Vertical jaw relations /certified fixed orthodontic courses by Indian dental academy


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Vertical jaw relations /certified fixed orthodontic courses by Indian dental academy

  1. 1. VERTICAL JAW RELATIONS INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. Contents Introduction  Classification of jaw relations  Vertical jaw relations  Physiologic rest position      hypothesis factors to be considered methods of recording significance
  3. 3.  Methods of recording vertical jaw relations   mechanical methods physiologic methods Tests to aid in confirming the correct vertical dimension.  Altered vertical dimensions and their effects  Conclusion  References 
  4. 4. Introduction  Complete dentures are constructed to function in the mouth as an integral part of the masticatory apparatus & there fore they should be designed to conform to the patient’s physiologic jaw relations.
  5. 5.  To achieve this goal the recording must include an appropriate vertical relation of occlusion, stable occlusal contacts in harmony with the existing T.M.J and masticatory muscle functions, and the relationship between the prostheses & oral & facial soft tissues and musculature.
  6. 6. Mandibular Movements  The constant function of swallowing saliva is the basis for establishing the mandibular position and occlusion.
  7. 7.  In swallowing the saliva, mandible raises to its habitual closing terminal and then as the saliva is forced backward into the pharynx by the tongue, the mandible is retruded to its physiologic centric relation.  These are the mandibular movements that are used in determining the vertical relation and the centric relation for the complete dentures.
  8. 8. Classification of jaw relations  Jaw relations are classified into three groups. They are:Orientation jaw relations. Vertical jaw relations. Horizontal jaw relations.
  9. 9. Vertical dimension  Distance between the two selected anatomic or marked points ( usually one on the top of the nose & the other upon chin), one on a fixed & one on a movable member. [Gpt]
  10. 10. Vertical jaw relations  They are classified as :Vertical dimension of rest. Vertical dimension of occlusion. Vertical dimension of other portions.
  11. 11. Physiological rest position  The Mandibular position assumed when the head is in an upright position and the involved muscles particularly the elevator and depressor groups are in equilibrium in tonic contraction, & the condyles are in a neutral , unstrained position.
  12. 12. Vertical dimension of occlusion  The distance measured between two points when the occluding members are in contact.
  13. 13. Review of literature  Thompson and Brodie (1942) suggested that the position of the mandible in relation to the face and head is unchangeable as is the form of the mandible, and “the proportions of any face as far as vertical height is concerned, are constant through out life.”
  14. 14. Niswonger , Boos, and Jaffe apparently agree with this view.  Leof (1950) believes that this relation is not constant but is readily affected by age, disease, and emotion.  It seems that the constancy of the vertical maxillomandibular relations through out the life represents the unique phenomenon, not generally found in relations of the other bones. 
  15. 15.  Garnick and Ram fjord (1962) stated that rest position is a vertical range rather than a point.
  16. 16. Physiological rest position Vertical dimension of rest.  Postural position of the mandible.  The postural position of the mandible when an individual is resting comfortably in an upright position and the associated muscles are in a state of minimal contractual activity. 
  17. 17. This rest position is established by the muscles and gravity.  Two main hypothesis explain about the rest position of the mandible.  One involves active mechanism.  Second one involves the passive mechanism. 
  18. 18. But according to the current concepts this position is actively determined.  The clinically recorded rest position is usually 2- 4mm below the maximum intercuspation position.  But according to the EMG activity a range of reduced muscle tension upto an interocclusal distance of about 10 mm is recorded. It is therefore more accurate to refer to a range of posture rather than to a single rest position. 
  19. 19. Factors to be considered while recording the rest position  Position of the mandible is influenced by the gravity.  It is a relaxed position of the mandible.  Neuromuscular disturbances.
  20. 20.  Rest position is a position in space.  No one method for determining the rest position is a valid method.  Space between the teeth is essential when the mandible is at rest.
  21. 21. Methods of recording the rest position Facial measurements.  Tactile sense.  Phonetics.  Facial expression.  Anatomical landmarks. 
