Table of Contents

Continuing Education

Inside Dentistry

July/August 2007, Volume 3, Issue 7
Published by AEGIS Communications

3-D Images for Implant Planning in 24 Hours or Less

The availability of high-quality 3-dimensional (3-D) imaging for interactive visualization and planning is an essential clinical tool for surgeons and restorative dentists performing implant procedures and looking for ways to reduce chair time, instill patient confidence, and ensure predictable outcomes.

Predictability in the placement of dental implants was difficult when clinicians had to rely on conventional radiographs. Today, however, 3-D images based on cone beam scans can provide an accurate 3-D picture that can be rotated to provide a clear picture of the jaw from any perspective to help ensure proper implant placement.

3D Diagnostix, Inc (3DDX, Brighton, MA) specializes in converting computed tomography (CT) scans into high-quality 3-D images that can be viewed using dental image reading software such as SimPlant®  (Materialise, Glen Burnie, MD) or Facilitate™ (Astra Tech, Waltham, MA). 3DDX converts raw data from DICOM CT image slices and output by cone beam computed tomography (CBCT) and multi-detector CT (MDCT) scans into SimPlant or Facilitate formats used to display 3-D images on a personal computer. In most practices, processing these 3-D images in the office is impractical as they represent a time-consuming and difficult challenge for dental technicians lacking extensive hands-on experience. As a dental specialist, 3DDX provides turn-key solutions for implant planning including planning software and conversions. The conversions are completed in a 24-hour turnaround time as well as same-business-day delivery on special orders.

3DDX services include clean-up of artifacts, optional colorization, and radiographic interpretation by a board-certified radiologist. High-quality reconstructions are only $100 per arch, and optional colorization to highlight teeth, roots, surgical guides, and other structures indicated by the clinician is only $50 extra.

PANORAMIC X-RAYS, PLAIN-FILM TOMOGRAPHY, AND CBCT SCANS

Panoramic x-rays provide 2-dimensional (2-D) images from a mesiodistal or anterior/posterior perspective that are both magnified and distorted. Magnification by itself is not a problem as long as one knows, or can calculate, the magnification factor. Distortion, on the other hand, is the unequal magnification of different parts of the same image. Because of distortion, panoramic images are notoriously unreliable in making the measurements needed for the construction of drill guides, as all the structures between the x-ray tube and the image detector are superimposed on one another.

Unlike panoramic radiography, plain-film tomography is distortion-free. However, the image is magnified to a degree that differs from manufacturer to manufacturer. Plain-film tomography provides direct (as opposed to reconstructed) cross-sectional, sagittal, and coronal views. The disadvantage is that plain-film tomography requires more chair time than a CT. This can be a problem with patients who are unable to remain still for a period of time.

Conventional CT scans take only 10 to 40 seconds to produce 1-dimensional buccolingual, cross-sectional, axial, coronal, sagittal, and panoramic images that can provide a strong indication of bone quantity and quality. At the same time, CT scans make it possible to focus on discrete structures: for example, to distinguish the left condyle from the right.

3-D software converts conventional CT scans into a 3-D image that can be viewed from any perspective, enabling the surgeon or restorative dentist to “see” what needs to be done, how much bone there is to work with, and where implants can be placed.

THE IMPORTANCE OF 3-D VISUALIZATION

The value of a 3-D conversion is demonstrated in the case of a patient with chronic periodontitis, generalized and severe. According to Dr. Joshua Grant, DDS, who has a periodontal practice in Buffalo, New York, initial therapy consisted of a plaque control program, scaling and root planing, and extraction of hopeless teeth with ridge preservation. Orthodontic therapy was accomplished and then a radiographic/surgical index was fabricated for the scan. 3-D imaging showed that virtual implants placed according to the plan would produce significant dehiscence defects on the palatal aspect of two existing posterior implants in the right maxilla (Figure 1). The 3-D image also showed that the apex of the anterior implant in the right mandible would impinge on the apex of the adjacent tooth. A 2-D view of that implant would have suggested impingement of the inferior alveolar nerve near the mental foramen (Figure 2). However, the 3-D image showed that there was adequate room (Figure 3).

Based on the 3-D imaging, Dr. Grant’s laboratory made adjustments to the guide (Figure 3 and Figure 4) for use during surgery, including lateral-window sinus elevation and the simultaneous placement of implants in the right maxilla.

After consulting with Dr. Grant and viewing the 3-D scans, the patient chose a comprehensive treatment as outlined above.

OPTIMIZING IMPLANT PLANNING

The availability of 3-D imaging for interactive visualization and planning is an essential tool for surgeons and restorative dentists performing implant procedures while looking for ways to reduce chair time, instill patient confidence, and make implant procedures more affordable for their patients.

CT scans and 3-D imaging are becoming a standard of care in oral and maxillofacial surgery and have been incorp-orated into clinical training at a growing number of dental schools.

ACKNOWLEDGMENT

The case and images are courtesy of Dr. Joshua Grant, DDS, and used with permission. Dr. Grant is an assistant clinical professor at the University at Buffalo School of Dental Medicine and an implant consultant for the Veterans’ Administration Hospital in Buffalo, New York.

For more information, contact:
3D Diagnostix, Inc
Phone: 617-820-5279
Web: www.3DDX.com

DISCLAIMER

The preceding material was provided by the manufacturer. The statements and opinions contained therein are solely those of the manufacturer and not of the editors, publisher, or the Editorial Board of  Inside Dentistry. The preceding is not a warranty, endorsement, or approval for the aforementioned products or services or their effectiveness, quality, or safety on the part of Inside Dentistry or AEGIS Communications. The publisher disclaims responsibility for any injury to persons or property resulting from any ideas or products referred to in the preceding material.

 
Figure 1 3-D palatal view of maxillary right showing dehiscence defects.   Figure 2 The mandibular right implant proximal to root apex. The point of view is coincident with conventional 2-D views showing apparent proximity to mental foramen.
     
 
Figure 3 3-D view showing adequate space between the implant and mental foramen. The implant has been corrected to allow space for the adjacent root.   Figure 4 Implants have been corrected to prevent palatal dehiscence.