This document provides information on dental x-ray films. It discusses the history and composition of x-ray film, including the film base, emulsion layer, and silver halide crystals. Different types of dental films are described, such as periapical, bitewing, and occlusal films. Characteristics of intraoral and extraoral films are compared. The document also outlines the contents of a dental film packet and its protective layers.

2. DEPARTMENT OF
ORAL MEDICINE,
DIAGNOSIS & RADIOLOGY

3. PRESENTED BY –
ASHISH KUSHWAHA
FINAL YEAR
8630016

4. • Introduction-
The X-Ray films, help us to record the information
regarding the object (tissue) through which the x-
rays passes & hence they greatly help in diagnosis,
& treatment of the patient problem.
Karjodkar 2nd edition
Image recorded on film is caused by exposure to
photons

5. • HISTORY -
• The first x-rays were recorded on glass plates.
• These were coated with emulsion on one side
only.
• The exposure dose was quite high.
• In 1839, the phenomenon of development
was discovered by Louis Daguerre

6. • One year later, it was discovered that treating
exposed silver chloride paper with sodium
chloride would make the image permanent.
• Nitrocelluose based film was found to be a more
feasible choice for recording x-rays.
• This film was single-emulsion.
• It was later discovered that double-emulsion
responded to x-rays faster.
• In 1924, cellulose acetate replaced the
nitrocellulose based film.

7. COMPOSITION
X- ray film
AdhesiveBase
Polyester
polyethylene
terephthalate
Emulsion
Silver
halide
grains
Vehicles
matrix

10. FILM BASE -
• It is a transparent supporting material.
• POLYESTER POLYETHYLENE TEREPHTHALATE
RESIN are used.
• Thickness - 0.18 mm
Film
Base
0.18 mm

11. IDEAL PROPERTIES BASE MATERIAL
1. Structural support for fragile emulsion
2. Low light absorption
3. Flexible, thick, & strong
4. Dimensional stability
5. NON -FLAMMABLE

12. FUNCTIONS OF BASE
 Provide support for emulsion layer.
 To transmit light.

13. ADHESIVE LAYER
13
 Also called subbing layer or Substratum layer.
 Made of mixture of gelatin solution and solvent of
film base.
 It keeps emulsion layer and base adhered to each
other during coating stage and processing.
 Provides uniform surface over which the emulsion
can be coated uniformly.

14. EMULSION LAYER
14
 Has 2 principle components –
I. Silver halide grains
II. Vehicle matrix
 It consists of a homogeneous mixture of gelatin and silver
halide crystals.
 In typical emulsion 90 to 99% is AgBr and about 1 to 10% AgI .
Emulsion
Layers
 The presence of AgI produce an emulsion of much
sensitivity than a pure AgBr emulsion.
 It also contains traces of sulfur (ALLYLTHIOUREA).

15. 15
 Silver halide in a emulsion is in the form of small crystals.
 Silver halide crystals may be tabular, globular, polyhedral,
or irregular in shape.
 Crystal size might vary from
1.0 –1.5 microns in diameter
with about 6.3 x 1010 grains
per centimeter of emulsion.

16. • Granular
• Tabular
Scanning electron micrographs
of emulsion comparing flat
tabular silver bromide crystals
of InSight film
Scanning electron micrographs of
emulsion comparing with
globular silver halide crystals of
Ultra-Speed film .

17. • How silver halide crystals are made … ???
Dissolve Metallic silver in nitric acid.
to form
Silver nitrate
by mixing
silver nitrate + KBr = Ag-Br + potassium nitrate

18. GRAIN SIZE AND DISTRIBUTION
18
GRAIN SIZE and DISTRIBUTION affects the following:
 SPEED: The bigger the average grain size, the higher the
speed of the film.
 CONTRAST: Affected by size distribution. The more
available in the film, the lower the contrast.
 GRAININESS: Graininess is the apparent clumping of the
crystal as seen on the radiograph. The bigger the crystal,
the higher the graininess o f the film.

19. GELATIN
 Gelatin is used as the suspending medium and
binding agent for the silver halide particles.
 It comes collagen fiber in which primary source are
the cartilage, skin and the protein matrix (ossein) of
bone of animals.

20. WHY WE USE GELATIN AS BINDER…?
20
 It is a medium in which SILVER NITRATE and SODIUM BROMIDE
can react and the resulting AgBr get finely and evenly
dispersed and remain suspended.
 In warm state it can be easily spread on the film base.
 On cooling, it sets firmly on the base as gel.
 It is flexible and does not crack easily on bending.
 It is optically transparent .
 Gelatin does not react chemically with the silver halide .
 It is porous so the processing chemicals can penetrate to the
silver halide crystals.
 Some of the constituents in gelatin enhances the activity of
Silver bromide and some act as antifoggant.

