1. A NEW CBCT CEPHALOMETRIC ANALYSIS
2D TO 3D
EMERGING IDEAS
A NEW CBCT CEPHALOMETRIC ANALYSIS
ENLIGHTNING THE MINDS
DR. RAGHU M.D.S
LM-1861
READER , DEPT. OF ORTHODONTICS
KARNATAKA

2. 2D TO 3D – A NEW CBCT CEPHALOMETRIC ANALYSIS
Introduction
Aims & Objectives
Study Design
Cephalometric Landmarks & Analysis
Statistical Analysis
Results
Discussion
Conclusions
References

3. Am j Orthod Dentofac Orthop 1997;112:165-70
Introduction
Conventional radiographic cephalometry – Orthodontics and Orthognathic Surgery
Has many errors:
Projection error
Imaging on 3D objects
Identification errors
Trpkova B et al. Cephalometric landmark identification and reproducibility: a meta ananlysis.
Am j Orthod Dentofac Orthop 1997;112:165-70

4. Introduction Has many errors:
4. Validity questionable in assessing facial deformities
5. Superimposition of midline and lateral structures
6. Tracing errors
Wylie GA et al. Cephalometrics: a comparison of five analysis currently used in the
diagnosis of dentofacial deformities
Int J Adult Orthodon Orthognath Surg 1987;2:15-36

5. Introduction
Three-dimensional cephalometry based on combination of two 2D cephalographs could not resolve the limitations
CT on patients was not justified- High radiation dose
Swennen GR et al.
A new method of 3D cephalometry Part I : The anatomic cartesian 3-D reference system.
J Craniofac Surg 1987;2:15-36

6. Am J Orthod Dentofac Orthop 2006;130:410-6
Introduction
CBCT –
More feasible and justifiable method to be used in routine dental practice
Lower radiation exposure and high bone contrast
Swennen GR et al.
Three dimensional cephalometry: Spiral multislice Vs Conebeam computed tomography
Am J Orthod Dentofac Orthop 2006;130:410-6

7. References: No.s 5 to 11 in the reference section
Introduction
CBCT –
Cephalometric studies on CBCT limited to,
Review articles with expert opinions and technical notes
Laboratory studies
Comparison with conventional cephalometry
Case reports/Case series
Reliability of 3D Cephlaometric measurements
References: No.s 5 to 11 in the reference section

8. Aims and Objectives
To develop a new 3D cephalometric analysis to assess the dentofacial deformities; and
To create a normative database of 3D cephalometric measurements for adult north karnataka population

9. Study Design Cross-sectional study performed in a CBCT center-
INsight C B C T Pune.
Subjects recruited from :
1. Patients presenting with impacted third molars requiring CBCT assessment
2. Volunteers from the locality

10. Study Design Subjects Subjects recruited from :
A total of 40 subjects were recruited
20 Males (Mean age: 24.20±0.44)
20 Females (Mean age: 24.38±0.74)
4. Patients presenting with impacted third molars
requiring CBCT assessment
5. Volunteers from the locality

11. Study Design Inclusion Criteria
Subjects belonging to north karnataka population
20 to 30 years of age
Normal balanced facial profile with balanced facial
thirds, lip/chin/nose harmony
Class I incisor relationship with overjet and overbite
between 2 to 4 mm
U1-Stms 1to 4mm
Minimal dental crowding and no obvious facial
asymmetry

12. Study Design Exclusion Criteria
Any contraindication for CBCT examination, including pregnancy, claustrophobia, Parkinson’s disease, or mental retardation
Acquired or inherited dentofacial deformities e,g : cleft; craiofacial syndrome; jaw protrusion or retrusion; post traumatic deformity
Previous plastic/ maxillofacial/ orthognathic or reconstructive surgery

13. Study Design Image Acquisition & Data Processing
SCAN PARAMETERS:
Voxel size:  0.25 mm 
Beam diameter: 16 x 13 cm  
Scan time: 26.9 sec

14. Study Design Image Acquisition & Data Processing
iCAT CBCT scanner and data were provided by
INsight CBCT
Data were exported in a DICOM
(Digital Imaging and Communications in Medicine)

15. Cephalometric Analysis
Landmark identification performed by same operator (D.G) twice at an interval of 7 days
Landmarks and Reference Planes were oriented at a standardized position: the anatomic Cartesian 3D Cephalometric Reference System according to Swennen et al.

16. Cephalometric Planes & Landmarks
Landmarks along with the individual measurements
-Explained under each description in the following slides
Fig. Reorientation of head and coordinate system.
N, Nasion; X, the horizontal plane; Y, the midsagittal plane; Z, the vertical plane.

