The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
IDEAL IMAGE CHARACTERISTICS
FACTORS RELATED TO THE RADIATION BEAM
FACTORS RELATED TO THE OBJECT
FACTORS RELATED TO THE TECHNIQUE
FACTORS RELATED TO RECORDING OF THE ROENTGEN IMAGE OF THE OBJECT
DARK/ LIGHT IMAGE IDEAL IMAGE
IDEAL QUALITY CRIETRIA
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
IDEAL IMAGE CHARACTERISTICS
FACTORS RELATED TO THE RADIATION BEAM
FACTORS RELATED TO THE OBJECT
FACTORS RELATED TO THE TECHNIQUE
FACTORS RELATED TO RECORDING OF THE ROENTGEN IMAGE OF THE OBJECT
DARK/ LIGHT IMAGE IDEAL IMAGE
IDEAL QUALITY CRIETRIA
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
brief description about CONTENTS Introduction Principles of panoramic imaging Image layer Panoramic machines Panoramic film Patient positioning Interpreting the panoramic imaging INDICATION Advantages Disadvantages Conclusion References
3. INTRODUCTION • Panoramic imaging also called pantomography is a technique for producing a single tomographic image of facial structures that includes both the maxillary and mandibular dental arches and their supporting structures . • This is a curvilinear variant of conventional tomography.
4. PRINCIPLES OF PANORAMIC IMAGE FORMATION • Patero and Numata - describe the principles of panoramic radiography • based on the principle of reciprocal movement of x-ray source and an image receptor around a central point or plane called the image layer, in which the OBJECT of image is located. • OBJECT in front or behind this image are not clearly captured because of their movement relative to the centre of rotation of the receptor and the x-ray source.
5. The film and x-ray tubehead move around the patient in opposite directions in panoramic radiography
6. ROTATION CENTER The pivotal point or axis around which the cassette carrier and tube head rotate is termed rotation center Three basic rotation center used in panoramic radiography Double centre rotation Triple centre rotation moving centre rotation The location and number of rotational centers INFLUENCE size and shape of focal trough
7. IMAGE LAYER • Also known as focal trough • It is a three dimensional curved zone where the structures lying within this layer are reasonably well defined on final panoramic image. • The structures seen on a panoramic image are primarily those located within image layer. • OBJECTSoutside the image layer are blurred magnified are reduced in size. Even distorted to the extent of not being recognizable. • This shape of image layer varies with the brand of equipment used.
8. FOCAL TROUGH
9. FACTORS AFFECTING SIZE OF IMAGE LAYER: Arc path Velocity of receptor and X-ray tube head Alignment of x-ray beam Collimator width The location of image layer change with extensive machine used so recalibration may be necessary if consistently suboptimal images are produced. As a position of object is moved within the image layer size and shape of image layer change.
10. PANORAMIC UNIT
11. A, Orthophos XG Plus extraoral x-ray machine. B, Orthoralix 8500 extraoral x-ray machine. C, Example of a digital panoramic system
12. PARTS OF PANORAMIC UNITS a. x-ray tube head b. head positioner: chin rest notched bite block forehead rest lateral head support c. exposure controls
13. X-RAY TUBE HEAD: • Similar to intraoral x-ray tube head • Each has a filament to produce electrons and a target to produce x-rays • Collimator is a lead plate with narrow vertical slit • Narrow x-ray beam emerges from collimator minimize patient exposure to radiation
1
Subtraction radiography and morphometric analysis in periodonticsR Viswa Chandra
“A Simple Method to Assess Bone Fill through Digital Subtraction Technique and Morphometric Analysis”- Guest lecture as a part of Dr NTRUHS Zonal CDE programme at Army College of Dental Sciences, Hyderabad, India on 18/1/2014.
this contains the occlusal radiography methods for both maxillary and mandibular different occusal radiographic techniques, principles, classification, indications
Image receptors & accessories/certified fixed orthodontic courses by Indian d...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
brief description about CONTENTS Introduction Principles of panoramic imaging Image layer Panoramic machines Panoramic film Patient positioning Interpreting the panoramic imaging INDICATION Advantages Disadvantages Conclusion References
3. INTRODUCTION • Panoramic imaging also called pantomography is a technique for producing a single tomographic image of facial structures that includes both the maxillary and mandibular dental arches and their supporting structures . • This is a curvilinear variant of conventional tomography.