21. SUPERCOAT (OVERCOAT)
21
Protective layer of gelatin
 Provides sturdiness to unexposed radiographic film.
 Antistatic
 Reduces damage from scratches, pressure, or
contamination during storage, handling and processing.
Supercoating

22. FEW ADDITIVES
22
 Preservative – Phenol as bacteriocide
 Silver iodide – To extend sensitivity towards blue
range.
 Some dyes may extend Colour sensitivity further
 Glycerin to make the emulsion pliable
 Saponin – To make the emulsion receptive to the
processing chemicals
 Alcohol – To prevent frothing during coating

23. characteristic Photographic film Radiographic film
Mode of image
capture
By reflected light By penetrated/
transmitted light
Emulsion layer On one side Either On one side or
both
Speed Slow Fast
Grain size Small Large
Resolving power 1000 lines/mm 6-10 lines/mm
Irradiation by Light only Light as well as x-ray
DifferenceInB/W PhotographicFilmAndRadiographic
Film
23

24. 1. According to their USES –
• Intraoral films
Periapical films
No. 0 – children
No. 1 – anterior adult
No.2 – standard adult
Occlusal films
Bitewing films
• Extraoral films

25. • 2. According to SPEED –
• Slow film
 Speed A
 Speed B
 Speed C
• Fast film
 D – ultra speed
 E – ekta speed
 F – ultra ekta speed
• Hyper speed G

26. • 3. According to emulsion layer -
• Single coated
• Double coated
• 4. According to packaging –
• Single film packet
• Double film packet

27. • What is speed of X-RAY FILM …???
 It is defined as the amount of the radiation
required to produce the radiograph of adequate
density.
 Slow film – Require more exposure & vice versa.
• Factors affecting film speed –
Size of crystals
Shape of grains
Thickness of emulsions

28. Differenceb/wSingleCoatedAndDoubleCoated X-ray
Film
Characteristic Single coated Double coated
Emulsion layer One side Both side
Patient Radiation dose More Less
Radiographic detail More Less
Average gradient (G) Very less more
Parallax effect No yes
Contrast Less more

30. • Periapical view –
Used to record crown, root & surrounding bone.
3 sizes-
0 - for children 22 X 35 mm
1 - narrow, for anterior teeth 24 X 40 mm
2 – standard size for adults 31 X 41 mm

31. Size ‘0’
22 X 35 mm
Size ‘2’
31 X 41 mm
Size ‘1’
24 X 40 mm
Standard adult
Anterior adultChild
Size of IntraOral Periapical

32. • Indications – to evaluate the -
Dental caries
Periapical infections
Periodontal diseases
Mixed dentition analysis
Cyst & tumor in the periapical region
Pathology of bone in the periapical region
Pulp calcification & pulp stone
Dental anomalies
Impacted teeth
Assessment of working length
Assessment of root morphology before extraction.

33. • Bitewing view – (Interproximal view) –
• A paper wing present on the middle of film.
Uses -
1.Crown of maxillary & mandibular teeth in one
image.
2.Interproximal caries
3.evaluation of height
of alveolar bone

34. Size ‘0’
22 X 35 mm
Size ‘2’
31 X 41 mm
Size ‘1’
24 X 40 mm
Posterior adult
Anterior child
Posterior Child
Size of Bitewing Film
Size ‘3’
27 X 54 mm
Anterior adult

35. • Occlusal view –
• Size 57 X76 mm (3 times larger than size 2)
• To show larger area.
• Used to obtain right angle views to the usual
periapical view.
• Film usually is held in position by having the patient
bite lightly on it to support it between the occlusal
surface of the teeth.
Size ‘4’
57 X 76 mm

36. • Indications –
 To evaluate the impacted canine, third molar &
supernumerary tooth
 To localize foreign body like sialolith in duct of
salivary gland
 To detect complete extension of large cyst an
tumor.
 Assessment of fracture of the anterior teeth and
alveolar bone.
 For determining the buccolingual relationship of
pathological lesions.

38. EXTRAORAL FILMS
• Panoramic, cephalometric, & other skull views are
more frequently used extra oral projections in
dentistry.
• Screen film is used with intensifying screens to
reduce patient exposure.
• It is placed in between 2 intensifying screens when
an exposure is made.

39. • intensifying screens absorb x-rays & emit visible
light.
• Silver halide crystals are sensitive to U.V. & blue
light and thus are sensitive to screens that emit U.V.
& blue light.
• When film is used with screens that emit green
light, the silver halide crystals are coated with
sensitizing dyes to increase absorption.

