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MUSCLE
FUNCTIONS AND
MALOCCLUSION
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
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INTRODUCTION
CLASSIFICATION OF OROFACIAL
MUSCLES
NORMAL MUSCLE FUNCTIONS
METHOD TO STUDY MUSCLE
FUNCTION
...
INTRODUCTION
• According To functional matrix theory

origin growth and maintenance of
skeletal unit depends exclusively o...
• Musculoskeletal system is governed by

•

muscles, a sort of “rubber bands” that on
stretching ,keep our skeletal archit...
www.indiandentalacademy.com
CLASSIFICATATION OF
OROFACIAL MUSCLES
• Depending upon site they can be
classified as
• Facial muscles
• Jaw muscles
• Por...
FACIAL MUSCLES
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•
•
•
•
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Derived from second branchial arch
Innervated by facial nerve
Main muscles in this group a...
FUNCTIONS
•
•
•
•

Expression of emotions
To maintain posture of facial structures
Assists swallowing in infants
Maintains...
INFANTILE SWALLOWING
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•
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•

Moyers characteristics
Jaw are apart with tongue between gum pads
Mandible is primarily stab...
www.indiandentalacademy.com
www.indiandentalacademy.com
BUCCINATOR MECHANISM
• It is a continuous muscle band that
•
•
•
•
•

encircles the dentition and is anchored at
the phary...
BUCCINATOR MECHANISM

www.indiandentalacademy.com
www.indiandentalacademy.com
JAW MUSCLES
• Designated as elevators depressors protractors
•
•
•
•

and retractors
Mainly derived from first branchial a...
www.indiandentalacademy.com
FUNCTION
• Maintenance of the balance of the head
on the vertebral column
• Opening and closing movements of the
mandible
...
www.indiandentalacademy.com
www.indiandentalacademy.com
• Study by Motoyosi M etal (Eur J Orthod Aug

2002) the biomechanical influence of the head
posture on the cervical column...
• Stress converged at the atlas in model a.

High level of stress was observed at the
spinous level of c6 and c7 in model ...
PORTAL GROUP OF
MUSCLES
• The term portal area was coined by

“Bosma“ to denote the upper alimentary
and respiratory tract...
COMPONENTS
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•
•
•
•

Muscle of tongue
Soft palate
Pharyngeal pillars
Pharynx proper
Larynx

www.indiandentalacademy.com
FUNCTION
•
•
•

Postural maintenance
Respiration
Deglutination in adults

• Mainly controlled by complex neural

reflexes ...
FOR ORTHODONTIC POINT
OF VIEW TWO PORTAL
REFEXES ARE OF GREAT
IMPORTANCE
• Mature swallowing
• Pharyngeal air way maintena...
MATURE SWALLOWING
•
•
•

According to Moyers:-Teeth together
Mandible supported by muscles supplied
by fifth cranial nerve...
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STAGES OF DEGLUTITION
•
•
•

ORAL STAGE
PHARYNGEAL STAGE
OESOPHAGEAL STAGE

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www.indiandentalacademy.com
RESPIRATION
• Respiration like mastication and swallowing is an
•

inherent reflex activity
The orofacial growth is signif...
METHOD OF STUDY MUSCLE
FUNCTION
•
•
•

ANATOMIC
FUNCTIONAL
BEHAVIORAL

www.indiandentalacademy.com
ANATOMIC

• Dissection-oldest method . the shape size

•

origin and insertion provide insight into
possible force vectors...
Muscle fiber

TYPE II
;Large, high tension, rapidly
contracting muscle fibers

Type I
Small , low
tension ,slowly
contract...
• A study was done by( Gedrange T etal J Appl

Gnet 46 ,2005)to determine the myosine heavy
chain proteins (MyHC) and MyHC...
• One of the study done by Anthea

Rowlerson et al [Am J Orthod Dentofac
Orthop 2005] showed a link between a
vertical gro...
FUNCTIONAL-three methods
• Movement-movement of facial structures are
•
•

recorded on moving film eg. – cineradiograph.
F...
•.
• Disadvantage-impossible to know how much
muscle activity is missed due to working of
antagonistic muscle synergistica...
BEHAVIORAL

• More applicable to human beings. Includes

disciplined observation of total muscle activity in
the natural s...
RECENT ADVANCES
•
•
•
•
•
•

Scoliosometer
Stabilometric board
Electronic axiograph
Mechanical axiograph
Kinesiograph
Comp...
• Scoliosometer: an

instrument for
optical evaluation
of posture allowing
to monitor gross
variations in
patient's postur...
STABILOMETRIC BOARD;
• Computer assisted system used to investigate
the type of plantar rest, distribution of the
barycent...
www.indiandentalacademy.com
AXIOGRAPH AND
KINESIOGRAPH
• Dental instrument used to assess

mandibular joint function and disorders.

www.indiandentala...
www.indiandentalacademy.com
COMPUTER TOMOGRAPHY
• Used to study muscle function in terms of
muscle cross section, muscle volume and
muscle density.

w...
• A study [Gedrange T etal Rofo. 2005
Feb;177(2):204-9 ] was done to determine

the relationship between the morphological...
MUSCLE MALFUNCTION
RELATED TO
MALOCCLUSION
• Malocclusion is a final outcome due to
interaction among various factors.

