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1
Q

X-ray Machine Components

A

Tube-head
P.I.D. (Position Indication Device)
Extension Arm
Control Panel

2
Q

radiation

A

A form of energy carried by waves or a stream of particles

3
Q

x-radiation

A

A high-energy radiation produced by the collision of a beam of electrons with a metal target in an x-ray tube

4
Q

x-ray

A

A beam of energy that has the power to penetrate substances and record image shadows on photographic film or digital sensors

5
Q

radiograph

A

An image or picture produced on a receptor by exposure to ionizing radiation. A two-dimensional representation of a three-dimensional object

6
Q

Radiology

A

The science or study of radiation as used in medicine; a branch of medical science that deals with the use of x-rays, radioactive substances and other forms of radiant energy in the diagnosis and treatment of disease

7
Q

Radiography

A

The art and science of making radiographs by the exposure of film to x-rays

8
Q

The ATOM consist of a central nucleus and orbiting

A

electrons

9
Q

Nucleus contains

A

Protons: positively charged particles, Accelerated particles, specifically hydrogen nuclei

Neutrons: carry no electrical charge, Accelerated particles with mass of 1 and no electrical charge

10
Q

The____ is located closest to the nucleus and has the _____ level

A

K shell

highest energy

11
Q

Ionization Radiation

A

Radiation that is capable of producing ions by removing or adding an electron to an atom

12
Q

Particulate radiation:

A

tiny particles of matter that possess mass and travel in straight lines at high speeds

13
Q

Beta particles:

A

: fast moving electrons emitted from the nucleus of radioactive atoms

14
Q

Cathode rays:

A

streams of high-speed electrons that originate in an x-ray tube

15
Q

Alpha particles

A

Emitted from the nuclei of heavy metals and exist as two protons and neurons, without electrons

16
Q

Wavelength

A

is the distance between the peaks or crest of a wave frequency

Energy moving through space

17
Q

Frequency

A

= the number of crest in a given period of time determines the energy

18
Q

The longer the wavelength

A

the less energetic the wavelength

19
Q

The shorter the wavelength the

A

more energetic the wavelength.

20
Q
  1. Control Panel
A

On and off switch
Indicator light
Exposure button
Controls for kVp and mA

21
Q
  1. Extension Arm
A

Suspends the x-ray tube-head
Houses electrical wires
Allows movement of tube-head

22
Q
  1. Tube Head
A

Where x-rays are produced

23
Q

Tube- head contains

A
Metal Housing
Insulating oil
Tubehead seal
X-ray tube
Transformer
Aluminum disks
Lead collimator
Position-indicating device (PID)
24
Q

X-ray Tube

A

Heart of x-ray generating system

25
Q

Leaded glass housing (envelope)

A

Prevents x-rays from escaping in all directions

26
Q

Cathode

A

Purpose is to supply the electrons necessary to generate x-rays

27
Q

Anode

A

purpose is to convert electrons into x-ray photons

28
Q

Production of dental x-rays

A
  1. Filament circuit is activated, filament heats up and thermionic emission occurs
  2. Exposure button is pushed
  3. Electrons strike the tungsten target, and their kinetic energy is converted to x-rays and heat
29
Q

Primary radiation (primary beam):

A

refers to penetrating x-ray beam

30
Q

Secondary radiation

A

X-radiation that created when primary beam interacts with matter (less penetrating than primary beam)

31
Q

Scatter radiation

A

A form of secondary radiation
X-ray has been deflected from its path by interaction with matter
Is detrimental to both patient and radiographer

32
Q

X-ray film used in dentistry has four basic components

A

A film base
An adhesive layer
Film emulsion
A protective layer

33
Q

Film Base

A

Is a flexible piece of polyester plastic
0.2mm in thickness
Constructed to withstand heat, moisture, and chemical exposure

Purpose : to provide a stable support for the emulsion and strength

34
Q

Adhesive layer

A

Purpose: attaches the emulsion to the base

Added to the film base before the emulsion is applied

35
Q

Film Emulsion

A

A homogeneous mixture of gelatin and silver halide crystals

Purpose: to give the film greater sensitivity to x-radiation

36
Q

Gelatin

A

Used to suspend and evenly disperse millions of microscopic silver halide crystals over the film base.
During film processing, the gelatin absorbs the processing solutions and allows the chemicals to react with the silver halide crystals

37
Q

Halide

A

a chemical compound that is sensitive to radiation or light

38
Q

Silver halide crystals absorb radiation during

A

x-ray exposure and store energy from the radiation

39
Q

Protective layer

A

Purpose: to protect the emulsion surface from manipulation, as well as mechanical and processing damage

