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Orthodontic Cephalometric analysis

Steiner analysis , Down analysis , Tweed analysis , Bjork analysis , Jarabak analysis , Ricketts analysis , McNamara analysis

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Orthodontic Cephalometric analysis

  1. 1. Dr Abelrahman Mosaad , BDS
  2. 2. Ceph tracing allows  1) Describe the subject’s dento-facial morphology  2) Quantitative description of morphological deviations  3) Make diagnostic and treatment planing decisions  4) Evaluate change over time - treatment induced and growth process
  3. 3.  Skeletal analysis  Dental analysis  Vertical analysis
  4. 4. 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
  5. 5.  Evaluating relationships, both horizontal and vertical of 5 major functional components of the face:  the cranial base  the maxilla  the mandible  the maxillary dento-alveolus  mandibular dento-alveolus
  6. 6. Landmarks (A) Deepest concavity on anterior profile of maxilla (B) Deepest concavity on anterior surface of mandibular symphysis Anterior nasal spine (ANS) Tip of anterior process of maxilla Posterior nasal spine (PNS) Tip of posterior nasal spine of maxilla Pogonion (Pg) Most anterior point on bony chin Nasion (N) Deepest point on frontonasal suture
  7. 7. Sella (S) Midpoint of sella turcica Orbitale (Or) Most inferior point on orbital margin Porion (Po) Upper and outermost point on bony external auditory meatus Condylion Most superior posterior point on the condylar head Gnathion (Gn) The most anterior inferior point on the mandibular symphysis Menton (Me) Lowest point on mandibular symphysis Gonion (Go) The most posterior inferior point on the angle of the mandible
  8. 8. Condylion Most superior posterior point on the condylar head Articulare Intersection of the posterior border of the neck of the mandibular condyle and the lower margin of the posterior cranial base Basion Posterior limit of midline cranial base
  9. 9. Planes SN line A line joining sella(S) and nasion(N) representing the anterior cranial base FH Frankfort horizontal plane A line joining porion(Po) and orbitale(Or) OP Functional occlusal plane A line drawn between the cusp tips of the permanent molars and the premolars or deciduous molars Md Mandibular plane A line joining gonion(Go) and menton(Me) Mx maxillary plane A line joining ANS &PNS E Ricketts ’ E - line A soft tissue line tangential to chin(Pg soft tissue ) and nasal tip
  10. 10. SNA SNB ANB MMPA Y-axis (growth) Angle between Frankfort H. plane and line from sella turcica and Gnathion Mandibular plane angle (MPA) SN-Go.Me U1-L1 angle (interincisal angle) L1-MP
  11. 11. Types of tracing  Manual  Digital or computerized : eg (dolphin) software for Windows , (quick ceph ) software for MAC
  12. 12. Analyses (analytic approaches) by various authors  Many authors have their analytical approaches to analize the cephalometric radiograph , each approach has its characteristics and values
  13. 13. *Steiner analysis - developed Steiner Analysis in 1953. He used S-N plane as his reference line in comparison to FH plane due to difficulty in identifying the orbitale(Or) and porion(Po) - drawbacks : reliability on N point , S-N plane rather than cranial base -
  14. 14.  Skeletal : SNA , SNB , ANB , SN-OP , SN-MdP  Dental : U1-NA , U1-NA mm , L1-NB , L1-NB mm , U1- L1 , L1-chin mm  Soft tissue : S.line ,, Line formed by connecting Soft Tissue Pogonion and middle of an S formed by lower border of the nose
  15. 15. Skeletal SNA 82 SNB 80 ANB 2 SN-OP 14 SN-MdP 32
  16. 16. U1-NA U1 inclination *= 22 *= 4mm L1-NB L1 inclination *= 25 *= 4mm Could Evaluates the chin also U1-L1 angle *= 130 Dental analysis
  17. 17. Soft tissue analysis
  18. 18. Egyptian Norms
  19. 19. Wits analysis : - jacobson 1975 in soutthafrica Witwaterssand university - it measured the AP positions of the jaw to each other
