Nancy Bouchard DDS, MHP
RADIATION SAFETY
Operator Safety
Patient Safety
Maximum Permissible Dose: 2rem/year
ALARA: As Low As Reasonably Achievable
1) Do Not Take Films When Pregnant
1) Take Films by Prescription:
Only When Necessary
2) Do Not Hold the Film in the
Patient’s Mouth
3) Achieve Certification and
Continuing Education
2) Use Fast Speed Film
3) Use Proper Processing Procedures and
Adhere to Quality Assurance
Measures
4) Wear Radiation Badges
5) Install Adequate Barriers:
Lead Lined Walls,
Leaded Windows,
Adequately Thick Cement or
Brick Walls
Movable Lead Barriers
6) Obey the Position and Distance Rule:
6 Feet from the Patient
90º - 135º to the Central Beam
4) Place Lead Apron and Thyroid Collar
on Every Patient
5) Have Adequate Filtration
6) Use Collimation
Patient
Category
Child
Primary Dentition
(prior to eruption of first
permanent tooth)
New Patient
Posterior bitewing
examination if proximal
surfaces of primary teeth
cannot be visualized or
probed
All new patients to
assess dental
diseases and growth
and development
Recall Patient
Adolescent
Adult
Transitional Dentition
(following eruption of
permanent tooth
Permanent Dentition
(prior to eruption of third
molars)
Dentate
Individualized radiographic
examination consisting of
periapical/occlusal views
and posterior bitewings or
panoramic examination and
posterior bitewings
Individualized radiographic examination consisting of
posterior bitewings and selected periapicals. A full
mouth intraoral radiographic examination is
appropriate when the patient presents with clinical
evidence of generalized dental disease or a history of
extensive dental treatment.
Full mouth intraoral
radiographic
examination or
panoramic examination
Posterior bitewing examination at 6-month intervals or
until no carious lesions are evident
Posterior bitewing
Posterior bitewing
examination at 6-to 12examination at12-to 18month intervals or until no month intervals
carious lesions are evident
Not applicable
Posterior bitewing
Posterior bitewing
examination at 12-to 24- examination at12-to 24month intervals if proximal month intervals
surfaces of primary teeth
cannot be visualized or
probe
Posterior bitewing
examination at 18-to 36month intervals
Posterior bitewing
examination at24-to 36month Intervals
Not applicable
Individualized radiographic examination consisting of
selected periapical and/or bitewing radiographs for
areas where periodontal disease (other than
nonspecific gingivitis) can be demonstrated clinically
Not applicable
Periapical or panoramic
examination to assess
developing third molars
Usually not indicated
Clinical caries or
high-risk factors for
caries**
No clinical caries and
no high-risk factors for
caries**
Periodontal disease or a Individualized radiographic examination consisting of
selected periapical and/or bitewing radiographs for
history of periodontal
areas where periodontal disease (other than nonspecific
treatment
gingivitis) can be demonstrated clinically
Growth and
development
assessment
Usually not indicated
/www.fda.gov/cdrh/radhealth/adaxray-1.html
Individualized radiographic
examination consisting of a
periapical/occlusal or
panoramic examination
Usually not indicated
Edentulous
EQUIVALENT BACKGROUND EXPOSURE
FROM DENTAL RADIOGRAPHY
EXAMINATION
FULL MOUTH
(20 films)
BITEWINGS
(4 films)
Panoramic
FILM
COLLIMATION
D
Round
E
Round
D
Rectangular
E
Rectangular
D
Round
E
Round
D
Rectangular
E
Rectangular
Rare Earth Tungstate Screens
BACKGROUND
EQUIVALENT
10 days
5 days
4 days
2 days
2 days
1 day
1 day
10 hours
10 hours
Background Radiation (or Natural)
 Largest contributor
 83% of the radiation exposure of people living in the United States today
 -3.6 mSV per year
EXTERNAL SOURCES: cosmic (e.g.: altitude, airline travel) and terrestrial
(that found in soil) radiation or that originating from the environment.
