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HAS BEEN SAID that an endodontic filling is equivalent to an angiogram;
each depicts the nuances, constrictions, and patency of its respective
organ. Graphic representations of a three-dimensional anatomic structure,
be it an accessory canal or collateral circulation, will provide more information
and data to help diagnose or treat both medical and dental problems than
will conventional X-rays.
With the increasingly common placement of dental
implants, the use of three-dimensional data from computed tomography (CT)
and cone beam volumetric tomography (CBVT) is invaluable in dental implant
treatment planning, temporomandibular joint (TMJ) dysfuntion, pathology,
and orthodontic evaluations. While CT scan technology has been available
for twenty years, a number of considerations limit its use in dentistry.
In addition to inflicting high-dose radiation exposure on the patient,
CT scans only take one arch at a time. A patient who needs the opposing
arch scanned would be exposed to the same exposure again (equal to
ten panoramic films). CT scans create so much scatter that it may
limit the quality of an image and make visualizing atrophic ridges or key
anatomy difficult.
By comparison, the CBVT scanner (e.g., the NewTom
9000) significantly reduces the radiation exposure (by 80 to 90 percent).
In addition, it significantly reduces scatter from existing restorations.
The NewTom 9000 CBVT scanner takes both arches at the same time, reduces
the patient’s exposure to unnecessary radiation, is available for future
studies, and saves a great deal of time.
APW Dental Services, located in midtown Manhattan,
is the only dental radiology center in the tri-state area that has the
NewTom 9000 CBVT scanner. Their tomographic services exceed expectations
when it comes to providing scans for comprehensive treatment planning,
TMJ, endodontic lesions, orthodontics, pathology, third molar cases, and
pre-surgical considerations for dental implants. In fact, so much
information is included in their cone-beam 3D volumetric tomograms that
it may very well become a new standard of care for pre-surgical analysis
for dental implants, chronic dental pain, recalcitrant endodontic lesions,
TMJ dysfunction, and more.
Like a well (laterally) condensed root canal, a
3D tomogram can give more information than any of us may have dreamed of
when it comes to seemingly routine clinical situations. Consider
Figure 1; the bridge had failed and the dentist wished to place implants
in the edentulous area. This is a panoramic view of a 3 mm slice
with a 12 mm trough. This means that everything 12 mm buccal and
lingual to the center 3 mm cut is captured in this view.
FIGURE 1: A panoramic view
of a 3 mm slice with a 12 mm trough.
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Consider that the information in these 25 mm is more
precise than a conventional panoramic radiograph, and that both are good
screening devices to observe impacted teeth, supernumerary teeth, retained
root tips, most periapical radiolucencies, and most anatomic structures.
But is this image, along with a dental periapical X-ray, enough to place
a dental implant? Perhaps not.
Figures 2 and 3 represent a 1 mm slice with a 1
mm trough, which equals a 3 mm view through the mandible.
FIGURE 2: A 1 mm slice with
a 1 mm trough.
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FIGURE 3: Showing major and
minor branches off the nerve.
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Notice how well-defined the mandibular nerve is and notice what appear
to be major and minor branches off the nerve. Figure 3 marks these
branches, which can easily be seen in transaxial (sagittal) slices.
Based on the analysis and report provided by APW Dental Services, the dentist
informed the patient that nerve damage could be expected if implants were
placed. Instead, an alternative treatment plan was designed for the
patient that would not jeopardize the nerve.
In a different but similar case, teeth were removed
in the mandibular left. In preparation for implant placement, the
dentist referred the patient to APW for a 3D tomographic study. While
the panoramic view (Figure 4, which is a 3 mm slice with a 12 mm trough)
did not raise any alarms, the 1 mm slice with the 1 mm trough (Figure 5)
indicated that placing an implant in the area of the mental foramen, which
the dentist intended to do, could be a problem.
FIGURE 4: A 3 mm slice with
a 12 mm trough.
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FIGURE 5: A 1 mm slice with
a 1 mm trough.
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The transaxial (Figure 6) cut demonstrates an atypical mental foramen
that extends to the lingual cortical bone.
FIGURE 6: Transaxial cut
demonstrates an atypical mental foramen that extends to the lingual cortical
bone.
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The distance from the crest to the nerve was 9.3 mm. When the
dentist indicated that he planned to place a 10 mm implant, it was suggested
that he alter his treatment plan. In the past, this dentist had used
only periapical films to determine where to place a dental implant.
With this added information, he was able to prevent a potential problem
and render better care to his patient.
In less than a year, APW Dental Services has brought
a welcome change, enabling tri-state dentists to provide better, more accurate
pre-surgical analyses for their patients. Not only are implant patients
better served, but APW has assisted surgeons in isolating impacted teeth,
cysts, retained roots, oral-antral communications, and more. When
it comes to implant cases, APW provides a unique service: they highlight
and identify the mandibular nerve in the 1 mm panoramic frames and in all
transaxial views. Upon request, they will provide measurements of
the amount of bone above the mandibular nerve in appropriate sites.
In addition, a formal oral radiological report (provided by Dr. Herb Frommer,
director of radiology at the New York University College of Dentistry)
may be requested for each patient.
APW Dental Services is located in a historic
landmark brownstone at 34 East 62nd Street. APW’s fees are highly
competitive, and they offer one-day service. They are open Monday
through Friday and can be reached at 212-838-8302.
February-March 2004
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