Digital cephalometrics involves recording cephalometric images digitally rather than on film. There are two main methods: indirect digital radiography (computed radiography) which uses photostimulable phosphor plates that are digitally scanned, and direct digital radiography which uses electronic sensors connected directly to a computer. Digital cephalometrics reduces radiation exposure and allows images to be enhanced, stored digitally, and analyzed using software. While a few parameters showed statistically significant differences between digital and conventional methods, the differences were deemed to not be clinically significant. Digital cephalometrics is now the preferred method over conventional film-based techniques.

1. Digital Cephalometric
‫الرحيم‬‫الرحمن‬‫هللا‬ ‫بسم‬
Mohanad Elsherif
BDS (U of K), MFD RCSI, MFDS RCPS(Glasg), MSc (Orthodontics), M.Orth. RCSEd
University of Khartoum
Faculty of Dentistry
Department of Orthodontics

2. Computerized and digital
Cephalometrics
 Computerized cephalometrics essentially means use of computers to make
cephalometric measurements for quick and accurate analysis and store data
for ease of retrieval and transfer.
 Computerized cephalometrics has now advanced with newer
developments in computer, Now Specific software's have developed for
reconstruction of 3D images, for the 3D analyses of face and craniofacial
structures through CT scan and lately CBCT.
 On the other hand, research and knowledge on growth of craniofacial
structures, growth prediction and soft tissue changes that occur due to
ageing, orthodontic treatment and following orthognathic surgery have
been integrated in cephalometric diagnosis software systems.

3. Digital Cephalometric
 Digital cephalometrics essentially involves recording of
cephalometric image on a non-film medium as a “digital
image” which is manipulated through computers and
viewed on screen.
 It substitutes analogue film to digital image and it is
possible to do simultaneous analysis of this image with
cephalometric softwares.

4. Method of recording digital
Cephalometrics
1. Indirect digital radiography {computed radiography (CR)}: it
uses plates that are radiated and then digitally scanned.
2. Direct digital radiography (ddR): it is connected directly to
the computer via USB and provide immediate images.

5. 1. Computed radiography (CR)
 It uses very similar equipment to conventional radiography
except that it makes use of photostimulable phosphors plate which
replace silver halide crystals of a conventional film.
 How to record the image:
1. The photostimulable phosphors when contacted by radiation
energy cause them to fluorescence, releasing a high fraction of the
absorbed energy, while some remnant energy is stored in the
phosphors, essentially as a latent image.

6. 1. Computed radiography (CR)
2. When stimulated with infrared, high frequency helium-neon laser or white
light, photostimulable phosphors release light (blue light) proportional to the
stored energy which can be detected by a photomultiplier tube (PMT) to
generate an electrical signal that is ultimately reconstructed into a digital
radiographic image.
3. An optical filter is used to filter out the laser light from the luminescent light
of the CR screen during read-out.
4. Electrical signal from the PMT is sent to the analog-to-digital converter
where it is converted to digital bits or binary coded numbers.
5. Each CR screen must be erased after use or before use if the cassette has not
been used in over 24 hours. The reader erases the plate using fluorescent white
light.

7. 1. Computed radiography (CR)

8. 2. Direct digital radiography
(ddR)
 Here film and film holder (cassette) are replaced by an electronic
sensor that captures the radiographic image and delivers the image
to a computer for digital conversion, demonstration, and storage.
 Direct digital radiography (ddR) offers full resolution images that
are displayed and stored in about 8 seconds and therefore have
greater advantages over CR which requires plate processing.
 Commonest types of sensors:
1. Charged coupled device (CCD)
2. Complimentary metal oxide semiconductor (CMOS) systems.