INTERNAL SOURCES: radionuclides that are taken up from the external
environment by inhalation and ingestion (e.g.: radon)
Artificial Radiation:
 Medical diagnosis and treatment
 Consumer and industrial products (i.e. televisions and airport inspection systems)
LEVELS OF RISK FOR X-RAY EXAMINATIONS
X-Ray Exam
Equivalent Period of
Natural Background
Radiation
Lifetime Additional
Risk of Cancer per
Examination
Chest / Teeth /
Hands and Feet
A few days
Skull / Head / Neck
A few weeks
Breast / Hip /
Spine /
CT Scan of Head /
Lung Isotope
Kidneys and
Bladder /
Colon—Barium
Enema /
CT Scan of Chest
A few months to a year
NEGLIGIBLE
Less than
1 in 1,000,000
MINIMAL
1 in 1,000,000 to
1 in 100,000
VERY LOW
1 in 100,000 to
1 in 10,000
A few years
LOW RISK
1 in 10,000 to 1 in
1,000
DENTAL RADIOGRAPH EXPOSURE
mSV
Bitewings (4 films)
Full-mouth series (about 19 films)
Panorex (panoramic jaw film)
0.038
MEDICAL RADIOGRAPHS EXPOSURE
mSV
Lower GI series
Upper GI series
Chest
Average radiation from outer space in Denver, CO
(per year)
Average radiation in the U.S. from Natural sources
(per year)
4.060
0.150
0.019
2.440
0.080
0.510
3.600
Radiographic Interpretation
When interpreting radiographs, remember that we are viewing a two-dimensional picture
of a three-dimensional object. Therefore, some items which are in front of or behind the
object may not show on the radiograph; some items may make the object appear
different than expected.
For instance, imagine that the tooth is a box:
If the x-ray beam strikes the tooth/box straight on,
there will only be one shade on the film.
If the x-ray beam is not parallel to the tooth/box
or If the tooth is misaligned, then the edges of the
tooth/ the corners of the box will appear more
radiolucent on the film because there is less
material for the beam to go through.
Cervical Burnout
This is diffuse radiolucent areas with ill-defined borders in the area of the CEJ. These
shadows are caused from the contrast of adjacent materials (enamel, bone, metals).
When the x-ray beam hits all these materials, the photons bounce and seek a less
dense area or an opening to go through. The area then appears dark.
CARIES
Occlusal decay is not seen on radiographs
unless it is large due to the thickness of the enamel.
Interproximal decay is found right in the contact area.
Do not look more coronally as the cusps may appear
like decay.
Root decay is difficult to distinguish from cervical
burnout. First, check if there is any bone loss. If there
is not, any shadow see at the cervical area is probably
burnout. Root caries appear as defined, half-moon
shaped shadows. Long vertical shadows are often
cervical burnout or the grooves of the roots.
PERIODONTAL EVALUATION
When we examine radiographs, we estimate the periodontal support of the teeth. This
will be an approximation because we are viewing the teeth on the film and not in their
three-dimensional space.
Lamina Dura / Periodontal Ligament Space
The lamina dura is a white line around the roots of the teeth. The periodontal ligament
space is radiolucent. When either appears thickened, it may be a sign of occlusal
trauma.
Crestal Irregularities
The crest of alveolar bone between teeth should appear solid sometimes having a white
line. There should be no loss of density at the ridge. When the crest appears thin, has
lost its whiteness, or has cupping, then the bone is undergoing breakdown the day the
radiograph was taken. This is NOT an indication of the severity of loss. Someone who
has no bone loss may exhibit crestal irregularities if the bone is beginning to break
down. Someone who has bone loss may show solid crestal bone is he/she has had
corrective treatment and has been seeking adequate maintenance.
Severity of Bone Loss
20 % bone loss from the CEJ to the apex = slight
30% bone loss from the CEJ to the apex = moderate
40 % bone loss from the CEJ to the apex = severe
What is moderate on one tooth may be severe on another.
Type of Bone Loss
Comparing the bone to the CEJs,
horizontal bone loss is when adjacent
teeth have lost the same amount of
bone;
vertical loss is when adjacent teeth
have differing amounts of loss.
Calculus
Appears as radiopaque spicules or spurs in the interproximal regions or as a line along
the CEJ region on mandibular anteriors when there is a ridge present.
Furcations
There is a radiolucency in the furcation area.
slight
moderate
severe