40
Q

latent image

A

image is not visible before processing

41
Q

Latent Image Formation

A

When radiation interacts with the silver halide crystals in the film emulsion, the image on the film is produced

42
Q

three types of x-ray film

A

Intraoral film
Extraoral film
Duplicating film

43
Q

Intraoral Film

A

Film used to examine teeth and supporting structures

44
Q

X-ray film

A

A double-emulsion film

Requires less radiation exposure to produce image

45
Q

Paper Film Wrapper

A

Protective sheet that covers film

Shields the film from light

46
Q

Lead Foil Sheet

A

Protects film from backscattered (secondary) radiation that results in film fog.
Contain an embossed pattern on foil sheet
Will appear on x-ray is it was positioned in mouth backwards

47
Q

Outer Package Wrapping

A

Protects film from exposure to light and saliva

48
Q

Label Side of Film Packet Contains the following information

A

A circle or dot that corresponds with the raised identification dot on the film
The statement “opposite side toward tube”
The manufacturer’s name
The film speed
The number of films enclosed

49
Q

Periapical Film

A

Used to examine the entire tooth (crown and root) and supporting bone

50
Q

Bite-Wing Film aka inter proximal film

A

Used to examine the crowns of both maxillary and mandibular teeth on one film

51
Q

Occlusal Film

A

Used for examination of large areas of the maxilla or mandible

52
Q

Periapical film sizes

A

Size 0 is smallest intraoral film
Size 1 is used primarily to examine anterior teeth of adults
Size 2, also know as the standard film, is used to examine the anterior and posterior teeth in adults

53
Q

Bite-wing film sizes

A

Size 0 is used to examine posterior teeth of small children
Size 2, is used to examine posterior teeth of adults. This is the most frequently used bite-wing
Size 3 is longer and narrower that the standard size 2, shows all posterior teeth in an arch.

54
Q

Occlusal film size

A

Size 4, is the largest intraoral film, used to show large areas of the maxilla and mandible

55
Q

Intraoral Film Speed

A

Film speed refers to the amount of radiation required to produce a radiograph of standard density

56
Q

Film speed or sensitivity is determined by

A

Size of the silver halide crystals (Larger =Faster)
Thickness of the emulsion
Presence of special radiosensitive dyes

57
Q

Speeds of X-ray films are given alphabetical classification :

A

A speed (slowest) to F speed (fastest)

58
Q

Only _ and _ speeds are used for intraoral radiography

A

D and F

59
Q

Extraoral Film

A

Are used to examine large areas of the skull and jaws

60
Q

Common extraoral film include:

A

panoramic and cephalometric

61
Q

Panoramic film

A

Shows a panoramic (wide) view of maxilla and mandible and surrounding structures

62
Q

Cephalometric film

A

Shows the bony and soft tissue areas of the facial profile

63
Q

Screen film

A

Requires intensifying screens and cassettes
Intensifying screens transform x-ray energy into visible light, which exposes the film
Requires less radiation = less patient exposure

64
Q

Nonscreen film

A

Not recommended for use in dentistry

Slower = more patient exposure

65
Q

Duplicating Film

A

A type of photographic film used to make an identical copy of an x-ray
Used in a darkroom setting and is not exposed to x-radiation

66
Q

Duplicating film has emulsion on one side only

A

Emulsion side appears dull
Non –emulsion side appears shiny
The emulsion side must contact the radiograph to duplicate it

67
Q

Films are adversely affected by

A

heat, humidity, and radiation

68
Q

film Must be stored away from radiation sources at

A

500 to 700 F

69
Q

film storage:

A

Relative humidity of 30% -50%

70
Q

Dark room requirements

A
Conveniently located
Adequate size
Equipped with correct lighting
Arranged with ample work space with adequate storage
Temperature and humidity controlled
71
Q

dark room Location and Size

A

Should be near, where x-ray units are installed
Accommodate film processing equipment
Allow ample work space

72
Q

At what distance from the working area should the safelight be place?

A

(Four feet.)

73
Q

Why does the safelight need to be placed at this distance?

A

To decrease the intensity of the light reaching the indeveloped film. Safelight will still expose a film if left long enough or help close enough

74
Q

Safelight filter

A

Removes short wavelengths in the blue-green portion of the visible light spectrum

75
Q

Darkroom work space

A

Must include an adequate counter area where films can be unwrapped
Must be kept clean, dry, and free from processing chemicals

76
Q

Darkroom storage space

A

Humidity level

Darkroom plumbing

77
Q

Steps that produce a visible image on a dental radiograph

A

Convert the latent image to a visible image

Preserve the image so it is permanent

78
Q

The film used in dentistry has three primary components

A

Emulsion = photosensitive crystals that ultimately form the radiographic image

Base = made of polyester plastic providing support for the emulsion

Gelatin = the specialized “glue” that holds the emulsion to the base.

