This document discusses functional examination in orthodontics. It outlines the key aspects of functional examination including examination of the postural rest position and maximum intercuspation, examination of the temporomandibular joint, and examination of orofacial dysfunctions.
It describes in detail the examination of the postural rest position and its relationship to maximum intercuspation. Various methods for determining and registering the postural rest position are provided. The document examines the path of closure in the sagittal, vertical, and transverse planes and how to evaluate different malocclusion types based on the path of closure. It distinguishes between true and pseudo deep bites, class II and III malocclusions, as well as
2. INTRODUCTION
Modern orthodontics is not restricted to static
evaluation of the teeth and their supporting
structures,but also includes all functional units of the
masticatory system (Eschler 1952).
Function is the common denominator joining the
individual parts of the oro-facial system.
Disturbance in one part of this system do not remain
isolated but effect the equilibrium of the whole
system.
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3. Nowadays, functional examination constitute a
considerable part of clinical examination. It is not only
significant for the etiologic part of evaluation of the
malocclusion but for determining the type of orthodontic
treatment indicated.
The three most important aspects of orthodontic functional
examination are :
• EXAMINATION OF THE POSTURAL REST POSITION
AND MAXIMUM INTERCUSPATION.
• EXAMINATION OF TMJ
• EXAMINATION OF OROFACIAL DYSFUNCTIONS.
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4. EXAMINATION OF THE POSTURAL
REST POSITION AND MAXIMUM
INTERCUSPATION
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5. EXAMINATION OF THE RELATIONSHIP –
POSTURAL REST POSITION & HABITUAL
OCCLUSION
The initial task of functional examination is the
assessment of mandibular position as determined by
the musculature. The position in the adult dentition
is generally centric relation.
Centric relation of the mandible is a superior
limit position of the condyles in the fossae
with the mandible centered and at its most
closed position.
Source: JCO Volume 1981 Jan(32 - 51): Functional Occlusion for the
Orthodontist.
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6. The movement of the mandible from postural rest to
habitual occlusion as of special interest for all
functional examination.
It consists of 2 components :
1. Hinge (rotary) action
2. Translating (sliding) movement
The objective of examination is to assess not only
the magnitude and direction of these movements
but also the extend of action of each hinge or
sliding component.
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7. During closing from the rest position, several maneuvers
can occur
A. A normal arc can progress into the occlusal position.
B. In such a case the condyle action is primarily rotary
C. An abnormal and posteriorly deviated path can produce
translatory condylar movement.
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8. During the closing maneuver from rest
position, 2 phases of movement can be
observed
1. The free phase from postural rest to the point
of initial premature contact
2. The articular phase from initial contact to the
centric or habitual occlusal position
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9. A slight sliding component (as much as 2mm)
is a normal phenomenon. If the pattern is
abnormal, the sliding may be caused by
neuromuscular abnormalities, disturbances in
the interrelationships, or compensations of
skeletal discrepancies. The abnormal pattern
may combine component from one or more of
these causes,therefore differential diagnosis is
important for planning.
Source: JCO Volume 1984 May(335 - 341): The Influence of Three Types of
Positioners on Mandibular Condyle Relationships - EUGENE H. WILLIAMSON,
DDS, MS, JACK C. FISH
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10. The regimen for the examination
1.
Determination of the postural rest position
2.
Registration and measurement of the postural rest
position.
3.
Evaluation of the relationship of rest position to occlusal
position in the following dimensions.
•
•
•
Saggital
Vertical
Transverse
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11. Assessment of the postural rest position
The rest position of the mandible depends on head and
body posture as they are influenced by gravity. For this
reason, postural rest position must be determined from a
standard head position.
The patient is seated upright, preferably with the back
unsupported. The head is oriented with the patient
looking straight ahead at eye level. Having the patient
look directly into mirror helps establish optimal head
posture.
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12. In order to determine the postural rest, the patient’s
Orofacial musculature must be relaxed. Muscle
exercises (e.g..tapping test) can be used to help
relax the musculature prior to carrying out the
actual examination. When using the “tapping test”
the patient is told to relax and the clinician opens
and closes the mandible. Should the patient be
very tense the musculature can be relaxed with
mild electric impulses(e.g..myomonitor).
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14. The space between the teeth, when the mandible is
at rest, is referred to as FREEWAY SPACE or
INTER OCCLUSAL CLEARENCE.
