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Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy
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Physiology of the stomatognathic system /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
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  • 1. PHYSIOLOGY OF THE STOMATOGNATHIC SYSTEM INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2. INTRODUCTION  Stomatognathic- of or relating to the jaws and the mouth :webstar’s medical dictionary  As a dentist and especially as an orthodontist,it is essential that we have a sound knowledge of and understand the importance of the stomatognathic system  Until we know what is normal we will not be able to recognise aberrancy www.indiandentalacademy.com
  • 3. Functional Osteology  Bone is one of the hardest tissues of the human body  But it is most adaptive and responsive to functional forces  Meyer -1864:proposed the trajectory theory of bone formation  >the arrangement of the trabeculae in the spongiosa followed a trajectory pattern  1870:julius wolff>these trabecular arrangement was due to functional forces  Any change in direction or intensity of the forces would change the internal archietecture www.indiandentalacademy.com
  • 4. www.indiandentalacademy.com
  • 5. Contd.  Was expresseds by a mechanical mathematical law= law of orthogonality  Now it is established that cartilagenous and membranous bones react differently to forces  Tajectories need not pass at right angles to each other—even their course may be wavy  Increased function increases bone density while decreased function decreases itmuscles have a great influence over bones and may even change their shape  Thus the timed manipulation of the musculature may be beneficial to the orthodontist www.indiandentalacademy.com
  • 6. www.indiandentalacademy.com
  • 7. Beninghoff’s trajectories  Concluded that trajectories can be demonstrated in the maxillo-facial area  Lines pass through both the spongy and compact bone  They obey no individual bone margins     Maxilla: Transfers the whole stress to the cranium Has thin cortices that are interconnected by trabeculae Stress trajectory:can be considered as the craniofacial unit www.indiandentalacademy.com
  • 8.  3 main pillars of trajectories:  All from the alveolar bones an endin in the base of the skull    The canine pillar The zygomatic pillar The pterygoid pillar  Curve around the sinuses,nasal and orbital opening  The supra and infra orbital ridges and the zygomatic buttress reinforce these pillars www.indiandentalacademy.com
  • 9.  Mandible  Absorbs all the stresses  Thick cortices and more radially arranged trabecuae  Stress trajectories  From beneath the teeth-join together in comman pillar—ends at the condyle  Mandibular canal and nerve are protected-unloading of nerve www.indiandentalacademy.com
  • 10.  Thick cortical layer at the base rovides esistance to bending forces  Trajectories from www.indiandentalacademy.com and coronoid the symphysis,angle process join this main pillar
  • 11. www.indiandentalacademy.com
  • 12. myology www.indiandentalacademy.com
  • 13. myology  Property of muscles that are important fr help in kinetic activity are  Elasticity= the ability to return to oiginal lemgth and shape after contraction or extension  Normally relaxed muscle withstand only a certain amount of elongation  Contractility=the ability to contract forcefully when stimulated by an action potential  Energy for this is provided by high energy bonds of ATP  Lactic acid accumulation leads to fatigue www.indiandentalacademy.com
  • 14.  Each fibre is either relaxed or in complete contraction(all or none law)  The state of the muscle depends on how many such fibres are active  Isometric contraction when muscle resists external stress withot shortening-only the tension increases  Isotonic contraction when the tone or tension remains the same but the length decreases www.indiandentalacademy.com
  • 15. www.indiandentalacademy.com
  • 16.  The greatest of contraction is seen when the muscle approximates its resting position  The strength reuces as the muscle shortens or lengthens beyond this position  Other principles of muscle physiology  All or none law  Intensity of contraction is independent of the strength of thr action potential as long as the threshold is crossed  Seen only when the muscle is not fatigued  Muscle tonus  State of slight constant tension  Basis of reflex posture www.indiandentalacademy.com
  • 17.  Resting length  Rather constant  Permits maintenance o postural relationship  Reciprocal innervation and inhibition  Inhibition of contraction may be brought about by excitation of the antagonist  It is through this that movements are coordinated www.indiandentalacademy.com