9. A. charge-coupled device (CCD)
 The charge-coupled device was invented in 1969 at AT&T Bell Labs by
Willard Boyle and George Smith.
 A charge-coupled device (CCD) is made up of arrays of x-ray sensitive or
light-sensitive cells or pixels that can generate voltage in proportion to
the amount of light or x-rays striking them.
 A scintillator (material that produces light energy when hit by x-rays)
is fiberoptically coupled with the sensor. As a result, the x-ray energy is
converted to light energy just before the sensor and, so, light will excite
the sensitive pixels of the sensor.
 This process actually reduces the patient exposure because the
presence of the scintillator intensifies the x-ray energy when converting
it to light (for each x-ray photon striking the scintillator several light
photons are produced).

10. A. charge-coupled device (CCD)
 The electrical charge that is generated in each of the pixels of the CCD
is transferred from one pixel to another in a sequential fashion that is
known as “charge coupling” (hence, the name “charge-coupled device”).
 The final destination of the collected electrical charge is the readout
amplifier, where the voltage generated from each pixel is identified,
stored, and eliminated from the sensor so this is rendered ready for new
exposures.
 An analog-to-digital converter will convert all these charges to digital
by assigning a number to each one of them, in proportion to the
electrical energy. This number will eventually represent the pixel
intensity value (shade of gray) of the specific location of the digital
image.

11. B. Complimentary metal oxide
semiconductor (CMOS)
 The biggest problem with CCDs is their high cost because they
are created using specialized and expensive equipment.
 A more cheaper sensor are now available which called
complementary metal oxide semiconductor (CMOS refers to how a
sensor is manufactured and not to aspecfic sensor technology).

12. Advantages of digital computed
Radiography
1. X-ray exposure can be greatly reduced (40-50%).
Visser et. al. Angle Orthod 2001
2. Need for the X-ray film developing and processing is eliminated and
therefore all the technique and chemical related errors associated with
it.
3. Provide more sensitive, higher-definition, and diagnostically more
meaningful images than those provided by conventional radiology.
4. Multiple “original images” can be made and made available to
multiple stations simultaneously without intermediate copying of the
images as with screen-film radiographs.

13. Advantages of digital computed
Radiography
5. Digital images of X-rays can be transmitted to the end user from
the place of radiography within hospital setup using local area
network (LAN) or wide area network (WAN) without any
deterioration in any details of image spatial frequency.
6. The digital image can be manipulated and enhanced through
image processing algorithms and post-processing functions of
software.
7. Ease of data storage and retrieval.
8. Superimposition of cephalograms/on photographs is possible.

14. Digital VS Conventional
Cephalometrics
A Comparison of Conventional and Digital Radiographic Methods and Cephalometric Analysis
Software: I. Hard Tissue
Mark D. Gregston et. al ; Semin Orthod 10:204-211 (2004)
Aim and objectives:
 The purpose of the present study was to compare the reliability of measurements of
cephalometric parameters on storage phosphor digital cephalograms and conventional
cephalograms by using traditional hand tracing and commercially available cephalometric
analysis software.
 The second purpose of the study was to determine if there are differences in the dispersion
of measurements among the various modes of imaging and cephalometric analysis software.

15. Digital VS Conventional
Cephalometrics
Materials and Methods:
 Seven male and four female white subjects between 13 and 18 years of age who required
cephalometric radiographs at the University of Missouri-Kansas City Orthodontic Postgraduate
Clinic were selected.
 The exclusion criteria were:
(1) obese subjects whose excess soft tissue could interfere with locating anatomic points.
(2) asymmetric subjects whose landmarks could introduce variables involved with halving the
differences between the two nonmidline structures.
(3) subjects with known craniofacial defects that would confound landmark identification.
(4) Only white patients were selected to limit confounding variables and to minimize the effects of
ethnic characteristics on landmark identification.

16. Digital VS Conventional
Cephalometrics
Materials and Methods:
 Two lateral cephalograms(one conventional and one digital) were taken simultaneously of each
individual.
 Within the cassette, the conventional cephalogram film was placed closest to the patient.
 The Phosphor screen was placed behind the conventional film (hybrid cassette technique) and
further from the patient since it needed less radiation for adequate exposure than the
conventional film.
 The conventional cephalograms were traced and landmarks identified.
 The conventional cephalogram was also scanned.
 Thus, there were a total of seven image/measurement groups.
 10 angular and 5 linear parameters were measured.