Source: JCO Volume 1981 Jan(32 - 51): Functional Occlusion for the
Orthodontist.
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15. Methods to determine the postural rest
position of the mandible
1.
2.
3.
4.
Phonetic exercises
Command methods
Non-command method
Combined method
H
Dentofacial orthopedics with functional appliances
Thomas m. graber , alexandre G. petrovic
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16. Phonetic Exercises
The patient is told to pronounce certain
consonants words repeatedly (e.g.. ‘M’
Mississippi). The mandible returns to the
postural resting position 1-2 seconds after
the exercise. The patient is instructed not to
move the lips or tongue at this time, even
while the dentist gently parts the lips to
observe the inter occlusal space.
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17. Command Method
Usually, having the patient lick the lips and
then swallow produces the desired
relationship because the mandible returns to
postural rest within 2 seconds after the
exercise.
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18. Non- Command Method
The patient has no idea of the parameter
being examined. Careful observations are
made as the patient talks, swallow and turns
the head while being questioned on a
number of unrelated subjects. While being
distracted, the patient relaxes, causing the
musculature to relax as well and the
mandible reverts to the postural rest
position.
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19. Combined Method
The combined method usually provides the best
reproduction of the postural rest position. The
patient performs a prescribed function(e.g..
Swallowing) and then relaxes. After instructing
the patient not to move, the clinician gently
palpates the submental muscles to assess whether
they are relaxed.
muscle tone is increased in occlusion and closing
maneuvers.
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20. Components affecting the rest position
Short Term
Long Term
1. Inconsistency in
muscle tonicity
2. Respiration
3. Body Posture
4. Stress
5. TMS dysfunction
1. Attrition
2. Premature loss of
teeth
3. Diseases of neuromuscular system
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21. Registration of the rest position
Registration of the mandibular rest position is important in
those orthodontic cases where the functional analysis is
significant for the treatment planning.
Various methods are recommended for producing the best
record
• Direct intraoral method
• Direct extraoral method
• Indirect extraoral method
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22. Direct intraoral method
In addition to the visual observation, the
clinician can perform a direct intraoral
procedure by using a plaster tape
registration similar to that one sometimes
used in prosthodontics. Measurement is
difficult, although millimeter calipers can
be used to record the interocclusal space in
the canine and incisor area.
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23. Direct extraoral method
Direct caliper measurement can be made on the
patient’s profile measuring the distance from the
soft tissue nasion(at the bridge of the nose) to
menton (on the lowest curvature of the chin). This
measurement is done in both postural rest and
habitual occlusion. The difference between the
two measurements constitutes the interocclusal
clearance.
The disadvantage of this procedure are that of the
soft tissue reduce reliability and no record of the
saggital relationship is produced.
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24. Direct extra oral assessment method enables the examiner
to measure the difference between rest position and
occlusal position using lower face height to sub-nasale to
gnathion or menton.
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25. Indirect extraoral method
Cephalomertric registration offers the most uniformly
successful results. The clinician takes 2 or 3 lateral
cephalograms under identical exposure and patient
positioning conditions.
The first in postural rest, the second in initial contact
and the third in full habitual occlusion.The
measurements can be performed on each head film.
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27. Guiding the mandible into centric relation begins with
having the patient recline and directing the chin upwards.
Okeson JP: orofacial pains,ed
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5,chicago,1995,pp 147-150
28. Evaluation of Path of closure in
Saggital plane
Condylar movement from postural rest to
occlusion can consist of :
• Pure rotational movement(hinge movement)
• Hinge and anterior translatory displacement
• Hinge and posterior superior translatory
displacement
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29. Class II malocclusion
1. In class II malocclusion without
functional disturbance the path of closure
is straight up and forward with a hinge
movement of the condyle in the fossa.
These are true class II malocclusion.
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30. Hinge movement from
the rest
To occlusal
Position in a functionally
class II relationship with
path of closure.
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31. 2.
In class II malocclusions with functional
disturbances a rotary action of the condyle in the
fossa from postural rest to occlusion is evident.
From initial contact to full occlusion, condyle
action is both rotary and translatory up and
backward (posterior shift).Thus the movement
combines rotary and sliding components. This
type of activity is the most common, particularly
in cases of excessive overbite.
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32. Posterior translation or
sliding into the occlusal
position in an abnormal
functional pattern with a
deviated path of closure
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33. 3.
