Burstone analysis

cephalometric analysis

1. Department of orthodontics Surgical Orthodontic Treatment Planning: Profile Analysis and Mandibular Surgery FRANK W. WORMS, ROBERT J. ISAACSON and T. MICHAEL SPEIDEL The Angle Orthodontics  Jan 1976, Vol. 46, No. 1 (January 1976) pp. 1-25

2. Charles J. Burstone et al (1978) developed an analysis specially designed for patients requiring Orthognathic surgery. They used the landmarks and the measurements that can be altered by common surgical procedures. This analysis is also called as Cephalometrics for Orthognathic Surgery (COGS)

3. COGS system describes the horizontal and vertical positions of the facial bones by the use of constant coordinate systems as follows: Size of the bone are represented by direct linear measurements. Shape of the bones are represented by the angular measurements. 

4. Skeletal And Dental Analysis ☺Landmarks Sella (S) - The center of Pituitary Fossa Nasion (N) – The most anterior point of the nasofrontal suture in the midsagittal plane Anterior Nasal Spine (ANS) – The anterior most midsagittal point on the tip of sharp bony process of maxilla Subspinale (A) – The deepest midsagittal point on the concavity between Anterior Nasal Spine and Prosthion Supramentale (B) – The deepest point in mid sagittal plane on the concavity between infradentale and pogonion  

5. Pogonion (Pg) – Most anterior mid sagittal point on the contour of the chin Gnathion ( Gn ) – Constructed by bisecting the Facial plane and tangent to lower border of mandible Menton (Me) – Most inferior point on the inferior contour of the chin Pterygomaxillary fissure ( Ptm ) – The most posterior point on the anterior contour of the maxillary tuberosity

6. Posterior Nasal Spine (PNS) – The most posterior point on the contour of the palate. Articulare ( Ar ) – The intersection of sphenoid and the posterior border of the condyle Gonion (Go) – constructed by bisecting the posterior ramal plane and mandibular plane. Mandibular Plane (MP) – It is the line joining Gonion and Gnathion Nasal Floor (NF) – A plane constructed by joining ANS and PNS

7. Reference plane The base line used for comparison of most of the data in this analysis is a constructed plane called as Horizontal Plane (HP) Most measurements in this analysis will be made either parallel to or perpendicular to this Horizontal Plane. It is constructed by drawing a line 7⁰ from SN, intersecting at N

8. ☺Parameters Cranial Base ☺ Ar-Ptm (linear) ☺ Ptm -N (linear) Horizontal Skeletal Profile ☺N-A-Pg (angle) ☺N-A (linear) ☺N-B (linear) ☺N-Pg (linear) Vertical Skeletal ☺N-ANS (linear) ☺ANS- Gn (linear) ☺PNS-N (linear) ☺MP-HP (linear Vertical Dental ☺Upper 1 – NF (linear) ☺Lower 1 – MP (linear) ☺Upper 6 – NF (linear) ☺Lower 6 – MP (linear) Maxilla and Mandible ☺PNS-ANS (linear) ☺ Ar -Go (linear) ☺Go-Pg (linear) ☺B-PG (linear) ☺ Ar -Go- Gn (angle) Dental ☺OP-HP (angle) ☺A-B parallel to OP (linear) ☺Upper 1 – NF (angle) ☺Lower 1 – MP (angle)

9. Cranial Base Length ☺Cranial base length is measured by measuring the distance between Ar and N ☺It is measured parallel to HP ☺The measurement Ar to N is a relatively stable anatomical plane, however it can be changed by cranial surgery ☺Le Forte II and Le Forte III surgery changes position of N ☺Autorotation of Mandible changes position of Ar

10. ☺Two measurements are considered in Cranial Base length – Ar-Ptm and Ptm -N ☺ Ar-Ptm is the distance between Ar and Ptm which is measured parallel to HP ☺Standard Value ☺MALES 37.1 ± 2.8 mm ☺FEMALES 32.8 ± 1.9 mm ☺ Ar-Ptm indicates the position of mandible in relation to posterior surface of maxilla  

11. ☺ Ptm -N is the distance between Ptm and N which is measured parallel to HP ☺Standard Value ☺MALES 52.8 ± 4.1 mm ☺FEMALES 50.9 ± 3 mm ☺ Ptm -N indicates the position of posterior border of maxilla in relation to Nasion ☺If this value increases it indicates more posterior position of maxilla in relation to N and if it decreases it indicates anterior position of maxilla in relation to N

