At its annual general meeting today, the German Society for Dentistry and Oral Medicine will be presenting this year's Miller Prize to PD Dr. med. Dr. med. dent. Stefan Hassfeld and Dr.-Ing. Wolfram Stein. At Heidelberg's University Hospital for Oral, Maxillary and Facial Surgery the two scientists have developed a 3D system enabling dentists to work out on screen the optimal positioning of implants for individual patients and to implement this knowledge with a high degree of precision during the actual operation. This facilitates assessment of the outcome of the implantation and reduces risks for the patient.
Dental implants are used either as artificial roots for a crown or as the foundation for stay-put dentures. So far dentists planning or inserting an implant have operated on the basis of a two-dimensional panorama X-ray projection. Such a projection does not however provide the necessary three-dimensional information essential in difficult clinical cases, e.g. badly atrophied jawbones. Implantology in the lateral areas of the lower jaw also requires exact information on the position of the nerves in that area. Nerve damage resulting from implants can lead to permanent numbness in the lower lip and chin. Penetration of the paranasal sinuses in the upper jaw can cause dangerous infection.
In the new procedure developed in Heidelberg the patient is first of all examined via computer tomograph (CT), enabling charting of bone surfaces for visualisation. Nerves are very small in diameter, contrast hardly at all with their environment and wind their way three-dimensionally through the space of the jaw. This makes it very difficult for radiologists and dentists to determine the course of nerve canals manually. In the new system they are mapped automatically by computer.
In the three-dimensional image provided by the new software the dentist can then position the virtual implants. In this way he can assess the quality of the available bone material and the proximity to risk-prone structures, proceeding from there to select the ideal location for the implant in the context of the care programme envisaged for the patient. On the basis of the dentist's planning the dental technician inserts small titanium tubes into the splint worn by the patient during the CT examination. These later serve as a drill guide for the dentist during the actual operation. The system requires new methods of registration between real world and virtual world, which have been developed together with a special positioning device.
In the framework of a commercial enterprise the hardware and software prototypes are to be further developed into a user-friendly system and thus made more generally available to the dentistry community (see www.med3D.de).
For more information and colour images contact:
German Society for Dentistry and Oral Medicine
Lindemannstrasse 96, D-40237 Duesseldorf
phone: 0211/675955, fax: 0211/6910199
Dr. Michael Schwarz
Press Officer of the University of Heidelberg
phone: 06221/542310, fax: 542317