  • 18. Buccinator mechanism  there is strong inter relarionship between bone an muscle  Muscles are a potent force-at rest or when active  Teeth and supporting tissues are influenced by the contiguous musculature  The balance between the tongue and the perioral musculature influences the morphology of the dental arches and the teeth www.indiandentalacademy.com
  • 19.  The shape and size o the tooth root and the periodontal spaces also helps in the final adaptation  During swallowing and mastication- tongue exerts 2-3 times more force than the peri oral muscles  Counter acted by the tonal contraction,atmospheric pressure,peripheral recruitment from the buccal musculature www.indiandentalacademy.com
  • 20. www.indiandentalacademy.com
  • 21.  Even though doubs still eist about such a balance o force-we must admit that aberration of muscles can an do lead to markedmalocclusion  The continuous band of muscle that encircle the dentition and attach to the pharyngeal tubercle comprises the buccinator mechanism www.indiandentalacademy.com
  • 22. Mechanism contd. www.indiandentalacademy.com
  • 23. Tongue  Opposing the buccinator mechanismis a very powerful structure- the tongue  It has multiple functions  Most developed in a new born  In infancy extrinsic suspensory muscles attach the tongue to the osseous structures  Produces gross movement in the gorizontal direction(suckle-swallow) www.indiandentalacademy.com
  • 24. www.indiandentalacademy.com
  • 25. Contd.  Attached only at the posterior end-can perform many functions  Abnormal functions cause deformation in the dental arches  May be caused by either deformed arches or visceral swallow pattern  Leads to proclination o the maxillary incisors,constriction of buccal segment an may create an open bite  Compensating action of mentalis causes retraction of the lower incisors www.indiandentalacademy.com
  • 26. MUSCLES OF THE TONGUE INTRINSIC EXTRINSIC Superior longitudinal Genioglossus Inferior longitudinal Hyoglossus Transverse Styloglossus Vertical Palatoglossus www.indiandentalacademy.com
  • 27. Muscles of the tongue www.indiandentalacademy.com
  • 28. SUPERIOR LONGITUDINAL MUSCLE Shortens the tongue & makes the dorsum concave INFERIOR LONGITIDINAL MUSCLE Shortens the tongue & makes the dorsum convex www.indiandentalacademy.com
  • 29. TRANSVERSE MUSCLE Makes the tongue narrow & elongated VERTICAL MUSCLES Makes the tongue broad & flattened www.indiandentalacademy.com
  • 30. jhg www.indiandentalacademy.com
  • 31. EXTRINSIC MUSCLES Genioglossus - Mandible Hyoglossus - Hyoid bone Styloglossus - Styloid process Palatoglossus - Palate www.indiandentalacademy.com
  • 32. Hyoglossus – depresses the tongue Styloglossus - pulls it upward & backward Genioglossus – Protrudes the tongue out of the mouth by pulling the posterior part forwards Palatoglossus – brings the palatoglossal arches together, thus shutting the oral cavity from the oropharynx www.indiandentalacademy.com
  • 33. TMJ www.indiandentalacademy.com
  • 34.  Articulation between the mandibular condyle and the inferiorsurface of the sqamous portion of the temporal bone  Compound –movable joint  Meniscus-a fibrous connective tissue wafer fills most of the space between the condylar head and the articular fossa and divides the joint cavities into 2 compartments. www.indiandentalacademy.com
  • 35. normally occupies only half of the joint space, with its posterior attachments filling the posterior half. The disc and its posterior attachments are generally referred to as the soft tissue component of the TMJ. all the above mentioned structures are enclosed with in the capsular ligament It is lined by synovial membrane www.indiandentalacademy.com
  • 36. www.indiandentalacademy.com
  • 37. Head of the condyle is tubular or ellipsoidal Unique feature of the joint is that there are actually 2 joint spaces-seperated by the disc Thus the joint is capable of dual funcion Lower cavity—rotary/hinge movement Upper cavity—gliding/translatory movement www.indiandentalacademy.com
  • 38. www.indiandentalacademy.com
  • 39.  Activity only in the lower cavity till the mnible is opened to the physiological rest position  After tis even gliding motion takes place  When opened in his manner the articular disc glides over the articular eminence  The condyle rotates against the inferior surface of the disc  Lateral pterygoid helps to move the disc anteriorly www.indiandentalacademy.com
  • 40.  In the lateral shift/bennet movement the conyle on the working side rotates nd moves laterally  The condyle on the other ide noves forwards and mesially in an arc  There is no muscle which ertracts the discnothig opposite the action of the lateral pterygoid  Posterior limit formed by the squamo-tympanic fissure—medially by the petro-tympanic fissure www.indiandentalacademy.com
