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Alan Winter, D. D. S.
A New Standard of Care?

IT 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

FIGURE 1: A panoramic view of a 3 mm slice with a 12 mm trough.

    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

FIGURE 2: A 1 mm slice with a 1 mm trough.

Figure 3

FIGURE 3: Showing major and minor branches off the nerve.

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

FIGURE 4: A 3 mm slice with a 12 mm trough.

Figure 5

FIGURE 5: A 1 mm slice with a 1 mm trough. 

The transaxial (Figure 6) cut demonstrates an atypical mental foramen that extends to the lingual cortical bone.
 

Figure 6

FIGURE 6: Transaxial cut demonstrates an atypical mental foramen that extends to the lingual cortical bone.

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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