Second opinions are common in health care, whether a doctor is sorting out a difficult case or a patient is not sure what to do next.
In the context of our magazine, the first opinion will always belong to the reader. This feature will allow fellow dental professionals
to share their opinions on various topics, providing you with a "second opinion." Perhaps some of these observations will change
your mind, while others will solidify your position. In the end, our goal is to create discussion and debate to enrich our profession.
- Thomas Giacobbi, DDS, FAGD, Editorial Director, Dentaltown Magazine
If you've been on a long trip with kids you've
probably heard the question many times - Are we
there yet? It's easy to answer if you are driving the
family car, not so easy in the dental practice when
the patient asks you "Why do I need these X-rays?"
or "Are these X-rays safe?" Hopefully this brief discussion
of current concepts and guidelines, updated
recently, jointly by the AAOMR and ADA, will give
you the information necessary to take the final steps
to minimize all of your patients' X-ray burden successfully
and easily as well as answer their questions.
What Have We Done Well?
Manufacturers and clinicians have continued
the move to faster image receptors. We've gone from
D-speed film to F-speed film with conventional
film-based imaging. Many offices have adopted
PIDs (position indicating devices), largely because
their staff members who take radiographs have been
trained this way in dental schools and in dental auxiliary
programs. The use of the PIDs with any type
image receptor facilitates the correct placement of
the receptor and greatly reduces retakes - a significant
factor for increased patient dose. Every retake
increases the X-radiation burden to the patient by
100 percent for that area.
Dental offices using conventional film are more
routinely using the leaded aprons and thyroid collars
for their film-based imaging procedures. With the new
NCRP #145 report,1 dental offices that switch to
become totally digital for their X-ray procedures do not
actually have to use a leaded apron except on females
who are pregnant or might be pregnant. Use of the
leaded apron for procedures where the apron might
interfere with the diagnostic information (panoramic
and cone beam imaging) is unnecessary according to
the new NCRP guidelines. However, if the patient asks
for a leaded apron, one should be provided.
These current guidelines have both "should" and
"shall" statements, and the "shall" statements are considered
mandatory. Thus, the use of the thyroid collar
on all children is mandatory, independent of the
type of image receptor - conventional film, phosphor
plates or solid-state detectors (sensors).
Only about 45 percent of North American dentists
have adopted solid-state, digital imaging receptors.
These clinicians and their offices should be
commended for using fast image receptors.
Manufacturers have also helped the profession
minimize radiation to the patient. We now have
contemporary X-ray generators that are DC
(direct current) with state-of-the-art timers to
accurately match the very fast exposure times for
solid-state detectors. And, of course, all of the
companies who make or resell solid-state systems
should be commended for helping the profession
advance the radiation-minimization cause.
Institutionally, dental schools and dental auxiliary
programs continue to adopt faster image receptors
when economically feasible. Dental auxiliary
schools teach long cone, rectangular collimation
technique and rectangular collimation devices.
Unfortunately no one is using them in their offices.
After graduation, dentists, assistants and dental
hygienists all abandon rectangular collimation. The
main reason being, "I can't possibly hit the image receptor with a small rectangular beam of X-rays."
Since this is a major way of minimizing radiation to
all patients we will address this and describe simple
and easy technology for the office to adopt.
What Can We Do Better?
It goes without saying that we should continue
our move to the solid-state detector environment -
digital sensors. And by this, I mean the direct capture
receptors, not indirect capture devices like
phosphor plate systems. There is a reason why only
three to four percent of North American dentists
have adopted phosphor plates. Although initially
they seem like a great substitute, without a wire
and an easier transition to film, dentists soon realize
that phosphor plate systems not only require
"care and feeding" but also do not give the dose
reduction obtainable by solid-state detectors, wired
Dentists should carefully examine and adopt
the recommendations in the current NCRP report.
The report contains guidelines for radiation protection
in their dental offices (report #145). Dentists
should also locate those companies that carry products
to reduce the patients' X-ray burden. One such
company is called HealthFirst (Mountlake Terrace,
Washington). They carry a simple retrofit, rectangular
collimator and personalized dosimeters that
the patient can wear to quantify X-ray dose for
every X-ray procedure received in the dental office.
The company also provides promotional materials
to help the dentist advertise low-dose practices and
promote them to patients.
Almost all patients fear X-ray procedures, have
been alarmed, been made more aware of potential
problems through the media, or ask dentists and
their staff members daily, "Why do I need these Xrays?"
So, the dentist and his/her staff should be
well-versed in the current guidelines published and
re-published by the American Dental Association
and the AAOMR (American Academy of Oral and
Maxillofacial Radiology) on several occasions.2,3 I,
in collaboration with Dr. Robert Langlais, published
(2004) an abridged version4 of the entire set
of guidelines shortly after they were released in
2003. Our "Cliff Notes" version can be downloaded
for free from my website: www.learndigital.
net. On the site there are other publications
that would be helpful to assist dental offices in
educating patients about the effects of dental Xrays
and how their offices can take measures to
reduce the burden and protect the patient.
In addition to education in these physical
measures for reducing the patient's dose, the use of
"Selection Criteria,"4 is important. This is examining
and prescribing only those X-ray images that
are necessary for the patient and for the dentist to
make clinical decisions. These guidelines, too,
have been published since 1987,2 republished over
the years by the American Dental Association,
taught in every dental school and dental auxiliary
program in North America and yet have been
largely ignored for the past 40 years. This is unacceptable.
Unfortunately, the "non-adoption" by
most dental offices falls into the category of what
we have failed to do.