• ...
EQUILIBRIUM THEORY

• States that an object subjected to unequal force will be

•

accelerated and thereby will move to di...
DIAGRAMMATIC REPRESENTATION OF
INTERDEPENDENCE OF ETIOLOGICAL FACTORS IN
MALOCCLUSION
ENVIRONMENTAL

GENETIC

DEVELOPMENTA...
• Malocclusion represents nature attempt to

establish a balance between all
morphogenic functional and environmental
comp...
www.indiandentalacademy.com
www.indiandentalacademy.com
Muscle Function Causing
Malocclusion Or Malocclusion
Produced By Active Muscle
Function Participation Are

• TONGUE THRUST...
TONGUE THRUST
SWALLOWING
• Defined as placement of tongue tip

forward between the incisors during
swallowing—Proffit.

ww...
Tongue Thrust

Simple
tongue
thrust

Complex
tongue
thrust

Normal
infantile
swallow

www.indiandentalacademy.com

Retaine...
Muscle pathophysiology associated
with abnormal deglutition

•
•
•
•

Heavy mentalis activity.
Heavy labi superioris and i...
www.indiandentalacademy.com
www.indiandentalacademy.com
www.indiandentalacademy.com
• A case report by Valiathan A. AND Sameer H
Shaikh. (J Ind Ortho Soc 1998;31:53-57)
showed the effect of an abnormally la...
• .An additional lateral ceph was taken following
the administration
of radio- opaque contrast
medium to highlight the dor...
CLINICAL APPLICATION
SIMPLE TONGUE THRUST
MOYER’S

COMPLEX TONGUE
THRUST

CONSCIOUS LEARNING OF
NEW REFLEX.
MYOFUNCTIONAL
...
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www.indiandentalacademy.com
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www.indiandentalacademy.com
www.indiandentalacademy.com
MOUTH BREATHING
• Moyers—one who breathes orally even in
relaxed and restful situations

www.indiandentalacademy.com
MOUTH BREATHING
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•
•
•
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•

Characterized by
Lowering of mandible
Positioning of tongue downward
Tipping back of head
Ups...
www.indiandentalacademy.com
• Study done by Vig ps et al (ajo 77;258;268
–1980) showed changes in posture as
change of about 5 degree in the
craniover...
CLINICAL APPLICATION
• Mouth breathing can be effectively treated
by oral screen,
• It is inserted at night, before going ...
www.indiandentalacademy.com
THUMB SUCKING

• Thumb sucking---placement of thumb or
one or more finger in varying depth into
the mouth
• The effect on ...
MUSCLE
PATHOPHYSIOLOGY
•
•
•
•

Contraction of cheek muscles.
Hypotonic upper lip
Hyperactive mentalis
Tongue is displaced...
www.indiandentalacademy.com
DIAGNOSIS
•
•
•
•
•
•

Proclination of upper incisors
Retroclination of lower incisors
Anterior open bite
Tongue thrusting...
www.indiandentalacademy.com
CLINICAL APPLICATION
• DEPENDING UPON THE AGE OF THE
PATIENT

REMOVABLE
CRIB

PSYCHOLOGICAL
METHODS

INTRA ORAL
HABIT
CORR...
www.indiandentalacademy.com
LIP SUCKING
• Can be defined as forceful wedging of the
lip between upper and lower teeth. Lip
sucking involves puling the...
www.indiandentalacademy.com
MUSCLE PATHOPHYSIOLOGY
•
•
•

Hyper active mentalis
Non functional upper lip
Tongue to lower lip seal during swallowing

w...
• A study done by Jung MH et al (Am J Orthod

Dentofacial 2003 Jan) to evaluate the influence
of force of orbicularis musc...
DIAGNOSIS
• Diagnosed as a deleterious, compulsive,

functional, muscular habit, either primary
or secondary to the increa...
CLINICAL APPLICATION

REDUCTION OF
EXCESSIVE OVER JET
ORTHODONTICALLY IN
CASE IF IT IS THE
PRIMARY CAUSE

INTRA ORAL APPLI...
www.indiandentalacademy.com
www.indiandentalacademy.com
• A case report by Vaishali and Utreja ( JCO feb

