Cephalomeric radiography

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Cephalomeric radiography

  1. 1. Cephalometric radiography Islam Kassem ikassem@dr.com
  2. 2. • Cephalometric radiography is a standardized and reproducible form of skull radiography used extensively in orthodontics to assess the relationships of the teeth to the jaws and the jaws to the rest of the facial skeleton. ikassem@dr.com
  3. 3. Standardization was essential forthe development of cephalometry ikassem@dr.com
  4. 4. Main indications1-Orthodontics2-Orthognathic ikassem@dr.com
  5. 5. 1-Orthodontics1- Initial diagnosis — confirmation of theunderlying skeletal and/or soft tissueabnormalities2-Treatment planning3- Monitoring treatment progress, e.g. to assessanchorage requirements and incisor inclination4- Appraisal of treatment results ikassem@dr.com
  6. 6. 2-Orthognathic surgery1- Preoperative evaluation of skeletal and softtissue patterns2- To assist in treatment planning3-Postoperative appraisal of the results ofsurgery and long-term follow-up studies. ikassem@dr.com
  7. 7. Equipment• Cephalostat (or craniostaf)• Cassette (usually 18 x 24 cm).• Aluminium wedge filter.• X-ray generating apparatus. ikassem@dr.com
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  9. 9. Main radiographic projections1-True cephalometric lateral skull2- Cephalometric postero-anterior of the jaws ikassem@dr.com
  10. 10. 1-True cephalometric lateral skull ikassem@dr.com
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  13. 13. Cephalometric tracing /digitizing• The outline and inclination of the anterior teeth• The positional relationship of the mandibularand maxillary dental bases to the cranial base• The positional relationship of the dental basesto one another, i.e. the skeletal patterns• The relationship between the bones of theskull and the soft tissues of the face. ikassem@dr.com
  14. 14. ikassem@dr.com One-shot cephalometric imagingMultiple image format including exclusive 30x30 cm Autotracing
  15. 15. Main Cephalometric points• Sella (S). The centre of the sella turcica,• (determined by inspection).• Orbitale (Or). The lowest point on the infraorbital margin.• Nasion (N). The most anterior point on the frontonasal suture.• Anterior nasal spine (ANS). The tip of the anterior nasal spine.• Subspinale or point A. The deepest midline point between the anterior nasal spine and prosthion.• Prosthion (Pr). The most anterior point of the alveolar crest in the premaxilla, usually between the upper central incisors. ikassem@dr.com
  16. 16. • Infradentale (Id). The most anterior point of the alveolar crest, situated between the lower central incisors.• Supramentale or point B. The deepest point in the bony outline between the infradentale and the pogonion.• Pogonion (Pog). The most anterior point of the bony chin.• Gnathion (Gn). The most anterior and inferior point on the bony outline of the chin, situated equidistant from pogonion and menton.• Menton (Me). The lowest point on the bony outline of the mandibular symphysis.• Gonion (Go). The most lateral external point at the junction of the horizontal and ascending rami of the mandible.• Note: The gonion is found by bisecting the angle formed by tangents to the posterior and inferior borders of the mandible. ikassem@dr.com
  17. 17. Posterior nasal spine (PNS). The tip of the posteriorspine of the palatine bone in the hard palate.Articulare (Ar). The point of intersection of thedorsal contours of the posterior border of themandible and temporal bone.Porion (Po). The uppermost point of thebony external auditory meatus, usually regardedas coincidental with the uppermost point of theear rods of the cephalostat. ikassem@dr.com
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  19. 19. Main cephalometric planes and anglesFrankfort plane. A transverse plane throughthe skull represented by the line joining porion andorbitale.Mandibular plane. A transverse plane through the skullrepresenting the lower border of the horizontal ramus ofthe mandible.There are several definitions:• A tangent to the lower border of the mandible• A line joining gnathion and gonion• A line joining menton and gonion. ikassem@dr.com
