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Cephalometrics in orthodontics/certified fixed orthodontic courses by Indian dental academy

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Cephalometrics in orthodontics/certified fixed orthodontic courses by Indian dental academy

  1. 1. www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com Cephalometrics
  2. 2. • Introduction • Historical perspective • Cephalostat • Uses and advantages of cephalogram • Obtaining the cephalogram • Cephalometric landmarks • Cephalometric analysis • Limitations of cephalometrics Contents www.indiandentalacademy.com
  3. 3. cephalometrics ceph=head metrics=measure • Defn : cephalometrics is a specialised radiographic technique for abstracting the human head into a geometric scheme. • The basic elements used in geometric analysis of cephalograms are curves, landmark points and lines. www.indiandentalacademy.com
  4. 4. • Cephalometric analysis is a collection of numbers to compress information from the cephalogram for clinical use. • Different analysis are required for different purposes. www.indiandentalacademy.com
  5. 5. Historical perspective • 1899 – Edward Angle – Classification of Malocclusion • 1915 – Van Loon – developed a method for 3D registration of face and dentition – Cubus Craniophorus • 1922 – Simon – modified Van Loon’s inventon by using a face bow. • 1922 – Pacini – Paved the way for standardized head radiography • 1931 – Hofrath in Germany and Broadbent in United States – published their works in the ‘ Forschritte der Orthodontie’ and the Angle Orthodontist respectively. • 1939 – Lucien de Coster – published his work on proportional relationships of the face. www.indiandentalacademy.com
  6. 6. The Bolton Room in the Anatomical Laboratory of the Medical School at Western Reserve University, Cleveland. www.indiandentalacademy.com
  7. 7. Uses and advantages • Important diagnostic aid. • Helps in classifying dental and skeletal abnormalities as well as establishing facial type. • Helps in treatment planning • Helps in prediction of growth related changes and that associated with surgical treatment. • It is a valuable aid in research of craniofacial region. www.indiandentalacademy.com
  8. 8. TYPES OF CEPHALOGRAMS • Can be of two types 1. Lateral cephalogram: This provides lateral view of the skull 2. Frontal cephalogram: This provides antero-posterior view of the skull www.indiandentalacademy.com
  9. 9. Lateral and frontal cephalogram www.indiandentalacademy.com
  10. 10. 5 feet X-ray source Cephalostat Film www.indiandentalacademy.com
  11. 11. Cephalometric equipment • Consists of an X-ray source and a head holding device called cephalostat • Cephalostat consists of two ear rods that prevent movement of the head in horizontal plane • Vertical stabilization is provided by an orbital pointer that contacts the lower border of the left orbit • The upper part of the face is supported by a forehead clamp positioned above the region of the nasal bridge www.indiandentalacademy.com
  12. 12. • The distance between X-ray source and the mid-sagittal plane of the patient is fixed at 5 feet (152.4 cm) • Thus the equipment helps in standardization using a constant head position which helps to compare serial radiographs • Natural Head Position (NHP) is a standardized and reproducible orientation of the head in space when one is focusing on a distant point at eye level. www.indiandentalacademy.com
  13. 13. Definition of terminology Anthropometry – Measurement of dimensions of the human body and it’s parts. Craniometry – Branch of anthropometry dealing with measurements of dimensions and angles of bony skull. Cephalometry – Scientific measurement of dimensions of the ‘living’ head. Cephalometric analysis – Process of evaluating the skeletal, dental, and soft tissue relationships of a patient by comparing measurements performed on the patient’s cephalometric tracing with population norms for respective measurements, to come to a diagnosis of the patient’s orthodontic problem.www.indiandentalacademy.com
  14. 14. www.indiandentalacademy.com
  15. 15. Cephalometric landmarks Types – Anatomic – Derived  Hard tissue landmarks  Soft tissue landmarks Anatomic These landmarks represent actual anatomic landmarks of the skull. Derived landmarks These are obtained secondarily from anatomic landmarks. www.indiandentalacademy.com
