021.Removable complete dentures: Is it a thing of the past?

DR. ABDULLAH SALEH AL-KRAIDIS
Riyadh Dental Center,Riyadh Medical Complex, Riyadh, Saudi Arabia

The use of osseointegrated dental implants to support a dental prosthesis has become an accepted treatment modality because of the high implant success rate observed by clinicians and researchers. The original application of osseointegrated implants was made to support fixed prosthesis in edentulous patients who experience problems with complete dentures subsequently, their use has been extended to support fixed prosthesis for one or more missing teeth in partially edentulous patients as well as to provide mechanical attachment for support and retention of removable overdenture. The presentation will include concept, principles, indications, advantages and case selection for overdentures as a treatment modality. Also, clinical cases will be presented which includes the clinical and laboratory work.
Saudi Dental Journal 2006;18(SI)-Abstr.021

022.Decision making in implant dentistry: The overdenture alternative

DR. PHILIPPE ARAMOUNI
School of Dental Medicine, Saint Joseph University, Beirut, Lebanon

For many patients, being edentulous is regarded as a handicap with respect to oral function and psychological impact on quality life. As a result, placement of implants is often welcome. The number of implants to be placed in an edentulous ridge depends on the type of prosthesis and the choice of prosthetic design. Conversely, the number of implants that can be placed with respect to anatomic-morphologic conditions will determine to a certain degree the type and design of prosthesis, while the size, curvature and the shape of the ridges determine the distribution of the implants over the arch. This lecture is aimed to help prosthodontists in decision making with implant prosthodontics rehabilitation of totally edentulous jaws.
Saudi Dental Journal 2006;18(SI)-Abstr.022

Purpose: The purpose of this study was to investigate the influence of commercially pure titanium and Ti-6Al-4V titanium alloys on the final shade of the low-fusing porcelain bonded to them, and to compare the shade changes with those of three conversional metal-ceramic systems.

Material and Methods: Titanium casting unit was used to cast the commercially pure titanium and T1-6A1-4V alloy specimens and A3 shade low-fusing porcelain (Noritake) was bonded to them. The gold-based, palladium-based and the Ni-Cr alloys were cast with an automatic centrifugal casting machine and the A3 shade conventional porcelain material (Vita, VMK 95) was applied to them. Ten specimens of each metal were fabricated. The CIE L*a*b* color coordinates of the specimens were measured with spectrophotometer.

Results: All alloys had significant color changes in comparison with the A3 shade tabs. The color differences from the shade tabs were 5.79 for the Ti-6A1-4V group, 6.46 for the palladium-based alloy, 8.12 for the gold-based alloy, 8.15 for the Ni-Cr alloy and 12.58 for the commercially pure titanium. The specimens differed from the shade tabs primarily because of the differences in a* and b* coordinates values.

Conclusions: Predictable shade reproduction of MCR may be impaired by the underlying metal. The commercially pure titanium had the greatest color differences among all the tested metal when compared with the shade tabs, whereas the T1-6A1-4V alloy had the lowest. The commercially pure titanium is more likely to affect the final shade of low-fusing porcelain than Ti-6Al-4V alloy.
Saudi Dental Journal 2006;18(SI)-Abstr.023

DR. CAMILLE HADDAD
School of Dental Medicine, Saint Joseph University,Beirut, Lebanon

All-ceramic restorations were largely able to fulfill the requirement of high esthetics and biocompatibility from inlays to single crowns, as well as small anterior tooth dental bridges.

The innovative zirconia CAD/CAM process has allowed an easy, reliable and rapid fabrication for all-ceramic posterior bridges with high mechanical strength and good biocompatibility. Laboratory tests of 3-unit bridges fabricated in this way resulted in an approximately 2.5 times higher chewing force-bearing capacity in comparison to glass-infiltrated aluminum oxide ceramic frameworks. High strength and stable zirconia made lifetime of all-ceramic bridges for the posterior region actually longer comparing to other ceramics systems. Lifetime judgments are made on reviews of research concerning the fit of the bridges, fractures, discoloration of the marginal gingiva, the quality of the surface and allergenic reactions. The framework ceramic consists of zirconia supplemented by a specially designed veneer ceramic with a coefficient of thermal expansion close to that of zirconia. Preparation can be achieved with removal of less tooth structure, and cementation can be carried out according to proven conventional techniques. Resistance has also been significantly increased by improving the design in the connector area.

The frameworks are fabricated using CAD/CAM procedures (scanning, computer-aided framework design and milling) from zirconia blanks.

The color shade system is based on the Vita-Lumin range. Ideal translucency resulting from the material properties, the coloration and the low wall thickness of the framework gives the restorations excellent esthetics.
Saudi Dental Journal 2006;18(SI)-Abstr.024

PROF. MOHAMED EKRAM
College of Dentistry, King Saud University
 Riyadh, Saudi Arabia

Clicking is one of the most common symptoms detected during examination of the TMJ. This symptom reflects an internal derangement of the TMJ which means an abnormal relationship of the articular disc to the condyle. This derangement can interfere with the smooth action of the joint resulting in clicking or joint sounds. Most patients with Temporomandibular Disorders (TMD) complain first from pain without clicking, followed by painless clicking, and then clicking may become less. Finally, the patient complains first from occasional pain and locking of the joint that become more persistent. The best accepted imaging modality used for the clicking TMJ is Magnetic Resonance Imaging (MRI). However, other modalities as Computed Tomography (CT) Panoramic and other extra-oral views are only suited for examination of the bony parts pf the joint. Temporomandibular Disorders are differential in nature, therefore a complete examination of the case is always required. This presentation is a trial to simplify understanding the Temporomandibular Disorders related to joint clicking (joint sounds) and how can these disorders be diagnosed.
Saudi Dental Journal 2006;18(SI)-Abstr.025