Saudi Dental Journal 2007;19(SI)-Abstr.046

In the last twenty years, the quantity of available bone determined the position of dental implants. Today, the prosthetic requirements are the exclusive measure for the implant position and surgery subsequently has to support these requirements. 15 years ago, the donor site for bone transplantation to the alveolar ridge was predominantly the iliac crest. This approach led to long hospital stays, high donor site morbidity and even to functional deficits concerning posture and movement. Thus, today this approach is increasingly being replaced by less invasive methods. The augmentation with so-called bone substitutes is conceivable in bone defects with bony walls on at least two or more sides. But the success rate is higher with autologous bone transplant which is still the gold standard and will remain so for the foreseeable future.
For bone transplantation today, most donor sites are suitable. The chin is a well documented donor site but sensory impairment, frequent injury to the lower incisors and the unpleasantness of the procedure if undertaken under local anesthesia which leads to a retraction of the lower lip provide a strong impulse to look for a better and less invasive donor sites. Therefore the transplant of choice today is the J-Graft which is taken from the oblique line of the mandible. Here, a graft of sufficiently large quantity can be taken with a minor operative procedure.
In 2003, in the Department of Oral and Maxillofacial Surgery in Karlsruhe, Germany we evaluated 20 patients who had been treated involving a J-Graft. Complications were rare. One patient showed temporary sensory disturbance/hypothesis involving the mental nerve, and another patient had a fracture of the mandible angle 3 weeks after surgery.
To minimize the risk of injuring in the nerve, we utilize only circular bone saws with a maximum penetration depth of 4 mm, thus safely avoiding the mandible channel. To prevent fractures, we instruct the patients to rely on a soft-food-diet for a period of 4 weeks post-operatively. While augmentation is still the procedure of choice for deficiencies of the maxillary alveolar ridge, osteodistraction is becoming increasingly dominant for the treatment of alveolar atrophy of the mandible.

Saudi Dental Journal 2007;19(SI)-Abstr.047

048. Shade determination - An evidence-based approach

Color determination in dentistry can be categorized into visual and instrumental. From a clinical standpoint, the human eye remains unsurpassed in its ability to detect subtle nuance in color between two comparable objects. Furthermore, visual assessment using shade guides remain the chief mechanism for determining the color of teeth in clinical dentistry. However, color research has demonstrated that currently available shade guides do not represent the color space of natural dentition,
On the other hand, advanced intraoral computerized instruments can precisely quantify color and reduce the subjectivity inherent in visual color perception. However, recent studies indicate that intraoral colorimeters are significantly influenced by translucency and suffer from edge loss. Furthermore, colorimeters are designed for flat rather than curved surfaces. In contrast, natural teeth are polychromatic, translucent and have curved surfaces. This explains why instrumental color assessment of teeth is not error-proof.
The aforementioned controversies explain why color matching of restorations to natural dentition continues to be one of the most frustrating problems in dentistry. This presentation would provide information about the basics of color science and how to utilize this information to enhance the ability of clinicians in shade determination.
Saudi Dental Journal 2007;19(SI)-Abstr.048