1. Dental Radiography

2. Dental radiographs
Are an important part of the patient’s dental record
Allow the operator to see what is not visible to the eye
Often essential for
Correct diagnosis
Treatment planning

3. Radiation
Radiation is the energy that is produced from natural and man-made materials. It is present in the environment due to naturally occurring radioactive mineral that remain from the very early formation of our planet.
Ionising radiation means radiation that produces ions. Ions are atoms (small particles) that are able to hold or lose electrical charge i.e x-ray

4. The Discovery of X-RAYS
First documented by Wilhelm Conrad Roentgen in the winter of 1895.
Early 1896 Dr Edmund Kells builds his own x-ray machine, makes film packets & holder and takes first dental radiograph.
Tested on his dental assistant.
“Ladies in Attendance”.
Had 42 operations due to radiation damage.
Committed suicide in 1928.

5. How X-rays are produced
X-rays are produced when electrons (minute particles of magnetic matter) are electrically charged and are forced against a target. This occurs within a glass envelope inside the x-ray machines tube. Inside the tube a piece of tungsten metal is heated, which generates the electrically-charged electrons. These electrons are aimed at high speed by the x-ray tubes focusing device towards the object being radiographed. The electrons rush at the target until they are stopped. As they hit the target they release their energy and an x-ray image is formed.

8. Tube head Position-indicating device is attached to the tube head
PID indicates the direction of the beam
Sets the ideal distance from tube head to skin
Photo courtesy Halas Dental and Sirona

9. The control panel An on/off switch
A warning light indicating that machine is on
An electronic timer that determines the duration of x-ray production
A warning orange light and sound indicating when x-rays are generated
An exposure switch
Photo courtesy Halas Dental and Sirona

10. Activating button
Located on the end of a cord or mounted outside the x-ray room
Allows the operator to stand at least two meters away from tube head and patient
Exposes the patient to a defined quantity of radiation
The Nurses role

11. Essential for patient, operator and dental nurse
Radiation protection
Essential for patient, operator and dental nurse

12. What is the risk?
Although dental radiography delivers a very small radiation dose, risk does exist.
A broad estimate of the risk of a standard 30 year old patient developing a fatal radiation induced malignancy
B/W, P/A (D-speed) - 1 in 1,000,000
B/W, P/A (F-speed) in 10,000,000
CT Scan (Abdomen) - 1 in 3500
CT Scan (Head) in 14,300
Panoramic in 1,000,000

13. Code of practice for radiation protection in dentistry
X-ray examination performed only if necessary for diagnosis or treatment planning
Exposure of patients and staff to radiation must be minimized – As low as is reasonably practicable ALARP
Patient radiographic records maintained for at least eleven years after conclusion of treatment
High standard of processing required so that repeat radiography is not necessary
Equipment registered and well maintained

14. Radiation Protection
There are two sets of regulations, enforced by the Health & Safety Executive, that govern the use of radiation in dental practice.
The Ionising Radiations Regulations 1999.(workers, general public)
The Ionising Radiation (Medical Exposure) Regulations (patients)

15. Radiation Protection Advisor
A suitably trained RPA must be appointed in writing and consulted to give advice on IRR99. Should be an expert in radiation protection and will be able to advise on compliance with the Regulations and all aspects of radiation protection, including advice on:
Controlled and designated areas for all radiation equipment
Installation of new or modified X-ray equip
Periodic testing

16. Radiation Protection Adviser
Risk Assessment
Contingency Plans
Staff Training
Assessment and recording of doses
QA programmes

17. Radiation Protection Supervisor
Appointed to ensure there is compliance with IRR99 and local rules
Usually a dentist

18. Local Rules
All practices should have a written set of Local Rules relating to radiation protection measures – information should include:
The name of the RPA and RPS
Description of the controlled area.
Summary of working instructions including the names of staff qualified to use the x-ray equipment.
Arrangements for pregnant staff.
Reminder to employees of their legal responsibilities.
Plans specifying action to be taken in the event of a equipment malfunction.