  16. 16. Criteria for landmark selection • Should be easily identifiable • Should be uniform in outline and reproducible • Should permit valid quantitative measurements of lines and angles projected from them. www.indiandentalacademy.com
  17. 17. Anatomical structures • The major bony structures are: • Sphenoid bone • Zygomatic bones • Maxilla • Mandible www.indiandentalacademy.com
  18. 18. Unilateral landmarks in lateral cephalograms • Nasion (Na)- frontonasal suture at its most superior point on the curve at the bridge of nose • Anterior nasal spine (ANS)-the most anterior point on the maxilla at the level of the palate • Subspinale(“A” point)-the most posterior point on the curve between ANS and superior Prosthion www.indiandentalacademy.com
  19. 19. • Superior Prosthion(SPr or Pr)- also called supradentale. The most anterior ,inferior point on the maxillary alveolar process, usually found near the CEJ of the maxillary central incisors • Incision superius (Is)- The incisal tip of the most anterior maxillary central incisor. • Incision inferius (Ii)-The incisal tip of the most labial mandibular central incisor. www.indiandentalacademy.com
  20. 20. • Infradentale (Id) or inferior prosthion-The most anterior superior point on the mandibular alveolar process,near CEJ of mandibular central incisor. • Supramentale (“B” point)-The most posterior point of the bony curvature of the mandible below Infradentale and above Pogonion . www.indiandentalacademy.com
  21. 21. • Pogonion (Pog)-the most anterior point on the contour of the chin • Gnathion (Gn)-The most anterior inferior point on the lateral shadow of the chin • Menton (Me)-The lowest point on the symphyseal outline of the chin www.indiandentalacademy.com
  22. 22. • Basion (Ba)-The most inferior posterior point in the sagital plane on the anterior rim of the foramen magnum • Posterior nasal spine (PNS)-The most posterior point on the bony hard palate in the sagital plane • Sella (S)-The center of the hypophyseal fossa • Broadbent registration point:It is the midpoint of the perpendicular from the center of sella tursica to Bolton’s plane www.indiandentalacademy.com
  23. 23. • Glabella-the most prominent point of the forehead in mid-saggital plane • Chelion-the lateral terminus of the oral slit on the outer corner of the mouth www.indiandentalacademy.com
  24. 24. Bilateral landmarks Both left and right points are located and used, but some clinicians use the midpoint of the two. Following are the points- – Orbitale (Or)-The lowest point of the bony orbit. Usually the lowest point on the averaged outline is used for construction of Frankfurt Plane – Gonion (Go)-The most posterior inferior point at the angle of the mandible. – Condylion (Co)-The most posterior superior point on the condyle of the mandible. www.indiandentalacademy.com
  25. 25. Bilateral landmarks Both left and right points are located and used, but some clinicians use the midpoint of the two. Following are the points- – Orbitale (Or)-The lowest point of the bony orbit. Usually the lowest point on the averaged outline is used for construction of Frankfurt Plane – Gonion (Go)-The most posterior inferior point at the angle of the mandible. – Condylion (Co)-The most posterior superior point on the condyle of the mandible. www.indiandentalacademy.com
  26. 26. • Articulare (Ar)-The intersection of three radiographic shadows :the inferior surface of the cranial base and the posterior surface of the necks of the condyles of the mandible • Pterygomaxillary fissure (PTM)-Bilateral tear- drop shaped area of radiolucency ,the anterior shadow of which is the posterior surfaces of the maxillary tuberosities www.indiandentalacademy.com
  27. 27. • Sphenoethmoidal point (SE)-The intersection of the great wing of sphenoid and cranial floor. • Frontomaxillary nasal suture (FMN)-The most superior point of the suture where the maxilla articulates with the frontal and nasal bones. www.indiandentalacademy.com
  28. 28. Cephalometric Lines (Planes) • Horizontal • Vertical Horizontal planes: • S-N plane :It is the cranial line between center of sella and the nasion • Frankfurt horizontal plane :The common tangent to the upper external auditory meatus (at porion) and the inferior border of the orbit (orbitale) www.indiandentalacademy.com
  29. 29. • Functional occlusal line (FOL):A line averaging the points of posterior occlusal contacts from first permanent molars to the primary molars or bicuspids • Mandibular plane :several exist, based on different analysis 1. Tangent to the lower border of the mandible (Tweed) 2. A line connecting gonion and menton(Downs) 3. A line connecting gonion and gnathion (Steiner) www.indiandentalacademy.com
