By Lewis Sharp, CDT
The dental industry is seeing rapid changes in all aspects. Economic pressures, new and emerging technologies, and soaring precious metal prices have caused a shift in restorative choices. As a material, zirconia is the strongest of the all-ceramic restoration materials available today. Zirconia ceramic materials have been used for more than 20 years in medicine, mainly for hip replacements, and is used in aerospace technology. These materials have shown over this long history that they are fully biocompatible. It is the new material of choice for dental restorative procedures. In a recent issue of the CRA Newsletter, a status report on all-ceramic vs. PFM restorations states: "Dental technology is moving rapidly toward computers and all-ceramics, with zirconia leading the trend currently."
Characteristics of zirconia:
- It has extremely high tensile strength, and is referred to as ceramic steel.
- It virtually eliminates any allergic reactions.
- It is not an electrical conductor, so it doesn't generate an electrical charge. Electrical conductivity contributes to the corrosion of other metals in the mouth.
- Being nonmetallic, there is no corrosion. Therefore, gingival reactions such as the common "black line" at the gumline of traditional porcelain-fused-to-metal restorations will not occur.
- As an insulator, it protects against unpleasant hot/cold sensitivity in the mouth.
In our second case study, we received a case prescribing a Dura-Diamond bridge for teeth Nos. 4 through 8, once again with zirconia occlusal and lingual and porcelain facials. The esthetic demands of this case were more difficult. We had received photos of the patient, which were very helpful in achieving a good match of the surrounding dentition. Once again the bridge was milled, colored, sintered, and porcelain applied to the facial surfaces. The final restoration was delivered to the doctor and inserted (Figs. 5 and 6).