2005)—a 4 year female child was reported with
chief complain of protrusi...
• The lip sucking habit was remarkably

reduced after 15 days and completely
eliminated after three months of
appliance we...
MUSCULAR WEAKNESS
SYNDROME
• Causes mandible to drop down away from

the facial skeleton
• Distortion of facial proportion...
www.indiandentalacademy.com
TORTICOLIS
• Struggle between muscle and bone, where

bone yields. There is foreshortening of
sternocleidomastoid muscle w...
www.indiandentalacademy.com
CEREBRAL PALSY

• Lack of motor control which leads to abnormal
•

muscle function.
Uncontrolled and aberrant activities u...
ASSOCIATED MALOCCLUSION
• Malocclusion occurs twice as often than in

average population
• Protrusion of max. Ant teeth
• ...
• A study by (Ghafari J, Clark RE et al AJO- DO

Feb 1988) 79children having neuromuscular
disorder were examined for occl...
• In primary myopathy group the patient suffering
from Duchene muscular dystrophy exhibited
statistically significant dela...
• COMPENSATORY MUSCLE CHANGES
ASSOCIATED WITH GENETICALLY
DETERMINED CLASS II AND CLASS III
MALOCCLUSION.

www.indiandenta...
CLASS TWO DIV ONE
MALOCCLUSSION
• Muscle pathophysiology-hyperactive

mentalis activity. Hypotonic upper lip.
Increased bu...
www.indiandentalacademy.com
www.indiandentalacademy.com
CLASS TWO DIV TWO
MALOCCLUSION

• Mainly hereditary. Muscle changes take place

•

as a compensatory mechanism for existin...
CLASS THREE
MALOCCLUSION
– MUSCLE PATHOPHYSIOLOGY-SHORT UPPER
LIP.INCREASED ACTIVITY OF UPPER LIP
DURING SWALLOWING.TONGUE...
www.indiandentalacademy.com
www.indiandentalacademy.com
www.indiandentalacademy.com
CONCLUSION

• The effect of muscle force is three dimensional.

Whenever there is struggle between bone and muscle,
bone y...
REFERENCES;-----• Handbook Of Orthodontics 4th Edition—ROBERT E.MOYERS
• CONTEMPORARY ORTHODONTICS,3rd Edition.—WILLIAM R....
• Resistance to nasal airflow related to changes in head
•
•

posture. [Z.J. Weber, C. B. Preston, et al. vol -80, No5, Am...
• Malocclusion and the tongue :[Ashima Valiathan,Sameer H
•
•
•
•
•

