Most dental professionals are not convinced of the need for regulatory control of dental radiography practice. They believe doses are too low to warrant regulatory control and consequently patient protective measures. This study shows that individual doses in dental radiology are relatively low. However, there is no safe level of radiation dose and that no matter how low the doses received are, there is a mathematical probability of an effect. Consequently, appropriate patient protection measures must be instituted to keep exposures as low as reasonably achievable (ALARA).

1. PROTECTION OF PATIENTS IN
DENTISTRY
Peter Selato Selato

2. Objective
To review the current literature on dental radiology in order
to achieve the following:
 to give justification for the need for radiological
protection of patients in dental radiography
 to explore the different factors affecting patient dose in
dental radiography
 to derive practical guidance on how to achieve
radiological protection of patients in dentistry

3. Relevance and justification
 Most dental professionals are not convinced of the
need for regulatory control of dental radiography
practice
 They believe doses are too low to warrant regulatory
control and consequently patient protective measures

4. Background
 Discovery of the X-rays by German physicist Wilhelm
Conrad Roentgen in 1895
 Fourteen days after Roentgen published his discovery,
Dr. Walkhoff, a dentist in Braunschweig, Germany,
produced radiographic images of teeth
 General medical diagnostic radiography and
radiotherapy started within a year of Roentgen’s
discovery
 Almost immediately after ionizing radiation was
discovered, its deleterious effects became apparent

5. Background
 1915- the British Roentgen Society took the first
organized action in radiation safety
 1925- the radiological societies of several countries
convened the First International Congress of Radiology
in London
 1928- a committee called the International X-ray and
Radium Protection Committee was established
 1950- committee name changed to the International
Commission on Radiological Protection (ICRP)

6. Background
 ICRP 103 categorizes all ionizing radiation exposures
into three types: occupational exposure, public
exposure, and medical exposure
 It defines medical exposure as follows:
Exposure incurred by patients as part of their own medical or
dental diagnosis or treatment; by persons, other than those
occupationally exposed, knowingly, while voluntarily helping in the
support and comfort of patients; and by volunteers in a program of
biomedical research involving their exposure.
 Project explores how justification of medical
procedures, optimization of protection and the use of
diagnostic reference levels can be used for radiological
protection of patients in dentistry

7. Literature Review
RADIATION DOSE IN DENTAL RADIOLOGY
Source Annual per caput effective dose
(mSv)
Contribution
(%)
Natural background
Diagnostic medical radiology
Diagnostic dental radiology
Nuclear medicine
Fallout
2.4
0.62
0.0018
0.031
0.005
79
20
<0.1
1.1
<0.2
Total 3.1 100

8. Literature Review
RADIATION DOSE IN DENTAL RADIOLOGY
Source Annual collective effective dose
(man Sv)
Contribution (%)
Natural background
Diagnostic medical radiology
Diagnostic dental radiology
Nuclear medicine
Fallout
16 000 000
4 000 000
11 000
202 000
32 000
79
20
<0.1
1.0
<0.1
Total 20 200 000 100

9. Literature Review
RADIATION DOSE IN DENTAL RADIOLOGY
average effective dose per dental radiological examination is
0.024 mSv
average effective dose per medical radiological examination
is 1.28 mSv.
Approximately 3.14 billion diagnostic medical radiological
examinations done annually (87% of exams)
 0.48 billion diagnostic dental radiology examinations done
annually (13% of exams)
 UNSCEAR 2008, number of dental examinations may be
under-reported in many countries

10. Literature Review
DAMAGE AND RISKS FROM RADIATION EXPOSURE
UNSCEAR 2010- simultaneous damage of both strands of
DNA double helix is difficult to repair correctly
often results in breakage of DNA molecule with associated
complex chemical changes
Even at low doses of radiation it is likely that there is a very
small but non-zero chance of the production of DNA
mutations that increase the risk of cancer developing
European guidelines on radiation protection in dental
radiology, 2004 -a number of epidemiological studies have
provided evidence of an increased risk of brain , salivary gland
and thyroid tumors for dental radiography

11. Literature Review
DAMAGE AND RISKS FROM RADIATION EXPOSURE
ICRP 103 defines Detriment as follows:
The total harm to health experienced by an exposed group and its
descendants as a result of the group’s exposure to a radiation source.
Detriment is a multi-dimensional concept. Its principal components
are the stochastic quantities: probability of attributable fatal cancer,
weighted probability of attributable non-fatal cancer, weighted
probability of severe heritable effects, and length of life lost if the harm
occurs
The detriment-adjusted risk factor for the whole population
is 5.7 x 10-2
Sv-1
.

