1. Cephalometric Analysis
Prediction is only a goal
and not a guarantee

2. 1937……
In 1937
Broadbent publishes two
papers, which describes
details of the technique that
he devised to establish
craniofacial measurements in
normal children.
For all this, Broadbent, with
much justice, is considered
the father of radiographic
cephalometry.

3. USES OF CONVENTIONAL CEPHALOMETRY
 Helps in diagnosis.
 Helps in classification of skeletal and dental
abnormalities.
 Helps in planning treatment of an individual.
 Helps in evaluation of treatment results.
 Helps in predicting growth related changes.

4. Conventional ceph
DISADVANTAGES
•A significant amount of external error.
•Manual data collection and processing.
•Lack of well defined outlines .

5. 1970’s….
PHOTO CEPHALOMETRY
-Introduced by Thomas Hohl in 1978.
-Photocephalometric planning was developed by Derek Henderson
in the 1970s.

6. METHOD
-patient is made to assume natural head position with relaxed lips.
-radio opaque markers are placed on patients face and lat and A.P.
ceph are made.
-lateral and frontal photos are made in the same position.
-photo negatives are enlarged and super imposed on the
radiographic image.
-the projection of enlarged negative is put onto a photographic film
which produces a transparent photograph which can be
superimposed over cephalometric film

7. Lateral cephalometry
profile transparency showing the tracing of
dental and skeletal structures

8. Prediction planning of the soft tissue changes following bimaxillary
osteotomy using photocephalometry.

9. ADVANTAGES
-Quantitative information of the soft tissue.
-Direct measurements between the skeletal and soft tissue
landmarks.
-Changes in soft tissue can be compared pre and post op.
-Useful in serial growth studies.
DISADVANTAGES
-Difference in enlargement factors between photos and X-rays
with compromised accuracy.
-Complex procedure.
-Expensive.

10. DIGITAL CEPHALOMETRY
ADVANTAGES
 Dose reduction
 Image prediction
 Reduced overall time
 Measurements [Digital Calipers]
 3-D Reconstruction
 Contrast enhancement
 Storage
 Tele radiology
 Environmental Friendly

11. 1980’S…..
COMPUTERIZED 2D PLANNING
WITH PREDICTED SOFT TISSUE
CHANGES FOLLOWING
ORTHOGNATHIC SURGERY……..

12. SOFTWARE SYSTEMS FOR CEPHALOMETRIC
ANALYSIS.
Rocky Mountain Orthodontics (RMO) was the first to provide the
dental profession in the late 1960s with a computer-aided
cephalometric diagnosis.
5 programs with largest market share.
1.
2.
3.
4.
5.
Dento Facial Planner plus (DFP), Windows 98 Platform
Dolphin Imaging (DI), Windows 98,2000,XP Platform
Quick Ceph System (QC), Macintosh Platform
Vista Dent (GAC), Windows XP Pro
Practice Works (OTP), WINDOWS
-J.Dempsey Smith and Paul M. Thomas, AJO May 2004, vol125, issue 5.

13. IN A PATIENT WITH MANDIBULAR
ADVANCEMENT….
DFP prediction
DI prediction
QC prediction
Actual post op.
GAC prediction
OP prediction

14. IN PATIENT WITH MAXILLARY IMPACTION AND
MANDIBULAR SETBACK…..
DFP prediction
GAC prediction
QC prediction
Actual post op.
DI prediction
OP prediction

15. Inference from the study…..
1. Dento Facial Planner plus (DFP) were the clear favorites.
2.
Dolphin Imaging (DI) and Quick Ceph System (QC) were
the next favorites.
3. Vista Dent (GAC) and Practice Works (OTP) were
consistently rated poor.
-J.Dempsey Smith and Paul M. Thomas, AJO May 2004, vol125, issue 5.

16. At Present……
3D IMAGING
Many 3D techniques have been used in attempt to capture facial
topography and to meet short comings of 2D methods . These
include,
1. Morphoanalysis
2. LASER Scanning
3. 3D CT Scanning
4. 3D UltraSonoGraphy
5. 3D FacialMorphometry
6. Moire Topography
7. Contour Photography
8. Stereolithography
9. Streophotogrammetry

17. STEREOLITHOGRAPHY
Brix et al introduced 3D model planning to maxillofacialsurgery
in 1985 using copy milling technique.
Stereolithography has replaced traditional CAD/CAM, in
making anatomical models.
Term Stereolithography / 3 Dimensional printing was coined by
CHARLES W.HULL in 1986.(patent)
First commercial stereolithographic prototype generator SLA-1
system was introduced at Autofact show in Detroit, Nov 1987.