•

Shaikh.31:53-57,J Ind Orthod Soc,1988]
Biomechanic...
Thank you
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Muscle function in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. MUSCLE FUNCTIONS AND MALOCCLUSION INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. • • • • • • • • INTRODUCTION CLASSIFICATION OF OROFACIAL MUSCLES NORMAL MUSCLE FUNCTIONS METHOD TO STUDY MUSCLE FUNCTION MUSCLE MALFUNCTIONS AND MALOCCLUSION CLINICAL APPLICATIONS CONCLUSION REFERENCES www.indiandentalacademy.com
  3. 3. INTRODUCTION • According To functional matrix theory origin growth and maintenance of skeletal unit depends exclusively on soft tissue matrix • As muscle is an important part of the soft tissue matrix ,it changes the morphology of bone which is plastic in nature. www.indiandentalacademy.com
  4. 4. • Musculoskeletal system is governed by • muscles, a sort of “rubber bands” that on stretching ,keep our skeletal architecture together. It is roughly like a present day architectural cable structure . Each relationship between bone is controlled by muscles and restricted by the shape of the joints and ligaments. So mandibular movement can be perceived as that of a free body manipulated in an intricate web with the teeth and joints acting as stops and guides. www.indiandentalacademy.com
  5. 5. www.indiandentalacademy.com
  6. 6. CLASSIFICATATION OF OROFACIAL MUSCLES • Depending upon site they can be classified as • Facial muscles • Jaw muscles • Portal group of muscles www.indiandentalacademy.com
  7. 7. FACIAL MUSCLES • • • • • • • • Derived from second branchial arch Innervated by facial nerve Main muscles in this group are Frontalis Zygomaticus major and minor Buccinator Mentalis Orbicularis oris www.indiandentalacademy.com
  8. 8. FUNCTIONS • • • • Expression of emotions To maintain posture of facial structures Assists swallowing in infants Maintains integrity of dental arch www.indiandentalacademy.com
  9. 9. INFANTILE SWALLOWING • • • • Moyers characteristics Jaw are apart with tongue between gum pads Mandible is primarily stabilized by contraction of muscles of seventh cranial nerve Guided mainly by sensory exchange between lips and tongue www.indiandentalacademy.com
  10. 10. www.indiandentalacademy.com
  11. 11. www.indiandentalacademy.com
  12. 12. BUCCINATOR MECHANISM • It is a continuous muscle band that • • • • • encircles the dentition and is anchored at the pharyngeal tubercle. Components;-Orbicularis oris Buccinator Pterygomandibular raphae Superior constrictor of pharynx www.indiandentalacademy.com
  13. 13. BUCCINATOR MECHANISM www.indiandentalacademy.com
  14. 14. www.indiandentalacademy.com
  15. 15. JAW MUSCLES • Designated as elevators depressors protractors • • • • and retractors Mainly derived from first branchial arch and are supplied by fifth cranial nerve Muscle in this group are Muscles of mastication Hyoid group of muscles www.indiandentalacademy.com
  16. 16. www.indiandentalacademy.com
  17. 17. FUNCTION • Maintenance of the balance of the head on the vertebral column • Opening and closing movements of the mandible www.indiandentalacademy.com
  18. 18. www.indiandentalacademy.com
  19. 19. www.indiandentalacademy.com
  20. 20. • Study by Motoyosi M etal (Eur J Orthod Aug 2002) the biomechanical influence of the head posture on the cervical column and the craniofacial complex during masticatory simulation were quantified using 3-d finite element analysis. 3 types of FEM were designed to examine the relationship between the head posture and the malocclusion.. model a with standardized cervical column curve and b and c with forward and backward head posture respectively .during masticatory simulation model b moved forward and model c moved backward. The stress distribution on the cervical column for model a ,b, and c showed difference . www.indiandentalacademy.com
  21. 21. • Stress converged at the atlas in model a. High level of stress was observed at the spinous level of c6 and c7 in model c. Stress converged at the anterior edge of the vertebral body of c4 in the model b. However stress distribution on the occlusal plane and the maxillofacial structure did not show absolute differences among three models . www.indiandentalacademy.com
  22. 22. PORTAL GROUP OF MUSCLES • The term portal area was coined by “Bosma“ to denote the upper alimentary and respiratory tract. • Mainly derived from third and fourth branchial arch and are supplied by third and fourth cranial nerve. www.indiandentalacademy.com
  23. 23. COMPONENTS • • • • • Muscle of tongue Soft palate Pharyngeal pillars Pharynx proper Larynx www.indiandentalacademy.com
  24. 24. FUNCTION • • • Postural maintenance Respiration Deglutination in adults • Mainly controlled by complex neural reflexes eg retching and coughing reflex in foreign body aspiration . www.indiandentalacademy.com
  25. 25. FOR ORTHODONTIC POINT OF VIEW TWO PORTAL REFEXES ARE OF GREAT IMPORTANCE • Mature swallowing • Pharyngeal air way maintenance www.indiandentalacademy.com
  26. 26. MATURE SWALLOWING • • • According to Moyers:-Teeth together Mandible supported by muscles supplied by fifth cranial nerve • Tongue tip is held above and behind the upper incisors against the palate • Minimum contraction of lips www.indiandentalacademy.com