  30. 30. • Palatal plane: A line joining ANS and PNS • Bolton-Nasion plane: Line connecting basion and nasion • Bolton’s plane: This plane connects bolton’s points posterior to the occipital condyles and nasion www.indiandentalacademy.com
  31. 31. Bilateral landmarks Both left and right points are located and used, but some clinicians use the midpoint of the two. Following are the points- – Orbitale (Or)-The lowest point of the bony orbit. Usually the lowest point on the averaged outline is used for construction of Frankfurt Plane – Gonion (Go)-The most posterior inferior point at the angle of the mandible. – Condylion (Co)-The most posterior superior point on the condyle of the mandible. www.indiandentalacademy.com
  32. 32. • Articulare (Ar)-The intersection of three radiographic shadows :the inferior surface of the cranial base and the posterior surface of the necks of the condyles of the mandible • Pterygomaxillary fissure (PTM)-Bilateral tear- drop shaped area of radiolucency ,the anterior shadow of which is the posterior surfaces of the maxillary tuberosities www.indiandentalacademy.com
  33. 33. • Sphenoethmoidal point (SE)-The intersection of the great wing of sphenoid and cranial floor. • Frontomaxillary nasal suture (FMN)-The most superior point of the suture where the maxilla articulates with the frontal and nasal bones. www.indiandentalacademy.com
  34. 34. Cephalometric Lines (Planes) • Horizontal • Vertical Horizontal planes: • S-N plane :It is the cranial line between center of sella and the nasion www.indiandentalacademy.com
  35. 35. • Frankfurt horizontal plane :The common tangent to the upper external auditory meatus (at porion) and the inferior border of the orbit (orbitale) www.indiandentalacademy.com
  36. 36. • Functional occlusal line (FOL):A line averaging the points of posterior occlusal contacts from first permanent molars to the primary molars or bicuspids www.indiandentalacademy.com
  37. 37. • Mandibular plane :several exist, based on different analysis 1. Tangent to the lower border of the mandible (Tweed) 2. A line connecting gonion and menton(Downs) 3. A line connecting gonion and gnathion (Steiner) www.indiandentalacademy.com
  38. 38. • Palatal plane: A line joining ANS and PNS www.indiandentalacademy.com
  39. 39. • Bolton-Nasion plane: Line connecting basion and nasion • Bolton’s plane: This plane connects bolton’s points posterior to the occipital condyles and nasion www.indiandentalacademy.com
  40. 40. Vertical planes • A-Pog line :Line from Point A to pogonion www.indiandentalacademy.com
  41. 41. • Facial plane :Line from nasion to pogonion www.indiandentalacademy.com
  42. 42. www.indiandentalacademy.com
  43. 43. DOWN'S ANALYSIS www.indiandentalacademy.com
  44. 44. • One of the most commonly used analysis • Downs based his findings on 20 Caucasian individuals of 12-17 years age group of both sexes • Downs analysis consists of 10 parameters -5 skeletal and five dental www.indiandentalacademy.com
  45. 45. Skeletal parameters 1. Facial angle: It is the angle formed by the intersection of nasion-pogonion plane and the FH plane Average value is 87.8° and range between 82- 95°.This angle gives us an indication of the antero-posterior positioning of the mandible in relation to the .This value increases in cases of skeletal CL III while it decreases in CL II cases www.indiandentalacademy.com
  46. 46. www.indiandentalacademy.com
  47. 47. Mean Reading : 87.5o Range : 82o – 95o N Pog Po Or www.indiandentalacademy.com
  48. 48. www.indiandentalacademy.com
  49. 49. www.indiandentalacademy.com
  50. 50. Mean Reading : 0o Range : -8.5o – 10o Angle of convexity: this is formed between the intersection of a line from nasion to Point A ,and a line from Point A to pogonion This angle reveals the convexity or concavity of the skeletal profile A positive angle or an increased angle shows a prominent maxillary base compared to mandible or a retrognathic profile,while a negative or decreased angle shows a prognathic profile www.indiandentalacademy.com
  51. 51. www.indiandentalacademy.com
  52. 52. www.indiandentalacademy.com