4. PRINCIPLES OF PANORAMIC IMAGE FORMATION • Patero and Numata - describe the principles of panoramic radiography • based on the principle of reciprocal movement of x-ray source and an image receptor around a central point or plane called the image layer, in which the OBJECT of image is located. • OBJECT in front or behind this image are not clearly captured because of their movement relative to the centre of rotation of the receptor and the x-ray source.
5. The film and x-ray tubehead move around the patient in opposite directions in panoramic radiography
6. ROTATION CENTER The pivotal point or axis around which the cassette carrier and tube head rotate is termed rotation center Three basic rotation center used in panoramic radiography Double centre rotation Triple centre rotation moving centre rotation The location and number of rotational centers INFLUENCE size and shape of focal trough
7. IMAGE LAYER • Also known as focal trough • It is a three dimensional curved zone where the structures lying within this layer are reasonably well defined on final panoramic image. • The structures seen on a panoramic image are primarily those located within image layer. • OBJECTSoutside the image layer are blurred magnified are reduced in size. Even distorted to the extent of not being recognizable. • This shape of image layer varies with the brand of equipment used.
8. FOCAL TROUGH
9. FACTORS AFFECTING SIZE OF IMAGE LAYER: Arc path Velocity of receptor and X-ray tube head Alignment of x-ray beam Collimator width The location of image layer change with extensive machine used so recalibration may be necessary if consistently suboptimal images are produced. As a position of object is moved within the image layer size and shape of image layer change.
10. PANORAMIC UNIT
11. A, Orthophos XG Plus extraoral x-ray machine. B, Orthoralix 8500 extraoral x-ray machine. C, Example of a digital panoramic system
12. PARTS OF PANORAMIC UNITS a. x-ray tube head b. head positioner: chin rest notched bite block forehead rest lateral head support c. exposure controls
13. X-RAY TUBE HEAD: • Similar to intraoral x-ray tube head • Each has a filament to produce electrons and a target to produce x-rays • Collimator is a lead plate with narrow vertical slit • Narrow x-ray beam emerges from collimator minimize patient exposure to radiation
1
Subtraction radiography and morphometric analysis in periodonticsR Viswa Chandra
“A Simple Method to Assess Bone Fill through Digital Subtraction Technique and Morphometric Analysis”- Guest lecture as a part of Dr NTRUHS Zonal CDE programme at Army College of Dental Sciences, Hyderabad, India on 18/1/2014.
this contains the occlusal radiography methods for both maxillary and mandibular different occusal radiographic techniques, principles, classification, indications
Image receptors & accessories/certified fixed orthodontic courses by Indian d...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
X ray films.pptxThe system measure deflection of a laser beam from a re...NISHANT KUMAR
A Film holder is a device to hold the film which allow easy and predictable alignment of the X- ray tube.
Three types of film holders:
Uncoupled positioning devices consisting of intraoral film holders, but no aiming devices;
Semi rigidly coupled devices that have intra oral film holders and attached aiming rods with or without aiming rings;
Rigidly coupled positioning devices where the intra oral film holder, beam aiming devices, and x-ray cone are all physically connected.
hemostat with rubber biteblock held the film and a long metal rod .
1951: The snap a ray instrument was developed.
1962: The precision X-ray instrument was introduced.
1967: Rinn instruments for use with bisecting angle technique
1968 : for use with the parallel technique.
1987: Cephalometric unit was used for the stabilization of the patient.
1993: Kwik bite and Intrax devices uses for orthodontic purposes. And Rinn xcp bitewing device was also used.
1996: Electronically Guided Alignment Device (EGAD) system was introduced. With this system a custom made occlusal biteblock held an aluminium wedge.
The system measure deflection of a laser
beam from a refernce mirror attached to a
bracket bonded to the patient’s mirrorIntensifying screens are image receptor system used in combination with x ray film for all extra oral radiographic procedures such as OPG , ceph and skull radiography
Types- Depending on light emitted
Blue emitting visible light
Green emitting visible light
Consist of light sensitive phosphor crystals suspended in plastic material
When the phosphors are struck by x ray photons they emit visible light that exposes the xray film.
Most frequently used- calcium tungstate – Blue visible light
Rare earth element-
Advantages-
4 x more efficient
Green emission spectrum
hich allow easy and predictable alignment of the X- ray tube.
Three types of film holders:
Uncoupled positioning devices consisting of intraoral film holders, but no aiming devices;
Semi rigidly coupled devices that have intra oral film holders and attached aiming rods with or without aiming rings;
Rigidly coupled positioning devices where the intra oral film holder, beam aiming devices, and x-ray cone are all physically connected.
hemostat with rubber biteblock held the film and a long metal rod .