12. Horizontal Skeletal Profile Analysis ☺A few simple measurements should be made on the skeletal profile to assess the amount of discrepancy in anteroposterior direction. ☺It is called as Horizontal Skeletal Profile analysis because all the measurements in this set of analysis are made parallel to HP

13. ANGLE OF SKELETAL CONVEXITY ☺It is the angle formed between N-A and A-Pg ☺Standard Value ☺MALES 3.9⁰ ± 6.4⁰ ☺FEMALES 2.6⁰ ± 5.1⁰ ☺A positive angle indicates convex profile while negative angle indicates concave profile

14. N Perpendicular to A, parallel to HP ☺A perpendicular to HP is dropped from N (N perpendicular) and horizontal distance parallel to HP is measured from point A ☺Standard Value ☺MALES 0 ± 3.7 mm ☺FEMALES -2 ±3.7 mm ☺This measurement describes the position of apical base of maxilla in relation to nasion  

15. N Perpendicular to B, parallel to HP ☺It is obtained by measuring the distance between Point B and Nasion perpendicular (N perpendicular) ☺Standard Value ☺MALES -5.3 ± 6.7 mm ☺FEMALES -6.9± 4.3 mm ☺This measurement describes the position of apical base of mandible in relation to nasion

16. N Perpendicular to Pg, parallel to HP ☺It is obtained by measuring the distance between Pogonion and Nasion perpendicular (N perpendicular to HP) ☺Standard Value ☺MALES -4.3 ± 8.5 mm ☺FEMALES -6.5 ± 5.1 mm ☺This measurement describes the position of mandibular chin in relation to nasion  

17. Vertical Skeletal Analysis ☺A Vertical skeletal discrepancy may reflect an anterior, posterior or complex dysplasia of the face ☺It is divided into two components ☺Anterior component ☺Posterior component

18. N-ANS perpendicular to HP ☺Distance between N and ANS measured perpendicular to HP gives us the Middle third facial height. ☺Standard Value ☺MALES 54.7 ± 3.2 mm ☺FEMALES 50 ± 2.4 mm ☺Any increase or decrease in this value indicates increased or decreased middle third facial height respectively 

19. ANS- Gn perpendicular to HP ☺Distance between ANS and Gn measured perpendicular to HP gives us the Lower third facial height. ☺Standard Value ☺MALES 68.6 ± 3.8 mm ☺FEMALES 61.3 ± 3.3 mm ☺Any increase or decrease in this value indicates increased or decreased lower third facial height respectively

20. PNS-N, perpendicular to HP ☺Distance between PNS and HP gives us the posterior maxillary height. ☺Standard Value ☺MALES 53.9 ± 1.7 mm ☺FEMALES 50.6 ± 2.2 mm ☺Any increase or decrease in this value indicates increased or decreased posterior maxillary height respectively 

21. MP – HP Angle ☺ Mandibular plane angle in relation to Horizontal plane intersecting at Gn gives us posterior divergence of mandible ☺Standard Value ☺MALES 23⁰ ± 5.9⁰ ☺FEMALES 24.2⁰ ± 5⁰ ☺Any increase or decrease in value suggests increased or decreased posterior facial divergence

22. Upper 1 to platal plane ☺To obtain upper anterior dental height, perpendicular distance from incisal edge of upper incisor to palatal plane is measured ☺Standard Value ☺MALES 30.5 + 2.1 mm ☺FEMALES 27.5 + 1.7 mm ☺Any increase or decrease in this value indicates increased or decreased upper anterior dental height respectively 

23. Lower 1 to MP ☺To obtain lower anterior dental height, perpendicular distance between incisal edge of lower incisor to MP is measured ☺Standard Value ☺MALES 45 ± 2.1 mm ☺FEMALES 40.8 ± 1.8 mm ☺Any increase or decrease in this value indicates increased or decreased lower anterior dental height respectively 

24. Upper 6 to NF ☺To measure upper posterior dental height a perpendicular line is dropped from the tip of mesiobuccal cusp of upper first molar to palatal plane ☺Standard Value ☺MALES 26.2 ± 2.0 mm ☺FEMALES 23 ± 1.3 mm ☺Any increase or decrease in this value indicates increased or decreased upper posterior dental height respectively 

25. Lower 6 to MP ☺To measure lower posterior dental height a perpendicular line is dropped from the mesiobuccal cusp of lower first molar to MP ☺Standard Value ☺MALES 35.8 + 2.6 mm ☺FEMALES 32.1 + 1.9 mm ☺Any increase or decrease in this value indicates increased or decreased lower posterior dental height respectivel

