Growth prediction /fixed orthodontic courses

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  • Growth prediction /fixed orthodontic courses

    1. 1. GROWTH PREDICTION • • • • • Introduction Definition Uses Methods Limitation www.indiandentalacademy.com
    2. 2. INDIAN DENTAL ACADEMY • Leader in continuing dental education • www.indiandentalacademy.com www.indiandentalacademy.com
    3. 3. GROWTH PREDICTION • Introduction • • • Scammon’s curve Cephalocaudal gradient Data from various studies Bolton brush study Iowa growth study www.indiandentalacademy.com
    4. 4. GROWTH PREDICTION Definition • Assumption of ability to estimate practically future growth. • Asserting on the basis of theory, data or experience but in advance of proof. www.indiandentalacademy.com
    5. 5. GROWTH PREDICTION Why it is necessary ? • Helps in diagnosis • Development of satisfactory treatment plan www.indiandentalacademy.com
    6. 6. Growth prediction Methods of predicting facial growth change  According Bjork  Computerized prediction methods  Logarithmic spiral  Arcial growth of the mandible  Visual treatment objective • Jacobson and Sadowsky • Ricketts • Holdways www.indiandentalacademy.com
    7. 7. GROWTH PREDICTION Methods of predicting facial growth change According Bjork • Longitudinal approach • Metric approach • Structural approach www.indiandentalacademy.com
    8. 8. Growth prediction • Longitudinal approach - Tweed on growing pt. 2 lateral ceph. 12-18 months apart 3 categories Type A Type B Type C www.indiandentalacademy.com
    9. 9. Growth prediction type A – middle & lower face growth in unison + equal change in vertical & horizontal dime. Type B – middle face > lower face Type C – lower face < middle face www.indiandentalacademy.com
    10. 10. Growth prediction Tweed – growth pattern remain constant. - Moore et al - No use in predicting changes. • Limitation Accurate in Retrospective. • Conclusion – Not accurate method. www.indiandentalacademy.com
    11. 11. Growth prediction • Metric approach - consist of measuring different structure on a single radiograph & then relating these measurement to future growth changes . Correlation coefficient =r - Association b/w 2 variable - Direction either positive or negative of the relationship - It is used in prediction by Squaring the value of ‘r’ = coefficient of determination ( amount of www.indiandentalacademy.com variation of 2nd variable )
    12. 12. Growth prediction • Bjork ,Harvold ,Lande, Solow ,others - Correlation Coefficient not more 0.4 or 0.5 - 16% to 25% variation Conclusion this methods is least clinically siginificant www.indiandentalacademy.com
    13. 13. Growth prediction • Structural approach - To predict mandible growth direction - Superimposition on metallic implant - 7 areas 1. Inclination of condyle 2. Curvature of the mandibular canal 3. Inclination of symphysis www.indiandentalacademy.com
    14. 14. Growth prediction 4. Shape lower border of 5. 6. 7. the mandible The interincisal angle The interpremolar or molar angle The anterior lower facial height Conclusion This is also least clinically siginificant www.indiandentalacademy.com
    15. 15. Growth prediction • Skeiller ,Bjork, and Linde – Hansen • 1. 2. 3. 4. (Tried to quantify it) 4 variable MP inclination - Anterior cranial base (MP:SN) or Ratio of posterior & anterior facial height The intermolar angle Shape of lower border of the mandible (GO - ME to lower border of the mandible) Symphysis inclination (sym. Anterior surface –SN) www.indiandentalacademy.com
    16. 16. Growth prediction • Measurement of these variables were included R squar = 0.8612 = 86% variation in direction of mandibular growth • But 86% was high value www.indiandentalacademy.com
    17. 17. Growth prediction Methods of predicting facial growth change  According Bjork  Computerized prediction methods  Logarithmic spiral  Arcial growth of the mandible  Visual treatment object www.indiandentalacademy.com
    18. 18. Growth prediction • Computerized prediction methods • • 1. 2. Tool of analysis not a method Advantage Facilitates testing Complex formulas to growth prediction www.indiandentalacademy.com
