How to Choose the Best Zirconia Blocks for Dental Restorations?

It has been more than 20 years since zirconia blocks were used in oral clinics. After years of research, improvement and development, a wide variety of zirconia block restoration materials have been launched at home and abroad, which confuses clinicians in making the right choice. How to choose the best zirconia blocks that is most suitable for patients' tooth restoration?

So in summary, it is necessary to classify and divide zirconia restoration materials. This is not only conducive to the basic research of zirconia blocks, but also conducive to dentists' better understanding of the performance of zirconia blocks, and can better guide clinical applications. There are many factors to consider when choosing the most suitable zirconia blocks for dental restorations. According to numerous academic research materials at home and abroad, the following are the key factors to consider when choosing zirconia blocks.

1. Mechanical properties

The mechanical properties of zirconia blocks are crucial to the success of tooth restoration. We divide zirconia blocks into four generations according to the time when zirconia products were launched, and different generations of zirconia blocks have different properties. For example, the third-generation high-transmittance zirconia all-ceramic materials, such as 4Y-TZP (containing 4 mol% yttria as a stabilizer), have high light transmittance and good mechanical properties, and are suitable for making all-ceramic crowns and bridges. However, the mechanical properties of this type of material are relatively low, with a bending strength between 500 and 800 MPa and a fracture toughness of about 2.2 to 3.5 MPa·m1/2, so further research and evaluation are needed in clinical applications.

Therefore, it is not difficult for us to find that different generations of zirconia blocks have different mechanical properties. During clinical treatment, we should choose the one that best suits our needs and situation.

2. Aesthetics

At present, zirconia blocks have improved the shortcomings of single color and poor transparency. More and more specifications and varieties of zirconia blocks have entered the market to meet the needs of different restorations. There will be more and more choices for zirconia restorations in the future, which will become an unstoppable trend. 

The color of zirconia has also gradually developed from the original white color to the corresponding color of Vita 16. Some manufacturers have also launched their own unique colors to meet the color needs of different markets and races. The emergence of colored zirconium blocks can reduce or simply abandon the subsequent technician dyeing operation, which not only reduces the technician operation steps, but more importantly, maintains the performance of zirconia itself and avoids the adverse factors of strength reduction that may be caused by dyeing operations.

3. Biocompatibility

Zirconium dioxide is a material with excellent biocompatibility and is suitable for oral applications. Over the years, a large number of experiments and clinical cases have proven that zirconia blocks have no toxic damage to bone and soft tissue cells, and no allergic reactions have been reported. At the same time, it can effectively avoid adverse reactions such as allergies, irritation, and corrosion caused by metals in the mouth. When it comes into contact with air, water or any other electrolyte, a micro-oxide film will quickly form, which not only avoids metal corrosion, but also prevents the generation of metallic odor.

4. Clinical application adaptability

For example, the third-generation zirconia all-ceramic material can be used for the restoration of anterior teeth full zirconia single crowns and bridges, and anterior teeth veneers due to its good optical properties. However, the latest studies have shown that the failure rate of this type of zirconia in the anterior teeth area is greater than 2% within 5 years. The use of some minimally invasive restorations such as veneers, inlays, and high onlays still needs clinical evaluation.

Therefore, when we repair teeth, we must choose zirconia blocks with high success rates and strong application adaptability.