In class II malocclusion with functional
disturbances if the path of closure is up and
forward from rest to initial contact(usually in the
molar region) , the mandible may be anteriorly
displaced from initial contact as the cusp guide the
mandible into the forward position, with
translatory movements of the condyle down and
forward on the posterior slope of the articular
eminence. The path of closure appears more up
and forward than it is without tooth interference.
This malocclusion is more severe than it appears
with the teeth in occlusion. However, this
variation of path of closure is least frequent for
class II malocclusion.
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35. Class III malocclusion
Hinge type Condylar function is often associated
with class III malocclusion with straight paths of
closure.
The closing path can be divided into 3 types:
•
•
•
Rotational movement without sliding action
Rotational movement anterior sliding action
Rotational movement with posterior sliding
action
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36. Various functional relationship in class III malocclusion
A. Anterior rest position in a severe class III malocclusion
B. Posterior rest position in a forced bite type of class III
malocclusion (e.g. pseudo –class III).
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37. TRUE Class III
True Class III: It is a skeletal malocclusion showing
Edge to edge relationship or anterior cross bite
Narrow upper arch and broad lower arch
Crowding in upper teeth and spacing in the lowers
Concave profile with prominent chin
May show anterior open bite
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38. • Edge to edge relationship or anterior cross bite
• Concave profile with prominent chin
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39. Pseudo Class III
(Postural or Habitual Class III): It involves the forward movement of the
mandible during jaw closure.
Causes: • Occlusal prematurities
• Premature loss of deciduous posteriors
• Enlarged adenoids in children
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40. Mandibular Prognathism – true
and pseudo forced bite
In cases of mesiocclusion, an anterior
sliding action is not always a symptom of a
functional Cl III malocclusion. With this
functional diagnosis, the “true forced bite”
with its favorable prognosis and the
“pseudo forced bite” with its unfavorable
prognosis, must be differentiated.
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41. Pseudo bite
The term pseudo bite includes those true skeletal
class III malocclusions where due to partial
dentoalveolar compensation of the skeletal
dysplasia in the anterior region(Labial tipping of
the upper and lingual tipping of the lower
incisors),the mandible occludes at the end of the
closing path by means of an anterior sliding action.
If one reconstructs the tipping of the anterior teeth
in a pseudo forced bite, these cases have
pronounced negative overjet. The dentoalveolar
compensation of the skeletal dysplasia which
already exists when treatment is started, gently
restricts the range of orthodontic treatment
possibilities and unlike a true forced bit, indicative
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of a very unfavorable prognosis.
42. Pseudo-forced bite relationship with labial tipping of the
upper incisor and lingual tipping of the lower incisors.
This is a true class III problem with a marked basal sagittal
malrelationship. After uprighting of the incisors, the
severity of the class III relationship is quite evident.
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43. Evaluation of path of closure in
vertical plane
Two types of deep overbite can be
differentiated:
1. The true deep over bite with a
large inter occlusal clearance is
caused by infra occlusion of the
posterior segments.It often results
from a lateral tongue posture or
tongue thrust habit.
2. The pseudo deep over bite with a
small inter occlusal space has
normal eruption of the posterior
segment teeth. The bite is
combined with over eruption of
incisors.
TROUTEN, JAMES C., ENLOW,
DONALD H., RABINE, MILTON, PHELPS,
ARTHUR E., SWEDLOW, DAVID.
1983: Morphologic Factors
in Open Bite and Deep Bite.
The Angle Orthodontist:
Vol. 53, No. 3, pp. 192–211
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44. A. True deep overbite with a wide freeway space.
B. Pseudo-deep overbite with a small freeway space
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45. Evaluation of path of closure in
transverse plane
Two types of cross bite with lateral
shifting of Mandibular midline can
be differentiated
1. A cross bite in which the midline
shift of the mandible can be
observed only in the occlusal
position. The mandible slides
laterally from rest position into a
cross bite in occlusion. This is
called as “laterocclusion or pseudo
cross bite”.
2. A cross bite in which the midline
shift are present in both occlusal
and postural rest position.This is
referred to as “laterognathy.”
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46. • Laterooclusion
Skeletal midline
shift of mandible
can be observed
only in occlusal
position,in
postural rest both
midlines are well
aligned
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47. • Laterognathy
The center of the
mandible is not aligned
with the facial midline
in rest and in
occlusion. These
dysplasia constitute
true neuromuscular or
anatomical asymmetry.
