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

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

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

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

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

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

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

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

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

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

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

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

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

Study Design Image Acquisition & Data Processing iCAT 17-19 CBCT scanner and data were provided by INsight CBCT Data were exported in a DICOM (Digital Imaging and Communications in Medicine)

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.

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.

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

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

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

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  

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

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

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)

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

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

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

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

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) 0.00001*

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*

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) 0.00001* 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*

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)

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

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

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

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

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

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

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.

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.

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

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

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

THANK YOU THANK YOU

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

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