79
Q

The ___form a pattern and creates an invisible image within the emulsion on the exposed film.

A

silver halide crystals

80
Q

Silver halide crystals

A

Absorb x-radiation during x-ray exposure

81
Q

The Emulsion of the film:

A

Is composed of crystals of silver halide (AgBr2, AgCl2)

82
Q

Reduction

A

The halide portion of the exposed, energized silver halide crystal is removed.
This results in a precipitated black metallic silver

83
Q

Selective Reduction:

A

The energized, exposed silver halide crystals are black
The unenergized, unexposed crystals are removed from the film
Resulting in the latent (visible) image

84
Q

From Latent Image to Visible Image

A

The film is placed in developer solution.
The film is placed in fixer solution.
The film is washed in water.
The film is dried.

85
Q

The Visible Image

A

Made of black, white, and gray areas

86
Q

Radiolucent

A

Readily permits passage of the x-ray beam

87
Q

radiolucent appears what color

A

black

88
Q

Radiopaque

A

Resists passage of the x-ray beam

89
Q

Radiopaque appears what color

A

white

90
Q

Film Processing Solutions May be obtained as:

A

Powder
Ready-to-use liquid (Automatic Processors)
Liquid concentrate

91
Q

___ ___ is by far the most commonly used solution.

A

Ready-to-use liquid

92
Q

What would films look like if the developer solution was not diluted?

A

(The film would appear overdeveloped.)

93
Q

Film Processing Solutions (Automatic Processor) To maintain freshness:

A

Must be checked for replenisher daily.

Must be replaced every 2 to 6 weeks (or manufacturer’s recommendations).

May need to change more frequently when large numbers of films are processed.

94
Q

The purpose of the developer is to

A

chemically reduce the exposed silver halide crystals to black metallic silver.

95
Q

The developer solution also____ the film emulsion during this process.

A

softens

96
Q

Developer Solution

A

Developing agent
Hydroquinone: black tones and sharp contrast
Elon: shades of gray

Preservative – sodium sulfite
Accelerator – sodium carbonate
Restrainer – potassium bromide

97
Q

Fixer Solution

A

Fixing agent
Sodium thiosulfate or ammonium thiosulfate
Commonly called “hypo”

Preservative – sodium sulfite
Hardening agent – potassium alum
Acidifier – acetic acid or sulfuric acid

98
Q

The purpose of the __ ___ is to remove or clear all unexposed and underdeveloped silver halide crystals from the film emulsion.

A

fixer solution

99
Q

Automatic Film Processing

A

Often preferred over manual film processing
Less processing time required
Time and temperature automatically controlled
Less equipment used
Less space required

100
Q

Daylight loader

A

May be used in a room with white light

101
Q

What beam alignment devices may be used with the paralleling technique?

A
Rinn XCP instruments
Precision Film Holders
Stabe Bite-Block
EEZEE-Grip Film Holder
Hemostat with Bite-Block
102
Q

What are the advantages of the paralleling technique?

A

The primary advantage of the paralleling technique is that it produces a radiographic image without dimensional distortion.

  • Accuracy
  • Simplicity
  • Duplication
103
Q

What are the disadvantages of the paralleling technique?

A

Receptor placement

Discomfort

104
Q

What are the basic principles of the paralleling technique?

A
  • The receptor is placed in the mouth parallel to the long axis of the tooth being radiographed.
  • The central ray of the x-ray beam is directed perpendicular to the film and the long axis of the tooth.
  • A beam alignment device must be used to keep the receptor parallel with the long axis of the tooth.
105
Q

Object-receptor distance (tooth – film)

A

Must be increased to keep the receptor parallel with the long axis of the tooth

106
Q

Target-receptor distance (x-ray beam-film)

A

Must be increased to ensure that only the most parallel rays will be directed at the tooth

107
Q

Beam Alignment Devices

A

A device used to position the receptor in the mouth and retain the receptor in position during exposure

108
Q

How do film holders reduce exposure?

A

(In two ways: by preventing cone cuts, thus reducing retakes; and by allowing the film to be held in place without the aid of the patient’s finger in the field of radiation.)

109
Q

What does XCP stand for?

A

(extension-cone paralleling.)

110
Q

Rules for Paralleling Technique

A
Receptor placement
Receptor position
Vertical angulation
Horizontal angulation
Film receptor exposure
111
Q

Receptor Placement for Paralleling Technique

A

The specific area where the receptor must be positioned before exposure
Dictated by teeth and surrounding structures

112
Q

Modifications in Paralleling Technique

A

Shallow Palate
Bony Growths
Mandibular Premolar Region

113
Q

What factors influence film density?