    19. 19. Growth prediction • Ricketts 1970 – potential of computerization - Cephalogram (diagnosis ,T/P) • Greenberg & Johnston - Computer forecasts not better than the assumption of average growth - No difference bet. this & method based on simple addition of the average changes. www.indiandentalacademy.com
    20. 20. Growth prediction Methods of predicting facial growth change According Bjork Computerized prediction methods Logarithmic spiral Arcial growth of the mandible Visual treatment object www.indiandentalacademy.com
    21. 21. Growth prediction • Logarithmic spiral Golden triangles Why  how the position of 3 foramina on the unitary , logarithmic spiral in anterior open bite and deep bite pt. (Melvin. Moss ) www.indiandentalacademy.com
    22. 22. Logarithmic spiral www.indiandentalacademy.com
    23. 23. Evolution of logarithmic spiral • • • • Sectioning of a line Smaller section is proportional to large section Larger portion is called ‘golden section’ Larger section is Phi / www.indiandentalacademy.com
    24. 24. Evolution of logarithmic spiral • Small section is 1 • Larger = 1.618 times • the smaller The smaller is 0.618 the length of the larger www.indiandentalacademy.com
    25. 25. Evolution of logarithmic spiral • Phi relationship - Plants, animals, human body , face • Golden progression – series of these proportions - Symbols - 2 3 , , 4 www.indiandentalacademy.com
    26. 26. Evolution of logarithmic spiral • Golden triangle • • • Base of a triangle 1.0 Sides of equilateral triangle 1.618 Forms a 72 – 72 -36 degree www.indiandentalacademy.com
    27. 27. Evolution of logarithmic spiral • Bisection of one base angle cross the opposite side • Divide that side into a golden section • Form new golden triangle www.indiandentalacademy.com
    28. 28. Evolution of logarithmic spiral • Bisection of golden triangle can be made in a series www.indiandentalacademy.com
    29. 29. Evolution of logarithmic spiral • Curve used to connect the points on a series of the triangles • Form Logarithmic spiral. www.indiandentalacademy.com
    30. 30. Logarithmic spiral • So human mandible grows as a logarithmic spiral on the arc. www.indiandentalacademy.com
    31. 31. • • • 1. 2. 3. Logarithmic spiral Melvin Moss Aim - determine the position of 3 foramina on the unitary , logarithmic spiral in anterior open bite and deep bite pt. These conditions can be anticipated at young age even before orthodontic diagnosis Foramen Foramen ovale Mandibular foramen inferior alveolar nerve Mental foramen www.indiandentalacademy.com www.indiandentalacademy.com
    32. 32. Logarithmic spiral • Introduction Studied the position of the inferior alveolar nerve • Conclusion These foramina , at all ages fit precisely upon a single mathematically defined logarithmic spiral www.indiandentalacademy.com
    33. 33. Logarithmic spiral Foramen “moved” down along this same logarithmic spiral in geometric fashion The gradient of motion directly increasing with the distance of the foramina from cranial base. www.indiandentalacademy.com
    34. 34. Logarithmic spiral • Method and materials 2 group of pt. Columbia university University of utah 16 pt - 3 m & 4 f 4 groups (Ant Open bite) 10 pt Normal swallowers -4m&5f 10 pt Tongue thrust (Deep bite) 5 pt Angle II div 1 5 pt Ant open bite www.indiandentalacademy.com
    35. 35. Logarithmic spiral • Tracing of cranial base & mandibular outline from films • Superimposed the logarithmic spiral • Position of 3 foramen marked on it. www.indiandentalacademy.com
    36. 36. Logarithmic spiral • Result  Singular position of foramen ovale in anterior open bite.  Foramen ovale located farther down the spiral. Help in diagnosis  No sexual dimorphism www.indiandentalacademy.com
    37. 37. Logarithmic spiral  Mandibular & mental   foramen also further down the logarithmic spiral in AOB Not as diagnostically unique Distance between these not decreased. www.indiandentalacademy.com
    38. 38. Logarithmic spiral  Foramen oval cluster relatively ‘high’ up on the spiral in deep bite. www.indiandentalacademy.com
    39. 39. Logarithmic spiral Discussion Mandibular shape - inferior alveolar nerve - 2 factors foramina position on the spiral distance between them. • Fetal & circumnatal periods - All foramina placed near the origin of spiral and nearer to each other - Flatter curvature - Mandible gonial angle relatively obtuse or flat. www.indiandentalacademy.com
