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


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

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. The Physiology of the Stomatognathic System 1.Functional Osteology 2.Myology 3.Functions of the Stomatognathic System 4.TMJ functions of the stomato -gnathic system… Respiration Deglutition Speech Olfaction Mastication
  3. 3. INTRODUCTION Mostly in the past orthodontic evaluations were done in based on how the upper jaw meet the lower jaw in occlusion which is static analysis,but nowadays its mandatory to appreciate the concept of dynamic occlusion since function can influence the overall pattern and relationship of the parts,the very foundations of the stomatognathic system.
  4. 4. FUNCTIONAL OSTEOLOGY Although bone is the hardest tissue in the body,it is one of the most responsive to change when there is an alteration in the environmental balance .as an orthodontist can establish a perfect occlusion of teeth,but unless he takes into consideration the effects of the use of these teeth,unless he makes allowances for the manifold environmental functional influences,the delicately responsive bony structures are apt to change,and the tooth positions will also change with them.
  5. 5. There are various bones that make up the skull,we will study these from the orthodontic point of view as the cranial component and the mandibular component.Both these components are joined by the Temporomandibular joint which is the most often used joint.functionally all the various bones act as a single unit.
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  7. 7. Functional Osteology Relationship of form and function
  8. 8. The functional matrix hypothesis This theory describes the relationship of form and function. It claims that the origin,form,position,growth and maintenance of all skeletal tissues and organs are always secondary,compensatory and necessary responses to chronologically and morphologicaly prior events or processes that occur in specifically related nonskeletal tissues,organs or functioning spaces.
  9. 9. Functional matrix hypothesis
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  11. 11. Trajectorial theory of bone formationMeyer & Culmann The alignment of the bony trabeculae followed definite engineering Principles.when lines were drawn following discernible columns of oriented bony elements,these lines showed a structure similar to the trajectories seen in a crane. Trajectories were seen to be crossing at right angles to each other.Enabling the bones to resist the Functional stresses it is subjected to.
  12. 12. Beninghoff’s trajectories of Force Categorized the trajectories of forces for the maxilla and the Mandible.trajectories are nothing but lines of orientation of bony trabeculae. These are the pathways of Maximal pressure and tension And bone trabeculae is Thicker in these regions where Stresses are greater. Maxillary trajectories are… Vertical: a) Canine b) Zygomatic buttress c) Pterygo-maxillary Horizontal: Hard palate, orbital floors
  13. 13. Trajectories of the mandible
  14. 14. trajectories for mandible The trabecular columns radiate from beneath the alveolar process and join together in a common stress pillar that terminates in the mandibular condyle.The mandibular canal and nerve are protected at the same time by this concentration of trabaculae(this demonstrates the unloaded nerve concept)
  15. 15. Wolff’s Law and internal architecture of Bone. The size and the shape of bone is a direct representation of the function it performs or carries out.according to this law the trabecular alignment was due primarily to functional forces.Bone elements once formed rearrange themselves in the direction of the functional pressure and increase or decrease their mass to Reflect their… “functional stress”.this law is also known as the law of orthogonality.
  16. 16. The internal Architecture of bone. Changes in the functional forces can produce a remarkable change in the bony architecture..
  17. 17. Postural abnormalities and bony changes Kyphosis –or curvature of spine,in which some vertebrae are stressed unevenly Osteoporosis- lack of function leads to reduced density of bone tissue ,Osteosclerosisincreased function produces a greater density of bone in a particular area.
  18. 18. Changes associated with hyper functioning and hypo functioning . Changes in size and shape. . Alveolar bone density and associated radiological changes. . Due to postural changes and Increased stresses
  19. 19. Sexual and ethnic variations
  20. 20. Myology In defining normal muscle Functions… Swallowing patterns Neutral zone Buccinator mechanism
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  22. 22. Muscles of facial expression The muscles of the face are…. Epicranium,orbicularis oris,zygomaticus major,levator labii superioris,buccinator,mentalis,platysma, risorius,orbicularis occuli,corrugator supercilii,levator palpebrae superioris.
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  24. 24. Importance of the Buccinator mechanism Force exerted by the lip musculature anteriorly and buccinator,and muscles of the cheek posteriorly is counteracted by the force exerted by the tongue.Thus balanced force is transmitted to the teeth and supporting bone
  25. 25. Buccinator mechanism The major factor in environmental balance is the muscle musculature.muscles are a potent force,whether they are in active function or at rest.As already seen even a resting muscle is performing a function,that is maintaining posture and a relationship of contiguous parts.The teeth and supporting structures are constantly under the influence of the contiguous musculature.The integrity of the dental arches and the relations of the teeth to each other within each arch and with opposing members are the result of the morphogenic pattern,as modified by the stabilizing and active functional forces of the muscles.