26. Maxilla and Mandible ANS to PNS ☺ANS and PNS are projected on HP ☺Distance between these two points on HP gives us total effective maxillary length ☺Standard Value ☺MALES 57.7 + 2.5 mm ☺FEMALES 52.6 + 3.5 mm

27. Ar to Go ☺ Mandibular ramal length is the linear distance between Articulare and Gonion ☺Standard Value ☺MALES 52 ± 4.2 mm ☺FEMALES 46.8 ± 2.5 mm ☺Variation in Ramal length can be a causative factor for skeletal open bite or deep bite 

28. Go to Pg ☺ Mandibular body length is the linear distance between Gonion and Pogonion ☺Standard Value ☺MALES 83.7 ± 4.6 mm ☺FEMALES 74.3 ± 5.8 mm ☺increase in length denotes skeletal class III ☺decrease in length signifies skeletal class II

29. Ar -Go- Gn Angle ( Gonial angle) ☺This measurment represents the relationship between the ramal plane and mandibular plane ☺Standard Value ☺MALES 119.1 ⁰ + 6.5 ⁰ ☺FEMALES 112⁰ + 6.9 ⁰ ☺ Gonial angle also contributes to skeletal open bite or deep bite

30. Dental parameters OP-HP (Angle) ☺OP is Occlusal Plane constructed from buccal groove of first permanent molars through a point 1 mm apical to the incisal edge of the upper central incisors ☺When incisors are not in proper overbite relation, two OP are to be constructed, upper and lower and mean to be taken . ☺Standard Value ☺MALES 6.2 ⁰ ± 5.1 ⁰ ☺FEMALES 7.1 ⁰ ± 2.5 ⁰

31. ☺An increased OP-HP angle may be associated with skeletal open bite, lip incompetence and increased anterior facial height ☺An decreased OP-HP angle may be associated with skeletal deep bite, decreased anterior facial height and lip redundancy

32. A-B parallel to OP ☺ This distance is obtained by measuring the distance between projection of Point A and Point B on OP ☺Standard Value ☺MALES - 1.1 + 2.0 mm ☺FEMALES - 0.4 + 2.5 mm ☺This distance gives us relationship between maxillary and mandibular apical bases in relation to OP

33. Upper 1 to NF (Angle) ☺ This angle is constructed by intersecting a line passing through the tip of insical edge through the root tip of upper incisor and NF line ☺Standard Value ☺MALES 110 ± 4.70 ☺FEMALES 112.50 ± 5.30 ☺This angle gives us the inclination of upper incisors in relation to palatal plane (NF) 

34. Lower 1 to MP (Angle) ☺ This angle is constructed by intersecting a line joining the incisal edge of lower incisor passing through its root tip and MP ☺Standard Value ☺MALES 95.9⁰ ± 5.2 ⁰ ☺FEMALES 95.9⁰ ± 5.7 ⁰ ☺This angle gives inclination of lower incisors in relation to MP

35. SOFT TISSUE ANALYSIS

36. Glabella (G) - The most prominent point in the midsagittal plane of the forehead

37. Columella point (Cm) – The most anterior point on the columella (nasal septum) of the nose

38. Subnasale ( Sn ) – The point at which the columella merges with the upper lip in the midsagittal plane

39. Labrale superius (Ls) - A point indicating the mucocutaneous border of the upper lip 

40. Stomion superius ( Stms )- The lower most point on the vermilion border of the upper lip

41. Stomion inferius ( Stm i )- The upper most point on the vermilion border of the lower lip

42. Labrale inferius (Li) - A point indicating the mucocutaneous border of the lower lip

43. Soft tissue Pogonion ( Pog ’)- The most prominent or anterior point on the chin in midsagittal plane

44. Soft tissue Menton (Me’) – lowest point on the contour of the soft tissue chin

45. Cervical Point (C) – the innermost point between the submental area and neck

46. Soft tissue Gnathion ( Gn ’)- The constructed midpoint between soft tissue pogonion and soft tissue menton

47. G – Sn – Pg ( angle ) - Facial convexity / contour angle • Drop a line form Glabella ‘G’ to Subnasale ‘ Sn ’ and a line Sn to soft tissue pogonion ‘Pg’. • Mean value : 12 ± 4⁰ • increased + ve value - convex profile Increased - ve value - concave profile (class3 skeletal and dental relationship)

48. G - Sn - Maxillary prognathism • Drop line perpendicular to horizontal plane from Glabella . Measure the distance from perpendicular line to Sn ( parallel to HP) • Mean value: 6 ± 3 mm Inference • Describes the amount of maxillary excess/deficiency in anteroposterior dimension • + ve =maxillary prognathisum • – ve =maxillary retrognathisum

49. G - Pg - Mandibular prognathism • Drop a perpendicular line to HP from Glabella . Measure the position of the pogonion from this line parallel to HP. • Mean value: 0 +/- 4  • Increased – ve value indicated mandibal is retrognathic .