A lateral cross-bite
with laterognathy is
termed true cross-bite.
The prognosis is
unfavorable for causal
therapy.
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49. Examination of TMJ and Condylar movement
Symptoms of TMJ problems include:
• Clicking and Crepitus
• Sensitivity in the Condylar region and masticating
muscles
• Functional disturbances –
hypermobility
limitation of movement
deviation
• Radiographic evidence of morphologic and
positional abnormalities.
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50. The term temporomandibular joint disorders (TMD)
describes a condition characterized by pain in the
preauricular area, the temporomandibular joint (TMJ) or
the muscles of mastication, by a limitation of the range of
mandibular motion, and by the presence of joint sounds
during jaw function.
1.In addition, pain on movement and deviation on opening
have been considered signs of TMD.
2.Temporomandibular joint sounds have been described as
clicking, popping, crepitus, and grating and are the most
prevalent of all the signs of TMD.
Source: AJO-Volume 1994 Mar (279 - 287): TMJ sound risk factors in children - Keeling,
McGorray, Wheeler, and King www.indiandentalacademy.com
51. The simplified examination of the TMJ
area consists of three steps.
1. Auscultation
2. Palpation
3. Functional analysis
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52. Auscultation
•
•
A stethoscope is used to check for sign of clicking
and crepitus.
The examination is performed by having the
patient open and close the jaw into full occlusion.
If clicking or crepitus is noted, the patient is
instructed to bite forward into incision and then
repeat the opening and closing movements. These
movements are checked for any sounds with the
stethoscope. Most often, sounds disappear in the
protruded position.
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53. Types of clicking
Initial clicking
Retruded condyle in
relation to disc
Intermediate clicking
Unevenness of condylar
surface in relation to disc
Terminal clicking
Condyle is too far forward
with relation to disc
Reciprocal clicking
Incoordination between
displacement of condyle
and disc
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54. ITEM
Reciprocal click
DESCRIPTION
Noise made on opening and closing from centric occlusion position
that is reproducible on every opening and closing.
Reproducible opening click
Noise with every opening, no noise when closing
Reproducible laterotrusive click
only
Noise with every full laterotrusive movement, no noise on opening
Reproducible closing click
Noise with every closing, no noise when opening.
Non reproducible click
Present on opening in laterotrusion but not repeatable
Crepitus (fine)
Fine grating noise suggestive of mild bone-on-bone contact
Crepitus(coarse)
Coarse grating noise suggestive of gross bone-on-bone contact
Popping
Distinctly audible sound on opening.
Source: AJO-Volume www.indiandentalacademy.com sounds - Rinchuse, Abraham,
1990 Dec (512 - 515): TMJ
Medwid, and Mortimer.
55. Palpation
The condyle and the fossa are palpated with
the index finger during opening and closing
maneuvers. The posterior surface can be
palpated by inserting the little finger in the
auditory meatus. The condyles can thus be
checked for tenderness, synchrony of action
and coordination of relative position in the
fossae.
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56. Palpation of the TMJ.
•
Lateral aspect of the joint
with the mouth closed.
•
Lateral aspect of the joint
during opening and
closing.
•
With the mouth fully
open, the finger is moved
behind the condyle to
palate the posterior
aspect of the joint.
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57. The prevalence of TMJ sounds in children
determined by palpation/unaided listening has
been reported to range from 2.7% to 26.6%. In
studies that used a stethoscope, prevalence rates
range from 0% to 35.8% In an adult population,
TMJ sound prevalence has been described as
dependent on the method used with rates
increasing to 78% when a stethoscope was used
and to 94% when phonographic recordings were
made.
Source: AJO-Volume 1994 Mar (279 - 287): TMJ sound risk factors in
children - Keeling, McGorray, Wheeler, and King
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58. Functional analysis
Dislocation of condyles and discoordination
of movement are symptoms of functional
disturbance.
Functional movements of the mandible and
condyle are carefully assessed. The extent
of maximum opening is measured between
the upper and lower incisors.
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59. Measuring the amount of mandibular opening. A
Boley gauge may be used. The distance is
normally between 40 and 65 mm.
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60. Opening and closing movements
of the mandible
•
The opening and closing movements of the
mandible as well as its protrusive, retrusive and
lateral excursion are examined as part of the
functional analysis
• The path taken by the midline of the mandible
during maximum mouth opening is observed.