    40. 40. Logarithmic spiral With growth , all foramina moved down along the spiral and distance • Ramus becomes more erect relatively to corpus • Gonial angle becomes acute www.indiandentalacademy.com
    41. 41. Logarithmic spiral • Anterior open bite  Foramen ovale down along the spiral Distance mand. &mental foramen not decrease Course of inferior alveolar nerve flatter  Ramus & corpus more obutse www.indiandentalacademy.com
    42. 42. Logarithmic spiral • Deep bite ‘Higher’ up on the spiral  3 neural foramina distance not decreased  Inferior alveolar nerve curvilinear course  Ramus & corpus more acute www.indiandentalacademy.com
    43. 43. Logarithmic spiral • Anterior cranial base – Richardson Sella - NA Deep bite Anterior open bite www.indiandentalacademy.com
    44. 44. Logarithmic spiral Anterior open bite • Gonial angle Ar –Go-Me Obtuse • Mandibular size Ramus Corpus Shorter Normal length • Anterior cranial base (S-Na) No difference www.indiandentalacademy.com Deep bite Acute No significant linear difference
    45. 45. Logarithmic spiral Anterior open bite • Periosteal functional matrix (Massater) Deep bite No difference in attachment site • Capsular functional matrix Oral functioning space Abnormal www.indiandentalacademy.com Normal
    46. 46. Growth prediction Methods of predicting facial growth change According Bjork Computerized prediction methods Logarithmic spiral Arcial growth of the mandible Visual treatment objective www.indiandentalacademy.com
    47. 47. Principal of Arcial growth of the mandible Robert M. Ricketts • Purpose – explain a method for finding the arcial growth of the mandible and to enumerate some uses of the principal • Based on computer study • Predict long range growth forecast www.indiandentalacademy.com
    48. 48. Arcial growth of the mandible • Principal – mandible grows by superioranterior apposition at the ramus on a curve or arc which is a segment formed from a circle. • Radius – Pm to point Eva. www.indiandentalacademy.com
    49. 49. Arcial growth of the mandible • Growth of the mandible 1. 2. 3. Roentgenographic cephalometric Bjork Enlow Bjork - variation in the mandibular bending. - Resorption of lower angular border - 3rd molar crypt – stable longitudinal reference Enlow 3D growth pattern Remodeling area Reversal areas of stability www.indiandentalacademy.com
    50. 50. Arcial growth of the mandible Prediction of mandibular growth • Primary methods - • • • Long axis of condyle & neck Lower border of mandible ‘Central core’ cephalomertrically Search for ‘reference point’ External mandible (mandibular plane,ramus plane, condyle – symphysis ) www.indiandentalacademy.com
    51. 51. Arcial growth of the mandible • Xi point – center of ramus Occlusal plane Entrance of neurotrophic bundles www.indiandentalacademy.com
    52. 52. Arcial growth of the mandible • Bisect the height of ramus from the sigmoid notch www.indiandentalacademy.com
    53. 53. Arcial growth of the mandible www.indiandentalacademy.com
    54. 54. Arcial growth of the mandible • • • • Dc point Condyle axis Corpus axis Change in angle - change in mandibular form • Second method – • Magnitude & angular relation. More successful as a method of forecasting www.indiandentalacademy.com
    55. 55. Arcial growth of the mandible • Suprapogonion / Pm Reference point Ricketts – stress center Enlow – site of reversal line Bjork - cosistent www.indiandentalacademy.com
    56. 56. Arcial growth of the mandible • The objective of research was still towards finding a method to critically predict future form and size of the mandible over the long range. www.indiandentalacademy.com
    57. 57. Arcial growth of the mandible computer study • 5 yrs growth study of mandible & lower dental arch • In lateral & frontal head films -362 measurement www.indiandentalacademy.com
    58. 58. Arcial growth of the mandible • • • • • • Material 40 pt – lateral & frontal cephalometric film One group – 8 yrs another group -13 yrs No orth. t/t 20M & 20F 20 – class I with normal occlusion 20 - class II malocclusion www.indiandentalacademy.com
    59. 59. Arcial growth of the mandible Findings • Mandible bend ½ • • degree per year. Bending in an orderly manner. Growth arc was operative. www.indiandentalacademy.com
