This document provides information on extraoral radiographic techniques. It discusses various extraoral views including lateral oblique, cephalometric, submentovertex, and zygomatic arch views. For each view, it describes the positioning of the patient's head, placement of the radiographic cassette and film, and path of the x-ray beam. It also discusses the components and function of screen-film systems used in extraoral radiography, including intensifying screens, screen speeds, and the advantages of Ektavision film over T-Mat film. Common cephalometric landmarks and their use in orthodontic assessment are also summarized.
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
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
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
Bisecting angle vs paralleling technique /orthodontic courses by Indian denta...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
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
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
Bisecting angle vs paralleling technique /orthodontic courses by Indian denta...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
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
Diagnosis is the first step in planning any treatment. For implant placement there are various diagnostic methods which are used prior to its placement inside the oral cavity.
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.
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.
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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.
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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.
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.
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.
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Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
2. Extra oral Radiography:
• All extra oral radiographic projections should
be performed using screen film.
• Medium or high speed (rare-earth) screenfilm combination are recommended to reduce
pt’s exposure.
• Metallic letters (L) &(R) are used to determine
left & right sides of pt as well as grids to
reduce the fog.
4. Intensifying Screen Function
One of the properties of x-rays is that
they cause certain materials to
fluoresce (emit light); the phosphor
crystals found in intensifying screens
are one of these materials.
The light emission is usually green or
blue, depending on the type of
phosphor crystal used.
5. Intensifying Screen Function
The composition of the films used
with these screens is adjusted by
the manufacturer to be sensitive to
either blue light or green light.
correct film should be used with
corresponding screen type. (Bluesensitive film with blue lightemitting screen, etc.)
6. Screen Film
• Screen film is sensitive to the effects of light
from an intensifying screen. When these
screens, on either side of the film in a cassette,
are exposed to x-rays, they emit light which in
turn exposes the film.
• Using the screen-film combination allows a
very large reduction in the amount of radiation
needed to expose the film (30-60 times less
radiation than that required by direct exposure
film).
7. Intensifying Screen Composition
(this side toward film)
The base of the screen (yellow line above) is made of
above
plastic and provides support. A reflecting layer
(silver line) reflects light emitted by the phosphor
line
back toward the film. The phosphor layer (green line)
line
contains the phosphor crystals that emit the light.
The surface of the phosphor layer is covered with a
protecting coat (white line) , which is a thin layer of
plastic that protects the phosphor layer from
damage when the screens are handled.
8. Rare Earth Phosphor
The most common type of phosphors being used
are the rare earth phosphors, which emit blue or
green light depending on the type of rare earth
material being used.
film
= phosphor crystal
9. Intensifying Screen Speed
The speed of the screen depends on crystal size and
the thickness of the phosphor layer (larger crystals
and thicker layer increase speed). Image quality
decreases as the screen speed increases. The three
speeds are:
• Fast (Rapid): requires the least exposure but the
images are less sharp
• Medium (Par): medium speed, medium sharpness
• Detail (Slow): produces the sharpest images but
requires the most exposure
10. Screen Film
The two types of screen film used with rare earth
screens are T-Mat and Ektavision. These films are
available in three styles: G, which is used to
provide the best contrast; L, which has the widest
latitude (long-scale contrast) and is good for soft
tissue visualization and H, which is used to provide
an extra film for referral purposes (two films are
placed in the cassette at the same time).
The advantage of Ektavision film over T-Mat film is
that it has anti-crossover layers incorporated into
the film. This prevents light from one screen
affecting both emulsion layers; this produces a
sharper image on the film.
11. T-Mat (crossover)
Light produced by the phosphor crystal spreads out
as it goes toward the film and with T-Mat film it
affects the emulsion on both sides. Since it has
spread out more when it reaches the emulsion on
the opposite side of the film (crossover), the
crossover
sharpness (edge detail) of the image is decreased.
film
12. Ektavision (anti-crossover)
Ektavision film has a crossover control layer on each
side of the film base. These layers allow the light from a
phosphor crystal to reach the emulsion on the same
side as the crystal but prevent the light from reaching
the emulsion on the opposite side of the film. X-rays
easily pass through this anticrossover layer.
film
14. 1] Lateral oblique projection:
• 2 views for mandibular projection;
• a) body projection:
• For demonstration premolar-molar region
and inferior border of the body of the
mandible.