  22. 22. Significance It is a bone to bone relation.  In the absence of the pathosis the relation is fairly constant through out the life.  Position can be recorded and measured with in the acceptable limits.  It is used in determining the vertical dimension of occlusion. 
  23. 23. Vertical dimension of occlusion  Mechanical methods Ridge relation:1) Distance from the incisive papilla to the mandibular incisors. 2) Parallelism of the ridges. Measurement of the former dentures. Preextraction records:1)Profile radiographs. 2)Casts of the teeth in occlusion. 3)Facial measurements.
  24. 24. Physiological methods Physiological rest position.  Phonetics and esthetics.  Swallowing threshold.  Tactile sense.  Patient reported perception of comfort 
  25. 25. Relationship of ridge/ridge relations
  26. 26.  The incisal edges of the maxillary central incisors are an average 6 mm below the incisive papilla. So the average vertical overlap is about 2 mm.  This relationship of maxillary and mandibular anterior teeth concerns not only the vertical ridge height but also esthetic values.
  27. 27.  Disadvantage:  In the absence of lower anterior teeth, this method cannot be used.
  28. 28. Parallelism of ridges:  Paralleling of maxillary and mandibular ridges plus 5 degree opening in the posterior region as suggested by sears often gives a clue to the amount of jaw separation.
  29. 29.
  30. 30.  Disadvantages: This theory cannot be used when there is great amount of bone loss which would change the ridge relation, also if the patient has lost the teeth at irregular intervals, the line of ridges is naturally thrown out of parallel.
  31. 31.  Measurement of former dentures:  Measurement between the borders of the maxillary and mandibular dentures can be made and can be correlated with the observation of the patients face to determine the amount of change required.
  32. 32. Measurement of former dentures using Boley’s gauge
  33. 33.
  34. 34. Pre extraction records  When natural teeth are in maximum occlusion, the jaws are not necessarily in centric relation.  For this reason all the pre extraction records must be evaluated.
  35. 35. Profile radiographs  Radiograph before extraction must be taken and preserved.  After extraction and after establishing the tentative jaw relation, another radiograph should be taken.
  36. 36.  The two radiographs must be super imposed and compared.  The inaccuracies that exist in either the technique or the method of comparing measurements make these methods unreliable.
  37. 37. Radiographs:
  38. 38. Profile photographs   Profile photographs are made and enlarged to life size. The photograph should be made with teeth in maximum occlusion. Measurements of anatomical land marks are compared with the measurements of face using same land marks .
  39. 39. Disadvantages: Angulations of photographs might differ with the patients posture.  Enlargement can cause inaccuracies.
  40. 40. Profile tracing:  Lead wire adaptation .  This method is full of pitfalls as it is not possible to contour the wire accurately against the soft tissue without producing distortion.
  41. 41.  A piece of soft lead wire is molded to contour of the face starting from the eyebrow to just below the chin along the midline. Then the contour is transferred to the cardboard. The resultant cutout is stored and compared to by placing against the profile which is established after the extraction and estimation of the vertical relation using the record blocks.
  42. 42. Profile silhouettes   Similar to profile tracing. An accurate reproduction of the profile silhouettes can be cutout in a cardboard. Then the silhouettes can be positioned onto the face necessary adjustments can be made.
  43. 43. Diagnostic casts  Various methods to determine vertical relation of occlusion by using the diagnostic casts. Heinz and Peters method.  Quinn et al method.  Bissasu method. 
  44. 44. Casts of teeth articulated in occlusion Heinz and peters method Accurate casts of maxillary and mandibular arches made.  The maxillary cast is related to its correct anatomic position on an articulator with a face bow transfer.  An occlusal record with the jaws in centric relation is used to mount the mandibular cast. 
  45. 45.  After the teeth has been removed, edentulous casts are mounted on the articulator, the interarch measurements are compared and necessary adjustments are made.  They give information of the vertical overlap and size and shape of teeth.
  46. 46.  The casts also assist in the selection of size, shape and position of the teeth.