    60. 60. Arcial growth of the mandible • To determine the true arc of growth of the mandible • First arc – Pm ,Xi ,Dc • Straightening of the mandible www.indiandentalacademy.com
    61. 61. Arcial growth of the mandible • Second arc - tip of coronoid , R1 , Pm • Segment of circle small in radius. • Excessive bending of mandible www.indiandentalacademy.com
    62. 62. Arcial growth of the mandible • True arc – • • • Condylar & Coronoid process , Ramus center & it’s ant. Border Radius increase or changing with the size of the mandible Changing arc or ultimate spiral would result. Growth could not be represented as simple segment of circle www.indiandentalacademy.com
    63. 63. Arcial growth of the mandible Stress lines • 850 yrs. Old mandible – • • William B. Downs Disintegration of interprismatic subs. Stress lines in the outer & inner plates www.indiandentalacademy.com
    64. 64. Arcial growth of the mandible • Examination of stress lines / lateral surface Convergence at protuberance menti Upward ,backward & outward from EO Gnarled area at the coronoid base. www.indiandentalacademy.com
    65. 65. Arcial growth of the mandible • Stress line /medial side  Mylohyoid ridge  YM /Y-shaped bony prominence - Center of quadrant of ramus - Inner & outer cortical tables showed confluence  TP/ Triangular plane – Nutritive foramina www.indiandentalacademy.com
    66. 66. Arcial growth of the mandible • 2 new point - Eva &TR • Eva- forking of stress lines in ramus • TR /true radius – center of circle from Pog through Eva • Mu point www.indiandentalacademy.com
    67. 67. Arcial growth of the mandible • Mandible size increased, increment added to the arc at the sigmoid notch. • Predicted mandible was almost absolutely correct in size and form when compared with the final composite www.indiandentalacademy.com
    68. 68. Arcial growth of the mandible • Mandible growth occurs on a arc • This method proved extremely accurate in 50 treated cases which were predicted and compared for periods of as long as 14 yrs later. www.indiandentalacademy.com
    69. 69. Arcial growth of the mandible • Amount of growth to forecast on the arc - 2.5 yearly increase 14.5 F & 19M • Symphysis lower border – 1mm each 8 yrs / M www.indiandentalacademy.com
    70. 70. Arcial growth of the mandible • Coronoid & condylar process – different • Coronoid – 0.8mm/yr • Condylar 1. 2. 3. - variable Short & weak – 0.0mm Long condyles – 0.4mm/yr Average – 0.2mm /yr www.indiandentalacademy.com
    71. 71. Arcial growth of the mandible • Gonion angle growth 50% of the total increase in mandibular growth • Females - no further addition • Males – above +0.2mm www.indiandentalacademy.com
    72. 72. Arcial growth of the mandible • External oblique ridge 0.4mm/yr. • RR point – stable bone Ramal width www.indiandentalacademy.com
    73. 73. Arcial growth of the mandible • Impaction of third molar and Arcial growth prognosis –25 adult skull normal occlusion 1. Lower third molar 50 % ahead the EOR 50% favorable prognosis 2. Mesial to the EOR – 100 % favorable prognosis 3. Distal to the EOR – poorer 45 % of the nonextracted cases required third molar extraction. www.indiandentalacademy.com
    74. 74. Arcial growth of the mandible • Bisect the height of ramus from the sigmoid notch down to the lower border in a perpendicular plane from FH ,then bisected the width of the mandible called XI point www.indiandentalacademy.com
    75. 75. Arcial growth of the mandible www.indiandentalacademy.com
    76. 76. Arcial growth of the mandible • Xi point – center of ramus Occlusal plane Entrance of neurotrophic bundles www.indiandentalacademy.com
    77. 77. Arcial growth of the mandible • 2 new point - Eva &TR • Eva- forking of stress lines in • • ramus A center of upward & forward quadrant of ramus By bisecting R2 & R3 point • TR /true radius – center of circle from Pog through Eva • Mu point www.indiandentalacademy.com
    78. 78. Arcial growth of the mandible • Class III The amount of mandibular growth in the forecast is one sixth more in the classIII www.indiandentalacademy.com
    79. 79. Arcial growth of the mandible • May be occur in closed bite faces www.indiandentalacademy.com