  27. 27. www.indiandentalacademy.com
  28. 28. STAGES OF DEGLUTITION • • • ORAL STAGE PHARYNGEAL STAGE OESOPHAGEAL STAGE www.indiandentalacademy.com
  29. 29. www.indiandentalacademy.com
  30. 30. RESPIRATION • Respiration like mastication and swallowing is an • inherent reflex activity The orofacial growth is significantly influenced by the development of respiratory spaces and maintenance of the airway eg. as we can see collapse of pharynx and poor orofacial growth in tracheotomised infant. www.indiandentalacademy.com
  31. 31. METHOD OF STUDY MUSCLE FUNCTION • • • ANATOMIC FUNCTIONAL BEHAVIORAL www.indiandentalacademy.com
  32. 32. ANATOMIC • Dissection-oldest method . the shape size • origin and insertion provide insight into possible force vectors of the mandible . Disadvantage-limited value in predicting the real muscle force because muscle are never fully contractile during function Histological-based on concentration of oxidative enzymes and/or ATPase in muscle fiber , and are classified as type one and two. www.indiandentalacademy.com
  33. 33. Muscle fiber TYPE II ;Large, high tension, rapidly contracting muscle fibers Type I Small , low tension ,slowly contracting motor units. Very resistant to fatigue Richly supplied by capillaries A B Fatigue resistant Fatigue sensitive Good capillary circulation Poor capillary circulation www.indiandentalacademy.com
  34. 34. • A study was done by( Gedrange T etal J Appl Gnet 46 ,2005)to determine the myosine heavy chain proteins (MyHC) and MyHC mRNA in masseter muscles of patients with different mandibular positions. 10 patients were selected with distal and mesial malocclusion.and amount of MyHC and its different isoforms was determined by western blot essay .and PCR.. The ant. part of masseter muscle showed more type i and 2x myhc in distal occlusion than in the mesial occlusion. www.indiandentalacademy.com
  35. 35. • One of the study done by Anthea Rowlerson et al [Am J Orthod Dentofac Orthop 2005] showed a link between a vertical growth disturbance and particular muscle fiber composition. Type one fibers were find to be increased in open bite cases ;type two fibers were increased in deep bite cases, where as there were more no of hybrid fibers and type one in class three cases. www.indiandentalacademy.com
  36. 36. FUNCTIONAL-three methods • Movement-movement of facial structures are • • recorded on moving film eg. – cineradiograph. Force and pressure - measures the pressure of lip tongue and cheek against the teeth using strain gauges Electromyogram -Contain two type of electrodes. Surface electrodes-to study large portion of muscles and needle electrodes-to study few motor units in a specific region. Measures the electrical activity of the muscle . www.indiandentalacademy.com
  37. 37. •. • Disadvantage-impossible to know how much muscle activity is missed due to working of antagonistic muscle synergistically to control the movement or provide stabilization. www.indiandentalacademy.com
  38. 38. BEHAVIORAL • More applicable to human beings. Includes disciplined observation of total muscle activity in the natural state. Non invasive and most practical method. any type of muscle function which are carried out in the head and neck region can be genetically predetermined or can be a learned behavior. In the oral phase of swallowing the bolus propelling component is predetermined where as anterior tongue - lip seal and stabilization components are learned. which can be altered by the muscle training. eg. myofunctional appliances. but a predetermined muscle activity is less likely to change by the orthodontic appliances. www.indiandentalacademy.com
  39. 39. RECENT ADVANCES • • • • • • Scoliosometer Stabilometric board Electronic axiograph Mechanical axiograph Kinesiograph Computer tomography www.indiandentalacademy.com
  40. 40. • Scoliosometer: an instrument for optical evaluation of posture allowing to monitor gross variations in patient's posture. www.indiandentalacademy.com
  41. 41. STABILOMETRIC BOARD; • Computer assisted system used to investigate the type of plantar rest, distribution of the barycentre and its balance system, microvariations in patient’s postural behavior and postural muscle activity. www.indiandentalacademy.com
  42. 42. www.indiandentalacademy.com
  43. 43. AXIOGRAPH AND KINESIOGRAPH • Dental instrument used to assess mandibular joint function and disorders. www.indiandentalacademy.com
  44. 44. www.indiandentalacademy.com
  45. 45. COMPUTER TOMOGRAPHY • Used to study muscle function in terms of muscle cross section, muscle volume and muscle density. www.indiandentalacademy.com
  46. 46. • A study [Gedrange T etal Rofo. 2005 Feb;177(2):204-9 ] was done to determine the relationship between the morphological parameters of the masticatory muscles and the jaw bone by computer tomography, lat.ceph. and denture models. It showed higher densities of medial pterygoid, masseter and genioglossus in deep bite individuals than in the open bite cases. Significant difference in the muscle cross section of the masseter muscle was found in individuals with retroclined maxillary incisors and the individuals with open bite . www.indiandentalacademy.com