  • 41.  Due to overclosures-the isc is move forward and the conyle rides over the posterior border of the disc  Impinges on the retrodiscal soft tissues-cicking an discomfort to the patient-misdiagnosed as arthritic changespain may be ue to impingment or ue to pterygoid muscle spasm(mpd)  The main reason fo the mpd is neurogenic or psychological www.indiandentalacademy.com
  • 42.  The tmj is beautifully engineerd to hanle multiple tasks endowed to it  To maintain it-proper occlusal management an mainenance of vertical dimensions is essential www.indiandentalacademy.com
  • 43. functional movements of the mandible  Mandible ah 13 muscles attached to it  Due to limitations of morphology and structure of the tmj-can be moved only in certain directions  Has postural stability along with primay movements www.indiandentalacademy.com
  • 44. www.indiandentalacademy.com
  • 45. Forced retrusion Posterior fibres of the temporalis,masseter,suprahyoid muscles opening lateral pterygoid-main. Supra,infra hyoidgenio,mylo hyoids,digasric>stabilising Temporalis,masseter,medial pter.>controlled relaxation closure Temporalis, masseter >main action medial ptery. >part action Lateral ptery >cntrolled relaxation protrusion Lateral and medial pter. Lateral movement Temporalis + lat. pter www.indiandentalacademy.com
  • 46. www.indiandentalacademy.com
  • 47. www.indiandentalacademy.com
  • 48. www.indiandentalacademy.com
  • 49. www.indiandentalacademy.com
  • 50. www.indiandentalacademy.com
  • 51. COMPENSATORY MUSCLE FUNCTIONS  While mastication may call for most potent effort from the associated muscles, the most frequent demands are made by deglutition, respiration, speech and posture.  At times two or more of these functions are carried on simultaneously.  where there is malocclusion or abnormal morphologic relationship certain compensatory or adaptive muscle functions may arise, either to restrain the dental malocclusion or to actually increase the discrepancy. www.indiandentalacademy.com
  • 52. Positions of the mandible  basic positions are  Postural resting position (Physiologic rest)  Centric relation  Initial contact  Centric occlusion  Most retruded position (terminal hinge position)  Most protruded position  Habitual resting position www.indiandentalacademy.com  Habitual occlusion position
  • 53. POSTURAL RESTING POSITION           It is one of the earliest posture positions to be developed. Mandible is suspended from the cranial base by the cradling musculature. Here the jaws are separated by a constant distance. Factors influencing the postural position are the following: Body and head posture Sleep Psychic factors influencing muscle tonus Age Proprioception from the dentition and muscles Occlusal changes such as attrition Pain Muscle disease and muscle spasm and www.indiandentalacademy.com Temporomandibular joint disease.
  • 54. CETRIC RELATION  As far as muscle physiology is concerned, centric relation may be defined as unstrained, neutral position of the mandible in which the anteriosuperior surfaces of mandibular condyles - in contact with the concavities of the articular disks as they approximate the posteroinferior third of their respective articular eminentia.  This means that the mandible is deviating neither to the right nor to the left and is neither protruded no retruded.  Such a relation can be the same as the postural resting position, the point of initial occlusal contact and centric occlusion. www.indiandentalacademy.com
  • 55. INITIAL CONTACT  As the mandible moves from physiologic rest or the postural resting position toward occlusion of teeth, if all is normal it maintains a centric relation position as far as the articular fossae are concerned.  If there is normal occlusion the point of initial contact produces no change in the function of temporomandibular joint and all inclined planes are brought together simultaneously in the maxillary and mandibular teeth.  Premature contacts are seen quite frequently, they can initiate deflections in the mandibular path of closure.  This causes traumatic forces to be exerted on the teeth and severe cases will produce www.indiandentalacademy.com temporomandibular joint problems
  • 56. CENTRIC OCCLUSION  Centric occlusion is a static position  It is harmonious with the centric relation  Teeth brought into contact with unstrained relation of the condyles  Few patients can show centric occlusion  Establishes the occlusal vertical dimension  Not necessarily the maximum intercuspation position www.indiandentalacademy.com