    80. 80. Growth prediction Methods of predicting facial growth change According Bjork Logarithmic spiral Arcial growth of the mandible Computerized prediction methods Visualized treatment objective www.indiandentalacademy.com
    81. 81. Visualized treatment objective • • • • • Definition Uses Jacobson and Sadowsky Ricketts Holdways www.indiandentalacademy.com
    82. 82. Visualized treatment objective • Definition It is a visual plan to forecast the normal growth of the pt and the anticipated influences of treatment , to establish the individual objectives we want to achieve for that pt www.indiandentalacademy.com
    83. 83. Visualized treatment objective • Uses 1. 2. 3. Predict growth over an estimated T/t time Analyzes the soft tissue facial profile Determines favourable incisor repositioning based on an ‘ideal’ projected soft tissue profile 4. Determines total arch length discrepancy www.indiandentalacademy.com
    84. 84. Visualized treatment objective 5. Aids in determining b/w extraction & nonextraction treatment 6. Surgical orthodontic correction www.indiandentalacademy.com
    85. 85. Visualized treatment objective • • • Jacobson and Sadowsky Ricketts Holdways www.indiandentalacademy.com
    86. 86. Visualized treatment objective ALEX JACOBSON & P.LIONEL SADOWSKY • All cephalometric headfilms to be taken in the lips closed position even if they are strained to close • Construct a VTO by considering average growth for an estimated 2 yr period of active t/t & the objective we want to achieve with our mechanics www.indiandentalacademy.com
    87. 87. Visualized treatment objective • • • • • • • • • • • Cephalometric tracing for VTO Anterior & posterior cranial base Pterygomaxillary fissure Orbit Anterior outlines of frontal bone Nasal bone & Nasion ANS &PNS ,hard palate Upper central incisor & it’s alveolar process Mandible External auditory meatus Soft tissue profiles www.indiandentalacademy.com Upper & lower molar
    88. 88. Visualized treatment objective • • • • • • • • Cephalometric tracing for VTO BAN (Basion-nasion line) Line Na - POINT A F H PLANE Occlusal plane Downs mandibular plane Facial axis Holdway’s line Facial plane www.indiandentalacademy.com
    89. 89. Visual treatment objective Step of VTO • Step 1 obj. – To draw frontonasal area , BAN & NA line. • Step 2 obj. – Growth in frontonasal area over 2 yr. - Frontonasal area 1.5 mm growth - 1/4mm per year ( Dr. Holdway’s studies ) www.indiandentalacademy.com
    90. 90. Visual treatment objective • Step 3 object – Mandible growth in vertical direc. - Ant. Portion of mandible - Soft tissue chin - Down’s mandibular plane • Superimpose on the facial axis • The distance b/w VTO & ceph Ban line should be 3 times the amount of growth expressed previously in FN area www.indiandentalacademy.com
    91. 91. Visual treatment objective Step 4 obj. – Mandible growth in horizontal direction. - Draw the Post border of mandible • Forward growth at chin point = Nasion • Total vertical facial height as well as forward location of chin established www.indiandentalacademy.com
    92. 92. Visual treatment objective Step 5 obj. – To locate maxilla & lower half of nose • • • Superimpose on NA line & move up There is 40% of total vertical growth above BaN line & 60% below mandible Nose growth 1mm/year. Step 6 obj. – To locate and draw the occlusal plane • Superimpose on NA plane • Vertical growth is 50% above maxilla & 50% below mandible www.indiandentalacademy.com
    93. 93. Visual treatment objective Step 7 obj. – To determine soft tissue lip contour using the new H-line • The distance b/w upper lip contour & H-line is 3 - 7mm (Dr. Holdway’s studies ) www.indiandentalacademy.com
    94. 94. Visual treatment objective • Step 8 obj. – To relocate the maxillary central incisor Upper lip thickness = Basic upper lip thickness ( within 1 mm ) • Lip strain is difference b/w above measurement • Maxillary incisor rebound - 0.5mm in class I - 1.5 mm in class II In this case Lip strain = 4 mm Lip movement = 4 mm Maxillary incisor rebound = 1.5 mm Total 9.5 mm www.indiandentalacademy.com
    95. 95. Visual treatment objective Step 9 obj. – To reposition lower incisor - Calculate resultant arch length change • Arch length change - measure the distance b/w • old and new incisor position (2mm) Double the above distance • Arch length change is in this case is 4 mm www.indiandentalacademy.com