A

Milliamperage
Operating kilovoltage
Exposure time
Subject thickness

114
Q

Density

A

Refers to the overall darkness or blackness of a dental radiograph

115
Q

influencing factors of contrast?

A

Increasing the kilovoltage affects image contrast by increasing the mean or average energy of the x-rays and by producing higher energy x-rays.

116
Q

what controls contrast

A

kilovoltage

117
Q

Short-scalecontrast (high contrast)

A

A radiograph with only two densities, black and white

Occurs with machines functioning at low kVp

118
Q

Long-scale contrast (low contrast)

A

A radiograph with many densities, many shades of gray

Occurs with machines functioning at high kVp

119
Q

Long-scale contrast (low contrast)

A

A radiograph with many densities, many shades of gray

Occurs with machines functioning at high kVp

120
Q

A lack of ____ can change a diagnosis dramatically. It may cause a problem to be undetected in a early stage when the prognosis would have been more favorable

A

sharpness

121
Q

_____ is especially important when measuring the length of a tooth during root canal therapy.

A

Magnification

122
Q

_____ occurs when a radiograph is taken at a vertical angle that is greater than or less than necessary, resulting in a film image that appears either stretched out or shorter than it really is.

A

Distortion

123
Q

Sharpness

A

is the capability of the x-ray receptor (film) to reproduce the distinct outlines of an object.
Is the fine outline of the image on a radiograph

124
Q

penumbra.

A

A certain lack of image sharpness is present in every radiograph;

Penumbra is the fuzziness of an outline.

125
Q

sharpness is influenced by 3 factors

A

focal spot size
film composition
movement

126
Q

Film speed may affect sharpness due to

A

the different sizes in silver bromide crystals. The faster the film speed, the larger the crystals.

127
Q

Magnification

A

Results from the divergent paths of the x-ray beam as they radiate from the focal spot
The object size appears larger on the film than its’ actual size.

128
Q

Influencing factors of magnification

A

Target-receptor (Source (PID) to film) distance

Object-receptor (Tooth to film) distance

129
Q

Object-receptor (Tooth to film) distance

A

An increase in object-receptor distance results in an increase in image magnification.

130
Q

Target-receptor (Source (PID) to film) distance

A

A longer PID and target-receptor distance results in less image magnification.

131
Q

Distortion

A

Results from unequal magnification of different parts of the same object because of improper receptor alignment or angulation of the x-ray beam
Misshape of images on a radiograph

132
Q

influencing factors of distortion

A

Object-film alignment

133
Q

Object-film alignment

A

The object and film must be parallel to each other or there will be distortion.

The x-ray beam must be directed perpendicular to the tooth and film.

134
Q

Periapical Examination

A

Purpose:Used to examine the entire tooth and supporting bone

Type of imaging receptor: Periapical receptor

Technique:Paralleling and bisecting

135
Q

Interproximal Examination

A

Purpose: To examine the crowns of both the maxillary and mandibular teeth on a single film

Type of imaging receptor: Bite-wing receptor
#2 is standard (Premolar/Molar Views)
#3 premolar and molar on single film

Technique: Bite-wing technique

136
Q

This type of film is most often taken to check for cavities between teeth.

A

Interproximal

137
Q

Occlusal Examination

A

Purpose:Used to examine large areas of the maxilla or the mandible on one film

Type of imaging receptor: Occlusal receptor
Size #2 or #4

Technique:
Occlusal technique

138
Q

This type of film is most commonly seen in pediatric dental offices.

A

Occlusal film

139
Q

full-mouth series or complete series.

A

This series can include only periapicals or be a combination of periapicals and bite-wings.
A total of 14 to 20 films may be taken.
Film size selection is important.
Used to detect disease, foreign objects, retained roots.
Patients usually have a full-mouth series of x-rays taken every 3 to 5 years.

140
Q

full-mouth series or complete series.

A

This series can include only periapicals or be a combination of periapicals and bite-wings.
A total of 14 to 20 films may be taken.
Film size selection is important.
Used to detect disease, foreign objects, retained roots.
Patients usually have a full-mouth series of x-rays taken every 3 to 5 years.

141
Q

Diagnostic Criteria for Intraoral Images

A
  • Images must have optimum density, contrast, definition, and detail.
  • Images must have the least amount of distortion possible.
  • The CMS must include images that show all tooth-bearing areas.
  • Periapical images must show the entire crowns and roots of teeth being examined
  • Bite-wing images must show open contacts.
142
Q

Not all patients need a CMS.

A

CMS is appropriate when a new adult patient presents with clinical evidence of generalized dental disease or a history of extensive dental treatment.

Otherwise, a combination of bite-wings, selected periapicals, and/or a panoramic image should be prescribed on the basis of a patient’s individual needs.