Any alteration in opening are recorded.
Two types of alteration can occur
1. Deviation
2. Deflection
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61. Deviation is any shift of
the jaw midline during
opening that disappears
with continued opening(a
return to midline).
Deflection is any shift of
the midline to one side
that becomes greater with
opening and does not
disappear at maximum
opening(does not return
to midline).
It is due to restricted
movement in one joint
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62. The cause of TMD remains a subject of great controversy and is
generally viewed as multifactorial. A few articles have implicated
orthodontic treatment as a possible cause of TMD. Ricketts stated
that clinical symptoms of joint derangement have been noted as
occlusions were changed, and he suggested that the various
orthodontic forces provided during therapy may predispose patients
to temporomandibular joint problems. Other studies indicate that
orthodontic treatment does not lead to increased occurrence of
TMD. In a study by Sadowsky and BeGole the status of TM joint
function and functional occlusion was evaluated in 75 subjects who
received treatment as adolescents 10 to 35 years previously. The
findings suggested that in the orthodontically treated group, the
prevalence of TMJ signs and symptoms were similar to those of
untreated controls.
Source: AJO-Volume 1992 Jan ( www.indiandentalacademy.com - Hirata, Hernandez, and King.
Study of): signs of TMD
65. Swallowing
In neonates the tongue is relatively large and located in
the forward suckling position for nursing. The tip inserts
through the anterior gum pads and assists in the anterior
lip seal. This tongue position and coincident swallowing
are termed infantile or visceral.
With eruption of the incisors at around 6 months, the
tongue position starts to retract. Over a period of 12 to
18 months, as proprioception causes tongue postural and
functional changes, a transitional period ensues.
Between 2 to 4 years the functionally balanced , or
mature, somatic swallow is seen in normal
developmental patterns.
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66. Visceral swallowing can persist well after
the fourth year of life, however, and is then
considered dysfunctional or abnormal
because of its association with certain
malocclusive characteristics(e.g. tongue
thrusting).
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67. Various deglutitional
patterns.
A. visceral suckle swallow
in the neonates.
B. Persistance of the
infantile type of swallowing
C. Somatic, or mature, type
of swallowing
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68. Normal deglutition
In the normal mature swallow, no tongue
thrust or constant forward posture occurs.
The tip of the tongue is supported on the
lingual of the dentoalveolar area; the
contraction of the perioral muscles is slight
during deglutition, and the teeth are in
momentary contact during the swallowing
cycle.
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69. Based on the work by Gwynne-Evans (1954),
Ballard(1965) the deglutitional cycle may be
divided into 4 stages.
Stage 1.
The anterior third of the superior surface of the
tongue is flat or retracted. The food bolus is
collected on the flat anterior part of the tongue or
in the sublingual area in front of the retracted
tongue. The posterior arched part of the dorsum is
in contact with the soft palate. The posterior seal is
closed; swallowing cannot yet take place. The
teeth and lips are not in contact.
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70. Variations in the first phase of swallowing.
A. Collecting phase in front of the tongue tip
B. Collecting phase on the dorsum of the tongue.
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71. Stage 2.
The soft palate moves in a cranial and posterior direction.
The palatolingual and palatopharyngeal seals are now
open. The tip of the tongue moves up as the dorsum drops,
creating a groove or depression in the middle third and
permitting posterior transport of the bolus.
Stage 3.
The superior constrictor muscle ring in the epipharyngeal
wall (known as Passavant’s pad) starts to constrict. The
soft palate assumes a triangular form, both tissues together
form the palatopharyngeal seal, often reffered to as
velopharyngeal seal. With the closing of the nasopharynx
the posterior part of the dorsum of the tongue drops more,
this allows the bolus of food to pass through the isthmus
faucium.
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72. Stage 4.
The dorsum of the tongue now moves
posteriorly and superiorly as the
palatopharyngeal tissues moves down and
forward. The tongue pushes against the
tensed soft palate, squeezing the residual
food bolus out the oropharyngeal area.
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73. Four stages of the oral phase of swallowing. The changes
in tongue position as the food bolus is transported into the
oropharynx during the deglutitional cycle. Function of the
posterior seal in the four stages(velopharyngeal valving)
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74. Tongue
Size: The tongue can be small, long or broad. A
long tongue can usually reach the tip of the nose.
Macroglossia implies a large tongue.