19. IRR(ME)R
The employer - Responsible for providing the overall safety of the practice and for ensuring that staff and procedures conform with regulations
The referrer – the referrer is responsible for supplying the practitioner with sufficient information to justify an appropriate exposure
The practitioner – The practitioner must be adequately trained to take decisions and the responsibility for the justification of every exposure

20. IRR(ME)R
Operator - The person conducting any practical aspect of a medical exposure, practical aspects include
Patient identification
Positioning the film, patient or X-ray tubehead
Setting the exposure parameters
Pressing the exposure switch
Processing films
Clinical evaluation of radiographs
Exposing test objects as part of the QA programme
The operator must be adequately trained for his/her role in the exposure

21. Radiation Protection File
The legal person must keep a regularly reviewed and updated file containing written records of all the protective measures in force in the practice including:
Local rules
X-ray and film processing procedures
Any need for use of personal dosmeters
Named staff duties and responsibilities
Accident contingency plans

22. Protection for staff
Stand at least 2 metres from tube head and patient
Do not stand in the direct line of the primary beam
Never hold the x-ray film or tube head during exposure
Monitor radiation exposure by wearing a film badge (Number of films taken)

23. Personal monitoring Monitors the adequacy of radiation protection
Worn only while working in the surgery

24. Protection for patient
A radiograph is taken only if necessary
Ensure quality assurance for every radiograph
Use fast films
Use film holders
Provide pregnant patient and assisting adult with a lead apron

25. Role of radiographs in dentistry
Provide a pictorial record of the teeth and supporting structures, disease present and treatment carried out

26. Dental radiographs are used to
Diagnose dental caries
Monitor the progress of dental caries
Record and monitor condition and quantity of bone around each tooth
Monitor progress of endodontic treatment
Diagnose impacted teeth and missing teeth
Diagnose pathology and dental trauma

27. Intraoral radiography
X-ray film is exposed to the x-ray beam while positioned in the mouth

28. Contents of the film packet
A moisture and light proof packet with a tab opening
A sheet of lead foil placed behind the film
Black, lightproof paper either side of the film
Dental film
Diagram courtesy Kodak (Australasia) Pty Ltd

29. Intraoral Film Packet
A thin sheet of lead foil is positioned in the packet behind the film. The lead foil improves the quality of the radiograph and also absorbs some of the x-rays, preventing them passing through the film. This also protects the patient from added radiation exposure.
Black paper encases the film. It protects the film from light and damage from fingers when the film is being unwrapped ready for processing.
The radiographic film is coated on both sides with an emulsion of light sensitive crystals embedded in a gelatine medium.
Covering the film, lead foil and black paper is a moisture vinyl packet. One corner of the packet has a small raised dot. The film inside the packet has the same raised dot, this is used to orientate the film when mounting.

30. Film packet showing tab opening
The side of the film packet that contains the opening tab has two colours - usually blue and white
This side of the film always faces away from the x-ray beam.
Photo courtesy Kodak (Australasia) Pty Ltd

31. Periapical film Shows individual teeth and supporting tissues
Available in 3 film sizes
Size 0 used for deciduous teeth
Size 1 used for permanent incisors and canines
Size 2 used for premolars and molars
Photo courtesy Kodak (Australasia) Pty Ltd

32. Periapical film is used to
Detect apical infection within the bone
Assess the apical area before and after surgery
Assess the periodontal health
Assess the presence and position of unerupted teeth
Assess root shape prior to extraction
Determine the length of the root canal
Determine the adequacy of a root filling

33. Bitewing film
Shows the crowns of upper and lower teeth on one side of mouth
Has a paper tab projecting from middle of film packet
Available in 3 sizes
Size 0 - children
Size 2 - adults
Size 3 - extra length
Photo courtesy Kodak (Australasia) Pty Ltd