    96. 96. Visual treatment objective Step 10 obj. –To reposition mandibular first molar • Total arch length discrepancy = arch length loss +arch length discrepancy / model discrepancy 8 mm = 4 mm + 4mm • Extraction of 2nd PM on both side - 15 mm space Step 11 obj. – To reposition the maxillary first www.indiandentalacademy.com
    97. 97. Visualized treatment objective • • • Jacobson and Sadowsky Holdways Ricketts www.indiandentalacademy.com
    98. 98. A Soft - tissue cephalometric analysis Reed A. Holdway • Based on soft - tissue measurement Variations • Sella nasion line is used express forward growth • at nasion Growth on facial axis is 3mm/yr except during growth spurts www.indiandentalacademy.com
    99. 99. A Soft - tissue cephalometric analysis • Head films should be taken with the pt’s lip touching position www.indiandentalacademy.com
    100. 100. A Soft - tissue cephalometric analysis • • • • • • • • Original tracing – 9 reference line SN plane FH plane Occlusal plane Nasion to Pog line (hard & soft tissue) H- line Nasion to point A line / facial plane Facial axis Down’s Mandibular plane www.indiandentalacademy.com
    101. 101. A Soft - tissue cephalometric analysis Steps of VTO tracing Step 1 – Draw Frontonasal area Sella – nasion line Nasion- point A line www.indiandentalacademy.com
    102. 102. A Soft - tissue cephalometric analysis • • Step 2 - Express horizontal growth in the FN area for the estimated T/t Growth at nasion is 0.66 to 0.75 mm/yr Prediction of growth at nasion is an overall prediction for all midfacial structure www.indiandentalacademy.com
    103. 103. A Soft - tissue cephalometric analysis Step 3 – Mandible growth in vertical dire. • Growth on facial axis is 3 mm/yr except in growth spurt period Step 4 – Mandible growth in horizontal dire. • At this point total vertical height has been forecast www.indiandentalacademy.com
    104. 104. A Soft - tissue cephalometric analysis Step 5 – To locate maxilla, the new point A & lower half of nose • • Vertical growth above the SN line & below the mandible is in ratio of 40 :60 The vertical growth of the nose over 2 yr period keeps pace with the growth from the maxilla vertically to the anterior cranial base www.indiandentalacademy.com
    105. 105. A Soft - tissue cephalometric analysis Step 6 - locate and draw the occlusal plane • Vertical growth is 50% above maxilla & 50% • below mandible The occlusal plane is located 3 mm below the lip embrasure www.indiandentalacademy.com
    106. 106. A Soft - tissue cephalometric analysis Step 7 – To determine soft tissue lip contour using the new H-line • The distance b/w upper lip contour & H-line is • • 3 - 7mm Short & thin lip – 3 mm Long & thick lip – 5 mm www.indiandentalacademy.com
    107. 107. A Soft - tissue cephalometric analysis Step 8 – To relocate the maxillary central incisor • Upper lip thickness = Basic upper lip thickness • • ( within 1 mm ) Lip strain is difference b/w above measurement Maxillary incisor rebound - 0.5mm in class I - 1.5 mm in class II www.indiandentalacademy.com
    108. 108. A Soft - tissue cephalometric analysis Step 9 – To reposition lower incisor - Calculate resultant arch length change • Arch length change - distance b/w old and new • incisor position Double the above distance • Arch length change is in this case is 8 mm www.indiandentalacademy.com
    109. 109. A Soft - tissue cephalometric analysis Step 10 – To reposition mandibular first molar • Total arch length discrepancy = arch length change • +arch length discrepancy / model discrepancy 10 mm = 8mm + 2mm Extraction of 2nd PM on both side - 15 mm space Step 11 – To reposition the maxillary first www.indiandentalacademy.com
    110. 110. Visualized treatment objective • • • Jacobson and Sadowsky Holdways Ricketts www.indiandentalacademy.com
    111. 111. Visualized treatment objective • • • • • • • • • Original tracing RICKETTS Nasion ANS Point A PM POG CC Basion DC XI www.indiandentalacademy.com
    112. 112. Visualized treatment objective • • • • • • Construction of VTO Cranial base prediction Mandibular growth prediction Maxillary growth prediction Occlusal plane prediction The location of the dentition The soft tissue of the face www.indiandentalacademy.com