  47. 47. Disadvantage:  It cannot used when there is a long waiting period for fabrication of denture after extraction.  It cannot be used when there is excessive bone loss during the extraction procedure.
  48. 48. Quinn et al method    Quinn et al made maxillary & mandibular record bases and wax occlusion rims. Recorded the maxillo mandibular relationship and made wax flanges for the dentate areas of diagnostic casts. The maxillary and mandibular record bases, wax flanges, and the stone teeth were duplicated in a duplicating flask using reversible hydrocolloid impression material.
  49. 49.   The replica wax bases are used for making the definitive impression, the resultant stone casts and the replica wax bases and the wax teeth are mounted in an articulator in maximal intercuspation, and the artificial teeth are arranged with the impression material in place. Disadvantages :- 1) This method required additional procedures 2) Time consuming.
  50. 50. Use of lingual frenum Bissasu  Bissasu proposed in determining the original vertical relation by measuring the distance between the center of the Incisive papilla and the incisal edges of the maxillary central incisors and between the anterior attachment of the lingual frenum and then adjusting the maxillary and mandibular wax occlusion rims, anteriorly, to correspond with these measurements.
  51. 51. Advantages : Method is simple  Does not require any additional armamentarium
  52. 52. Facial measurements: These are also pre-extraction guides.  Various devices for making facial measurements are used in different forms.  Dakometer  Willis gauge  Orofacial device 
  53. 53. Dakometer  The instruments record both vertical dimension with the natural teeth in occlusion and the position of central incisors. In most cases recording can be obtained with an error range of + or - 1mm.
  54. 54.  i) The Dakometer
  55. 55. Willis gauge  The instrument is used for recording vertical height, before extraction.  The arm (A) is placed in contact with the base of the nose and arm (B) is moved along the slide (D) until it is firmly and lightly touching the lower border of the chin, then it is locked in position by the screw (C). The distance on the scale (D) is recorded and preserved.
  56. 56.  Disadvantage:  It is not accurate because the degree of pressure applied every time may not be the same.
  57. 57.
  58. 58.
  59. 59. Aabu-Ela and Razek method  They have recorded the vertical relation of occlusion by the use of an orofacial device.  The upper portion of the device extended between the orbital point and the external auditory meatus to form the Frankfort plane.
  60. 60.  The lower part of the device is placed against the inferior border of the mandible and pressed gently against the mandible.  This part of the device formed the mandibular plane.  The angle that was formed by the junction of Frankfort and the mandibular plane was recorded.
  61. 61.  After the removal of the teeth during recording of the vertical relation of occlusion of the edentulous patient, the wax occlusion rims are reduced or increased until the previously recorded angle is duplicated thus restoring the VDO.
  62. 62. Facial measurements using tattoo  Permanent tattoo markings are placed one on the upper half of face and another on lower half of face.  The distance is measured and preserved. These measurements are compared when artificial teeth are tried.
  63. 63.  Silverman has also suggested the placement of tattoo marking on the patient’s upper and lower gingiva, slightly, left to the middle between attached gingiva in depth of vestibule.
  64. 64.  Disadvantage: Patient may not agree for placement of permanent tattoo marks.
  65. 65. Swenson’s acrylic face mask:  Swenson’s described the construction of acrylic resin face mask of the lower third of the face as a record for future determination of vertical dimension.
  66. 66.
  67. 67.  Disadvantages: Time consuming.  Requires lot of skill and experience to make impression of the face.  Face assumes a different topography in the erect posture from that in the recumbent or semi-recumbent position 
  68. 68. The method suggested by Wright:    Wright marked the following measurements from photographs The interpupillary distance Brow chin distance
  69. 69. Interpupillary interpupillary distance in : distance : : Photograph of patient brow chin brow chin distance in : distance in photograph of patient
  70. 70. Physiologic methods
  71. 71. Niswonger method Niswonger suggested this method in 1934.  This method along with phonetics and esthetics is commonly used today.  The patient is seated in such away that ala -tragus line is parallel to the floor. 