  • 57. MOST RETRUDED POSITION (Terminal Hinge Position)  Reproducible retruded mandibular position with the teeth in occlusion  Normally starting point in occlusal rehabilitation  Some patients can easily retrude a few mm. while others find it difficult  Mandible should not be guided or forced beyond the unstrained position of the mandible-unbiological-would compress the tissues. www.indiandentalacademy.com
  • 58. MOST PROTRUDED POSITION  This position is variable from individual to individual than the detruded position.  Shows the range of movement of the mandible  Flacidity of capsular ligament allows ondyle to over ride the anterior margin of the eminence  Condyle locked-muscles tetanisedfatigue www.indiandentalacademy.com
  • 59. HABITUAL RESTING POSITION  There are certain types of malocclusions that prevent the patient from achieving a physiologic resting position.  Example in class II div 2 malocclusion with maxillary incisors inclined lingually there is a tendency to force the condyles posteriorly and superiorly in the articular fossae  the physiologic resting positions can be changed due to mental disturbances, enlarged adenoids, temporomandibular joint pathology, psychic trauma, selective paralysis by poliomyelitis and confirmed mouth breathing etc. www.indiandentalacademy.com
  • 60. HABITUAL OCCLUSAL POSITION  In normal occlusion the centric occlusion and habitual occlusion should be the same. But the occlusal relationship can be changed when there is an environmental imbalance induced by improper restoration, tooth loss etc.  It is vitally important that the dentist make sure that the habitual occlusal position and the centric occlusal position are the same  they are in harmony with centric relation and the postural resting position of the mandible. www.indiandentalacademy.com
  • 61. Functions of the system  These are     Deglutition Mastication Respiration Speech www.indiandentalacademy.com
  • 62. DEGLUTITION Infantile swallow ( visceral swallow) Mature swallow ( somatic swallow) www.indiandentalacademy.com
  • 63. INFANTILE (VISCERAL) SWALLOW www.indiandentalacademy.com
  • 64. CHARACTERISTICS OF INFANTILE SWALLOW The jaws are apart, with the tongue between the gum pads The mandible is stabilized by contraction of the muscles of the 7th cranial nerve & the interposed tongue. The swallow is guided, & to a great extent controlled by sensory interchange between the lips & www.indiandentalacademy.com the tongue.
  • 65. TRANSITION PERIOD At about the 5 to 6th month of age, as the incisors begin to erupt, certain proprioceptive impulses come into play & the peripheral portions of the tongue starts to spread laterally. An average infant would show a dominant & exclusive thrusting swallow for the first 6 months of life,a transitional thrusting & lateral spread of tongue during the next year & a dominant somatic swallow thereafter. www.indiandentalacademy.com
  • 66. MATURE ( SOMATIC) SWALLOW www.indiandentalacademy.com
  • 67. CHARACTERISTICS OF MATURE SWALLOW The teeth are together The mandible is stabilized by contraction of the mandibular elevators,which are primarily 5th cranial nerve muscles The tongue tip is held against the palate, above & behind the incisors There are minimal contractions of the lips during the mature swallow. www.indiandentalacademy.com
  • 68. DEGLUTITION CYCLE FLETCHER gave 4 phases 1.Preparatory swallow 2.Oral phase of swallowing 3.Pharyngeal phase of swallowing 4.Esophageal phase of swallowing www.indiandentalacademy.com
  • 69. PREPARATORY SWALLOW  Starts as soon as liquids are taken in, or after the bolus has been masticated  The liquid or bolus is then in a swallowpreparatory position on the dorsum of the tongue.  The oral cavity is sealed by lip & tongue. www.indiandentalacademy.com
  • 70. Oral phase of swallowing  Soft palate moves upward & the tongue drops downward & backward  Larynx & hyoid bone move upward  Smooth path for the bolus as it is pushed from the oral cavity by the wave like rippling of the tongue  Oral cavity is stabilized by the muscles of mastication, & maintains the anterior & lateral seal www.indiandentalacademy.com
  • 71. Pharyngeal phase of swallowing  Begins as the bolus passes through the fauces  The pharyngeal tube is raised upward en masse  Nasopharynx is sealed off by closure of the soft palate against the posterior pharyngeal wall  Hyoid bone & base of tongue move forward as the pharynx & tongue continue their peristaltic – like movement of the bolus of the food www.indiandentalacademy.com
  • 72. Esophageal phase of swallowing  Commences as the food passes the cricopharyngeal sphincter  While peristaltic movement carries the food through the esophagus, the hyoid bone , palate & tongue return to their original positions www.indiandentalacademy.com