  47. 47. MUSCLE MALFUNCTION RELATED TO MALOCCLUSION • Malocclusion is a final outcome due to interaction among various factors. • According to Dockrell:-CAUSE RESULTS (ACT AT) TIMES ON TISSUE www.indiandentalacademy.com PRODUCING
  48. 48. EQUILIBRIUM THEORY • States that an object subjected to unequal force will be • accelerated and thereby will move to different position in space. It follows that if any object is subjected to a set of force but remains in the same position those forces must be in a balance or equilibrium . from this perspective the dentition is obviously in equilibrium since the teeth are subjected to variety of forces but don’t move to a new location under usual circumstances The duration of force is more important than its magnitude, due to its biological effect. www.indiandentalacademy.com
  49. 49. DIAGRAMMATIC REPRESENTATION OF INTERDEPENDENCE OF ETIOLOGICAL FACTORS IN MALOCCLUSION ENVIRONMENTAL GENETIC DEVELOPMENTAL CONGENITAL FUNCTIONAL www.indiandentalacademy.com
  50. 50. • Malocclusion represents nature attempt to establish a balance between all morphogenic functional and environmental components • Muscle function causes malocclusion or its function changes as compensatory mechanism • So malocclusion is a dynamic balance at that particular time. www.indiandentalacademy.com
  51. 51. www.indiandentalacademy.com
  52. 52. www.indiandentalacademy.com
  53. 53. Muscle Function Causing Malocclusion Or Malocclusion Produced By Active Muscle Function Participation Are • TONGUE THRUST • • • SWALLOWING MOUTH BREATHING LIP BITING THUMB SUCKING • • • TORTICOLIS CEREBRAL PALSY MUSCULAR WEAKNESS SYNDROME www.indiandentalacademy.com
  54. 54. TONGUE THRUST SWALLOWING • Defined as placement of tongue tip forward between the incisors during swallowing—Proffit. www.indiandentalacademy.com
  55. 55. Tongue Thrust Simple tongue thrust Complex tongue thrust Normal infantile swallow www.indiandentalacademy.com Retained infantile swallowing
  56. 56. Muscle pathophysiology associated with abnormal deglutition • • • • Heavy mentalis activity. Heavy labi superioris and inferioris activity. Moderate post temporal muscle activity Moderate posterior masseter muscle activity. • Moderate supra and infrahyoid activity • Moderate medial pterrygoid activity. www.indiandentalacademy.com
  57. 57. www.indiandentalacademy.com
  58. 58. www.indiandentalacademy.com
  59. 59. www.indiandentalacademy.com
  60. 60. • A case report by Valiathan A. AND Sameer H Shaikh. (J Ind Ortho Soc 1998;31:53-57) showed the effect of an abnormally large tongue in producing the spaces similar in appearance to primate spaces. A 28 year male patient of south Indian origin was presented with a chief complain of proclination of upper anterior teeth along with spacing between the same. His face was fairly symmetrical with convex facial profile, prominent nose, acute nasolabial angle and incompetence of lip. www.indiandentalacademy.com
  61. 61. • .An additional lateral ceph was taken following the administration of radio- opaque contrast medium to highlight the dorsum of tongue and related soft tissue. Based on detailed examination of the tongue dimension, tongue volume, electromyographic activity and force exerted by the tongue, it was concluded that excessively large volume tongue and dimension produce excessive force which possibly causes the malocclusion. www.indiandentalacademy.com
  62. 62. CLINICAL APPLICATION SIMPLE TONGUE THRUST MOYER’S COMPLEX TONGUE THRUST CONSCIOUS LEARNING OF NEW REFLEX. MYOFUNCTIONAL APPLIIANCES MUSCLE EXERCISE TRANSFORMING TO SUBCONSCIOUS LEVEL REINFORCEMENT OF NEW REFLEX FIXED ORTHODONTIC THERAPY MUSCLE TRAINING MECHANICAL RESTRAINTS www.indiandentalacademy.com
  63. 63. www.indiandentalacademy.com
  64. 64. www.indiandentalacademy.com
  65. 65. www.indiandentalacademy.com
  66. 66. www.indiandentalacademy.com
  67. 67. www.indiandentalacademy.com
  68. 68. MOUTH BREATHING • Moyers—one who breathes orally even in relaxed and restful situations www.indiandentalacademy.com
  69. 69. MOUTH BREATHING • • • • • • Characterized by Lowering of mandible Positioning of tongue downward Tipping back of head Upset oral equilibrium Unrestricted buccinator activity www.indiandentalacademy.com
  70. 70. www.indiandentalacademy.com
  71. 71. • Study done by Vig ps et al (ajo 77;258;268 –1980) showed changes in posture as change of about 5 degree in the craniovertebral angle which leads to elevation of maxilla and depression of mandible in the study group individuals. When the nasal obstruction was removed the original posture immediately returned. www.indiandentalacademy.com
  72. 72. CLINICAL APPLICATION • Mouth breathing can be effectively treated by oral screen, • It is inserted at night, before going to bed and worn throughout the night • Precaution– should not be given to obstructive mouth breathers www.indiandentalacademy.com
  73. 73. www.indiandentalacademy.com
  74. 74. THUMB SUCKING • Thumb sucking---placement of thumb or one or more finger in varying depth into the mouth • The effect on dental arch and supporting system depends upon the duration frequency and intensity of the habit www.indiandentalacademy.com
