The Triangle of Bone -
  A Formula for Successful Implant Placement and Restoration

By Scott D. Ganz, D.M.D.
Call (201) 592 - 8888

The primary goal of implant dentistry is not to achieve osseointegration, but to replace the tooth, or the lost anatomy to proper function and aesthetics1,2. In order to achieve this goal it is necessary to visualize the final result prior to placing a scalpel to the patient. Various techniques have been proposed to help locate the proper position of the fixture in relation to the ultimate tooth position and emergence profile of the final restoration. The fixture location is also dictated by a combination of factors including available height and width of bone, and considerations as to the density, or quality of that bone3-9. During the early learning curve of implant dentistry, some clinicians assumed that the "osseointegrated" state of a titanium fixture indicated bone interfacing with 100% of the implant's surface area. Many clinicians are still under this misconception. The anatomy and physiology of the bone itself, whether mandible or maxilla does not exist as 100% bone in its pre-implant state. The bone consists of marrow space, blood vessels, fat cells, and other non-mineral entities. Current research confirms that the bone-implant interface falls far below 100%, and can range from 25% - 75% depending on the classification (Type I-IV) and location10,11,12. The clinician must have a full understanding that the implant fixture replaces, and acts only as the root. The prosthetic, transmucosal components allow this new "root" to support the clinical prosthetic crown or prosthesis. Long-term survival of an implant fixture is therefore dependent upon the amount of bone in direct contact with the fixture, the fixture size, and the subsequent forces applied to that fixture under function, and load. Consequently, the implant must be placed in a position which would enhance and maximize the potential volume of surrounding bone.
Fig. I (above left) The natural tooth illustrated in its alveolar housing, the extraction socket, and the implant replacement. The amount of bone as illustrated does not exist clinically Fig. 2 (above right)The implant follows the path of the extraction socket. After healing, the abutment post is placed, followed by the final prosthetic crown.
The natural tooth root in its alveolar bone housing, may appear to have an ample quantity of bone thickness between the root itself and the buccal or lingual plate [FIG. 1]. Once the tooth has been lost1 the clinician may visualize replacing the natural tooth with an implant fixture, within the residual socket site [FIG.2]. The technique for the placement of implants into immediate extraction sites has been well documented in the literature13-16. However the most common visual concept of the three dimensional, cross sectional view of the actual bone anatomy surrounding the natural tooth root is seriously flawed.

N E X T+ P A G E | The Triangle of Bone
Fig. 3 (left) Three cross- sectional images from a CT Scan film of a natural tooth in its alveolar housing.

Fig. 5 (left) A computer enhancement to help highlight the information Th the CT Scan image.
Fig. 4 (above) Close- up view of a single cross-sectional image. Contrast the amount of buccal or palatal plate with the illustration in Figure 1.

Fig. 6 (above) If the implant follows the socket site, it may perforate the buccal cortical plate of bone and lead to a poor prognosis.

Dr. Scott D. Ganz has published extensively. delivered presentations worldwide, and is a Clinical Attending at Hackensack Medical Center. Dr. Ganz completed a three-year Maxillofacial Prosthetic Residency at M.D. Anderson Cancer Center in Houston, Texas, and currently maintains a private Prosthetic and Implant practice in Fort Lee, New Jersey. He is a Fellow of the American Academy of Maxillofacial Prosthetics and a Diplomate of the International Congress of Oral Implantologists. Dr. Ganz's chairside patient education guide. An Illustrated Guide. to Understanding Dental Implants is now available. Call (201) 592-8228 for more information.
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Prosthodontics, Maxillofacial Prosthetics and Implant Dentistry
N.J. Specialty No. 3553
158 Linwood Plaza Suite 204 Fort Lee, New Jersey 07024
TEL (201) 592 - 8888 FAX (201) 592-8821

Copyright © 1998 by Scott Ganz, D.M.D.
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