  • 73. Mastication  In the infant food is taken by sucklingunlearned or automatic reflex  Rythmic cving in of the cheeks,bobbing of the hyoid bone,snake like movement of the tongue,anterior movement o the ongue and nodding movement of the head  Mandible is protuded  During deglutition rythmic contractionof the tongue and facial musclesaids in stabilising the mandible www.indiandentalacademy.com
  • 74. Contd.  Change to solid food-lesser action of the lips and lesser thrust o the mandiblelteral thrust of the mandible seen-more to the working side  6 phases outlined by murphy  1)preparatory phase=>food in mouth-tongue positions it-mandible moves to working side  2)food contact=>characterised by a pauseprobably to determine food consistency www.indiandentalacademy.com
  • 75. Contd.  3)crushing phase=>starts with high velocity and slows down as food is crushed  4)tooth contact=>takes place with skight change in direction-muscles are already ready for this  5)grinding phase=>transgression of the mandible across the maxillary teeth-most patients chew unilaterally-cyclic event  6)centric occlusion=>mandible back to terminal position-next cycle begins www.indiandentalacademy.com
  • 76. Respiration  Inherent reflex activity  Demand on muscles are more subtle and more difficult to appreciate  Posture has a significant effect on respiration  Oral musculature is responsible for vital positional relationships-maintains the airway  In the infant-airway maintained by Mandible maintained anteroposteriorly  Stability f the tongue and post. Pharyngeal wall  Axial musculature around the vertebrae www.indiandentalacademy.com
  • 77. Cont.  All the learned jaw functions are built around and accomodated to the tongue and mandibular positions wich ake clear airway possible  Maintainance of the respiratory spaces and airway is significant in facial growth  Respiration in the chil helps keeping the pharynx patent as well  Important for development of speech as well www.indiandentalacademy.com
  • 78. Speech         Learned activity –depends on maturation of organism Makes use of muscles that have other functions According to WEST other than speech functions are:: A>innate,automatic,vegetativeswallowin,breathing,gagging etc. B>learned,automatic,vegetative-biting,chewing,sucking C>lerned,automati,emotional-grimaces,mannerisms D>innate,automatic,emotional-laugh,smile.sob E>learned,non automatic,discriminatory,voluntaryexplore with tongue,spreading lips,kissing,blowing www.indiandentalacademy.com
  • 79.  F>learned,automatic practical reactionswhistling,playing instrument,humming Muscles involved Walls of the torso,the respiratory tract,the pharyx,the soft palate,the tongue,the lips and face and nasal passageways are involvedsimultaneou breathing is necessary to provide vibrations for sound Tongue,lips and velopharyngeal closure www.indiandentalacademy.com moify utgoing stream to produce sound
  • 80.  Normal structure is necessary for production of sound-in cleft palate cases not possible even with muscular compensation  Speech mechanism changes air direction,flow,release,pressure,general and lingual air path  Any aberrancy may lead to compensatory morphological changes like enlarged adenoids,compressed nares etc. With respect to tongue  In infancy-suckle reflex is active-only extrinsic muscles are well developed-only later the intrinsic muscles capable of speech develope www.indiandentalacademy.com
  • 81.  The lips and the tongue undergo maturational changes  Degree of lip protrution varys the length of the vocal tract  With the reduction of suckle swallow-delicate movements of the lips are noted. Velopharyngeal closure  Very important for the dentist-in conditions of cleft palate-inadequate valving is seen-even in rehabilitated cases  Upward and backward movement to contact the post pharyngeal wall is important for certain sound production  It is seen that compensatory lip and tongue activity is present to ward over www.indiandentalacademy.com malocclusions.
  • 82. conclusion  The study of the intra oral and peri oral structures-their normal morphology and activity is very important for us.  Unless we know what is normal it is difficult to recognise and correct abnormalities  Also, the structures are all inter related ::follow scientific principles and order in their development.  It becomes important to follow the functions of the structures which ultimately leads to changes in the morphology.. www.indiandentalacademy.com
  • 83. bibliography  Orthodontics:principles and practicesT.M Graber  Orthodontics:Graber and Vanarsdal  Contemporary Orthodontics: William.R.Proffit  Handbook Of Facial Growth :Donald.H.Enlow www.indiandentalacademy.com
  • 84. www.indiandentalacademy.com

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