1951: The snap a ray instrument was developed.
1962: The precision X-ray instrument was introduced.
1967: Rinn instruments for use with bisecting angle technique
1968 : for use with the parallel technique.
1987: Cephalometric unit was used for the stabilization of the patient.
1993: Kwik bite and Intrax devices uses for orthodontic purposes. And Rinn xcp bitewing device was also used.
1996: Electronically Guided Alignment Device (EGAD) system was introduced. With this system a custom made occlusal biteblock held an aluminium wedge.
The system measure deflection of a laser
beam from a refernce mirror attached to a
bracket bonded to the patie
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Recent advances in imaging techniques/ /certified fixed orthodontic courses b...Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Opportunity for Dentists (BDS/MDS )to relocate to United kingdom -Register as a DENTAL HYGIENIST/ DENTAL THERAPIST without Board exams and after approval you can register in GDC as a DH/DT and start working as a DH/DT Immediately and get paid.
You can complete the whole process in 3-4 months.Salary range for DH/DT is around 2500-3500 Pounds per month.
Eligibility / requirements-
1. An International English Language Testing System (IELTS) certificate
at the appropriate level.(Within 2 yrs of application date )
2: A recent primary dental qualification that has been taught and examined in English..(Within 2 yrs of application date )
3: A recent pass in a language test for registration with a regulatory authority in a country where the first language is English.
If you are interested Please contact us for more details.
1ST, 2ND AND 3RD ORDER BENDS IN STANDARD EDGEWISE APPLIANCE SYSTEM /Fixed ort...Indian dental academy
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals
who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry,
Periodontics and General Dentistry.
Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
I –Aligners are made with FDA approved transparent thermoplastic materials using 3D scanning, 3D Printing and finally Trays with Pressure vacuum formers.
Dear Doctor,
Indian Dental Academy Now offers comprehensive online Orthodontics course.
Course includes:
1.whiteboard lecture presentations
2.Case Discussions
3.with hundreds of pictures.
4.Demo on Models
5.Demo on Patients
6. subtitles in your own language
12 months unlimited access and support @350 USD only.
For Demo please visit :www.idalectures.com/preview/
For more details visit: www.idalectures.com
Please contact us for any clarifications:
idalectures@gmail.com
indiandentalacademy@gmail.com
Thanks & Regards
Indian Dental Academy
--
Indian Dental Academy
Leader in continuing dental education
www.indiandentalacademy.com
skype:indiandentalacademy
+919248678078
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Cytotoxicity of silicone materials used in maxillofacial prosthesis / dental ...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Diagnosis and treatment planning in completely endntulous arches/dental coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Properties of Denture base materials /rotary endodontic coursesIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Use of modified tooth forms in complete denture occlusion / dental implant...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
2. OMR, CODS, DVG
Image Receptors:
Initially glass plates were used
By 1900: celluloid base film
1913: Moisture proof dental packet
1919: Kodak ‘Regular’ film
1924: Kodak ‘Radiatized’ film
1940: Kodak ‘Ultraspeed’ film
1952: Selenium plates in Xeroradiography
1981: Kodak ‘Ektaspeed’ film
1989: CCDs developed for dental radiography
1994: Kodak ‘Ektaspeed Plus’ film
www.indiandentalacademy.com
4. IMAGE RECEPTORS
• Direct exposure films ( also called
as no n-scre e n films ) are used in
intra- oral radiography
• Indirect exposure films ( also called
as scre e n films ) are used
in extra- oral radiography in
combination with intensifying
screens OMR, CODS, DVG
X-ray Films:
www.indiandentalacademy.com
6. IMAGE RECEPTORS
Composition of an X-ray Film
OMR, CODS, DVG
• Supercoat: a thin layer of polyester or
gelatin covers both surfaces of the
film to protect the emulsion from
scratching
• Supercoat: a thin layer of polyester or