  72. 72.  There upon two marks , one at the base of the nose and one on the chin are made.  The patient is told to swallow and relax . the distance between the two marks is measured and recorded .
  73. 73.  Subsequently the occlusal rims are constructed so that when they meet the measured distance is 1/8 inch (2-4mm) less than original distance. This 1/8 inch is the average freeway space.
  74. 74.  Disadvantage : As the marks are on the skin, they tend to move with the skin. So it is difficult to obtain two constant measurements of the rest position.
  75. 75.
  76. 76. Concept of equal thirds: Willis suggested that the face can be divided into equal thirds, the forehead, the nose, the lips and the chin.  However this concept is of little practical value as the points of measurements are entirely vague. 
  77. 77. Vertical dimension by means of power point or Boos method Boos in 1940 stated that there was a point of maximum biting power.  He says that the patient registers the greatest amount of pressure on a spring dynamometer at a point.  So the Bimeter is used in this principle. 
  78. 78. The Bimeter is attached to an accurately adapted mandibular record base.  A metal plate is attached to the vault of an accurately adapted maxillary record base to provide a central bearing point. 
  79. 79.  Adjust the vertical distance by turning the cap.  The gauge indicates the pounds of pressure generated during jaw closure at different degrees of jaw separation.  When the maximum PowerPoint is reached, the lock nut is set, plaster registration is made.
  80. 80. Phonetics as a guide    Silverman’s closest speaking space method. Proposed by Silverman in 1952. Silverman identified that the production of certain sounds like “S” “yes”,”J” , “ch” brings the anterior teeth very close together.
  81. 81. Direct the patient into centric occlusion and draw the line on a lower anterior teeth at the horizontal level of the incisal edges of the opposing upper anterior teeth. This is called the centric occlusion line.  Ask the patient to say yes and while the phonetic sound s is pronounced, draw the closest speaking line on the same lower anterior teeth at the horizontal level of the upper incisal edge. 
  82. 82.  The distance between these two lines is called the closest speaking space.  The measurements ranged from 0 to 10 mm.  The closest speaking space as measured in the natural dentition must be reproduced in complete dentures after the loss of remaining natural teeth.
  83. 83.  This method aids the dentist to evaluate the vertical dimension of occlusion.  When correctly placed the lower incisors move forward to a position nearly directly under the upper central incisors and come close to them but do not contact.
  84. 84.  The position of the tongue and its relation to the teeth is also an important factor, by asking the patient to pronounce repeatedly the number “thirty three”.  The dentist can evaluate if there is enough space for the tip of the tongue to protrude between the anterior teeth.
  85. 85. Swallowing threshold : Shanaban Thomas :  Swallowing reflex is a primitive, innate reflex. The position of the mandible at the beginning of the swallowing act has been used as a guide to the vertical relation. The theory behind this method is that when a person swallows, the teeth come together with a very light contact at the beginning of swallowing cycle.
  86. 86.  The technique involves building a cone of soft wax on the lower denture base so that it contacts the upper occlusion rim with the jaws too wide open.
  87. 87.  The flow of saliva is stimulated and the repeated action of swallowing the saliva will gradually reduce the height of the wax cones to allow the mandible to reach the level of occlusal vertical dimension.
  88. 88. Facial expression and esthetics as a guide:  The experienced dentist learns the advantage of recognizing the relaxed facial expression when the jaws are at rest. In normally related jaws, the lips will be even anteroposteriorly and in slight contact.
  89. 89.  The lips of the patient in case of protruded mandible will not be evenly related , the lower lip will be anterior to the upper lip and not in contact. In case of retruded mandible the lower lip will be distal to the upper lip and not in contact.
  90. 90.  When the vertical dimension is increased both the, mentolabial and nasolabial grooves disappear when V.D is decreased the grooves are exaggerated and the chin appears close to the nose.