  20. 20. Maxillary plane. A transverse plane through the skullrepresented by a joining of the anterior and posterior nasalspines.SNplane. A transverse plane through the skull represented bythe line joining sella and nasion.SNA. Relates the anteroposterior position of the maxilla, asrepresented by the A point, to the cranial base.SNB. Relates the anteroposterior position of the mandible, asrepresented by the B point, to the cranial base.ANB. Relates the anteroposterior position of the maxilla tothe mandible, i.e. indicates the anteroposterior skeletalpattern — Class I, II or III. ikassem@dr.com
  21. 21. Maxillary incisal inclination. The angle betweenthe long axis of the maxillary incisors and themaxillary plane.Mandibular incisal inclination. The anglebetween the long axis of the mandibular incisorsand the mandibular plane. ikassem@dr.com
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  23. 23. CEPHALOMETRIC ANALYSIS
  24. 24. ANALYSIS UTILIZING THE CEPHALOMETRIC TRACING1) Describe the subject’s dento-facial morphology2) Quantitative description of morphological deviations3) Make diagnostic and treatment planing decisions2) Evaluate change over time - treatment induced and growth process
  25. 25. Morphological Description• Skeletal - horizontal and vertical• Dental - horizontal and vertical• Comparing individual subject’s tracing to the “ideal”
  26. 26. Cephalometric Evaluation• Identification of anatomic landmarks• Landmarks: stable reference structures and maxillary and mandibular skeletal and dental• Graphically relating the dento-facial elements to these reference structures• Angular and or linear measurements
  27. 27. METHODS OF CEPHALOMETRIC ANALYSIS• Two basic approaches• Metric approach - use of selected linear and angular measures• Graphic approach - “overlay” of individual’s tracing on a reference template and visual inspection of degree of variation
  28. 28. Metric Method - Use of selected linear and angular measures
  29. 29. Graphic Method - Use of a Composite Template
  30. 30. GOALS OF CEPHALOMETRIC ANLYSIS• Evaluating relationships, both horizontal and vertical of 5 major functional components of the face:• the cranial base;• the maxilla; the mandible,• the maxillary and mandibular dento-alveolus
  31. 31. REFERENCE LINES• Frankfort’s Horizontal (porion to orbitale)• Sella - Nasion line• True horizontal plane• True vertical plane
  32. 32. Reference Lines sella nasion porion orbitale
  33. 33. SNA 82 ± 2 degNA TO FH 90 ± 3deg SKELETAL HORIZONTAL - MAXILLA s n FH a
  34. 34. SNB 80 ± 2 degN-PG TO FH88 ± 6 deg SKELETAL HORIZONTAL - MANDIBLE n s FH b Pg
  35. 35. ANB 2 ± 2 deg SKELETAL HORIZONTAL - MAXILLA TO MANDIBLE N A B
  36. 36. FH TO GOGN 22 ± 5degY AXIS 59 ± 6 deg SKELETAL VERTICALLFH 55% OF TFH S FH GO ME GN
  37. 37. INTERINCISAL 130± 5 deg DENTAL - UPPER TO LOWER INCISOR
  38. 38. U1 TO FH 110 ± 5degU1 TO NA 22deg DENTAL - MAXILLARY INCISORU1 TO NA 4mm N FH A
  39. 39. L1 TO NB 25degL1 TO NB 4mmL1 TO GOGN 91 ± DENTAL - MANDIBULAR ANTERIOR6deg N GO B GN
  40. 40. NASOLABIALANGLE 102 ± 8 degL.LIP TO E PLANE -2±2mm SOFT TISSUE
  41. 41. Limitations of the Metric Method• Stable reference structures are only relatively stable• Validity of landmarks• Error in landmark identification
  42. 42. Graphic Method• Template• Changes between 2 time points
  43. 43. Superimposition Method - on the cranial base
  44. 44. Maxillary and mandibular superimposition
  45. 45. Limitations of Cephalometric Analysis• Individual variability• Ethnic variability• Gender variability
  46. 46. 2-Cephalometric postero-anterior of the jaws• This projection is identical to the P view except that it is standardized and reproducible. This makes it suitable for the assessment of facial asymmetries and for preoperative and postoperative comparisons in orthognathic surgery involving the mandible. ikassem@dr.com
  47. 47. ikassem@dr.com
  48. 48. Thank you• You can get the lecture on• http://www.slideshare.net/islamkassem ikassem@dr.com

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