  53. 53. Mean Reading : -4.6o Range : 0o – - 9o A-B Plane: this angle is formed between a line connecting Point A and Point B , and a line joining nasion to pogonion. This angle is indicative of the maxillo-mandibular relationship in relation to the facial plane It is usually negative as Point B is Positioned behind Point A In cases of CL III malocclusions , a positive angle is seen www.indiandentalacademy.com
  54. 54. 4 www.indiandentalacademy.com
  55. 55. www.indiandentalacademy.com
  56. 56. Mean Reading : 21.9o Range : 17o – 28o Formed by intersection of mandibular plane with FH Plane. An increased plane is suggestive of a vertical grower with a hyperdivergent facial pattern www.indiandentalacademy.com
  57. 57. 5 www.indiandentalacademy.com
  58. 58. www.indiandentalacademy.com
  59. 59. Mean Reading : 59.4o Range : 53o – 66o This angle is formed by joining sella- gnathion line with FH plane . This angle is larger in CL II patterns than CL III patterns.It indicates the growth pattern of the individual.If the angle is greater than normal, it indicates greater vertical growth of the mandible and if it is lesser ,it indicates horizontal growth of the mandible www.indiandentalacademy.com
  60. 60. Dental parameters 1 www.indiandentalacademy.com
  61. 61. www.indiandentalacademy.com
  62. 62. Mean Reading : 9.3o Range : 1.5o – 1.4o .. This angle is formed between occlusal plane and F.H. plane. Downs constructed the occlusal plane by bisecting the occlusion of first permanent molars and incisor overbite. This angle gives us a measure of the slope of occlusal plane relative to F.H. plane www.indiandentalacademy.com
  63. 63. 2 Inter-incisal angle- www.indiandentalacademy.com
  64. 64. www.indiandentalacademy.com
  65. 65. Mean reading : 135.4o Range : 130o – 150o This angle is formed between the long axes of upper and lower incisors. This angle decreases in CL I bimax.protrusion and CL II DivI.cases ,whereas it increases in CL II DivII cases www.indiandentalacademy.com
  66. 66. 3 Incisor Mandible Plane Angle- www.indiandentalacademy.com
  67. 67. www.indiandentalacademy.com
  68. 68. Mean reading : 1.4o Range : -8.5o – 7o This angle is formed by intersection of long axis of lower incisor and mandibular plane. An increase in this angle is indicative of lower incisor proclination www.indiandentalacademy.com
  69. 69. 4 Incisor occlusal plane angle :the inside inferior angle formed by intersection between long axis of lower central incisor and occlusal plane ;it is read +ve or –ve deviation from a right angle An increase in this angle is suggestive of increased lower incisor proclination www.indiandentalacademy.com
  70. 70. www.indiandentalacademy.com
  71. 71. 5 Upper incisor to A-Pog line-This is a linear measurement between incisal edge of maxillary central incisor and a line joining Point A to pogonion Average value is 2.7mm and range is -1 to 5mm It is more in patients with upper incisor proclination www.indiandentalacademy.com
  72. 72. www.indiandentalacademy.com
  73. 73. Vorhies and Adams (1951) Wriggle www.indiandentalacademy.com
  74. 74. STEINER’S ANALYSIS www.indiandentalacademy.com
  75. 75. • Developed in 1930 by Cecil C. Steiner • This analysis aims at providing maximal clinical information with the least number of measurements www.indiandentalacademy.com
  76. 76. STEINER’S ANALYSIS SKELETALANALYSIS DENTALANALYSIS SOFT TISSUE ANALYSIS www.indiandentalacademy.com
  77. 77. Skeletal parameter S.N.A. angle- www.indiandentalacademy.com
  78. 78. www.indiandentalacademy.com
  79. 79. www.indiandentalacademy.com
  80. 80. Mean reading : 82o It is the angle formed by the intersection of S.N. plane and a line joining nasion and point A This angle indicates the relative antero- posterior positioning of maxilla in relation to cranial base A larger than normal value indicates a prognathic maxilla while a smaller value suggests a retrognathic maxilla www.indiandentalacademy.com
  81. 81. S.N.B angle- www.indiandentalacademy.com
  82. 82. www.indiandentalacademy.com
  83. 83. Mean reading : 80o It is the angle between S.N. plane and a line joining nasion to Point B. This angle indicates the antero-posterior positioning of the mandible in relation to cranial base An increase indicates a prognathic mandible and lesser value suggests retrusive mandible www.indiandentalacademy.com
  84. 84. A.N.B. angle- www.indiandentalacademy.com
  85. 85. www.indiandentalacademy.com