34. Bitewing film is used to
Detect dental caries
Detect recurrent caries
Assess condition of existing restorations
Monitor the progress of dental caries
Assess periodontal health

35. Occlusal film
Shows a larger area of maxilla or mandible than can be seen using a periapical film
Available in 1 size 57mm x 76mm
Much larger than a standard intraoral film

36. Occlusal film is used to
Determine the position of displaced or unerupted teeth
Assess the extent of fractures of the anterior teeth and bone
Assess the size and extent of cysts and tumours

37. Extraoral radiography
Uses film placed outside the mouth

38. Extraoral film arrangement
A combination of two intensifying screens with a film sandwiched in between
Intensifying screens and film are enclosed in a protective light-tight container called a cassette
Used to produce lateral skull radiographs and dental panoramic (OPG) radiographs

39. Lateral skull radiograph
Radiograph courtesy Halas Dental and Sirona

40. Dental panoramic radiograph
Entire dentition and related structures can be viewed on one film
Radiograph courtesy Halas Dental and Sirona

41. Intensifying screens
Give off visible light when exposed to the x-ray beam
Light rays and X-rays combine to produce the image on the film
Reduce the amount of radiation needed to produce the image
Reduces the radiation dosage to the patient

42. Film cassettes ‘A’ and ‘B’ are rigid cassettes
The film lies between 2 rigid screens
The intensifying screens are attached to the inside cover and base of the cassette. The film lies between the two screens.
‘C’ is a flexible cassette. It has an opening at one end creating a pouch. The film is placed between two removable flexible intensifying screens that are then slid into the pouch.
Diagram courtesy Kodak (Australasia) Pty Ltd

43. Panoramic radiograph
X-ray beam and film-screen combination rotate together around the patient’s head
Patient must not move during the exposure
Photo courtesy Halas Dental and Sirona

44. Digital radiography Uses a sensor or imaging plate instead of film
Image is processed by the computer
Image can be stored on hard disc, CD or DVD
Different sizes available
Photo courtesy Halas Dental and Sirona

45. Advantages of digital radiography
Lower doses of radiation
No need for conventional processing
Easy storage and archiving of patient information – the image can be stored on hard disc, CD or DVD
Ease of incorporation of radiographic images into patient files
Ease of transfer on information between dentists

46. Disadvantages of Digital Radiography
Higher Initial set up cost Requirements for data storage and back up Breakage of intra oral sensors Inadequate handling of Phosphor plates

47. Solid state Sensors
Small, flat rectangular boxes about the same size as conventional film and varying in thickness from 5-7mm. Most are attached to a cable which allows data to be transferred directly between the patients mouth and the computer. Some do not have a cable and transmit radio waves from the sensor to a base station which is then connected by cable to a computer. (can be more bulky) Cannot be sterilised so must be placed inside a protective barrier.

48. Phosphor plate system
The phosphor plate stores the xray energy after exposure to radiation and then emits the stored energy as light when scanned by a laser. The scanner stores a record of the light detected and a digital image is produced and displayed on the computer screen. The imaging plates are erased after they are scanned. They are light sensitive and must be scanned quickly to ensure a high quality image. Same size as conventional film. The use of barriers is essential Must be handled with care

49. Computer Monitors
The computer monitor used to view digital radiographs should be clean and free of finger prints. It should be calibrated at least once a month to ensure optimum visual quality.

51. QUIZ
CAN YOU LIST 3 TYPES OF RADIOGRAPHS AND DESCRIBE WHAT EACH IS USED FOR.

52. Preparing for Radiography
Assisting with the exposure
Preparing for processing

54. Errors in preparing the patient
Failing to ask the patient to remove a partial denture
Produces an artifact superimposed over the dental structures
Photo courtesy Halas Dental and Sirona

55. Errors in panoramic radiography
Photo courtesy Kodak (Australasia) Pty Ltd
Earrings that are not removed appear as ‘ghosts’
The ghost image is enlarged and appears above the real image

56. Preparing for processing
After exposure the film is prepared for processing

58. Processing Radiographs
Processing is the term used to describe the sequence of events required to convert the latent image captured on the dental film into visible permanent radiograph.
It is crucial that this stage is performed under controlled, standardised conditions with careful attention to produce a good diagnostic radiograph.