    113. 113. Visualized treatment objective VTO – Cranial base prediction • • • • Mark at CC point Trace BaN Plane Nasion -1mm /yr Basion – 1 mm/yr www.indiandentalacademy.com
    114. 114. Visualized treatment objective VTO –Mandibular growth prediction • Condylar axis growth • Corpus axis growth • Symphysis growth www.indiandentalacademy.com
    115. 115. Visualized treatment objective VTO – Mandibular growth prediction – Rotation • Mandible rotates open or closed from the effects of mechanics used & the facial pattern present • Mechanics 5 mm convexity reduction Facial axis open 1 degree 4 mm overbite correction • Facial pattern www.indiandentalacademy.com
    116. 116. Visualized treatment objective VTO – Mandibular growth prediction – Rotation • Superimpose at Basion • Rotate VTO tracing up to open the bite at nasion or • • down to open the bite This rotation depends on treatment effect Trace condylar axis, coronoid & condylar process www.indiandentalacademy.com
    117. 117. Visualized treatment objective VTO – Mandibular growth prediction Condylar axis , Corpus axis growth • Condylar axis moves 1mm /yr down from DC point • PM moves forward 2mm /yr in normal growth • • • VTO – Mandibular growth prediction -Symphysis growth Coincide old & new PM Copy the symphysis , mandibular plane www.indiandentalacademy.com Construct facial plane & facial axis
    118. 118. Visualized treatment objective • • • VTO – Maxillary growth prediction Superimpose at nasion along the facial plane Divide the original & new menton into 3 part by using 2 mark Superimpose mark 1 on original menton , copy the maxilla www.indiandentalacademy.com
    119. 119. Visualized treatment objective VTO – Maxillary growth prediction Point A change related to BA – NA • Position of Point A change with growth & different mechanics Mechanics Maximum range 1. HG - 8 mm 2. Class II elastics - 3 mm 3. Torque - 1 to 2 mm 4. Class III elastics + 2-3mm 5. Facial mask + 2- 4mm • Point A and APO plane www.indiandentalacademy.com
    120. 120. Visualized treatment objective VTO – Occlusal plane prediction • Superimpose mark 2 on original menton along facial • plane Copy the occlusal plane VTO - Dentition - Lower central incisor • • Superimpose on the corpus axis at PM Place a point 1mm above to occ. Plane & 1mm ahead to APO line www.indiandentalacademy.com
    121. 121. Visualized treatment objective VTO - Dentition - • • Lower first molar Arch length change is 4mm Leeway space is 4mm VTO - Dentition - Upper first molar Upper central incisor VTO – Soft tissue area www.indiandentalacademy.com
    122. 122. Growth prediction • Overall changes in size and relationship of human face from childhood to adulthood are difficult to accurately predict due to influence of the combined and complex effects of genetic and environment factor. www.indiandentalacademy.com
    123. 123. Growth prediction • Facial and dental changes in Adolescent and their clinical • • • • • implication Samir –E Bishara ,AO 2000,Vol.60,No.6 Difference between functional matrices in anterior open bite and in deep bite Melvin L. Moss, AJO 1970, Vol. 42,No.3 A principal of Arcial growth of the mandible Robert M . Ricketts AJO 1972,Vol .42 ,No.4 Provocations & perception in craniofacial orthopedics Robert M . Ricketts Issues related to the prediction of craniofacial growth James Todd , AJO 1981,Vol .79 ,No. 2 A soft tissue cephalometric analysis and it’s use in orthodontic treatment planning Holdway , AJO www.indiandentalacademy.com 4 1984 ,Vol. 84 ,No.
    124. 124. Growth prediction • A Visulized treatment objective • • • • • • Alen Jacobson , P Lionel Sadowsky Prediction of the mandibular growth rotation Bjork , AJO 1969 , Vol. 39 Bioprogessive Therapy – VTO Ruel W Bench , James J. Higler , JCO 1977, November Contemporary orthodontics - William R. Proffit Orthodontic current principles & techniques T.M Graber , Robert Vanarsdall Orthodontic principles & practice T.M Graber Ricketts interview ,JCO 1975 ,may, jun ,july www.indiandentalacademy.com
    125. 125. Thank you • www.indiandentalacademy.com • Leader in continuing dental education www.indiandentalacademy.com

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