17. Locating the Cephlometric Landmark- ANS
FRONTAL VIEW
Locating the Cephlometric Landmark- ANS

18. Locating the Cephlometric Landmark-Gonion
LATERAL VIEW
Locating the Cephlometric Landmark-Gonion

19. Locating the Cephlometric Landmark- Menton
SUBMENTOVERTEX VIEW
Locating the Cephlometric Landmark- Menton

20. Cephalometric Analysis
CHART OF VALUES FOR DIFFERENT VARIABLES
Cephalometric Analysis
Frontal View (4 linear Measurements) 1
Z - Z
UPPER FACIAL WIDTH  2
Or - MB6 (Right & Left)
MAXILLARY HEIGHT  3
M-M
 POSTERIOR MAXILLARY BASAL WIDTH 4
CE-CE
 ANTERIOR MAXILLARY BASAL WIDTH

21. Cephalometric Analysis
Lateral View maxilla
(3angular & 3 linear) Measure S-N and measure from a midpoint 1
ANS-R-PNS
MAXILLARY ANGLE TO CRANIUAM 2
R-PNS-ANS
MAXILLARY POSTERIOR ANGLE 3
PNS-ANS-R
MAXILLARY ANTERIOR ANGLE 4
R-PNS
MAXILLA TO CRANIUM LENGTH POSTERIOR 5
PNS-ANS
MAXILLARY LENGTH 6
ANS-R
MAXILLA TO CRANIUM LENGTH ANTERIOR

22. Cephalometric Analysis
Lateral View Mandible
(3angular & 3 linear measurements)
Measure S-N and measure from a midpoint 1
Me-R-Go
MANDIBULAR ANGLE TO CRANIUAM 2
R-G-Me
MANDIBULAR POSTERIOR ANGLE 3
Go-Me-R
MANDIBULAR ANTERIOR ANGLE 4
R-Go
MANDIBLE TO CRANIUM LENGTH POSTERIOR 5
Go-Me
MANDIBULAR PLANE LENGTH 6
Me-R
MANDIBULAR TO CRANIUM LENGTH ANTERIOR

23. Cephalometric Analysis
POSTERIOR VIEW OF MANDIBLE
MEASUREMENTS TO MSP 1
Co-MSP (Right)
CONDYLION TO MIDSAGITTAL PLANE 2
Co-MSP (Left) 3
Go-MSP (Right)
GONION TO MIDSAGITTAL
PLANE 4
Go-MSP (Left)

24. Cephalometric Analysis
Mandibular Body 1
Go rght-Me-Go lft
MENTON ANGLE 2
Go-MBC-Me (Right)
MBC ANGLE (Right) 3
Go-MBC-Me (Left)
MBC ANGLE (Left) 4
Me-MBC Lft
ANTERIOR MANDIBULAR BODY LENGTH 5
MBC-Go Lft
POSTERIOR MANDIBULAR BODY LENGTH 6
Me-MBC rght 7
MBC-Go rght

25. Cephalometric Analysis
MANDIBULAR BASAL CURVE LENGTH
Go right-MBC-CE-Me-CE-MBC-Go left

26. Cephalometric Analysis
MAXILLARY BASAL CURVE LENGTH
MAXT right-MB6-CE-ANS-CE-MB6-MAXT left

27. Statistical Analysis SPSSS Version 16 (SPSS, Chicago, IL)
Frequencies, means and standard deviations of all the linear and angular measurements were generated
Independent t-tests and 1-way analysis of variance (ANOVA) were used to analyze the gender- and age -related differences, respectively

28. MAXILLARY HEIGHT (RIGHT/LEFT) ANTERIOR MAXILLARY BASAL WIDTH
Results
NORMS FOR DIFFERENT
CEPHALOMETRIC PARAMETERS
S.No.
Parameters
MALES
Mean (S.D)
FEMALES
P VALUE
Frontal View (4 linear Measurements) 1
UPPER FACIAL WIDTH 
94.27(2.22)
95.07(1.67)
0.2041 2
MAXILLARY HEIGHT  (RIGHT/LEFT)
45.16(1.84)/
45.45(1.37)
40.64(1.63)/
39.84(1.93)
0.0001*/
0.0001* 3
 POSTERIOR MAXILLARY BASAL WIDTH
38.51(1.52)
38.73(1.55)
0.6650 4
 ANTERIOR MAXILLARY BASAL WIDTH
34.90(1.35)
32.26(2.18) *