  86. 86. ANB Mean reading : 2o This angle is formed by intersection of the lines joining nasion to Point A, and nasion to Point B. It denotes the relative position of maxilla and mandible to each other. An increase is suggestive of CLII skeletal tendency while lesser than normal suggests CLIII skeletal relationship www.indiandentalacademy.com
  87. 87. Occlusal plane angle- www.indiandentalacademy.com
  88. 88. www.indiandentalacademy.com
  89. 89. Mean reading : 14o Formed between occlusal plane and S.N. plane .The occlusal plane is represented by a line passing between the overlapping cusps of first premolars and first molars. This angle denotes the relation of occlusal plane to cranium and face. www.indiandentalacademy.com
  90. 90. Mandibular plane angle-It is the angle formed between Mandibular plane and S.N. plane. The mandibular plane is a line connecting gonion and gnathion Mean value is 32 degrees This angle indicates growth pattern;a lower angle suggests a horizontal growing face and increased angle shows a vertical pattern www.indiandentalacademy.com
  91. 91. www.indiandentalacademy.com
  92. 92. Mean reading : 32o www.indiandentalacademy.com
  93. 93. Dental parameters Upper incisor to N-A(angle)- Formed by intersection of long axis of upper centrals and line joining nasion to point A. Mean is 22 degrees. It indicates the relative inclination of upper incisors; increased angle is seen during proclination www.indiandentalacademy.com
  94. 94. Lower incisor to N.B (angle)-Formed between N-B plane and long axis of lower incisor Mean value is 25 degrees. It shows us the inclination of lower central incisor; an increased value shows proclined incisor and decreased angle gives retroclined incisor www.indiandentalacademy.com
  95. 95. www.indiandentalacademy.com
  96. 96. www.indiandentalacademy.com
  97. 97. Upper incisor to N.A (Linear)-It is a linear measurement formed between labial surface of upper central incisor and a line joining nasion to Point A . Mean value is 4mm This value helps in determining upper incisor position ;it increases in proclined upper incisors www.indiandentalacademy.com
  98. 98. Lower incisor to N.B (Linear)- It is the linear distance between Labial surface of lower central incisor and a line joining nasion to Point B. Mean value is 4mm. It helps us to assess lower incisor inclination; increased value shows proclination and vice-versa www.indiandentalacademy.com
  99. 99. www.indiandentalacademy.com
  100. 100. Interincisal angle-Formed between long axis of upper central and long axis of lower central incisors. Mean value is 130-131 degrees. A decreased angle is seen in proclination of incisors and increased in retroclined incisors www.indiandentalacademy.com
  101. 101. www.indiandentalacademy.com
  102. 102. Mean reading : 130o www.indiandentalacademy.com
  103. 103. www.indiandentalacademy.com
  104. 104. Soft tissue analysis S-line – Steiner suggests that in a well balanced face the lips should touch a line extending from soft tissue contour of the chin to the middle of an ‘S’ formed by lower border of nose If lips are beyond this line , it indicates protrusive lips and convex profile;and if behind the line shows retrusive lips and the patient may have concave profile www.indiandentalacademy.com
  105. 105. www.indiandentalacademy.com
  106. 106. www.indiandentalacademy.com
  107. 107. TWEED’S ANALYSIS www.indiandentalacademy.com
  108. 108. TWEED’S ANALYSIS • Three planes are used forming a diagnostic triangle: 1)Franfurt horizontal plane (FH PLANE) 2)Mandibular plane(MP) 3)Long axis of mandibular incisor(MIA) • Frankfort mandibular plane angle : formed by intersection of FH plane with mandibular plane (mean=25°) www.indiandentalacademy.com
  109. 109. www.indiandentalacademy.com
  110. 110. SOFT TISSUE NASION PRONASALE SUB NASALE SUB SPINALE LABRALE SUPERIUS STOMION LABRALE INFERIUS SUB MENTALE SOFT TISSUE POGONION SKIN GNATHION SOFT TISSUE CEPHALOMETRIC LANDMARKS www.indiandentalacademy.com
  111. 111. Problems and limitations • It is a two dimensional representative of three dimensional structures. • Problems in orientation of patient while procuring radiograph. • Fallacy of false precision- difficulty in location of landmarks precisely. • Fallacy of ignoring the patient- mean population averages differ from characteristics of a particular patient. • Fallacy of using chronological age for comparisons and references within age classes. www.indiandentalacademy.com
  112. 112. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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