  75. 75. MUSCLE PATHOPHYSIOLOGY • • • • Contraction of cheek muscles. Hypotonic upper lip Hyperactive mentalis Tongue is displaced inferiorly in to the floor of the mouth and laterally between the posterior teeth www.indiandentalacademy.com
  76. 76. www.indiandentalacademy.com
  77. 77. DIAGNOSIS • • • • • • Proclination of upper incisors Retroclination of lower incisors Anterior open bite Tongue thrusting Posterior bilateral cross bite High lip line due to hypotonocity of upper lip • Presence of callus on fingers www.indiandentalacademy.com
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  79. 79. CLINICAL APPLICATION • DEPENDING UPON THE AGE OF THE PATIENT REMOVABLE CRIB PSYCHOLOGICAL METHODS INTRA ORAL HABIT CORRECTING APPLIANCES ORAL SCREEEN RAKES FIXED QUAD HELIX PALATAL CRIB www.indiandentalacademy.com
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  81. 81. LIP SUCKING • Can be defined as forceful wedging of the lip between upper and lower teeth. Lip sucking involves puling the entire lip, including the vermillion border into the mouth www.indiandentalacademy.com
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  83. 83. MUSCLE PATHOPHYSIOLOGY • • • Hyper active mentalis Non functional upper lip Tongue to lower lip seal during swallowing www.indiandentalacademy.com
  84. 84. • A study done by Jung MH et al (Am J Orthod Dentofacial 2003 Jan) to evaluate the influence of force of orbicularis muscle on the incisor position and craniofacial morphology where average and maximum upper lip force was determined by a device ‘y’ meter. The skeletal structure and the incisal angulation were recorded by lateral cephalogram. The result showed that the upper incisor proclination was significantly related to the magnitude of the orbicularis oris force. So the disuse atrophy of orbicularis might be an significant factor in the development of malocclusion. www.indiandentalacademy.com
  85. 85. DIAGNOSIS • Diagnosed as a deleterious, compulsive, functional, muscular habit, either primary or secondary to the increased overjet that results in the collapse of the lower anterior alveolus. www.indiandentalacademy.com
  86. 86. CLINICAL APPLICATION REDUCTION OF EXCESSIVE OVER JET ORTHODONTICALLY IN CASE IF IT IS THE PRIMARY CAUSE INTRA ORAL APPLIANCE TO KEEP THE LOWER LIP AWAY FROM WEDGING BETWEEN THE TEETH eg. ORAL SCREEN , LIP BUMPER LIP EXERCISES www.indiandentalacademy.com
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  89. 89. • A case report by Vaishali and Utreja ( JCO feb 2005)—a 4 year female child was reported with chief complain of protrusive upper anterior teeth and crowding in the lower anteriors and had a history of abnormal speech.. Clinical examination revealed a lower lip sucking habit , a nonfunctional upper lip and hyperactive lower lip. An oral screen was fabricated and was instructed to wear the appliance full time removing it only for eating and brushing ; exercise were also prescribed to improve the lip competence by pulling on the holding ring and closing the lip against the pressure. www.indiandentalacademy.com
  90. 90. • The lip sucking habit was remarkably reduced after 15 days and completely eliminated after three months of appliance wear. There has been no recurrence of the lip sucking habit and the lower alveolus and dentition have remained stable during three years of follow –up observation… www.indiandentalacademy.com
  91. 91. MUSCULAR WEAKNESS SYNDROME • Causes mandible to drop down away from the facial skeleton • Distortion of facial proportions, increased facial height • Excessive eruption of posterior teeth, narrowing of maxillary arch and anterior open bite. www.indiandentalacademy.com
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  93. 93. TORTICOLIS • Struggle between muscle and bone, where bone yields. There is foreshortening of sternocleidomastoid muscle which leads to profound change in the bony morphology of cranium and face, clinically seen as bizarre facial asymmetries with severe malocclusion. www.indiandentalacademy.com
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  95. 95. CEREBRAL PALSY • Lack of motor control which leads to abnormal • muscle function. Uncontrolled and aberrant activities upset the muscle balance that is necessary for the establishment and maintenance of normal occlusion SPASTIC ATHETOSIS TYPES ATAXIA MIXED TREMORS www.indiandentalacademy.com RIGIDITY
  96. 96. ASSOCIATED MALOCCLUSION • Malocclusion occurs twice as often than in average population • Protrusion of max. Ant teeth • Excessive overjet open bite and unilateral cross bites • In spastic type class I div II and in athetoid group class II div I malocclusion is seen along with high and narrow palatal vault www.indiandentalacademy.com
  97. 97. • A study by (Ghafari J, Clark RE et al AJO- DO Feb 1988) 79children having neuromuscular disorder were examined for occlusal and dental characteristics.56 children suffered from primary muscle disorders, 19 suffered from neuropathies and remaining 4 having disorder of neuromuscular junction ..Results showed that post. cross bite occurred more in primary myopathies(57%) as compared to neurogenic disorders(14%). www.indiandentalacademy.com