gelatin covers both surfaces of the
film to protect the emulsion from
scratching
• Emulsion: coated on both sides of the base
~ made up of gelatin matrix in which silver halide
( mainly AgBr2 ) crystals are suspended
~ crystals are 1 / 0.7 micrometer in thickness
• Emulsion: coated on both sides of the base
~ made up of gelatin matrix in which silver halide
( mainly AgBr2 ) crystals are suspended
~ crystals are 1 / 0.7 micrometer in thickness
• Base:
~ made up of polyethylene terephthalate ( polyester )
~ 0.2 mm in thickness
~ translucent, chemically inert
~ supports emulsion
• Base:
~ made up of polyethylene terephthalate ( polyester )
~ 0.2 mm in thickness
~ translucent, chemically inert
~ supports emulsion
www.indiandentalacademy.com
7. IMAGE RECEPTORS
Uses & Dimensions of Intra-oral X-ray
Films
OMR, CODS, DVG
• Periapical Projection: to record teeth and alveolar
bone
3 sizes ~ ‘0’ : 22 x 35 mm ( for children )
~ ‘1’ : 24 x 40 mm ( for anterior
teeth )
~ ‘2’ : 32 x 41 mm ( for adults )
• Bitewing Projection: to record crown portion of
maxillary and mandibular teeth in one image
~ Size ‘0’ and ‘1’ for children
~ Size ‘2’ for adults
~ Size ‘3’ ( 27 x 54 mm )
• Occlusal Projection: to record larger areas of maxilla
or mandible
~ Size ‘4’ ( 57 x 76 mm )www.indiandentalacademy.com
8. IMAGE RECEPTORS
Uses & Dimensions of Intra-oral X-ray
Films
OMR, CODS, DVG
Size ‘4’ (57 x 76 mm)
Size ‘0’ (22 x 35 mm)
Size ‘2’ (32 x 41 mm)
www.indiandentalacademy.com
10. IMAGE RECEPTORS
Contents of an X-ray Film Packet
OMR, CODS, DVG
† Plastic cover
† Black paper
† Lead foil
† Direct exposure
film
Protects the film
from moisture and
light
Protects the film
exposure to light
1. Protects tissues on the other
side of the film from radiation
2. Prevents backscatter radiation
from reaching the film
3. Gives sufficient stiffness to the
film packet
Captures the image
pattern and forms a latent
image
www.indiandentalacademy.com
11. IMAGE RECEPTORS
• Direct exposure films ( also called
as no n-scre e n films ) are used in
intra- oral radiography
• Indirect exposure films ( also called
as scre e n films ) are used
in extra- oral radiography in
combination with intensifying
screens OMR, CODS, DVG
X-ray Films:
¤ These films are similar in their
composition to the non-screen films with the
exception that certain impurities are added
to make the emulsion more sensitive to
light.
¤ The latent image is formed by the light
emitted from the intensifying screens.
www.indiandentalacademy.com
13. ACCESSORIES
OMR, CODS, DVG
Intensifying screens - Composition
Protective layer
Phosphor
layer
Reflecting
layer
Base
~ made up of polyester
~ about 0.25 mm thick
~ provides mechanical
support to the screen
~ made up of polyester
~ about 0.25 mm thick
~ provides mechanical
support to the screen
~ made up of titanium dioxide
~ about 0.025 mm thick
~ reflects the light from the
phosphor layer back to the
film
~ made up of titanium dioxide
~ about 0.025 mm thick
~ reflects the light from the
phosphor layer back to the
film
~ made up of phosphor crystals
suspended in plastic
~ phosphor materials used are : calcium
tungstate or rare earth elements like
# terbium activated gadolinium
oxysulfide
# thulium activated lanthanum
oxybromide
~ emits light when exposed to x-radiation
~ exposure to an x-ray photon results in
emission of several light photons
~ help in reducing radiation dose in extra-
oral
radiography
~ made up of phosphor crystals
suspended in plastic
~ phosphor materials used are : calcium
tungstate or rare earth elements like
# terbium activated gadolinium
oxysulfide
# thulium activated lanthanum
oxybromide
~ emits light when exposed to x-radiation
~ exposure to an x-ray photon results in
emission of several light photons
~ help in reducing radiation dose in extra-
oral
radiography
~ made up of polyester
~ about 0.8 microns thick
~ protects the phosphor layer and
provides
a surface that may be cleaned
~ made up of polyester
~ about 0.8 microns thick
~ protects the phosphor layer and
provides
a surface that may be cleaned
www.indiandentalacademy.com
15. ACCESSORIES
OMR, CODS, DVG
Intensifying screens - Functioning
The x-ray film, therefore, needs to kept very close to
the intensifying screen. In fact, it is sandwiched
between a pair of intensifying screens inside a metallic
cassette.