59. Follow manufacturer’s recommendations for
Development time
Developer temperature
Preparing, mixing and adding chemicals
Always pour fixer into the processor first
A small spill of fixer into developer drastically weakens the developer

60. Processing is a chemical reaction
Darker film
Increased temperature
Increased development
Darker film
Increased development
Increased time

61. Light film Light film Contaminated or depleted developer
Incomplete development
Light film
Decreased development
Decreased time or temperature

62. Degree of blackening of the film Density
Radiographs that are too dense
Appear too dark
Radiographs that have too little density
Appear to light

63. Relative difference in density between lightest and darkest parts
Contrast
Allows the operator to distinguish objects on the radiograph

64. A dense image – over development
Processing temperature that is too high
Developing time that is too long
Photo courtesy Kodak (Australasia) Pty Ltd

65. A light image – Under development
Processing temperature that is too low
Developing time that is too short
Depleted developer solution
Photo courtesy Kodak (Australasia) Pty Ltd

66. Processing solutions
Processing solutions must be fresh to work properly
Avoid inhaling fumes
Avoid Skin Contact
Use protective equipment

67. Black/grey parts of the image
Developer solution
Changes the exposed silver crystals
Into black metallic silver
Black/grey parts of the image

68. Fixer solution Removes the unexposed silver crystals
To reveal the white parts of the image

69. A completely dark image results
If the film is not fixed
A film that is greenish yellow in colour results
If the fixing time is too short

70. Equipment for manual processing
Darkroom
Processing tanks and solutions
Thermometer and timer

71. The darkroom
Excludes all natural and artificial light while film is unwrapped, developed and fixed
Has a standard white light and a safelight
Use standard white light only after the film has been fixed

72. Processing stages
Developing
Rinsing
Fixing
Washing
Drying

73. Manual processing
Prepare solutions according to the concentration recommended by the manufacturer
Check the temperature of the developer
Turn off the room light and turn on the safelight
Unwrap the film
Carefully clip the film onto the hanger set timer for the developer temperature
Immerse film quickly into the developer dislodging air bubbles
Do not agitate the film during development
Remove the hangar and drain excess developer into the water bath

74. Manual processing cont...
Immerse the hangar rapidly into the water rinse tank for 30 seconds
Place the hangar in the fixer solution and agitate gently for a few seconds
Fix for 2 to 4 minutes
Wash films in clean running water for minutes
Dry in a dust free area

75. Automatic Processing
This term is used when processing is carried out automatically by a machine.
The automatic processors carry the film through the complete cycle by a system of rollers.
Most processors have a daylight loading facility, eliminating the need for a dark room.
The cycle is the same as manual processing except that the rollers squeeze off any excess developing solution before passing the film in to the fixer, eliminating the need for water between these stages.

76. Automatic processor/processing stages
Photo courtesy Halas Dental and Sirona

77. Automatic processing errors
Opening the lid too soon results in room light fogging the trailing edge of the film
Feeding film too quickly or too close can overlap or stick films together
Touching the film with wet or contaminated fingers before processing can cause spotting

78. Self Developing Film

79. Self Developing Film

80. Radiographic Errors
Errors result in an image that does not provide the detail necessary for diagnosis

81. Radiographic errors may be caused by
Processing errors
Radiographic errors may be caused by
Handling errors

82. Processing errors
Manufacturer's recommendations for development time and temperature must be closely followed

83. Developer temperature too low or developing time inadequate
A radiograph that is too light
Developer temperature too high or excessive developing time
A radiograph that is to dark

