the size of the air channel.


• This results in faulty articulation of consonants t, d, s, n, k, c, where the lateral margins of the tongue make contact with the palatal surface of the upper posterior teeth.



• Hence the artificial teeth should be placed in place previously occupied by the natural teeth.


Postdam area.

• Errors in construction in this region involve the vowels u, o and the palatolingual consonants g and k


• In this group the air stream is checked by the base of the tongue being raised upwards & backwards to make contact with soft palate.


• If the denture is thick in this area or the posterior edge is not sloppy it irritates the tongue thus impending speech.


Use of phonetics in denture construction.


Contouring the palatal vault

• This is done after processing of the dentures.

• This was done according to the tongue contact made by the patient while speaking different vowels and consonants.


• Contouring the palate:

1. The external surface of the palatal section of the denture was roughened and painted with physiologic wax lingual to the premolars and molars, in the midline, and palatal to the anterior teeth.


2.The waxed up denture is placed in the mouth along with the mandibular denture and patient was asked to read 10 stimulus sentence having /ch/, /j/, sh/, /zh/, /t/, /n/, /d/, /s/ ,/t/, /n/, /d/, /z/.


3. After completion of 10 sentences ,the maxillary denture was removed from the mouth and chilled in the cold water.

Freshly developed wax contour was examined.


• A positive contact with wax was smooth and shiny, while lack of contact appeared dull and irregular.


• Converting the wax contour into acrylic resin.






The use of speech patterns as an aid in prosthodontic reconstruction

• Edward J. Mehringer. JPD196313(5).

• He described denture construction to conform with the neuromuscular patterns for speech.


• The wax rims are fabricated to provide esthetically accepted lip fullness and lip line.

• Then a tentative centric relation record is made.


• The occlusal rims are contoured to simulate the shape of the natural teeth.

• The phonetic formats are evaluated as to their conformity with patients own neuromuscular speech pattern.


• This is accomplished by having patient count slowly and distinctly from 3-10 three times.


1-1.5mm space for sibilants.


2-4mm space for nasal consonants.


5-10mm space for diphthongs.


• If the patient phonetic spaces during counting procedures, the centric occlusion is recorded and transferred to the articulator.


Vertical dimension.

• Determination of vertical dimensions by phonetics.

• Meyer M. Silverman.


• The occlusal rims are fabricated .• They are trimmed to allow normal

space for the tongue .• The palatal and lingual surfaces of

the teeth are trimmed to simulate the width and shape of the teeth.


• The patient is instructed to pronounce the s sound and then to speak or read a magazine.

• By sight or measuring the approximate closest speaking space is noted.

• A closest speaking space of 2mm is decided arbitrarily.



• Why /s/ sound is used?1.Most forward and most closed

position of the mandible during speech is assumed when /s/ sounds are enounciated.

2./s/ sound is created when air is forced through a 1-1.5mm gap between the incisal edges of the lower CI and coronal surfaces of the upper CI.



Determining the class of occlusion.




Ribner (1965)

• Summarized the benefits of utilizing phonetics exercises in denture prescription by listing following examples.


1.Posterior border of the denture /ah/

2.Vertical dimension 1mm space exists between the upper and lower rim when patient says /s/.

3.Height of the anterior teeth and thus occlusal plane /f/, /v/.


• Thickness in the anterior region of the palate a lisp in /t/ indicates excessive thickness.

• Thickness of postdam difficulty in saying /g/ indicates excessive thickness.


Summary.


Conclusion.


References.

• Prosthodontic treatment for edentulous patients.12 ed.

• Clinical dental prosthetics 3 Edn• Speech patterns of edentulous patients

JPD1973;29(1).• A study of phonetic changes in edentulous

patients following complete denture treatment. JPD 1972;27(2).


• Phonetic determinants of tooth placement in complete dentures. Quint Int 1994;25:341-45.

• The speaking method of determining vertical relation. JPD 1953;3(2).

• Palatal pressures of the tongue in phonetics and deglutation. JPD1957;7(3).


• Controlling anamolies of vertical dimension. JPD 1976;36(2).

• A simple method of adding palatal rugae to complete dentures. JPD1999;81:237-9.

• The whistle and swiss sound in denture patients. JPD 1967;17(2).


• Can dental prostheses influence vocal parameters. JPD 1999.81:57-85.

• The influence of maxillary central incisors in complete dentures in /s/ sound production. JPD2001;85:485-95.


• Phonetic considerations of chromium cobalt alloy plates for complete dentures.

JPD 1975;34(6).

Analysis of speech in prosthodontics. JPD 1974;31(6).

The whistle and swiss sound in denture patients. JPD 1967;17(2).


• Effect of new dentures on interocclusal distance during speech. JPD 2003; 16:533-37.


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Phonetics in complete dentures./ dentistry course in india