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Mc namara analysis /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078


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  • 1. Mc Namara Analysis INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2. According to him, “during the last 3 decades, clinical orthodontics has seen the advent of numerous orthognathic surgical procedures that allow 3-D repositioning of almost every bony structure in the facial region. Similarly, facial orthopedics has become part of everyday clinical practice..Therefore we perceived a need for 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 maxilla, mandible and cranial base structures, one to another.” www.indiandentalacademy.com
  • 3. He asserts that his analysis method is presented as a language, which can be used by the clinician to better identify and describe the structural relationships of the jaws, as well as to communicate easily with other clinicians as well as lay persons. This method of analysis is derived in part from the principles of the Ricketts’ and Harvold analyses. www.indiandentalacademy.com
  • 4. Basis: The Mc Namara analysis is useful in Basis: diagnosis and treatment planning of the individual patient when values derived from the tracing of the patients’ head film are compared to established norms; the norms from 3 gps have been derived: The Bolton study (4-18) The Ann Arbor sample (200 adults) The Burlington sample (6-30) Composite norms. www.indiandentalacademy.com
  • 5. This analysis consists of 5 major sections: Relating maxilla to cranial base Relating maxilla to mandible Relating mandible to cranial base The dentition Airway analysis www.indiandentalacademy.com
  • 6. I.Relating the maxilla to cranial base: soft tissue evaluation: As part of the clinical examination as well as during evaluation of the lateral cephalogram, the nasolabial angle and the cant of upper lip should be examined. A)Norms 110° (scheidemann et al) 102° ± 8° (Ann Arbor sample) www.indiandentalacademy.com
  • 7. Acute nasolabial angle= Dentoalveolar Protrusion Miyajima et al(1996 AJO) compared the above figures with untreated japanese with ideal occlusion and found more acute Nasolabial angle Greater Bilabial Protrusion www.indiandentalacademy.com
  • 8. B)Cant of upper lip: 14°± 8° in females (Ann Arbor sample) 8°± 8° in males (adult) with the nasion perpendicular. www.indiandentalacademy.com
  • 9. Hard tissue evaluation: The antero-posterior position of the maxilla is determined by Constructing the Nasion perpendicular. The Linear distance from point A to Nasion Perpendicular is Measured Ann Arbor Norm=0.4mm(male) Comp Norm=0mm(Mixed D) . 1mm(adult) www.indiandentalacademy.com
  • 10. Usually, the hard, soft tissue findings correlate well with each other. However, when a discrepancy exists between the two, the findings from the clinical examination (ie. Soft tissue findings) should take precedence. Treating patient only to specific cephalometric norms must be avoided. Drawbacks:  1) It is affected by position of nasion, which is itself affected by cranial base length. 2) There is displacement of point A labially when the roots are anteriorly tipped. Note: A measurement of the SNA angle is also included in this category. Ann Arbor norms for SNA: male= 82.4 ° female= 83.9° www.indiandentalacademy.com
  • 11. II) Relating the mandible to the maxilla (midface): A) Effective midfacial length and mandibular length: determined by measuring a line from condylion to point A. Effective mandibular length is derived by constructing a line from condylion to anatomic gnathion. There is a geometric relationship between the above two values; any given effective midface length corresponds to a given effective mandibular length. Maxillomandibular differential: it is the difference between the effective mandibular length and effective midface length.             www.indiandentalacademy.com
  • 12. A given effective midfacial length corresponds to an effective mandibular length within a given range. “these are not directly related to patient’s age or sex” Mid Face Length=91mm Range for Mandible=115-118mm www.indiandentalacademy.com
  • 13. B) Vertical Dimension: The clinical appearance of the relation between upper and lower jaws is affected greatly by lower anterior facial height (measured from ANS to mention). This linear measurement increases with age and is correlated to the effective length of the midface . Eg: In Mixed dentition Analysis Mid face Length= 85mm Lower Anterior Facial Height= 60-62mm In Medium sized individuals Mid face Length= 94 Lower Anterior Facial Height= 65-67mm In Large sized individuals Mid face Length= 100 Lower Anteriorwww.indiandentalacademy.com 70-73mm Facial Height=