What Have We Failed to Do?
All in all, I believe that many dentists have
done the best job of the health-care professions in
reducing X-ray dose to the patient. However, we
are not all adopting digital X-ray technology. We
are not all using thyroid collars on children. Very
few of us are actually using rectangular collimation
despite being taught this technique for the past 40
years. And, almost none of us are practicing the
principles of selection criteria - probably the single-
biggest way to reduce the dental population's
By now many of you are probably telling yourself
or realizing, "Boy, I really have failed to reduce
my patients X-ray burden." So what can you do?
What Should We Do Next?
Before I became a radiologist, I was a dentist.
Actually, I still am. Therefore, I like to see things in a
concise, logical pattern so that I can quickly learn
what needs to be done and take the necessary steps to
incorporate it into my office protocol. Consequently,
here's what we all should do next:
- Use selection criteria to determine, on an
individual basis, the number, type and frequency
of dental X-ray procedures needed for
- Go digital. Consider adopting solid-state
detector technology, which produces up to
90 percent less radiation than conventional
- Read and adopt the guidelines published by
the NCRP (report #145) and recommended
by our own American Dental Association.
- Use a thyroid collar on all children except
where it interferes with the diagnostic X-ray
exam (panoramic and CBCT procedures).
- Adopt and use rectangular collimation.
- Consider using personalized dosimetry for
patients concerned about X-radiation.
These suggestions can be fashioned into an
office protocol that helps you and your staff facilitate
safe dental X-ray practice. These procedures and
tools will help you reduce your patients' X-ray burden
and give you a marketing tool for your practice.
What Tools Are Available to Help Us?
Here are the educational links to find the most
current information on reducing X-radiation dose to
your patients from dental radiographic procedures:
http://learndigital.net/articles/article-table-of-contents.htm (look at 2004)
Besides educating yourselves by reading from
these sources, there are two simple tools that you can
employ to reduce the total X-ray dose the patient
receives and to give the patient peace of mind by
producing an electronic record of every exposure.
An X-ray Collimator
(fixed to your tube-head)
Recently, Interactive Diagnostic Imaging (IDI,
LLC, Marietta, Georgia) introduced a more contemporary
and simpler rectangular X-ray collimation
device, called Tru-Align. In the past, rectangular
PIDs and other devices to secondary collimator the
X-ray beam down to a small rectangle have been
ignored. Operators felt they could not hit the target
with this collimated beam. So round cone PIDs
remained the standard of care, the state-of-the-art.
IDI changed all that. They produced a rectangular
collimation device that can fit on more than 90 percent
of existing X-ray machines, collimating the size
of the beam to the required NCRP/ADA guideline
of restricting the beam to only two percent larger
than the image receptor. However, unlike all other
devices, the Tru-Align laser aligning collimator system
also fixes any image receptor to the tube-head
using magnets. This allows for simple alignment
without requiring a large beam to hit the target. In
full disclosure, I helped develop the design for this
device and I am an officer with the company.
However, also being one of those educators for the
past 30 years that taught you and your dental staff
the concepts of rectangular collimation, and being
frustrated with the lack of adoption, I believe that
this device offers a simple, easy-to-use product that
truly helps minimize patients' X-ray dose. The
device reduces the skin surface exposure (and deeper
structures of course) to the patient by 60 percent
because of the reduction in area between the large
round cylinder and the small rectangular cone. In
addition, this device eliminates horizontal and vertical angulation errors as well as cone cuts. The Tru-
Align system will also greatly reduce patient exposure
due to re-takes since the receptor is fixed to the tubehead.
About the only error one can make is by not
putting the receptor and bite block on the corrective.
The device is pictured in figure 1.
Although other beam-restricting devices exist,
they do not fix the image receptor to the tube-head
like the Tru-Align system. The list of these collimators
- Rectangular Position-Indicating Collimator -
Margraf Dental Manufacturing Inc. (Jenkintown,
Pennsylvania) (Fig. 3)
- Rinn Universal Collimator - Dentsply Rinn
- Tru-Align Laser Collimating System - Interactive
Diagnostic Imaging (Marietta, Georgia)
Using ion storage technology, there are now simple
USB devices, for example the Instadose dosimeter
(Fig. 4), that can precisely measure the X-ray
dose to the patient for each and every dental X-ray
procedure performed over a lifetime. The user, in
this case the patient, registers the device at a website
that will track the dose received from each radiographic
procedure and electronic record and allow
the patient to produce a report for themselves or
others on what procedures they've had done and the
total X-ray dose they have received for all of these
procedures. One of these devices is pictured below
in figure 4. This technology is offered by several distributors,
- HealthFirst (Mountlake Terrace, Washington)
- Steinbach and Associates IC Care radiation
- Spina Dental (Pittsburgh, Pennsylvania)
- Radiation Protection in Dentistry: Recommendations of the National Council on Radiation Protection and Measurements, report #145; December, 2003.
- Joseph LP. The Selection of Patients for X-ray Examinations: Dental Radiographic
Examinations. Rockville, MD: The Dental Radiographic Patient Selection Criteria
Panel, US Dept of Health and Human Services, Center for Devices and Radiological
Health; 1987.HHS Publication No. FDA 88-8273.
- Council on Scientific Affairs. An update on radiographic practices: information and recommendations.
Journal of the American Dental Association, 2001; 132:234-8.
- Miles DA and Langlais RP: NCRP Report No. 145 New Dental X-ray Guidelines: Their
Potential Impact on Your Dental practice. Dentistry Today. 23(9):128, 2004.