Magnification and Unsharpness of Image
www.indiandentalacademy.com
16. ACCESSORIES
OMR, CODS, DVG
Film Holders, Cassettes & Stands
Film Holders hold the film in
patient’s mouth, and
maintain its position during
exposure. They may also
aid in alignment of x-ray
beam with the x-ray film.
XCP (extension cone paralleling) Instrumentswww.indiandentalacademy.com
18. ACCESSORIES
OMR, CODS, DVG
Film Holders, Cassettes & Stands
Film Holders hold the film in
patient’s mouth, and
maintain its position during
exposure. They may also
aid in alignment of x-ray
beam with the x-ray film.
Snap-A-Ray Instrumentwww.indiandentalacademy.com
19. ACCESSORIES
OMR, CODS, DVG
Film Holders, Cassettes & Stands
Film Holders hold the film in
patient’s mouth, and
maintain its position during
exposure. They may also
aid in alignment of x-ray
beam with the x-ray film.
Artery forceps
or
needle holder
www.indiandentalacademy.com
20. ACCESSORIES
OMR, CODS, DVG
Film Holders, Cassettes & Stands
Cassettes carry a non-screen film between a pair of
intensifying screens. They protect the film from light
and moisture, and also maintain a tight contact
between the film and the intensifying screens.
www.indiandentalacademy.com
21. ACCESSORIES
OMR, CODS, DVG
Film Holders, Cassettes & Stands
Cassette stands are used in extra-oral radiography for
holding and maintaining the cassette in correct position
with respect to the patient.
www.indiandentalacademy.com
22. ACCESSORIES
OMR, CODS, DVG
Grids
A grid is composed of alternate strips of a radiopaque
material (usually lead) and strips of a radiolucent
material (usually plastic). Purpose of grid is to prevent
the secondary radiation coming from the tissues from
reaching the film, thus improving the image quality.
Grid
Film
U
S
E
F
U
L
R
A
D
I
A
T
I
O
N
Secondar
y
radiation
Secondar
y
radiation
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23. ACCESSORIES
OMR, CODS, DVG
Grids
Types of grids:
• stationary and mobile (Bucky, Potter-Bucky
diaphragm)
• parallel, focussed
Grid ratio: ratio of grid thickness to the width of
radiolucent spacer. Higher the grid ratio better is the
image quality. Generally a grid ratio of 8-10 is
satisfactory. Use of grids requires doubling of
exposure. Hence, grids should be used only when
sufficient improvement in image quality is expected.
As large amounts of secondary radiation is produced
by the maxillo-facial structures grids are useful in extra-
oral radiography. In intra-oral radiography, grids can
neither be used nor is there a need to use them.www.indiandentalacademy.com
25. IMAGE RECEPTORS
Charge-Coupled Device ( CCD )
OMR, CODS, DVG
A CCD is made of an array of
pho to dio de s (devices that
conduct electricity when light
or x-rays strike them) on top of
a semiconductor.
‘CCD’ is a sensitive electronic device that stores
packets of information as electric charge.
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26. Each element, called a
‘pixel’,
is 20-60 microns in size.
(A human hairis about 60
microns
in diameter!)
IMAGE RECEPTORS
Charge-Coupled Device ( CCD )
OMR, CODS, DVG
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30. IMAGE RECEPTORS
Charge-Coupled Device ( CCD )
OMR, CODS, DVG
High image quality at considerably less radiation
dose as compared to film radiography.
Image is dynamic and can be altered digitally.
No processing required; therefore environment
friendly.
Image is available instantly.
No processing errors.
No loss of image over a period of time.
Image duplication is very easy.
Telemedicine.
Advantages
:
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31. IMAGE RECEPTORS
Charge-Coupled Device ( CCD )
OMR, CODS, DVG
Limitations:
Very high initial cost.
Sensor is bulkier compared to an x-ray film
making it difficult to place in some parts
of the mouth and in children.
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32. DIRECTING THE X-RAY BEAM
TO THE OBJECT
INTERACTION OF X-RAYS
WITH MATTER
DIFFERENTIAL ABSORPTION
OF THE X-RAY BEAM
EMERGENCE
OF AN
INVISIBLE
IMAGE
PATTERN
CAPTURE OF THE
INVISIBLE IMAGE PATTERN
ON AN IMAGE RECEPTOR
‘Latent Image’
Processing
Latent image is formed when
tiny specks of metallic silver are
deposited in those silver
bromide crystals that are
exposed to radiation. This
image is invisible.
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