  91. 91. Based on harmony of face
  92. 92. Neuromuscular perception and tactile sense: The stretch reflex and proprioceptive mechanisms of muscles and ligaments of temporomandibular joints are retained in the fully edentulous patient.  A number of studies have been done by using this neuromuscular memory to determine the V.D of occlusion with mixed success (Lytle 1964, Tryde et al) 
  93. 93. Tactile sense method: The tactile sense of the patient is used as a guide in the determination of the occlusal vertical relation.  An adjustable central bearing screw is attached in the palate of the maxillary denture base or occlusal rim. The central bearing plate is attached to the mandibular occlusal rim or trial based denture base. 
  94. 94.  The central bearing screw is first adjusted so it is obviously too long i.e the mouth is opened beyond the physiologic rest position. Then in progressive steps, the screw is adjusted downwards until the patient indicates that the jaws are closing to far.
  95. 95. The procedure is repeated in the opposite direction until the patient feels that the length is about right, the adjustments are reversed alternatively until the height of contact feels right.  Patient participation in the decision to establish a vertical dimension record is very important. 
  96. 96. Disadvantage: This method cannot be used in senile patients and in those patients who have impaired neuromuscular perception.  The problem with this method relates to the presence of foreign objects in the palate and tongue space.  The final determination must be made at the try in after the teeth are in position. 
  97. 97.
  98. 98. Bio feed back using electromyography: Rest position of mandible can be determined by means of electromyography which would record the minimal activity of the muscles.  Electrodes can be placed on one or more muscles of mastication to demonstrate their activation potential in the form of visual and audio signs, which are fed back to the patient, to attain a mandibular position showing nil or minimum EMG activity. 
  99. 99. Disadvantages:  The equipment is too expensive  The operate should have considerable knowledge, skill and experience  The patient should be capable of correlating the visual signs to the correct mandibular position. 
  100. 100. Tests to aid in confirming the correct vertical relation: Judgment of overall facial support  Visual observation of space between the rims when the jaws are at rest  Measurement between the dots on the face when the jaws are at rest and when the occlusal rims are in contact 
  101. 101.  Observation made when the sibilant containing words are pronounced, to ensure that the occlusal rims come close together but do not contact. Patient can be asked to pronounce words like Emma,Mississippi,forty five and thirty three for evaluation.
  102. 102. Effects of increased vertical dimension:  It is very important to remember that as mentioned by Mehrson and Tench the tone of the muscles may be increased within physiologic limits but the functional length cannot be increased
  103. 103. Effects Discomfort to the patient  Trauma and pain to the basal seat areas  The jarring effect of teeth coming into contact sooner than expected may not only cause discomfort but in most cases it will also cause pain owing to the bruising of the mucosa by these sudden and frequent blows. 
  104. 104. Loss of freeway space: This will result in fatigue of any one or group of muscle of mastication. In turn, it will result in annoyance from the inability to find comfortable resting position.  Clicking sound when the teeth contact  Appearance: The face has an elongated appearance. The lips are apart at rest 
  105. 105. Effects of reduced vertical height Inefficiency  Cheek biting  Appearance  Angular chelitis  Costons syndrome 
  106. 106. Conclusion  No one method of recording or determining the jaw relations can be accepted as being valid for all patients, there fore it is desirable to use several methods and confirm the results. More over the components of the recording procedure include morphologic and physiologic phenomena, the functional activity, psychological and social criteria particularly in relation to esthetic decisions.
  107. 107. References      Boucher’s prosthodontic treatment for edentulous patients – 9th , 10th ,11th edition. syllabus of complete dentures –Heartwell. Essentials of complete denture prosthodontics –Sheldon Winkler. Complete denture prosthodontics – John J.Sharry. Evaluation diagnosis, and treatment of occlusal problems Peter E Dawson.
  108. 108.     Speaking method in measuring vertical dimension. J.P.D 2001 vol 85 no 5 427-430. Using the neutral zone to obtain maxillomandibular relationships.J.P.D 2001 vol 85 621-3. Pre extraction records for complete denture fabrication. J.P.D 2004 vol 91 55-8. Physiological jaw relations and oclusion of complete dentures. J.P.D 2004 vol 91 203-5.
  109. 109. Thank you For more details please visit