  20. 20. Wits Aprasial *average jaw relationship is -1 mm in Males (AO is behind BO by 1mm) & zero mm in Females (AO and BO coincide)
  21. 21. • Its clinical significance is that : • in a Class 2 skeletal patient, AO is located ahead of BO • In skeletal Class 3 patient, BO is located further ahead of AO • Therefore, the greater the witts reading, the greater the jaw discrepancy
  22. 22.  Drawbacks to Wits analysis includes: Left and Right molar outlines may not always coincide Occlusal plane may differ in mixed vs permanent dentition If curve of spee is deep then it may be difficult to create a straight occlusal plane Angulation of functional occlusal plane to pterygomaxillary vertical plane was shown to decrease from age 4 to 24
  23. 23. *Down Analysis  by Downs in 1948  It is one of the most frequently used cephalometric analysis.  Downs analysis consists of – 10 parameters (5 skeletal , 5 dental )
  24. 24.  according to down “balance of face is determined by position of mandible”.  in order to find this balance downs use frankfurt horizontal plane (FH)as a reference plane i.e. line from anatomic porion(po) to orbitale(or)  Downs elected to use this plane as a reference base from which he determine the degree of retrognathism, orthognathism, or prognathism
  25. 25.  Skeletal parametters : - facial angle :Angle between Nasion-Pogonion and Frankfurt Horizontal Line (N-Pg & FH ) - angle of convexity : Angle between Nasion - A point and A point - Pogonion Line (N-A & A-Pg) - Mand plane angle : Angle between Frankfort horizontal line and the line intersecting Gonion-Menton(FH &Go-Me) - y (growth) axis : Sella Gnathion to Frankfurt Horizontal Plane (S- Gn & FH) - AB plane angle : Point A-Point B to Nasion-Pogonion Angle (A-B & N-Pg)
  26. 26. Facial Angle *FH&N-Pg * Mean = 88 (82-95) *Mandibular prominance Angle of convexity * N-A & A-Pg * Mean = 0 (-8 - 10 ) *+ve suggest prominent maxilla * -ve suggests prognathic profile Mand. Plane angle *Go-Me & FH * Mean = 25 (17-28) * >28 , suggests prominence , retrusion , LAFH ? , lower prognosis vlaues , ….
  27. 27. Y (growth) axis angle * S-Go & FH * Mean =58 ( 53-66 ) * Downward forward position of chin to FH * Derease = horizontal growth rather than vertical A-B plane angle * A-B & N-Pg * Mean = -4 (-9 to 0 ) * Usually –ve except class 3 & class 1 prominent chin * High –ve values suggest class 2
  28. 28.  Dental parameters : - occlusal plane cant angle : angle between OP & FH - U1 - L1 angle : - L1 - Occlusal Plane Angle : - L1 - Mandibular Plane Angle : - U1 to A-Pog Line (mm) :
  29. 29. occlusal plane angle * OP & FH * Mean = 9 (1-14 ) * slope of occlusal plane *Decrease in long rami * Increase in class 2 facial U1-L1 * Mean 135 (130-150) * < 130 = protruded anteriors , stability ?? L1 – Occ.Plane * Mean = 14.5 (3.5-20) * > 20 suggests proclined L1
  30. 30. L1 – Mand.Plane *Mean = 90 (85-95) * > 95 suggests proclined L1 U1 – (A-Pg) *Mean 2.7 ( -1 to 5 ) *> 5 suggests proclined U1
  31. 31. * Tweed Analysis  Charles H. Tweed developed his analysis in the year 1966  In this analysis, he tried describing the lower incisor position in relation to the basal bone and the face.  This is described by 3 planes. He used Frankfurt Horizontal plane as a reference line  Useful in extraction planning and dertermine the position of lower anteriors after ttt , so the prognosis could be predicted
  32. 32.  Angles ( of the triangle ):  L1-MP  L1-FH  FH-MP
  33. 33.  FH-MP > 25 vertical growing  FH-MP < 25 horizontal growing  Prognosis is good when FH-MP 16-28  Prognosis is fair when FH-MP 28-35  Prognosis is bad when FH-MP > 35 extraction will worsen the results  Tweed stressed the importance of the FH-L1 angle recommending that it be maintained at 65° to 70°
  34. 34. Bjork analysis  Arne Bjork was developed in 1947 based on 322 Swedish boys and 281 conscripts  a facial polygon which was based on 5 angles  7 structural signs which indicates the mandibular rotator type  The analysis is based on 5 points: Nasion (Na), Sella (S), Menton (Me), Go (Gonion) and Articulare (Ar)