  • 14. Significance: Increase in Lower anterior Facial Height -- Mandible appears retrognathic Decrease in Lower anterior Facial Height Mandible appears prognathic In growing persons, an increased LAFH camouflages a similar increase in mandibular length, resulting in the appearance that the chin is in the same position A-P, with respect to cranial base structures. This analysis also includes two other measurements: ·   1)Mandibular plane angle: 1) 2)Facial axis angle of Ricketts: 2) www.indiandentalacademy.com
  • 15. Mandibular Plane Angle: Angle between F-H plane Go-Me N S Normal Value:22°+/- 4° Go Gn Higher Vaue: Excessive Lower Facial height Lower Vaue: Deficiency www.indiandentalacademy.com
  • 16. Facial axis Angle: Angle between a)Posterosuperior aspect of pterygomaxillary fissure to gnathion b)Line joining Basion to Nasion Balanced Face =90° Excessive vertical development , Anti clockwise growth =Less than 90°(negative value)  Deficient vertical development, Clock wise growth =Higher than 90°(positive value) Thomas and Valiathan (June 1993) reported normal directed growth of chin 90.65+/- 3.33 89.64 +/- 5.06 (Adult South Indians ) www.indiandentalacademy.com 90.07 +/- 3.16 (Adult North Indians)
  • 17. www.indiandentalacademy.com
  • 18.     III. Relating the mandible to the cranial base: The relationship of the mandible to the cranial base is determined by measuring the distance of the pogonion to the Nasion perpendicular. According to the composite norms: In a mixed dentition (balanced face) pog lies 8mm to 6mm (ie, posterior) with respect to Nasion In adult male the chin position is usually www.indiandentalacademy.com -2mm to +2,, relative to Nasion perpendicular.
  • 19. www.indiandentalacademy.com
  • 20. Dentition Analysis: A.Relating Upper Incisor To maxilla A vertcal line is drawn through point A parallel to nasion ⊥ The distance from point A to the facial surface of Upper incisor is measured  A-P position of Upper incisor Comp Norms= 4-6mm(MixedD) 4-6mm(Adults) www.indiandentalacademy.com
  • 21. www.indiandentalacademy.com
  • 22. VERTICAL POSITION Upper Incisor Clinically, and typically, the incisal edge of upper incisor lies 2-3 mm below upper lip at rest. This is subject to adjustment depending on functional state of lip musculature and axial inclination of the tooth prior to treatment. www.indiandentalacademy.com
  • 23. B. Relating the lower incisor to the mandible: Anteroposterior positionof Lower Incisor: Determined by using a traditional version of the Ricketts measurement of the facial surface of the lower incisor to the A-Pog line. Bolton study Norms: 1.5 mm anterior to the A Pog. Line. Ann Arbor Norms: 2.3-2.7mm anterior to the A Pog. Line. www.indiandentalacademy.com
  • 24. www.indiandentalacademy.com
  • 25. Vertical position Lower Incisor Evaluated on basis of existing lower anterior facial height. First, the lower incisor tip is related to the functional occlusal plane. If curve of Spee is excessive: a)lower incisor is to be intruded (if LAFH is normal/excess) OR b)lower molar is allowed to erupt and lower incisor extruded. (when LAFH is inadequate). www.indiandentalacademy.com
  • 26. V. Airway analysis: Two measurements are used to examine airway impairment. Upper pharynx: The upper pharyngeal width is measured from a point on the posterior outline of the soft palate to the closest point on the posterior pharyngeal wall. This is because the area immediately adjacent to the posterior opening of the nose is critical in determining upper respiratory patency. www.indiandentalacademy.com
  • 27. www.indiandentalacademy.com
  • 28. Apparent airway obstruction, as indicated by an opening of 2mm or less in the upper pharyngeal measurement is only an indicator of possible airway impairment.  For a more accurate diagnosis, an ENT examination is required. www.indiandentalacademy.com
  • 29. Lower pharynx: Lower pharyngeal width is measured from the intersection of the posterior border of the tongue and inferior border of the mandible to the closest point on the posterior pharyngeal wall. Ann Arbor sample =10-12mm ( average value) does not change appreciably with age.  Smaller than average values are not significant, Greater than average value,15mm suggests anterior positioning of the tongue, either as a result of habitual posture, or due to enlargement of tonsils. www.indiandentalacademy.com