  98. 98. • In primary myopathy group the patient suffering from Duchene muscular dystrophy exhibited statistically significant delay in the dental emergence(1.06y) unlike the others myopathies(.31y) and neurogenic disorders(.03y). The studies emphasizes the influence of muscular environment on dental development in general. The dentition may be more affected in the primary myopathies than in the neuropathies. www.indiandentalacademy.com
  99. 99. • COMPENSATORY MUSCLE CHANGES ASSOCIATED WITH GENETICALLY DETERMINED CLASS II AND CLASS III MALOCCLUSION. www.indiandentalacademy.com
  100. 100. CLASS TWO DIV ONE MALOCCLUSSION • Muscle pathophysiology-hyperactive mentalis activity. Hypotonic upper lip. Increased buccinator activity. • Treatment-correction of muscle imbalance using MYOFUNCTIONAL appliances in the growth period. www.indiandentalacademy.com
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  103. 103. CLASS TWO DIV TWO MALOCCLUSION • Mainly hereditary. Muscle changes take place • as a compensatory mechanism for existing malocclusion. Dominant activity of post. Fibers of both temporalis and masseter from initial contact position to the position of final occlusion take place Treatment-elimination of posterior fiber dominance by properly guided orthodontic therapy which restores VDO that is in harmony with postural vertical dimension. www.indiandentalacademy.com
  104. 104. CLASS THREE MALOCCLUSION – MUSCLE PATHOPHYSIOLOGY-SHORT UPPER LIP.INCREASED ACTIVITY OF UPPER LIP DURING SWALLOWING.TONGUE LIE LOWER IN THE FLOOR OF THE MOUTH.GRETER MOBILITY OF HYOID BONE DURING DEGLUTITION DUE TO GRETER ACTIVITY OF SUPRA AND INFRA HYOID MUSCLES.THE LOWER LIP IS RELATIVELY PASSIVE ,HYPERTROPHIC,REDUNDANT www.indiandentalacademy.com
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  108. 108. CONCLUSION • The effect of muscle force is three dimensional. Whenever there is struggle between bone and muscle, bone yields. Muscle function can be adaptive to morphogenetic pattern or a change in the muscle function itself can initiate morphological variation in the normal configuration of the teeth and the supporting bone or it can enhance the already existing malocclusion. Sometimes the structural abnormality is increased by compensatory muscle activity to the extent that a balance is reached between pattern, environment and physiology and so at times it is impossible to assign a specific cause and effect role to any one factor. So for an orthodontist it is necessary to conduct orthodontic treatment in such a manner that the finished result reflects a balance between the structural changes obtained and functional forces acting on the teeth and investing tissue at that time. www.indiandentalacademy.com
  109. 109. REFERENCES;-----• Handbook Of Orthodontics 4th Edition—ROBERT E.MOYERS • CONTEMPORARY ORTHODONTICS,3rd Edition.—WILLIAM R. • • PROFFIT, HENRY W.FIELDS.JR ORTHODONTICS PRINCIPLES AND PRACTICE [THIRD EDITION]---T.M.GRABER Dentofacial Orthopedics with Functional Appliance Second Edition —Thomas M.Graber, Thomas Rakosi, Alexandre G.Petrovic • Malfunction of the tongue, part III [WALTER J.STRAUB Am.J.Orthodontics,vol-48,no-7 July 1962 • • The “three Ms”: Muscles, malformation, and malocclusion [T.M.GRABER Am. J. Orthodontics vol-49 number- 6 June 1963] Muscle activity in normal and post normal occlusion [Johan G.A, Ahlgren.Am.J.Orthodontics,vol-64,no-5,November1973] www.indiandentalacademy.com
  110. 110. • Resistance to nasal airflow related to changes in head • • posture. [Z.J. Weber, C. B. Preston, et al. vol -80, No5, Am .J. Orthodontics November 1981] Dental and occlusal characteristics of children with neuromascular disease.[Ghafari J,Clark RE etal,Am.J.Orthod.Dentofac.Orthop,126-32 ,Feb 1988] The dimensions of the tongue in relation to its motility: [Kazuhiko Tamari, et al .Vol- 99 ,No -2, Am. J.Orthod. Dentofac. Orthop. Feb 1991] • Nasal airway impairment: The oral response in cleft palate patients [Donald W. Warren, et al Vol- 99 ,No -4 Am. J .Orthod .Dentofac .Orthop April 1991] www.indiandentalacademy.com
  111. 111. • Malocclusion and the tongue :[Ashima Valiathan,Sameer H • • • • • • Shaikh.31:53-57,J Ind Orthod Soc,1988] Biomechanical influence of head posture on occlusion:an experimental study using finite element analysis.[Motoyoshi M,Shimazaki T etal.Eur.J.Orthod.24(4):319-26,Aug 2002] Effect of upper lip closing force on craniofacial structures.[Jung MH,Yang WS etal.123,58-63,Am.J.Orthod.Dentofacial.Orthop Jan 2003] Fiber type differences in masseter muscle associated with different facial morphologies (Rowlerson A ,Raoul G et al Am .J .Orthod.Dentofacial.Orthop.Vol-127;37 -46 Jan 2005) Myosine heavy chain protein and gene expression in the masseter muscle of adult patients with distal or mesial malocclusion. [Gedrange T ,Buttner C,J.Apply.Genet,46,227-36.2005] Computed tomographic examination of muscle volume ,cross section and density in patients with dysgnathia. [Gedrange T etal,177(2),204-9,Rofo Feb 2005] An oral screen for early intervention in lower- lip -sucking habits– [Vaishali Nandini Prasad ,A . K. Utreja,Vol XXXIX, NO.297—100,Feb 2005JCO] www.indiandentalacademy.com
  112. 112. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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