  35. 35.  5 angles (facial polygon) : - Nasion Angle : Formed by line connecting ANS to Nasion to Sella (ANS-N & N-S ) - Saddle or Cranial Base Angle : Formed by line connecting Nasion to Sella to Articulare ( N-S & S-articulare ) - Articular Angle : Formed by line connecting Sella to Articulare to Gonion ( S-articular & articular-Go) - Gonial Angle : Formed by line connecting Articulare to Gonion to Gnathion (Art-Go & Go-Gn) - Chin Angle : Formed by line connecting Infradentale to Pogonion to the Mandibular Plane ( infradental –pog & pog- MandP )
  36. 36.  7 structural signs : 1.Inclination of the Condylar head 2.Curvature of the Mandibular canal 3.Shape of the lower border of mandible 4.Inclination of the Symphysis 5.Interincisal angle 6.Intermolar or Interpremolar angles 7.Lower Anterior face height
  37. 37. Jarabak Analysis  developed by Joseph Jarabak in 1972  The analysis interprets how the craniofacial growth may affect the pre and post treatment dentition  The analysis is based on 5 points: Nasion (Na), Sella (S), Menton (Me), Go (Gonion) and Articulare (Ar). They together make a Polygon on a face when connected with lines
  38. 38.  These points are used to study the anterior/posterior facial height relationships and predict the growth pattern in the lower half of the face.  Three important angles used in his analysis are: - 1. Saddle Angle - Na, S, Ar - 2. Articular Angle - S-Ar-Go, - 3. Gonial Angle - Ar-Go-Me.
  39. 39.  In a patient who has a clockwise growth pattern, the sum of 3 angles will be higher than 396 degrees. Posterior & anterior face height ratio:
  40. 40. Ricketts analysis  Aim: - to clarify the science of cephalometrics and free it from some of the confusion and misuse pervading the discipline. he also wanted to point out that the use of cephalometrics to describe and classify a malocclusion was one thing (analysis) and the act of treatment planning as a result of this classification and description was another thing (synthesis)
  41. 41. # CC= Center of cranium point of intersection of the basion Nasion plane and the facial axis. #DC=Point in the center of condylar neck along the Ba- Na Plane # PM= Suprapogonion/ protrubrance menti , The point at which the symphysis mentalis changes from convex to Concave # Ptv= point of intersection of thedistal outline of ptm fissure and perpendicular to the F- Hplane. #Xi= Geometric center of the ramus
  42. 42.  1960  Superficial Analysis: - 1.Facial Angle - 2. Facial axis( x-y axis) - 3.Facial Convexity( A- Pog) - 4. Lower Incisor position and angulation. - 5. Upper Incisor position - 6. Esthetic Plane  Deep Structure Analysis: - 1. Cranial Base Angle - 2. Cranial Base Length - 3. Condyle or Fossa position - 4. Condyle Axis - 5. Mandibular Plane Angle
  43. 43.  1981  I. Lateral Analysis - 1.Facial Axis - 2.Facial Angle - 3.Mandibular Plane Angle - 4.Mandibular arc( Mandibular Bend) - 5.Point A to Facial plane - 6.Palatal Plane to Frankfort horizotal plane - 7.Denture Height /lowerfacial height/ Oral Gnomom - 8.Lower incisor to Apog line(mm) and (Angulation) - 9.Upper Incisor to Apog(1960) - 10.Upper molar to Ptv - 11.Interincisal Angle - 12.Lower Lip to E Line
  44. 44.  II. Frontal Analysis - 1. Nasal width - 2.Mandibular width - 3.Maxillary width - 4.Molar width - 5.Actual intermolar width - 6.Intercuspid width - 7.Denture Symmetry - 8. Upper to Lower Molar relation
  45. 45. Xi point
  46. 46.  Mandibular arc (Mandibular Bend):  It measures the angulation of the condylar process to the body of the mandible. It is the angle between the Condyle axis(Xi through center of condyle neck) Posterior extent of the corpus axis(pm to Xi)  Norm = 26º+/- 2º A total increase of 3º is seen every 5 year