  • 30. Certain conditions associated with greater than average Lower pharyngeal width are:  Mandibular prognathism  Dento-alveolar anterior crossbite  Bialveolar protrusion of teeth www.indiandentalacademy.com
  • 31. www.indiandentalacademy.com
  • 32. Bhat M, Sudha P, Tandon S.(June 2001) Used Computerised cephalometrics, in measuring skeletal and dental relationship in order to establish norms for Bunt and Brahmin children of Dakshina Kannada using McNamara's analysis. www.indiandentalacademy.com
  • 33. www.indiandentalacademy.com
  • 34. PITCHFORK ANALYSIS the Presented by Dr Lysle E. Johnston in Britsh Journal of Orthodontics 1996 www.indiandentalacademy.com
  • 35. The purpose of this analysis is to describe a method of cephalometric analysis that has evolved over the past two decades and which is designed specifically to measure the dental and skeletal effects that combine to produce the occlusal changes that are the goals of treatment. The change in the molar and incisor relationship can be expressed as an exact algebraic sum positive= If it reduces overjet/ corrects a class II Negative = If it increases the overjet www.indiandentalacademy.com
  • 36. Accordingly, this accounting can support comparisons of change between treatments and between treatment phases, not only with respect to magnitude, but also source (i.e. skeletal or dental). www.indiandentalacademy.com
  • 37. www.indiandentalacademy.com
  • 38. Note: Apical base change (ABCH), the sum of maxillary and mandibular translatory growth relative to cranial base, represents the net effect of skeletal growth, usually the amount that the mandible has out-grown the maxilla. Thus, ABCH plus upper and lower molar movement equals the change in molar relationship; ABCH plus upper and lower incisor movement equals change in overjet. www.indiandentalacademy.com
  • 39. The pitchfork analysis thus requires that we measure skeletal change as actual physical displacement, rather than apparent change in the position of a landmark due to surface remodelling. Thus, our measurements must be executed with respect to landmarks that have a good chance of being physically the same at both time-points. All too often, this requirements is not met. The present analysis of occlusal change employs three general superimpositions – a)cranial base, b) maxilla, and c) mandible. www.indiandentalacademy.com
  • 40. Cranial base superimposition S and Na under go change by local remodeling during the growth period (Ford, 1958;Melsen, 1974). In contrast, the literature argues that the bony anatomy from the anterior half of sella turcica to the region of foramen caecum and the internal outline of the frontal bone is sufficiently stable to support meaningful anterior cranial base superimposition (De Coster, 1951; Bjork and Skieller, 1983;). www.indiandentalacademy.com
  • 41. Specifically, Bjork and Skieller (1983) suggest that the following ‘natural reference structures’ be employed: a)the anterior wall of sella turcica (and its point of intersection with the lower contours of the anterior clinoids), b)the greater wings of the sphenoid, c) thecribriform plate, d)the orbital roofs e)the inner surface of the frontal bone www.indiandentalacademy.com
  • 42. www.indiandentalacademy.com
  • 43. Maxilla Best-fit registration for the maxilla is both the a)zygomatic process of the maxilla (right and left sides averaged) and b)on the bony anatomical details superior to the incisors. The superior and inferior surfaces of the posterior hard palate assist in orientation, and to minimize the probability of gross errors in anteroposterior registration NOTE: PTM fissure of the older tracing should lies at or behind that of the younger. www.indiandentalacademy.com
  • 44. www.indiandentalacademy.com
  • 45. Mandible For the purposes of measuring tooth movement relative to basal bone, mandibular regional superimposition commonly is effected via a mandibular-plane orientation and a lingual-symphysis registration. Implant studies, however, suggest that greater validity can be achieved by using the mandibular canal, tooth germs (prior to the initiation of root formation), and the individual bony architecture in the labial aspect of the symphysis (Bjork and Skieller, 1983 ) www.indiandentalacademy.com .
