Choosing the Optimal Dental Material: Zirconia vs. E.Max

The goal of any dental restoration is to restore the patient’s oral environment back to its natural or improved appearance and functionality.

Dental materials have come a long way since porcelain fused to metal (PFM) was first introduced in the 60s. The push to provide improved materials has been driven primarily by the need to develop materials that offer improved esthetics combined with strength and durability.

Material Selection

The basic principle is to use the right material for every patient to have optimum results and patient satisfaction. Using the correct material helps decrease the chances for postoperative problems, which can lead to an overall negative experience of dental care.

The understanding of the attributes of different materials utilized during dental procedures allows for increased case success as well as a better overall dental experience for the patient.

There are several dental materials available in the dental industry. Two of the most prescribed materials are zirconia and lithium disilicate. Understanding when to prescribe one over the other is important in ensuring the patient is receiving the best option for their unique situation.

When looking at the strength of the material, it is important to note that the flexural strength of monolithic zirconia is approximately 1000 MPa, while lithium disilicate is approximately 400 MPa.

The problem, however, lies in the esthetics of the materials and their ability to mimic natural teeth. Monolithic zirconia results in a more opaque final restoration that may not be the most esthetic option. 

As a result, monolithic zirconia is often prescribed in the posterior region and not in the smile zone.  Often when zirconia is prescribed in the anterior, a coping of zirconia is fabricated, and then porcelain is layered over the coping, creating a more esthetic result.  However,  the porcelain used to layer over the coping usually has a flexural strength of approximately 100 MPa.

The Importance of Material Translucency

It is important to ensure that whatever the situation, when matching a restoration to the oral environment or when the desire is to achieve a natural result, the contours, size, and surface texture are achieved.  Both zirconia and lithium disilicate can offer excellent results.  The difference in these materials lies in the way they behave with light.  

Lithium disilicate, for example, comes in a wide range of translucent ingots and milling blocks. 

Translucency is one of the key factors that differentiates zirconia from lithium disilicate. Both zirconia and lithium disilicate offer varying levels of translucency. 

Zirconia, however, has a higher crystalline content that makes it much less translucent than lithium disilicate. The higher the translucency, the more light can penetrate the restoration. Higher translucent materials offer a more natural result that mimics natural dentition.  

It is important to note that there are some instances where a lower translucent material would be better suited to achieve the desired end results.

Zirconia’s opacity can mask severely discolored situations, including metal posts and cores. 

Lithium disilicate also has options that offer more opacity and mask-ability.

Cementation

A zirconia restoration can be cemented with any luting cement. The process to seat zirconia restorations is less technique sensitive. In contrast, lithium disilicate restorations are bonded to the tooth structure with a resin cement.

Lithium disilicate can be etched and bonded to the tooth, increasing the crown strength.  There are a lot more steps in the bonding process, making this more technique sensitive.

ZIRMAX M

At Burbank Dental Lab, we offer a variety of options when it comes to zirconia restorations. Our ZIRMAX M brand offers a high flexural strength of 1000MPa and is one of the most durable options available.

These restorations resist fracture and are long-lasting. They can be used for crown and bridge, including long-span bridges. In addition, when the option is to layer porcelain over a substructure, this is the option used to fabricate the substructures.

When compared to other zirconias on the market, ZIRMAX M offers 25 percent more translucency.

Some of the other benefits of ZIRMAX M include:

• One of the strongest all-ceramic materials
• Easy to customize, making it a great option for a variety of restorative options.
• Feels like natural dentition 
• Long-lasting
• Resistant to fractures and chipping
• Cementable 

In addition, Burbank Dental Lab offers ZIRMAX ME zirconia. This material’s flexural strength is approximately 750 MPa. It is more suited for posterior bridges of up to 3 units and anterior bridges of up to 4 units.

This material offers more translucency than many other brands on the market. The shades have been formulated to eliminate graying in lighter shades. This is a great option if anterior monolithic restorations are desired.

E.max

Lithium disilicate, most notably recognized as the brand E.max is an excellent option when esthetics is the number one concern. Emax preserves more tooth structure in order to provide an aesthetically pleasing result; it minimizes hypersensitivity. 

E.max can be monolithic and stained for optimal strength or layered to build in tooth structures. The benefits of E.max include: 

• Wide range of shades 
• Wide range of translucency levels
• High strength
• Years of clinical success
• Preparation design is conservative

E.max is a lithium disilicate glass-ceramic that can match any shade and is able to achieve a wide range of desired results. 

When it comes to dental materials, there are a wide variety of options available. The two most common types are zirconia and lithium disilicate. Each material has its own set of pros and cons that make them better suited for particular situations.

When strength is the biggest concern, monolithic zirconia is a good option because it offers approximately 1000 MPa flexural strength.

However, if esthetics is your main priority, then considering using lithium disilicate may be the best option.

For help deciding which type of prosthetic will work best for your particular case, contact Burbank Dental Lab today.