  47. 47.  Fronatal analysis (PA) 1.Nasal cavity width 2.Mandibular width 3.Maxillary width 4.Symmetry 5.Intermolar width 6.Intercuspid width 7.Denture symmetry 8.Upper to lower molar relation
  48. 48. McNamara analysis  James Mcnamara 1984  Analysis of craniofacial complex , via 5 major sections which are : - maxilla to cranial base - mandible to cranial base - maxilla to mandible - dentition - airway
  49. 49. Maxilla to cranial base
  50. 50. Mandible to cranial base
  51. 51. Maxilla to Mandible
  52. 52.  “small” , “medium” , “large” are used to describe the size  Maxillomandibular difference = midfacial length – mandibular length  In small individuals the difference should be between 20 and 23 mm  In medium sized persons the difference should be between 27 and 30mm  In large individuals the difference should be 30 and 33mm
  53. 53.  If the discrepency is greater or smaller than the normative values --------- Then next step is to identify which jaw is small or large or both
  54. 54. # Lower face height in the mixed dentition with a midface length of 85mm should be 60 -62mm # Lower face height in medium – sized individuals with a midface length of 94 mm should be 65 -67 mm # Lower face height in large individuals with midface length of 100mm should be 70 -73mm Vertically
  55. 55. Mandibular plane angle : • It is the angle between frankfort horizontal and the line drawn along the lower border of the mandible through constructed gonion and menton. • Mandibular plane angle is 22º ±4º
  56. 56. Facial axis angle : •Angle between a line from basion to nasion and the facial axis (PTM to Gn) •In a balanced face , the facial axis angle is 90 º •< 90º (- ve value ) indicates excessive vertical development •> 90º (+ ve value) indicates deficient vertical development
  57. 57.  Dentition  We need to know the relationship between dentition ( mainly anteriors ) in the both jaws to the underlying basal bone .  The dentition can be neutral , protrusive or retrusive
  58. 58. MAXILLARY INCISOR POSITION : •To measure the position of the maxillary incisors in relation to its apical base •A vertical line is drawn through point A parallel to nasion perpendicular •The distance from point A to facial surface of incisor is measured . • It should be 4-6 mm
  59. 59. 11 mm severe U1 protrusion
  60. 60. MANDIBULAR INCISOR POSITION : •The distance is measured between the edge of the mandibular incisor and a line drawn from point A to pogonion (A – Pog line) •In well balanced face, the distance should be 1-3 mm.
  61. 61.  Assessment of vertical position of lower incisor: - If the curve of spee is excessive , a decision must be made whether the lower incisor should be intruded or molars to be extroded. - The determining factor is the lower anterior facial height. - If the lower facial height is normal or excessive the lower incisor should be intruded. - If the lower anterior facial height is deficient then the lower incisor should be extruded or the buccal segments further erupted.
  62. 62. Air way UPPER PHARYNX:  Width is measured from a point on the posterior outline of the soft palate to the closest point on the pharyngeal wall  Average : 15 – 20 mm in width  A width of 2mm or less in this region may indicate airway impairment.
  63. 63.  LOWER PHARYNX :  Its width is measured from the point of intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior phanyngeal wall  Average : 11 – 14 mm
  64. 64. Conclusion  Lateral ceph analysis is not a must in orthodontics it is a supplemental diagnostic aid  Keep your analysis as simple as you can  Focus on what you need and pick it up
  65. 65. Eg. (A-P) *SNA *SNB *ANB i.e. class I , II , III Vertical *MMPA i.e high , average , low i.e. vertical growing *facial height i.e. LAFH Dental *(upper1-Max) i.e. proclined , average , retroclined *(lower1-Mand) i.e. proclined , average , retroclined
  66. 66. Thanks a lot

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