Position:
•It may be affected by enlarged tonsils/adenoids
•In class III cases, the tongue is broad and low
lying and extends over the dental arches. In such
cases, the size of the dental arch should not be
decreased by further Orthodontic treatment
(E.g.:- Extractions)
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76. Tongue
Movements:
• They may be restricted due to ankyloglossia.
• Proffit has stated that the resting pressure of the
tongue is one of the primary factors in the
maintenance of dental equilibrium
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77. Tongue Thrusting
•It is also called as deviated swallow, visceral
swallow, and reverse swallow, retained infantile
swallow.
•Tongue thrust is actually a misnomer as it
implies forced forward placement of tongue.
However, swallowing is not a learned behaviour
but, is integrated and controlled physiologically
at subconscious levels.
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78. Tongue Thrusting
•According to Proffit and Mason, it is the
combination of one or all of the 3 conditions,
1. Forward placement of tongue during
swallowing so that tip of tongue contacts
the lower lip
2. Inappropriate placement of tongue
between or against anterior dentition
during speech
3. Forward positioning of tongue at rest so
that the tip is against or between the
anterior teeth
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79. During rest the position of
the anterior teeth has been
altered by the forces of the
tongue.
An anterior open-bite
developed
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80. Tongue Thrusting Types (Moyers)
Simple
A tongue thrust with the teeth together
Associated with digital habit.
Complex
Tongue thrust with teeth apart
Retained Infantile
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81. Tongue Thrusting
•Tongue thrusting results in
Contraction of the circumoral musculature,
Separation of the mandibular and maxillary posteriors ,
Protrusion of tongue between incisors.
Proffit W, Mason R Myofunctional Therapy for tongue thrusting.
Background and recommendations
J AM Dent. Association 90:403 – 411, 1975
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82. SPEECH
The tongue ,pharynx,velum, palate and teeth play
central roles in phonation. In malocclusion with
malposed teeth, malposition of the tongue may
also occur impairing normal speech.
A simple test the dentist may use is to ask patient
to count from 1 to 10 or 1 to 20. The dentist
watches closely how the tongue and lips adapt to
the structures with which they are supposed to
articulate and listen to how the consonants sound.
Disturbance of resonance, phonation, rate,
loudness, pitch and articulation have all been
reported in cleft palate patient. Hypernasality and
defective articulation are the most predominant
speech disturbance, in cleft patients.
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83. Speech difficulties related to
malocclusion
Speech sound
Related malocclusion
{s}, {z} consonents
Ant. Open bite, large gap between incisors
{t}, {d}
Linguoalveolar stops
Irregular incisors, especially lingual position
of maxillary incisors
{f}, {v}
Laboidental fricatives
Skeletal class III
{Th},{sh},{ch}
Linguodental fricatives
Voiced or voiceless
Anterior open bite
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84. Lips
Normally the upper and the lower lip touch
each other when the jaws are at rest to form
a lip seal. The upper lip is 2-3 mm above
the incisal edge of the upper central incisor.
The lower lip extends up to the incisal third
of labial surface of upper anteriors.
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85. Lips
• Based on the lip seal the lips can be classified
as,
Competent – Lips are in slight contact when
the musculature is relaxed
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86. Lips
•
•
Incompetent – They are morphologically short lips
which do not form a lip seal in relaxed state.lip seal is
achieved only by active contraction of Orbicularis oris
and circumoral muscles.
(a) Short Upper Lip
(b) Short Lower Lip
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87. Lips
Potentially Incompetent – Normal lips that fail
to form a lip seal due to protruding upper
incisors.
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88. Lips
• Everted / Curled – They are hypertrophic lips
with redundant tissue but weak muscular
tonicity.
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89. Lip Projection
• According to ideal E-Line relationship
(Ricketts – E esthetic line) lower lip should
coincide with a line from the nasal tip to
anterior chin and upper lip should be 1 mm
behind it.
• Lip projection is affected by both dental and
skeletal protrusion or retrusion. Lip projection
is an important factor in facial esthetics and it
decreases with ageing.
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90. Lip Projection
• Lip prominence can also be evaluated by
relating the upper lip to a true vertical line
passing through the concavity at the base of
upper lip and relating the lower lip to a similar
true vertical line passing through a point in the
concavity between the lower lip and chin.
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91. Lip Projection
If the lip is forward to the line, it is prominent. If
it falls behind the line, it is retrusive. If both the
lips are prominent and are separated by more than
3-4 mm, it indicates dento alveolar protrusion.