50. G- Sn / Sn -Me - Vertical height ratio • (G- Sn / Sn -Me) 1:1 • Drop a perpendicular line to HP from Glabella , to this line drop a perpendicular line to Sn and M. Measure the distance from G- Sn and Sn – Me ( all perpendicular to HP )  INFERENCE • The ratio of middle 3rd to lower 3rd facial height measured perpendicular to HP. • Ratio less than 1 = denotes disproportionality and there is large lower 3rd face and vice versa. • Disadvantages • Further evaluation of lower 3rd of face is needed

51. Sn – Gn - C - Lower face throat angle • Formed by the intersection of lines Sn-Gn & Gn -C. • Mean value:100⁰ ± 7⁰  INFERENCE • Obtuse lower face neck angle indicates that any procedures that reduce the prominence of chin should not be done

52. ( Sn – Gn / C – GN ) - Lower vertical height depth ratio . • Drop a line from Sn to Gn and C to Gn . Measure the distance from Sn – Gn and C – Gn . • Mean value : 1.2 : 1 • If the ratio is more than 1 = short neck . • Useful in determining the feasibility of reducing / increasing the chin prominence

53. LIP POSITION AND FORM Cm – Sn - Ls - NASOLABIAL ANGLE • Draw a line from Sn to Cm and drop a line from Sn to Ls. Measure the angle formed. • Mean value : 102⁰ ± 8⁰ • Important measurement in assessing the anteroposterior maxillary dysplasias

54. • ACUTE nasolabial angle = treated by retracting the maxilla / maxillary incisors / both. • OBTUSE nasolabial angle = suggests the degree of maxillary hypoplasia and indicates for maxillary advancement or orthodontic proclination of maxillary incisors. 

55. Ls To Sn - Pg --- Upper lip protrusion . • Draw a line from Sn to soft tissue Pg the amount of lip Protrusion / Retrusion is measured with perpendicular linear distance from this line to the prominent point of the lip Standard value - 3±1mm • The abnormal values can be treated by retracting or protracting the incisors , surgically or orthodontically advancing or retracting the maxilla accordingly

56. Li to Sn -Pg -- Denotes the amount of protrusion of lower lip . • Drop a line from Sn to Pg and the amount of lip protrusion / retrusion is measured with perpendicular linear distance from this line to the most prominent point of both lips . standard value - 2±1mm   • By retracting / protracting the incisors surgically / orthodontically advancing or reducing the chin prominence , possible to achieve desired lower lip

57. Mentolabial Sulcus Depth It is perpendicular distance between deepest point on the mentolabial sulcus to Li-Pg’ line Standard Value 4 ± 2 mm

58. is due to : 1. Flared lower incisors. 2. Extruded upper incisors impinging on lower lip. 3. Flaccid lip tone and abnormal morphology of the lip itself . 4. Prominence of the chin also contributes to deepened mento labial sulcus TREATMENT • Up righting the lower incisors. • Intruding the maxillary incisors. • Cheiloplasty to retract lower lip – helps in reducing the MLS. • Advancement genioplasty increases the deepening of MLS. • Reduction genioplasty decreases the excess MLS

59. ( Sn – Stms / Stmi – Me ) -- Vertical Lip Chin Ratio • To assess lower third of face . • Mean values : ( 1 : 2 ) • Lower 3rd of the face ( Sn -Me ) can be divided into three parts : length of the upper lip ( distance from Sn to Stms ) should be approximately 1/3rd the total and distance from Stmi to Me should be 2/3rd. • If the ratio becomes less than the normal ( ½ ) -- vertical reduction genioplasty is recommended

60. Maxillary Incisor Exposure It is obtained by measuring the distance between tip of upper central incisor and Stms Standard Value --- 2 ± 2 mm Increased incisor exposure may be due to vertical maxillary excess or short upper lip Decreased incisor exposure may be due to vertical maxillary deficiency or larger upper lip 

61. Inter Labial Gap It is the distance between Stms and Stmi Standard Value - 2 ±2 mm Patients with vertical maxillary excess tend to have large interlabial gap and lip incompetence Patients with vertical maxillary deficiency tend to have no Inter labial gap and Lip redundancy

62. Thank you