The phonation
1.Introduction
The cephalic extremity groups the five senses: vision, touch, hearing, smell, taste. According to J. Talmant, the functions can be hierarchized according to their physiological importance for the survival of the individual and maximum efficiency.
Certain functions such as ventilation, chewing or swallowing ensure vital activity while phonation ensures relational activity.
The impact of their disturbances on facial growth is proportional to their importance, and can affect both basal bone and alveolar bone.
2.Definition
Phonation is the set of physiological and physical processes that allow the appearance of a sound vibration at the level of the vocal cords and its vocal enrichment. Its purpose is communication.
3. Physiology of phonation
Verbal communication is achieved through
Phonemes (smaller units of sound that distinguish words), the production of which requires sufficient air pressure.
It requires the participation of three anatomical levels:
• the pulmonary wind tunnel (aerodynamic energy);
• the vibrator, corresponding to the glottic plane (modifying aerodynamic energy into acoustic energy), producer of sounds;
• the bucco-pharyngeal resonators , corresponding to the air cavities located above the vocal cords up to the lips and the nostrils.
All this is done under the direction of the central nervous system, allowing the correct execution of phonation in a precise and qualitative manner.
In infants, laryngeal descent and neurological maturation allow the creation and management of resonance spaces from 4 months, in particular thanks to sequences of velopharyngeal closures/openings.
- Vowel formation
There is no pressure of the tongue on the teeth: the exhaled air flows freely without interference with the oral organs.
Vowel formation takes place:
- In the pharyngeal cavity for low vowels
- In the oral cavity for high vowels
The relationship of the tongue to the soft palate and posterior pharyngeal wall
conditions the opening of the pharyngo-buccal duct where the air flows. There therefore exists
a differentiation in the position of the back of the tongue which determines the point
articulation of the vowel on the back of the tongue:
- More anterior for the treble.
– More posterior for the bass
- Formation of consonants
They are formed under the dependence of buccal effectors and are due to the activity of
the lingual, labial, velar, supra and infrahyoid musculature.
04 groups of consonants are of interest to orthodontists:
Sibilants: SZ and sibilants: CH.J.
For S and Z : the tongue does not touch the anterior teeth, the lateral edges
Are in contact with the molars, the tip remains free to allow vibration and is flush with the lingual surface of the lower incisors. The back of the tongue is flattened, the labial commissures slightly stretched.
For CH and J , the support is a little more posterior and the tongue forms an antero-posterior gutter; the lips are folded forward.
The palatals : DTNL
The tip of the tongue is on the retro-incisive papilla:
· For D and T: press the tip of the tongue on the retro-incisive papilla
· For N: support 1 cm above and behind the retro-incisive papilla
· For L: support even higher and more posterior: above and behind the retro-incisive papilla
The labials: MBP
Pressing the upper lip on the lower lip
Fricatives or vibrating : VF
Support of the inner face of the lower lip against the upper incisors, so the lip should not pass behind the teeth.
4.Exploration of phonation
It is based on the pronunciation of short words containing phonemes involving the language such as:
- “Dinette”, “tartine”, “milk” which allow you to study the correct pronunciation of dentals and palatals (D, T, L, N) and to check the normal position of the tip of the
Tongue on the retro-incisive papilla.
- “Sausage”, “dog”, “cat” which correspond respectively to the sibilants and the hissing sounds.
5. Articulation disorders
Typically, when there is dysfunctional swallowing, there is inadequate tongue support when articulating consonants.
Stigmas :
These are alterations of S and CH. We can relate them to the alterations of I, Z, J.
They are very often linked to a delay in emotional maturation accompanied by childishness and
Of bedwetting.
Anterior hiss (lisp): the tip of the tongue comes between the
Upper and lower incisors.
Posterior hiss: passage of the edges of the tongue over the occlusal surface of the
Molars.
Clinically, S alteration is frequently encountered in cases of:
- Reverse incisal bite (class III)
- Incisor infraclusion
– upper incisor vestibulo-version
The palatal:
There is a hierarchy of dentals: when the highest phoneme (L) is disturbed (lambdacism), all the previous ones are also:
– If when pronouncing “L” there is pressure of the tip of the tongue on the incisors or lingual interposition, then DTN will be disturbed.
– If there is an anomaly in the pronunciation of D and T , this does not mean that there is
Anomaly of the articulation point of N and L.
The labials
- Interposition of the lower lip behind the upper incisors.
The vibrant ones
– Interposition of the lower lip behind the upper incisors.
6. Articulatory disorders and morphogenesis
In practice, the articulation of consonant phonemes does not affect morphology
dento-maxillary only when the point of articulation involves the anterior region.
– either it is done at the level of the anterior teeth instead of the palate: DTLN
– either there is interposition of the tip of the tongue between the incisors: sigmatism
or lisp.
Depending on the case, there will be proalveolia or gaping.
For CAUHEPE, NETTER, BOUVET, the phonation anomaly does not affect the
Morphology than in an unbalanced muscular environment.
Some people minimize the action of articulatory disorders on morphogenesis: knowing
that the action exerted by the tongue during the articulation of a consonant lasts one tenth
of second for one second of swallowing.
7. Articulation disorders and dysfunctional swallowing
- There is always a correlation between these two functions: if swallowing
dysfunctional; pathological points of articulation of the tongue and vice versa.
- Articulation disorders are paranormal before age 5 because
the acquisition of sibilants corresponds to the acquisition of mature swallowing.
- The acquisition of mature swallowing at 7 years of age normally allows the acquisition
points of articulation of consonants.
8. Conclusion
It seems unlikely that speech or language disorders themselves would affect ventilation or swallowing, or would cause dysmorphic disorders .
They are, however, frequently associated with them and must be taken care of very early.
The phonation
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