40. • They do not have embossed dot.
• They are used in film holder or cassette.
• High contrast medium speed – panoramic, skull
radiography.
• Less contrast & wider latitude – cephalometric
radiography.
• 2 types –
 Screened
 Non screened

41. • Size –
• Available in various size –
• Lateral Oblique film – 5” X 7”
• Panoramic film – 6” X 12” / 5” X 12”
• Cephalometric film – 8” X 12”
• Skull radiography – 10” X 12”

42. CHARACTERISTICS DIRECT EXPOSURE FILM INDIRECT EXPOSURE
FILM
Exposed with Only by x-rays Mainly by visible
light
Used Without Screen With screen
Emulsion layer Thick Thin
Image formation In deep superficialy
Processing time more less
Resolution more less
Exposure dose more less
Used in Orbit and extremities
radiography. Also in
Industrial Radiography
General radiography
DifferenceB/WNonScreen&ScreenFilm

43. CONTENT OF FILM PACKET
• Intraoral x-ray film packet contain –
 Outer plastic wrapper
 Lead foil
 Black paper
 X-ray film

45. • Wrapper –
• Made up of non absorbent paper or plastic.
• Water proof
• It is sealed to prevent the ingress of saliva & light.
• It has 2 sides –
• Tube side – (usually white, faces toward the x-ray
tube.)
• Labelled side- reverse side. Usually of 2 color

46. • Black paper –
• Protect the film from –
• Light
• Damaged by finger
• Lead foil –
• Placed behind the film
• Prevent back scattering
• Reduce exposure
• If film is placed in wrong way then embossed pattern
present on the film.

47. • X-Ray film – it has
• Rounded corner
• Raised dot
• One corner of each dental film has a small, raised
dot that is used for –
• Orientation
• Mounting
• Side determination

48. • Film Holding Device –
• It is the device that is used to position an intraoral
film in the mouth & maintain the film in position
during exposure.

49. Film Storage
• Clean, dry location, light tight location
• 40 – 60 % Humidity 70 º Fahrenheit
• Away from chemical fumes
• Safe from radiation exposure
• Standing on edge
• Expiration date clearly visible. Film can be
stored for about 45 days.

50. FILM BIN - STORAGE

51. Care And Protection Of Film
Films should be protected from
 Physical damage
 Light
 High temperature
 High relative humidity
 Harmful gases and fumes
 X-rays and radioactive source
 Fire
51

52. Reference
Oral radiology
Principle & interpretation
6th edition
By- white And pharoah
Textbook of
Dental and
maxillofacial radiology
2nd edition
By- Freny R. Karjodkar

53. THANK
YOU

54. INTENSIFYING SCREENS
• An intensifying screen is a plastic sheet coated
with fluorescent material called phosphors .
• Phosphors are materials which convert photon
energy to light

56. INTENSIFYING SCREENS

58. composition
• Intensifying screens are made of -
Phosphor
layer
Protective
coat
Base

59. • Base –
 form of polyester plastic.
Thickness about 0.25 mm.
Provide mechanical support.

60. • Phosphor layer –
• Is composed of phosphorescent crystals suspended
in a polymeric binder.
• When crystals absorb x-ray photons they fluoresce.

61. • Protective layer –
• Thickness 15 µm.
• Placed over phosphor layer to protect the phosphor layer.
• Provide a surface that can be cleaned.

62. • The speed & resolution of a screen depends on –
Phosphor type and phosphor conversion
efficiency
Thickness of phosphor layer
Amount of phosphor / unit volume
Presence of reflective layer
Phosphor grain size

63. • FUNCTIONS –
Create an image receptor system 10 to 60 times
more sensitive than the film alone.
Substantial reduction of patient exposure to x-
radiation.
The resolving power of screens is related to their
speed.
Slower the speed – greater its resolving power.

64. Image characteristics
• Depends on –
1. Radiographic density
2. Radiographic contrast
3. Radiographic speed
4. Film latitude
5. Radiographic blurring
6. Image quality

65. 1. Radiographic density –
Influenced by exposure and thickness & density of
the subject.
A. Exposure
• Overall film density depends on the no. of photons absorbed
by the film emulsion.
Exposuretime
no.ofphotons
Densityof
radiograph

66. B. Subject thickness
Thicker the subject, the more the beam is
attenuated and lighter the resultant
image.
C. Subject density
The greater the density of a structure , the
greater the attenuation of the x-ray beam

67. 2. Radiographic contrast –
 It is the difference in densities between light and
dark region on a radiograph.
 High contrast – low gray scale
 Low contrast – high gray scale
It is result of the interrelation of subject contrast,
film contrast & scattered radiation.

68. 3. Radiographic speed –1. -
• It is refers to the amount of radiation required to produce an
image of a standard density.
• A fast film requires relatively low exposure.
• A slow film requires relatively high exposure for same
density.
• Film speed is controlled by the size of silver halide grains.
• Although film speed can be increased slightly by processing
the film at higher temperature.

69. 4. Film latitude –

70. 5. Radiographic blurring -
• Sharpness – is the ability of a radiograph to
define an edge precisely.
• Resolution – is the ability of a radiograph to
record separate structures that are close
together.
• Radiographic blurring is caused by –
Image receptor blurring
Motion blurring
Geometric blurring

71. 6. Image quality -
• It is describes the subjective judgment by the
clinicians of the overall appearance of a
radiograph.
• It combines the features of density, contrast,
latitude, sharpness, resolution and other
parameters.

72. GRIDS
• Functions –
To reduce the amount of scattered radiation.

73. • Compositions –
A grid is composed of alternating strips of a
radiopaque material (lead) & radiolucent
material (plastic).