  26. 26. Passive muscle function / Neutral zone An arch form is defined by its encompassing soft-tissue Drape. What are the possible Effects due to imbalances !
  27. 27. TONGUE The physiology of tongue is important for the orthodontist,when swallowing,tongue thrust,open bite are taken into consideration .In infancy the extrinsic muscles attach the tongue to various osseous structures and are largely responsible for gross movements,mostly in the horizontal plane(suckleswallow).the genio glossus most involved in the plunger like suckleswallow.there are four intrinsic muscles,they are-superior longitudinal,inferior longitudinal,vertical and transverse. the tongue has amazingly versatile functional possibilities by the virtue of the fact that it is anchored at only one end.this very freedom permits the tongue to deform the dental arches when function is abnormal.when the tongue activity is abnormal,irrespective of its cause which may be a compensatory response to abnormal morphogenetic pattern or retained infantile or visceral swallow,the balance between the outside and inside force is disturbed which leads to development of malocclusion like maxillary anterior protrusion,open bite and narrowing of maxillary arch.
  28. 28. tongue --contd compensatory mentalis activity may follow this and exert a strong retracting force on mandibular incisors.malocclusion reprsents natures attempt to establish balance between all morphogenetic ,functional and environmental components.A malocclusion is dynamic balance at that particular time.tongue plays a very important role in the functions of stomatognathic system like mastication,deglutition,respiration and speech.most functions are a net result of the activity or two or more muscles.
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  31. 31. functional movements The mandible is the only movable bone in the body .The muscles bring about the movements of mandible.the muscles that bring about the functional movements of mandible aretemporalis,lateral pterygoid, masseter,supra hyoid,infra hyoid.
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  35. 35. Normal swallowing patterns Infantile swallow . Gum pads (absence of teeth) . Anterior Mouth seal . Mandibular stabilization Features of infantile swallow Lip seal thro’ circumoral activity and associated tongue posturing in-between the gum pads. Mandible stabilized against the tongue Nerve involved is the …..????
  36. 36. Normal swallowing patterns Adult swallow … Teeth together swallow. … Mandibular stabilization. … Anterior lip seal. Nerve involved….????
  37. 37. The Physiology of the Stomatognathic System Enumerating functions… Respiration Deglutition Speech Olfaction Mastication Maintenance of Head posture
  38. 38. Moyers characteristics of swallowing Characteristics of infantile swallow Jaws are apart with the tongue between the gum pads The mandible is stabilized by contraction of the muscles of the 7th Cranial nerve and the interposed tongue The swallow is guided and to a great extent controlled by sensory Interchange between the lips and the tongue. Characteristics of mature swallow Teeth are together Mandible is stabilized by the contraction of the mandibular elevators 5 th cranial nerve The tongue tip is held against the palate above and behind the incisors Minimal contractions of the lips during the mature swallow
  39. 39. Comparison…?
  40. 40. Phases of deglutition Fletcher’s division of the deglutition cycle Preparatory phase Oral phase Pharyngeal phase Esophageal phase … Once a minute during meals … Nine times during eating … 2400 in a twenty four our period !!!
  41. 41. Tongue positions during swallowing
  42. 42. Classification of tongue thrust James S Braner and Holt Deforming and NonDeforming Also… Simple tongue thrust Complex tongue thrust
  43. 43. Speech Labiodental - “f” and “v” Bi-labial “p, b--w, m” Linguo-dental “th” Linguo-alveolar “t”, “d”, “s”, “z” and “n” Linguo-palatal “Ch”, “j” , “sh”. Linguo-velar …ng” Linguo-velar-pharyngeal “k” “g”
  44. 44. T M J - Essential Anatomy
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  49. 49. Positions of the Mandible To understand the variations from the normal the basic sagitta Plane positions of the mandible with respect to the maxilla and The cranium. The Basic mandibular positions are… 1. 2. 3. 4. 5. 6. 7. Postural resting position-”Physiological rest position’ Centric relation Initial contact Terminal Hinge position-most retruded position Most protruded position Habitual rest position Habitual occlusal position
  50. 50. Factors affecting Physiological rest position Factors are… 1. 2. 3. 4. 5. 6. 7. 8. 9. Body and posture Sleep Psychic factors influencing the muscle tonus Age Proprioception from the dentition and the muscles Occlusal changes Pain Muscle disease and muscle spasm Tmj disease
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  56. 56. Conclusion
  57. 57. Thank you For more details please visit