12. Literature Review
JUSTIFICATION
All medical exposures to ionizing radiation must be justified
at three levels:
 first and most general level; use of radiation in medicine should do
more good than harm to the patient
 second level; specified procedure with a specified objective is
defined and justified
 third level; the application of the procedure to an individual
patient should be justified

13. Literature Review
OPTIMIZATION
ICRP 105 defines optimization as follows:
The optimisation of radiological protection means keeping the doses
‘as low as reasonably achievable, economic and societal factors being
taken into account’, and is best described as management of the
radiation dose to the patient to be commensurate with the medical
purpose.
Doses can be reduced without loss of diagnostic information
by using low-cost measures

14. Literature Review
OPTIMIZATION

15. Literature Review
OPTIMISATION
Optimisation Technique % reduction in
radiation exposure
Sources
switching from D to E speed Film 30-40
≤50
[20]
[8,11]
switching from E to F speed Film 20-50 [11,20]
switching from calcium tungstate to rare-earth
intensifying screens
50 [8,11,20,21]
switching from conventional to digital radiography 40-60
50-80
51-60
[20]
[8]
[11]
switching from circular to rectangular collimation 50
80
[8]
[11,20,21]
use of long source-to-skin distances of 40 cm,
rather than short distances of 20 cm
10-25 [20,21]

16. Conclusion
 Individual doses in dental radiology are relatively low;
 0.0018 mSv per caput effective dose
 0.024 mSv average effective dose per examination
 High frequency of examinations
 0.48 billion annual dental examinations
 13% of radiological examinations world wide
 There is no safe level of radiation dose and that no
matter how low the doses received are, there is a
mathematical probability of an effect;
 Appropriate patient protection measures must be
instituted to keep exposures as low as reasonably
achievable (ALARA);

17.  More conscious effort has to be put in reducing the
doses incurred by younger people.
 more radiosensitive
 Higher frequency of dental radiography examinations
 All medical exposures must be justified at three levels
 There is considerable scope for significant dose
reductions in dental radiology using techniques of
optimisation of protection.
Conclusion

18. Conclusion
Optimization techniques that can be used to ensure
patient dose is ALARA whilst achieving clinically adequate
image quality include:
image receptor selection, image receptor holders,
collimation, beam filtration, operating potential and
exposure time, patient protective equipment, film
processing, film storage, image viewing, quality
assurance, diagnostic reference levels, technique charts
and training and education.
18

19. Recommendations
Recommendations to dental healthcare professionals:
All medical exposures must be justified at three levels
The fastest film should be used in intraoral radiography
A combination of rare-earth intensifying screens and high-
speed film of 400 or greater for panoramic and
Cephalometric radiology
for intraoral radiography, choose digital imaging instead of
conventional radiography equipment.
19

20. Recommendations
 Rectangular collimation should be used in periapical and
bitewing radiography.
Image receptor holders should be used in periapical and
bitewing radiography.
Source-to-skin distances of between 20 cm and 40 cm are
appropriate, but longer distances are optimal.
Set exposure timer to the lowest setting providing an
image of diagnostic quality.
20

21. Recommendations
Protective leaded thyroid collars should be used whenever
possible. However they are strongly recommended for
children and pregnant women.
Dental films should not be processed by sight.
All films should be processed in accordance with the
recommendations from the film and processor
manufacturer.
Films should not be used after their expiry date.
21

22. Recommendations
Quality assurance protocols should be developed and
implemented for each dental health care setting.
Patient doses should be assessed on a regular basis and
compared with diagnostic reference levels.
Size-based technique charts with suggested parameter
settings must be displayed near the control panel.
Adequate theoretical and practical training for the
purpose of radiological practices and relevant competence
in radiation protection appropriate to dental radiography.
22

23. REFERENCES
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YORK
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