17. Digital VS Conventional
Cephalometrics

18. Digital VS Conventional
Cephalometrics
Results:
 Statistically significant differences between the imaging modalities were present for the following
parameters of the 10 patients:
 SN-GoMe.
 FH-GoMe.
 SNA.
 SNB.
 NBa-PTGn.
 U1-NA (mm)
 L1-NB (° and mm).

19. Digital VS Conventional
Cephalometrics
 The presenc of significant differences implies that values obtained from one or more imaging
modalities differed from the values obtained from other imaging modalities. Although these differences
are unlikely to have occurred by chance, the data in suggest that the size of the difference is not likely to
have clinical significance.

20. Digital VS Conventional
Cephalometrics
Conclusion:
 The results of this study indicate that digital radiography using storage phosphor
plates is a viable option for cephalometric films.
 Manual traced and scanned (digitized) conventional films and digital storage
phosphor images are clinically reliable for measuring hard tissue parameters.
 There were no clinically significant differences from manual traced conventional
film of conventional or storage phosphor images analyzed using Dolphin Imaging v.
6.7, Vistadent v. 7.33, and Vistadent v. 8.1 software programs when measuring hard
tissue parameters.
Gregston et. al ; Semin Orthod (2004)

21. Conclusion
 Digital cephalometics has eased out much of errors and limitations
associated with film processing and storage.
 The digital images can be instantly viewed on screen and thus save
time.
 The cephalometric analysis software have automated process of
cephalometric analysis to great extent.
 Therefore In near future the conventional film based technology
will be extinct.

22. Declaration
 The author wish to declare that; these presentations are his original work, all
materials and pictures collection, typing and slide design has been done by the
author.
 Most of these materials has been done for undergraduate students, although
postgraduate students may find some useful basic and advanced information.
 The universities title at the front page indicate where the lecture was first
presented. The author was working as a lecturer of orthodontics at Ibn Sina
University, Sudan International University, and as a Master student in Orthodontics at
University of Khartoum.
 The author declare that all materials and photos in these presentations has been
collected from different textbooks, papers and online websites. These pictures are
presented here for education and demonstration purposes only. The author are not
attempting to plagiarize or reproduced unauthorized material, and the intellectual
properties of these photos belong to their original authors.

23. Declaration
 As the authors reviews several textbooks, papers and other references during
preparation of these materials, it was impossible to cite every textbook and journal
article, the main textbooks that has been reviewed during preparation of these
presentations were:
Contemporary Orthodontics 5th edition; Proffit, William R, Henry W. Fields, and
David M. Sarver.
Handbook of Orthodontics. 1st edition; Cobourne, Martyn T, and Andrew T. DiBiase.
Clinical cases in orthodontics; Martyn T. Cobourne, Padhraig S. Fleming, Andrew T.
DiBiase, Sofia Ahmad
Essentials of orthodontics: Diagnosis and Treatment; Robert N. Staley, Neil T. Reske
Orthodontics: Current Principles & Techniques 5th edition; Graber, Lee W, Robert L.
Vanarsdall, and Katherine W. L. Vig
Evidence based Orthodontics; Greg J. Huang, Stephen Richmond, Katherine W.L. Vig.

24. Declaration
 For the purposes of dissemination and sharing of knowledge, these
lectures were given to several colleagues and students. It were also
uploaded to SlideShare website by the author. Colleagues and students
may download, use, and modify these materials as they see fit for non-
profit purposes. The author retain the copyright of the original work.
 The author wish to thank his family, teachers, colleagues and students
for their love and support throughout his career. I also wish to express
my sincere gratitude to all orthodontic pillars for their tremendous
contribution to our specialty.
 Finally, the author welcome any advices and enquires through his
email address: Mohanad-07@hotmail.com

25. Thank You