29. Results NORMS FOR DIFFERENT CEPHALOMETRIC PARAMETERS 53.79(2.06) S.No.
MALES
FEMALES
P VALUE
Lateral View Maxilla ( 3 angular & 3 linear)
Measure S-N and measure from a midpoint 1
MAXILLARY ANGLE TO CRANIUAM
58.56(2.40)
54.17(2.90)
0.0001* 2
MAXILLARY POSTERIOR ANGLE
69.31(2.59)
71.38(4.13)
0.0645 3
MAXILLARY ANTERIOR ANGLE
47.25(2.68)
48.40(3.34)
0.4193 4
MAXILLA TO CRANIUM LENGTH POSTERIOR
49.12(2.78)
47.21(3.20)
0.0500* 5
MAXILLARY LENGTH
47.42(1.76)
47.50(2.23)
0.9023 6
MAXILLA TO CRANIUM LENGTH ANTERIOR
51.79(1.73)
53.79(2.06)
0.0020*

30. Results NORMS FOR DIFFERENT CEPHALOMETRIC PARAMETERS 106.75(4.14)
MALES
FEMALES
P VALUE
Lateral View Mandible (3 angular & 3 linear)
Measure S-N and measure from a midpoint 1
MANDIBULAR ANGLE TO CRANIUAM
45.80(2.42)
46.41(2.41)
0.4267 2
MANDIBULAR POSTERIOR ANGLE
74.20(2.33)
73.13(2.73)
0.1903 3
MANDIBULAR ANTERIOR ANGLE
61.61(1.34)
52.90(1.36) * 4
MANDIBLE TO CRANIUM LENGTH POSTERIOR
95.30(2.36)
84.35(3.17) 5
MANDIBULAR PLANE LENGTH
83.07(2.43)
82.45(1.93)
0.3775 6
MANDIBULAR TO CRANIUM LENGTH ANTERIOR
106.75(4.14)
101.93(3.37)
0.0003*

31. CEPHALOMETRIC PARAMETERS
Results
NORMS FOR DIFFERENT
CEPHALOMETRIC PARAMETERS
S.No.
Parameters
MALES
FEMALES
P VALUE
Posterior View of Mandible (4 Linear) 1
Co-MSP (Right)
53.41(1.80)
47.46(2.32)
0.0001* 2
Co-MSP (Left)
46.22(1.74)
39.27(2.00) 3
Go-MSP (Right)
49.12(2.78)
42.63(3.27) 4
Go-MSP (Left)
49.27(1.78)
36.67(2.19)

32. ANTERIOR MANDIBULAR BODY LENGTH (Left)
Results
NORMS FOR DIFFERENT
CEPHALOMETRIC PARAMETERS
S.No.
Parameters
MALES
FEMALES
P VALUE
Mandibular Body (3 angular & 4 Linear) 1
MENTON ANGLE
67.38±1.85
60.11±3.18
0.0001* 2
MBC ANGLE (Right)
135.05±2.56
134.20±2.97
0.3385 3
MBC ANGLE (Left)
129.30±2.08
129.30±4.86
1.0000 4
ANTERIOR MANDIBULAR BODY LENGTH (Left)
12.56±1.14
14.95±1.39 5
POSTERIOR MANDIBULAR BODY LENGTH (Left)
72.87±1.96
72.66±1.78
0.7186 6
ANTERIOR MANDIBULAR BODY LENGTH (Right)
16.65±2.30
16.00±1.92
0.3381 7
POSTERIOR MANDIBULAR BODY LENGTH (Right)
69.98±2.84
68.47±1.44
0.0563

33. RESULTS-NORMS FOR DIFFERENT CEPHALOMETRIC PARAMETERS
MALES
FEMALES
P VALUE
Mandibular Basal Curve Length (Go-MBC-Me-MBC-Go)
176.50
(±2.95)
170.30
(±6.16)
Maxillary Basal Curve Length (MaxT-CE-ANS-CE-MaxT)
127.45
(±2.54)
123.25
(±4.94)
0.0002*
0.0017*
RESULTS-NORMS FOR DIFFERENT CEPHALOMETRIC PARAMETERS

34. Discussion
The 3D evaluation of cephalometric variables assists clinicians in obtaining enhanced diagnosis and treatment planning
3D analysis overcomes drawbacks/ weaknesses of the 2D analysis
This is the first 3D cephalometric analysis for the north karnataka population

35. Discussion
This analysis/database will be a useful reference for evaluation of the Indian facial form
This database will also be of value for orthodontist and oral and maxillofacial surgeons in India
These normal values could be used as a reference for assessing dysmorphology and evaluating treatment outcomes in young adults