84. A radiograph that is too light
Contaminated or weak developer
A radiograph that is too dark
Over concentrated developer

85. Under development
Film that is developed for less than the recommended time
Results in an image that is too light
Photo courtesy Kodak (Australasia) Pty Ltd

86. Normal development Film that is developed for the recommended time
Results in an image ideal for diagnosis
Photo courtesy Kodak (Australasia) Pty Ltd

87. Causes of images that are too light
Developing time that is too short
Developer solution that is too cold
Chemicals that are too diluted
Chemicals that are exhausted
Developer solution contaminated with fixer
Photos courtesy Kodak (Australasia) Pty Ltd

88. Causes of images that are too dark
Developer solution that is too hot
Developing time that is too long
Speed of film transport system that is too slow
Developer solution that is too concentrated
Photos courtesy Kodak (Australasia) Pty Ltd

89. Over development
Film that is developed for more than the recommended time
Results in an image that is too dark
Photo courtesy Kodak (Australasia) Pty Ltd

90. A radiograph that has no image detail
Film fog
A radiograph that has no image detail

91. Causes of film fog include
Inadequate storage of unexposed film
Exposure of film packet to stray radiation
Exposure of film to light
Using film that has passed its expiry date
Developer contaminated with fixer
Developer solution that is old or exhausted
Faulty darkroom or processing unit

92. Effect of chemical fog Normal radiograph Chemically fogged radiograph
Photos courtesy Kodak (Australasia) Pty Ltd

93. Effect of using film that has passed its expiry date
Normal radiograph
Fogged radiograph
Photos courtesy Kodak (Australasia) Pty Ltd

94. Handling errors
Film must be handled carefully under proper safelight conditions during processing

95. Handling errors include
Feeding film into the automatic processor too quickly
Feeding film into the automatic processor too closely together
Fingerprints
Chemical spills
Static electricity
Dirty rollers
Emulsion tears

96. Missing images Partial emersion in developer Extended rinse period
Photos courtesy Kodak (Australasia) Pty Ltd

97. Causes of missing images
Partial emersion in the developer
Leaving the film in the rinse water for extended periods of time
Films contacting each other or the sides of the tank
Splashing developer or fixer on the film before processing

98. Missing images cont. ‘A’ - contact with another film during processing
‘B’ - fixer acting on an area of undeveloped film
‘C’ - developer splashing on film before processing
Photo courtesy Kodak (Australasia) Pty Ltd

99. White marks Splashes of fixer on the film before processing
Bending the film before exposure
Photos courtesy Kodak (Australasia) Pty Ltd

100. Air bubble on the film surface
Photo courtesy Kodak (Australasia) Pty Ltd

101. Causes of white marks Air bubbles
Splashes of fixer onto the film before processing
Films contacting each other or the sides of the tank during processing
Bending the film packet before the film has been exposed

102. Preventing white marks
Keep the darkroom clean
Clean up all chemical splashes immediately
Handle film and film packets carefully
Avoid bending the film packet
Ensure unprocessed film does not come into contact with wet or contaminated surfaces

103. Dark marks Streaking marks on radiograph due to dirt rollers (left)
Black lines caused by bending the film packet after exposure (below)
Photos courtesy Kodak (Australasia) Pty Ltd

104. Fingerprint marks Developer on fingertips Fixer solution on fingertips
Photos courtesy Kodak (Australasia) Pty

105. Causes of fingerprint marks
Developer solution on the fingertips when handling the film before processing
Fluoride contacting the film before processing
Fixer solution on the fingertips when handling the film before processing
Causes white marks

106. Black smudge marks Black smudge marks caused by low humidity
static electricity
Photos courtesy Kodak (Australasia) Pty

107. Overlapping image Two exposures are made using the same film packet
Place exposed and unexposed films in separate sites away from radiation exposure
Photo courtesy Kodak (Australasia) Pty Ltd