  • 46. Unifortunately, many of these bony details are often absent, difficult to see, or distorted by among-series variation in head placement mandibular plane can be used as a substitute orientation line, especially if there has been minimal growth between cephalograms www.indiandentalacademy.com
  • 47. The pattern of craniofacial growth The main purpose of fiducial lines is to provide a permanent record of the regional superimpositions used in the measurement of skeletal and dental change. When each tracing has been executed in appropriate detail, ‘fiducial lines’ (arbitrary straight lines several inches long with registration crosses) are drawn adjacent to cranial base, maxilla, and mandible of one tracing. The fiducial lines have been transferred throughout the series, they serve not only to record the superimpositions to facilitate the process of measurement (and, if necessary, re-measurement), but also to provide a greatly simplified picture of change seen from the vantage point of any of the three facial areas. www.indiandentalacademy.com
  • 48. Eg: the cranial base fiducial lines are superimposed, the separation of the mandibular and maxillary fiducial lines represents the translatory growth – both in amount and angulation – of the jaws relative to cranial base. www.indiandentalacademy.com
  • 49. Measurement of change Although the face undergoes widespread change during orthodontic treatment, only effects that are felt at the level of the occlusion can have a direct impact on the molar and incisor relationships. The occlusion, therefore, represents the ‘bottom line’, the site at which change in the upper and lower jaws comes together and is integrated. For this reason, the pitchfork analysis measures change projected onto the plane of occlusion. www.indiandentalacademy.com
  • 50. When a two-film series is to be analysed, the maxillae are superimposed, and the two FOP(similar to that of jenkins 1955) then are averaged by inspection to yield a mean functional occlusal plane (MFOP), which is passed through to each tracing. Once the MFOP has been established and transferred to all tracings in the series, regional superimposition within cranial base, maxilla, and mandible is used to measure the various components of anteroposterior change that make up the times of the pitchfork. www.indiandentalacademy.com
  • 51. A)Jaw Growth/ Displacement relative to Cranial Base In the anterior cranial base, “wing point” (W, the point ; Wieslander, 1963; SE, Riolo et al., 1974) commonly serves as a registration point and is used here as the cranial-base reference point from which maxillary and mandibular displacement are measured. To measure displacement of the maxilla relative to cranial base (MAX), the maxillary fiducial lines are superimposed and the separation of the W points is measured parallel to MFOP Mandible: The separation of D-points (standardized in the two tracings by mandibular regional superimposition) is measured parallel to MFOP. This measurement represents the mandible relative to maxillary basal bone. www.indiandentalacademy.com
  • 52. www.indiandentalacademy.com
  • 53. Since the mandible ‘outgrows’ the maxilla, ABCH commonly is positive Note: displacement of D-point can be due to growth, a functional shift, or, more probably, some mixture of the two. So Unfortunately, the cephalometric technique offers no reliable means of differentiating between the two types of change. www.indiandentalacademy.com
  • 54. Whatever its sign (and cause), mandibular displacement relative to cranial base (MAND) then can be estimated by subtraction: MAND = ABCH – MAX. Eg: if the maxilla underwent 3 mm of forward translatory growth, and the mandible out-grew it by 4 mm, MAND = 4 – (-3) = 7 mm. These three measuerments abstract the sagittal growth of the jaws and together with tooth movement account for change in molar relationship and overjet. www.indiandentalacademy.com
  • 55. Tooth movement relative to basal bone The change in overjet and the molar relationship obtained from summing the individual tines of the pitchfork should be compared with direct measurements obtained from an MFOP superimposition. The change in molar relationship is measured by registering on the mesial contact point of one molar (upper or lower) and then measuring the separation of the contact point of the other : The change in overjet, by registering on the averaged incisal edge of the upper or lower incisors and then measuring the displacement of the averaged incisal edge in the other arch. www.indiandentalacademy.com