36. Plastic Reconstru Surg 2007;119:675-81; Discussion: 82-3
20 to 30 years Age Range - Sample recruited comparable to age of patients likely to have orthognathic surgery
By limiting age range- possibility of aging differences were ruled out
SN plane ; MSP plane; FH plane and zero meridian plane were used for facial orientation
Shaw RB Jr et al.
Aging of the midface bony elements: a 3-dimensonal computed tomographic stduy
Plastic Reconstru Surg 2007;119:675-81; Discussion: 82-3

37. Discussion
Linear /mill metric measurements
Should not be used exclusively for the clinical diagnosis and treatment planning
Should not be used for comparing results and treatment outcome
Angular/ Ratios/ Differences between 2 linear measurements
More acceptable of reflecting the harmony or any discrepancy of facial features
Can be very useful and accurate for comparing results and treatment outcome
Kim et al. Classification of the skeletal variation in normal occlusion.
Angle Orthod 2005;75:311-9

38. Discussion
So the Angular measurements, ratios and differences in linear measurements (e.g., asymmetric ramus length) in our analysis is of great help for the planning of orthognathic surgery and assessment of treatment outcome.

39. Discussion Limitation of the study:
Artifacts in the CBCT by dental amalgam fillings or bridges interfered with the analysis of molar regions.
Soft tissue analysis not included and requires virtual 3D model set up created through STEREOPHOTOGRAPHY and 3dMD surface model.

40. Am J Orthod Dentofacial Orthop 2013;144:672-81
Tasha E Metzger et al. Orthodontic soft-tissue parameters: A comparison of cone-beam computed tomography and the 3dMD imaging system
Am J Orthod Dentofacial Orthop 2013;144:672-81

41. Conclusions
This is the first database of 3D cephalometric norms based on
CBCT of the North Karnataka population
A valuable diagnostic aid for orthodontics and orthognathic surgery
Norms generated were comparable with those reported in the literature with the conventional 2D cephalometry- Accurate and Reliable
Moreover, 3D cephalomtric analysis has the potential of incorporating new measurement methods that are difficult if not impossible in 2D cepholmetric analysis

42. Acknowledgement IOS – President, Secretary and all members
Organizing committee – 48TH IOC 2013, Ahmedabad
Participants of the study
Dr. Deodatt Gosavi, Pune
Statistician-Dr. S H Javali, Dharawad.
Dr. Naveen Reddy Adamala Prof. & Head, M.D.S (Orthodontics)
Dept. of orthodontics, A.M.E’s DC Raichur
PRINCIPAL, My dear colleagues and all PG Students of Dept.
of orthodontics, A.M.E’s DC Raichur
Friends and family

43. THANK YOU
THANK YOU

44. References
Trpkova B et al. Cephalometric landmark identification and reproducibility: a meta ananlysis. Am j Orthod Dentofac Orthop 1997;112:165-70
Wylie GA et al. Cephalometrics: a comparison of five analysis currently used in the diagnosis of dentofacial deformities Int J Adult Orthodon Orthognath Surg 1987;2:15-36
Swennen GR et al. A new method of 3D cephalometry Part I : The anatomic cartesian 3-D reference system. J Craniofac Surg 1987;2:15-36
Swennen GR et al. Three dimensional cephalometry: Spiral multislice Vs Conebeam computed tomography. Am J Orthod Dentofac Orthop 2006;130:410-6
Cevidanes LH et al. Image analysis and superimposition of 3-dimensional cone beam computed tomography models. Am J Orthod Dentofac Orthop 2006;129:611-8.
Cavalcanti M Rocha S et al. Craniofacial measurements based on 3D-CT volume rendering : Implications for clinical applications. Dentomaxillofac Radiol 2004; 33: 170-6

45. References
Van Vlijimen OJ et al. A comparison between two dimensional and three dimensional cephalometry on frontal radiographs and on cbct skulls of human skulls. Eur J Oral Sci 2009; 117:300-5
Cattaneo PM et al. Comparison between conventional and CBCT generated cephalograms. Am J Orthod Dentofac Orthop 2008;134:798-82
Uechi j et al. A novel method for the 3-dimensional simulation of orthognathic surgery by using multimodel image-fusion technique. Am J Orthod Dentofac Orthop 2006;130:786-98
Hwang H et al. Maxillofacial 3-dimensional image analysis for the diagnosis of facial asymmetry. Am J Orthod Dentofac Orthop 2006;130:779-85
Lavgravere MO et al. Proposed reference point for 3-dimensional cephalometric analysis with CBCT. Am J Orthod Dentofac Orthop 2005;128:657-60