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92. Respiration
The mode of respiration is examined to establish
whether the nasal breathing is impeded or not
Following are typical of patients with oronasal
respiration.
1. A high palate
2. Persisting “tooth germ position”of upper
incisors
3. Narrowness of upper arch
4. Cross bite
5. Poor oral hygiene.
Humans may exhibit 3 types of respiration
• Nasal
• Oral
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93. A number of simple test exist that can be employed to diagnose
the mode of respiration.
• Mirror test – A double-sided mirror is held between the nose
and the mouth. Fogging on nasal side of mirror indicates nasal
breathing and fogging on oral side indicates oral breathing.
• Cotton Test – A butterfly shaped piece of cotton is placed
over the upper lip below the nostrils. If the cotton flutters
down, it indicates nasal breathing.
• Water Test – Patient fills the mouth with water and retains it
for some time. Oral breathers fail to perform this test.
• Observation of external nares – The external nares dilate
during inspiration for nasal breathers. No change is observed
in oral breathers.
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94. Muscle strength testing
MUSCLES
FUNCTION
TEST PROCEDURE
LIP-CHEEK
Lip movement and puts
pressure on the six anterior
teeth
Place thumb and index
finger in corners of mouth;
while patient holds lips
together, tester attempts to
pull lips apart
Orbicularis oris
Internal fibers
External fibers
Contact when teeth “pouch” Attempt to deflate cheeks
Buccinator
Lateral margins compress
Tester places index finger
the cheek against the buccal straight against the cheek
surface of the teeth
interiorly as the patient
pulls the cheek against the
teeth .Tester cannot break if
strength is normal
tTMJ and craniofacial pain James R. fricton; Richard J. kroening
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95. Muscle strength testing
Muscles
TONGUE
Function
Test procedure
Geniohyoid
Elevates tip of the tongue and
Hyoid bone
Patient touches tip of the
tongue to tester’s finger as
tester resists
Stylohyoid
Elevates hyoid bone and base Test procedure same as above
of the tongue.
Extrinsic tongue muscles
Genioglossal
Hypoglossal
Styloglossal
Depress,elevate, and laterally
deviate the tongue
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To test lateral motion, instruct
the patient to move to left; hold
against your resistance.
Repeat on right.
To test protrusion, have the
patient push the tongue
forward against your finger.To
test retraction, hold the
patient’s tongue with gauge. As
the patient retracts it, the tester
attempts to bring it forward.
96. Muscles strength testing
Muscles
MASTICATORY
Function
Test procedure
Masseter
Elevates jaw
Resist closing of jaw
from a two finger-width
opening
Superficial fibers
Deep fibers
Protrudes jaw slightly.
Retracts jaw slightly.
Not possible
Temporalis
Posterior fibers
Elevates jaw.
Retracts jaw.
Resist closing of jaw as
above
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97. Muscle strength testing
Muscle
MASTICATORY
Function
Test procedure
Lateral pterygoid
Superior fibers
Interior fibers
Inferior belly contracts
during translatory motion of
protrusion and during rotary
motion of early opening.
Superior belly relaxes
during opening allowing
disk to rotate posteriorly on
condyle
Resists jaw at end range of
lateral motions and
protrusions.
Medial pterygoid
Primary motion is jaw
elevation and assists lateral
and protrusive motions.
Resists jaw at range of
lateral motions and
protrusions
digasrtic
Pulls mandible back and
down.
When the hyoid is fixed, it
aids in jaw opening.
Raises the hyoid bone and
base of the tongue and also
steadies the hyoid bone
Attempts to pull jaw
forward.
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98. References
tTMJ and craniofacial pain
James R. fricton; Richard J. kroening
Management of TMJ disorders and occlusion
Jeffery P. okeson
OOrthodontics Current Principles and Techniques
Thomas Graber , Robert Vanarsdall, Katherine Vig
OOrthodontic diagnosis – Thomas Rakosi
HDentofacial orthopedics with functional appliances
Thomas m. graber , alexandre G. petrovic
CContemporary Treatment of Dentofacial Deformity
William R. Proffit
Contemporary Orthodontics - William R. Proffit
OOrthodontics Principles and Practice - T.M.Graber
EEnlow DH: Handbook of facial growth 2nd Edition Philadelphia,
PA: WB Saunder 1982
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