• Head position: Head tilted to the side to
be examined with the mandible
protruded.
15. Lateral oblique projection body
(cont.):
• Film placement:
• Film is placed against the patient’s
cheek and centered over the first
molar .
• The lower border of the cassette
should be parallel to the inferior
border of the mandible and at least
2cm below it.
• Point of entry:
• 2cm below angle of the mandible
directed toward the 1st molar region
of cassette side.
17. B) Mandibular Ramus projection:
• To view the ramus from the mandibular
angle to the condyle for examining the 3rd
molar region of both the maxilla and
mandible.
• Head position: head tilted towards the
projected mandible where the mandibular
angle of tube side and condyle of cassette
side parallel to the floor.
18. Mandibular ramus projection (cont.):
• Film placement :
• film is placed over the ramus of
the mandible to the far
posterior to include the
condyle. Lower border of the
cassette 2cm below the inferior
border of the mandible.
• Point of entry:
• 2cm below the inferior border
of the first molar region on the
tube side toward the center of
the ramus of the cassette side.
20. 2- True Lateral (Cephalometric):
Cephalo=Head
• Metric=Measurement.
Cephalometrics
introduced for use by
orthodontists by Dr.
Broadbent in 1931 for
studying dento -facial
growth.
21. True Lateral (Cephalometric) (cont.):
• Uses:
•
•
•
•
•
•
Evaluation of facial growth & development.
Le Fort I & II fractures.
Posterior wall of antera.
Perforation of hard palate.
A foreign body in the air way.
The film: is positioned parallel to the sagittal plane of
the film.
• The central ray :is ┴ the film in both horizontal &
vertical plane.
22. True Lateral (Cephalometric) (cont.):
• Reproducibility:
• Cephalometric has the
unique property of
presenting a
reproducible image,
unlike any other
radiographic technique
used for dental films
23. True Lateral (Cephalometric) (cont.):
• Reproducibility:
• The patients head is
oriented in the same
position relative to the xray beam every time a film
is taken, with the use of
positioning ear posts
24. True Lateral (Cephalometric) (cont.):
The distance from the x-ray source to the
patient’s midsagittal plane is always the same
60 inches to reduce the magnification.
25. • Soft tissue profile
can be added by
using reducing the
exposure to 50% or
put aluminum filter
in the front of
cassette.
26. Uses in orthodontics:
• Evaluate skeletal patterns
(bone-to-bone relations)
• Does the patient have a
Class I, Class II or Class III
skeletal pattern?
• Is the problem due to a
prognathic maxilla, a
retrognathic maxilla, a
prognathic mandible, a
retrognathic mandible or a
combination of these?
27. Cephalometric Landmarks
• Landmarks are
locations which
represent biological
homology between
image locations
• Example: The tip of
the chin in one
cephalometric image
corresponds to the tip
of the chin in another
cephalometric image
28. Cephalometric Landmarks
• Landmarks need to have 3 properties:
1.Landmarks should not remodel over time
(neither be created nor destroyed)
2.Landmarks need to capture biological form,
including the shape, size and position of the
tissue component of which it represents
3.Landmarks have to be reliably located on
cephalometric radiographs
29. Common landmarks
• Sella Turcica (S):
• midpoint of the
pituitary fossa.
• Orbitale (O):
lowest point on
lower margin
of orbit
30. Orthodontic tracing
• To the fixed anatomical points is applied to assess the
nature and extent of any malocclusion which may be
present.
• Tracing of anatomical landmarks should be drown
with sharp , hard (6H) pencil on good quality tracing
paper or acetate drafting sheet not on the film and
done on film viewer.
31. Main areas of concern:
- Skeletal relationships.
- Dento-skeletal
relationships.
- The facial profile.
Radiographs can be digitized
and measured in personal
computer with special
software or cephalometric
tracer attached to
computer can be used.
32. 4-Submentovertex (SMV) view:
• The projection shows the
base of the skull,
Sphenoidal sinuses and
facial skeleton from
below(radiographic
baseline is vertical).
• The pt’s head tipped
backwards and x-ray beam
is aimed upwards at 5° to
the horizontal.
34. 4-Submentovertex (SMV) view:
• Film placement: cassette
± floor and placed
vertically.
• Head position: tipped
backward & touch the
cassette .Frankfort plane
± floor.
• Beam alignment:
• center to the head and ±
cassette.