  • 56. If the individual components of growth and tooth movement do not add up to the direct measurements of change executed at the occlusal plane (say, to within 0.2-0.3 mm), the measurements are re-done. www.indiandentalacademy.com
  • 57. www.indiandentalacademy.com
  • 58. www.indiandentalacademy.com
  • 59. This method of cephalometric analysis is designed to provide an integrated accounting of the source – skeletal growth or tooth movement . Each of the components is measured separately; however, as a group, they sum to provide a complete ‘explanation’ of changes in overjet and molar relationship. Thus it answers to most of the controversies such as www.indiandentalacademy.com
  • 60. www.indiandentalacademy.com
  • 61. 1.Do treatments with functional appliances feature more skeletal change than do conventional fixedappliance treatments? 2.Does anchorage preparation preserve anchorage? 3.Do ‘Straight wire’ appliances ‘burn’ anchorage? 4.What are the penalties incurred by a failure to use extra-oral traction? How does the effect of a given appliance differ in children and adults? 5. Does premolar extraction ‘dish in’ the profile? If so, how much? 6. What is the apparent impact of normal growth (i.e. of excess mandibular growth) on tooth movement during and after treatment. www.indiandentalacademy.com
  • 62. Rush forth, Gordon and Arid (BJO June 1999) Did a retrospective study involving analyses of preand post-treament cephalograms of 63 Class II division 1 patients treated with the FR to demonstrate the relative maxillary, manidibular, incisor, and molar movements during treatment compared with normal growth within a control group of untreated 39 Class II division 1 cases drawn from the same demographic population. All cephalograms were digitized and subjected to a Pitchfork analysis www.indiandentalacademy.com
  • 63. It was shown that the FR was effective in treating Class II division 1 cases with the studied group being corrected to a clinically acceptable overjet and overbite of 2-3 mm. The majority of the correction came from dental movements, the most significant being the retroclination of the upper incisor teeth (mean 4.1mm, 95 per cent CI ±0.44) and proclination of the lowers (mean 2.2 mm 95 per cent CI ± 0.57). As regards skeletal correction, the most significant contribution was the restraint of normal maxillary forward growth (mean -0.2mm, 95 per cent CI ± 0.62) with forward manidiblar growth not being a significant factor. www.indiandentalacademy.com
  • 64. Mannchen (switzerland), Ejo 2001 Compared the PFA with the conventional Bjorks method. The pitchfork analysis consistently provided an overestimation of the skeletal effects and an under-estimation of the dental changes. The pitchfork analysis is not sufficiently sensitive to distinguish between the skeletal and dental effects of orthodontic treatment. www.indiandentalacademy.com
  • 65. Lysle Johnston, Ejo 2002 Reported that Mannchen was wrong in his finding because he used the frankforts horizontal plane (as he was forced by computerisation) to measure the skeletal change rather than the MFOP and the dental change was measured using the MFOP Thus the sum of the individual elements did not equal the molar and Overjet correction www.indiandentalacademy.com
  • 66. References: 1. Thomas G M, Valiathan A: A Cephalometric comparison of South Indian and North Indian population using six analysis. Dissertation submitted to mangalore university, June 1993 2.Bhat M, Sudha P, Tandon S: Cephalometric norms for Bunt and Brahmin children of Dakshina Kannada based on McNamara’s analysis. J Indian Soc Pedo Prev Dent ,June 2001 pg 41- 51 3. Johnston LE Jr: An objective evaluation of the pitchfork analysis (PFA), EJO 2002 vol 24 page 121- 123 www.indiandentalacademy.com
  • 67. 4. R Mannchen: A critical evaluation of the pitch fork analysis , EJO 2001 vol 23 pg 1- 14 5. CDJ Rushforth, PH Gordon, JC Arid: Skeletal and Dental changes following the use of Frenkel Functional Regulator , BJO June 1999 pg 127- 134 6. Johnston LE Jr :Balancing the Books on Orthodontic Treatment: An integrated Analysis of Change, BJO 1996 pg 93- 102 7. McNamara, J A Jr: A method of Cephalometric evaluation. AJO 1984, Dec Vol 86 pg 449- 469 www.indiandentalacademy.com
  • 68. 8.William Proffit: Contemporary Orthodontics 3rd Edition, 2000pg 179- 181 9. Athanasio E Athanasiou: Orthodontic Cephalometry, 1995 pg 269 10. A Jacobson, PW Caufield: Introduction to Radiographic Cephalometry, 1985 www.indiandentalacademy.com
  • 69. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com