18. Goals of 3D modeling for surgical application
1. To create accurate anatomical models.
2. To improve understanding of anatomical variation between
individuals.
3. Provide working model for pre operative surgical
simulation.
4. To improve patient education.
5. To manufacture custom implantable devices.
6. Maintain cost effectiveness.

19. STEPS IN PRODUCING AN ACCURATE
3D PROTOTYPE
Step 1:- Utilize accurate imaging
modality to obtain anatomical data,
viz CT/MRI.
Step2:- Design the prototype using
CAD.
Step3:- Build the prototype with
stereolithography.

20. APPLICATIONS OF STEREOLITHOGRAPY
•Craniofacial surgeries
•Distraction osteogenesis
•Trauma
•Dental implant surgery
•ORTHOGNATHIC SURGERY
•TMJ surgery
•Reconstruction / Augmentation

21. LIMITATIONS OF STEREOLITHOGRAPHY
Main limitation is the cost factor.
Higher radiation dose to which the patient is exposed.
Time consuming.
Study by Erickson et al about opinion of surgeons on stereolithography,
In 92% cases there was improvement in planning.
73% surgeons used models to educate the people.
77% surgeons believed using Stereolithography models saved
opreration room time.
73% surgeons referred to models during surgery to visualize the
approach.
-Erickson et al ‘An opinion survey of reported benefits from the use of stereolithographic
models’ JOMS 1999; 57, 1040-1043.

22. The imaging modalities needed to create a patient model
are,
1. MAXILLOFACIAL CT,
2. STEREOPHOTOGRAMMETRY IMAGE OF THE
FACE, AND
3.
LASER-SCANNED MODEL OF THE DENTITION.

23. MAXILLOFACIAL CT

24.  An interactive software
tool can manipulate the raw
CT DICOM data.
 The maxillofacial skeleton
data segmented (isolated),
and 3D skeletal model
rendered for visualization.

25. PRINCIPLE OF STEREOPHOTOGRAMMETRY
There are two geometric strategies for measuring in three
dimensions. They are
1. Orthogonal measurement-CT scans to 3D
2. Measurement by triangulation-Stereophotogrammetry
Systems that measure by triangulation analogize the
geometry of mammalian stereoscopic vision.
Stereophotogrammetry, first suggested for use in dentistry
by Mannsbach in 1922.
The earliest clinical use of stereophotogrammetry was
reported by Thalmann - Degan in 1944

26. I FACIAL IMAGE ACQUISITION
 A standard stereo camera
set-up is used to capture the
facial image pairs.
 Digitally controlled slide
projectors are used to flash
separate random texture and
FACIAL IMAGE ACQUISITION
structured light patterns
onto the subject's face.
 Using digitally controlled
switching between cameras
and projectors, the time
between capture is less than
one second.

28. The reconstructed
representation of the face can
be rotated on a standard
computer monitor and the 3D
coordinates of any visible point
can be captured by pointing and
clicking with a standard mouse
or other similar device

29. LASER-SCANNED MODEL OF THE DENTITION

30. FINAL OUTPUT

31. OCCLUSAL SPLINTS
THROUGH
CAD/CAM

33. STEPS IN SPLINT FABRICATION
•Neither CT or CBCT provided accurate enough
images of the patient’s dental structure.
• So the dental casts were scanned using
an optical 3D laser with a resolution of 20micron, to
visualize the 3D models via surface rendering.
• This gives precise details of the shape
and size of the patient’s teeth.
•3D treatment plan was sent to the CAD/CAM Centre
so that stereolithographic surgical splints could be
manufactured.

34. Computer aided occlusal wafers…..
Intermediate splint using CAD
Final splint using CA D

35. Data acquisition
Morphometric & orthodontic
• Clinical Examination
• Imaging (3D CT)
• Dental Arches Plaster Casts
•
•
Surgery
• Transfer of plan
•Guidance for bone
reposition
splint using CA D/CAM
Data Integration
3D Cephalometry
Surgeon’s Experience
Surgical Planning
•Type of Osteotomy (Maxillary
and/or mandibular)
•Quantitative displacement for
bone repositioning
Surgical Simulation
• Bone segmentation according to surgical
procedure
• Real time mobilization of bone segments with
6 degrees of freedom
•Prediction of facial soft tissue adaptations
according to underlying bone repositioning

36. THE FUTURE…
Navigation surgery
 Provides the surgeons with a 3D visualization at the tip of
surgical instruments.
 Require a sophisticated system which consists of a stereo pair
of infra red cameras which track and record the 3D orientation
of a surgical instrument within the field of vision.
 Use of a standard occlusal surgical wafer may then not be
required as the positioning of the osteotomy segment is guided by
the recorded change in the 3D coordinates of certain landmarks
from the preoperative to the pre-planned position.

37. Thanking you……
The past is a source
of knowledge and
future is a source
of hope.
To love the past
implies a faith in
the future.