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Steiner analysis

information and method of steiner analysis for lateral cephalometric analysis

Steiner analysis

  1. 1. Steiners analysis Dr Nabil Rahman
  2. 2.  Cecil c. Steiner(1896-1989)  One of Edward H.Angle’s first students in 1921.  He developed a form of cephalometric analysis, presented in 1953,referred to as the Steiner method of analysis.
  3. 3.  Steiner in his analysis took into account that it may not be possible to reach ideal proportions and relationtionships in all cases, but there are ways to maximize esthetics.  Steiner devised ways to alter incisor positions to achieve normal occlusions ever when the ideal ANB angle couldn’t be achieved. i.e. how much the teeth needed to be moved to compensate for a skeletal malocclusion.  For larger skeletal discrepancies ,the Steiner method would not be effective for treatment.
  4. 4. traditional lateral cephalometric headfilm landmarks
  5. 5. Steiner use SELLA to NASION line as a reference plane for his analysis. This line represents the anterior cranial base. Steiner highlighted difficulties in accurate location of the porion point and its relative variation, which could be observed in successive radigraphs.This in turn, affected the orientation of F-H plane. S and N points have another advantage of being located in the mid sagittal plane of the head and move minimally with any any deviation of head from true profile position. The cranial base undergoes very little change after the age of 6- 7 years.
  6. 6.  Skeletal analysis  Dental analysis  Soft tissue analysis Steiner analysis consist of
  7. 7. STEINER’S Analysis SKELETAL DENTAL SOFT ANALYSIS ANALYSIS TISSUE ANALYSIS -SNA (Maxilla) -Maxillary incisor position -S line -SNB (Mandiblar) -Mandibular incisor position -ANB (Maxillary-Mandibular) -Interincisal angle -Occlusal plane -Lower incisor to chin -Mandibular plane
  8. 8. Skeletal analysis
  9. 9. SNA Angle -Mean is 82° -Greater angle indicates relative forward positioning of maxilla & lesser angle indicates recessive location of maxilla
  10. 10. SNB angle -Mean is 80° -Angle less than 80 indicates recessive mandible while greater angle suggest Prognathic mandible
  11. 11. Relationship of maxilla to mandible (ANB) - Angle provides a general idea of anterioposterior discrepancy of maxilla to mandibular apical bases - Mean is 2° - Greater than the mean indicates a class II skeletal tendency, angle less than 2 & below zero indicates the mandible located ahead of maxilla suggesting class III
  12. 12. Relationship of maxilla to mandible (ANB) ANB angle tell us only about “Magnitude of the discrepancy between the jaws, not the absolute discrepancy” If treatment is based on the ideal ANB angle of 2 degree it may not necessarily obtain the ideal position of either the maxilla or the mandible. Steiner believed the main interest should be alleviating the magnitude of discrepancy.
  13. 13. -Occlusal plane drawn through the region of overlapping cusps of 1st premolars & 1st molars. -Angle of occlusal plane & S-N is measured. -Mean reading is 14° -The angle is increased in long face or vertically growing individuals and also skeletal open bite cases. - It may be decreased in horizontally growing individuals or cases with a skeletal deep bite. Occlusal plane
  14. 14. Mandibular plane (Go-Gn) - Drawn between gonion & gnathion - The mandibular plane angle is formed by joining the mandibular plane to the anterior cranial base (S-N plane) - Mean reading is 32° - Excessively high or low mandibular plane angles suggest unfavorable growth pattern in individuals
  15. 15. Dental analysis
  16. 16. Dental U1-NA distance Dental U1-NA angle  Angle is formed by intersection of long axis of upper central incisors & line joining N-A line  22 degree angle and 4mm distance is ideal.  Greater than 22 may be seen in class II div I .  Less than 22 degree may be seen in class II div 2 case. It is necessary to measure the distance from the most labial surface of the incisor to the NA line. Measurement >4 mm common in class I bimaxillary protrusion or in class II div 1 relationship. Less than 4 mm common in class II div 2 .
  17. 17. Incisor angle at 22 degrees but (a) Retro positioned (-2mm) (b) Ideally positioned (4mm) (c) Positioned too far forward (8mm) Show inadequacy of relating incisor tip to millimeter reading only. All three teeth are 4mm from the N- A line but angled differently
  18. 18. LI –NB distance LI –NB angle Angle is formed by intersection of long axis of lower central incisors & line joining N-AB line 25 degree angle and 4mm distance is ideal Angle greater than 25 degree may be seen in class II div 1 Less than 25 degree common in class II div 2 or class III
  19. 19. Interincisal angle  Mean value of 130-131°  Reduced angle suggest class II div 1  Larger angle indicates class II div 2
  20. 20. Lower incisor to chin (Holdaway ratio) This measurement is introduced to evaluate the relative prominence of the mandibular incisors, as compared to the size of the bony chin. • According to Holdaway distance between labial surface of Mb incisor to N-B line and the distance from pogonion to N-B line should be equal (i.e. 4mm) • Discrepancy • If discrepancy is • 2mm = Acceptable • 3mm = Less desirable • 4mm exceeds = Correction indicated
  21. 21. Soft tissue analysis The facial contour line called ‘S’ line of Steiner. A line is drawn on the soft tissue contour of the chin to the middle of the ‘S’ formed by the lower border of the nose .In a well balanced face, the lips should touch the line. If the lips are located beyond this line lips are believed to be protrusive & interpreted as convex profile If lip behind this line said to be retrusive with a concave profile.
  22. 22. PRINT MASTER
  23. 23. What is E line? In Ricketts analysis E line or estheic line runs from the tip of the nose to the soft tissue pogonion. S line extending from soft tissue contour of the chin to the middle of an “S” formed by the lower border of the nose

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