Mc namara analysis

1. AJEESHA NAIR M c N amara A nalysis

2. Dr JAMES A McNAMARA 1984

3. A method of cephalometric analysis that is sensitive not only to the position of the teeth within a given bone but also to the relationship of the jaw elements and cranial base structures one to another . In short, the method of analysis described here represents an effort to relate teeth to teeth, teeth to jaws, each jaw to the other, and the jaws to the cranial base.

4. Skeletal and dental components of the face in normal occlusion

5. Maxillary skeletal protrusion

6. Maxillary dentoalveolar protrusion

7. The method of analysis described here represents an effort to relate teeth to teeth, teeth to jaws, each jaw to the other, and the jaws to the cranial base .

8. THE COMPOSITE NORMATIVE STANDARDS DERIVED FROM 3 SAMPLES

9. MAXILLA TO CRANIAL BASE Soft tissue evaluation Hard tissue evaluation NASOLABIAL ANGLE CANT OF UPPER LIP

10. DRAWING A LINE TANGENT TO THE BASE OF THE NOSE AND A LINE TANGENT TO THE UPPER LIP FORMS THE NASOLABIAL ANGLE

11. CANT OF UPPER LIP

12. FH NP .A Hard tissue evaluation Relationship of point A to nasion perpendicular

13. 0 mm in mixed dentition 1 mm in adult male& female

14. Ant position of pt A -- + ve value

15. P ost position of pt A -- - ve value

16. In well – balanced faces,this measurement is: 0 mm in mixed dentition 1 mm in adult females and males.

17. Exceptions

18. MAXILLA TO MANDIBLE

19. Maxilla To Mandible Anteroposterior relationship Midfacial length Effective mandibular length Maxillomandibular differential Any effective midfacial length corresponds to an effective mandibular length .

20. MID-FACIAL LENGTH measuring a line from Condylion to point A. Condylion - most posterosuperior point on the outline of mandibular condyle MANDIBULAR LENGTH -measuring a line from Condylion to anatomic Gnathion Gnathion – most anteroinferior aspect of the mandibular symphysis . ()

21. Point A Gnathion Condylion

22. The effective lengths of max & mand are related to the size of the component parts . Thus termed: small for mixed dentition medium for adult female large for adult male The Maxillomandibular Difference : In small individuals : 20-24 mm, In medium sized individuals: 25-28 mm In large individual : 29-33 mm

23. Gn A

24. VARIATIONS

25. VERTICAL RELATIONSHIP

26. Lower anterior facial height

27. It is the angle between anatomic FH and the line drawn along the lower border of the mandible through constructed Gonion (Go ) and M enton (Me). Average is 22 ± 4 degrees . - Excessive lower facial height - Deficiency in lower facial height. MANDIBULAR PLANE ANGLE

28. It is formed by a line constructed from the posterosuperior aspect of the pterygomaxillary fissure (PTM) to gnathion ( Gn ) and a line perpendicular to cranial base ( ie a line from basion (Ba) to nasion (N ). An ideal relationship is when PTM- Gn lies on the perpendicular(0 degrees ). If PTM- Gn lies anterior to the perpendicular, the angle is positive, suggesting deficient vertical development of face and vice versa. Facial Axis Angle of Ricketts

29. MANDIBLE TO CRANIAL BASE

30. Is determined by measuring distance from pogonion to nasion perpendicular. In mixed dentition 6-8 mm (behind N per ) In adult female 0-4 mm (behind N per ) In adult male 2 mm(behind to 5 mm fwd of N per)

31. DENTITI0N Helps in determining the antero -posterior position of both upper and lower incisors

32. Ideal distance measured horizontally from point A to the facial surface of maxillary incisors is 4 to 6 mm Relating the upper incisor to maxilla

33. Anteroposterior position: Measurement of the facial surface of the lower incisor to the A- Pogonion line. Normal = 1 - 3 mm Relating lower incisor to mandible

34. In vertical position mandibular incisors are related to functional occlusal plane. If curve of S pee is excessive incisors intruded or molars Extruded LAFH is the determining factor

35. AIRWAY ANALYSIS

36. Upper pharynx Two measurements are used to examine the possibility of airway impairment. Lower pharynx

37. It is measured from a point on the posterior outline of the soft palate to the closest point on the posterior pharyngeal wall. Normal(adults) - 17.4 mm Increases with age UPPER PHARYNGEAL WIDTH

38. It is measured from the intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior pharyngeal wall. Normal – 10 – 12mm Does not change with age LOWER PHARYNGEAL WIDTH

39. SIGNIFICANCE Adenoid obstruction of upper airway – upper pharyngeal width decreases. Lower pharyngeal width –greater than 15 mm -anterior positioning of tongue – habitual or enlargement of tonsils .

40. McNamara Analysis 1. Maxilla to cranial base Normal Patient Inference Nasolabial Angle 102±8˚ 110˚ Normal upper lip Cant of upper lip 14±8˚ 8˚ Normal upper lip Point A to N-perpendicular 0-1mm -9mm retrusive maxilla

41. 2.Maxilla to mandible Normal Patient value Inference Anteroposterior Maxillary Length 100.9 103mm Maxillary length normal Mandibular Length 131mm 127mm (136-139) decreased mandibular length Maxillomandibular differential 30mm 24mm decreased Vertical LAFH(ANS-Me) 71.6mm 67mm Reduced Mandibular Plane Angle(FH-Go-Me) 22± 4˚ 34˚ VGP Facial Axis Angle 0±3.5˚ -7˚ VGP

42. Normal Patient Value Inference 3.Mandible to cranial base Pog to N-perpendicular 0-4mm -13mm Backwardly placed chin 4.Dentition Maxillary incisor to point A 4-6mm 7mm Protrusive upper incisor Mandibular incisor to A-p0g 1-3mm 5mm Protrusive lower incisor 5.Airway Upper pharynx 15-20mm 17mm Normal upper pharyngeal width L0wer pharynx 11-14mm 12mm Normal lower pharyngeal width

43. References Radiographic Cephalometry-Jacobson 2 nd edition AJO-DO 1984 Dec (449-469)-McNamara

44. Thank you…….