108. Storage of processing chemicals
Store chemicals at temperatures between 4.5ºC and 29.5 ºC
Shelf life is reduced by
Storing chemicals above 29.5 ºC
Opening the container
Chemicals that have passed their expiry date should be discarded

109. Film storage conditions
Put film in quantities that can be used within 1-2 months
Store in cool dry conditions
Ensure oldest film is used first
Store away form all sources of radiation
Store away from chemical fumes

110. A working plan that ensures consistent high quality radiographs
Quality assurance
A working plan that ensures consistent high quality radiographs

111. To ensure high quality radiographs using manual processing solutions
Replenish processing solutions every morning
Use separate, labelled stirring rods to mix each type of processing solution
Replace replenished solutions with fresh working solutions every 2weeks
Wipe up any spilled solutions immediately
Wash hangars after use
Use hangars that are clean and dry

112. Processing solution temperature
One of the most common errors is failing to check the temperature of the solution before development and making the appropriate adjustment
Even a slight increase in temperature can cause films to darken

113. To ensure high quality radiographs using automatic processing solutions
Replenish processing solutions according to manufacturer’s directions
Replace replenished solutions with fresh working solutions as recommended
Wipe up any spilled solutions immediately
Clean transport system as recommended by the manufacturer
Clean processing tanks as recommended by the manufacturer

114. The reference radiograph
A radiograph which reflects the quality expected of all radiographs taken in the surgery

115. D I Y
Film showing
one step change
Standard reference film

116. Unacceptable radiographs
A radiograph which the operator cannot use to make a diagnosis because of its poor quality
A record of the problem must be made which includes:
The date the radiograph was taken
The nature of the deficiency or defect
The known or suspected cause of this deficiency
The number of repeat radiographs taken

117. The processing log records
The date of preparation of the processing solutions
The date the processing solutions were replaced
Any processing problems that have occurred
Any corrective action taken

118. Routines for quality assurance
Film storage and handling
Store film in cool, dry conditions away from radiation and chemical fumes
Rotate film stock so that film is used before its expiry date
Handle film carefully
Cassettes
Clean intensifying screens monthly
Inspect intensifying screens monthly

119. Routines for quality assurance
Manual processing
Make up processing chemicals as recommended by the manufacturer
Always pour the fixer first into the processor or developer tank
Change or replenish solutions regularly – at least every two weeks and record in the processing log
Check the temperature of processing solution before development and make the appropriate adjustment
Monitor for deterioration of processing conditions by using the reference radiograph

120. Routines for quality assurance
Automatic processing equipment
Clean the transport system as recommended by the manufacturer
Clean the processing tanks as recommended by the manufacturer

121. Digital Phosphor Plates
Must be handled carefully and kept scratch and dust free Regular cleaning Regular visual checks for scratches and other defects

122. Assessing the quality of the radiograph
Quality control of dental radiographs is essential in dental practice. The faculty of General Dental Practice (UK) has produced criteria which are used by the operator and the DCP to monitor image quality.

123. Assessing the quality of the radiograph
Rating
Quality
Basis 1
Excellent
No error of patient preparation, exposure, positioning, processing or film handling 2
Diagnostically acceptable
Some errors of patient preparation, exposure, positioning, processing or film handling but which do not detract from the diagnostic use of the radiograph 3
Unacceptable
Errors of patient preparation, exposure, positioning, processing or film handling which make the radiograph diagnostically unacceptable

124. Minimum Targets for radiographic quality (Should be met within 3 years of the implementation of a QA programme)
Rating
Target
Interim Target 1
Not less than 70%
Not less than 50% 2
Not greater than 20%
Not greater than 40% 3
Not greater than 10%

125. Collate and maintain evidence that demonstrates
Correct preparation of patients for dental radiographic imaging procedures
Application of radiation occupational health and safety policy and procedures
Correct handling and storing of radiographic films
Correct processing, mounting and filing of radiographic films

126. Haven’t we moved on!