A new class of CAD/CAM material

Dentists with chairside CAD/CAM systems often rely on ceramic blocks to deliver adequate strength and esthetics, as well as to maintain polish and luster over time. Meanwhile, composite blocks are used less frequently, even though their reduced chipping make them easier to mill, and the material’s familiarity to the dentist makes them easier to handle. Additionally, composite blocks offer the ability to deform under a load without breaking.

In the past, some dentists may have believed composite blocks for in-office CAD/CAM systems were inferior to

ceramic blocks in long term survivability, but recent research offers evidence to contradict this. An IADR presentation by Dr. Dennis Fasbinder shows the 10-year success rate of inlays made with a composite block material, the 3M™ ESPE™ Paradigm™ MZ100 Composite Block, is not significantly different from restorations made with Vita Mark II porcelain blocks.

This study shows that after 10 years, no significant differences were found between the materials in margin finish, margin discoloration, margin adaptation, surface finish, anatomic form, caries or sensitivity.1   

Now, a new class of CAD/CAM material from 3M ESPE, Lava™ Ultimate CAD/CAM Restorative, offers dentists unique

properties as well as the benefits of durability, added strength and long-lasting esthetics. Indicated for a full range of permanent adhesive single-unit restorations, the material is a “resin nano ceramic,” based on 3M ESPE’s established nano technology, using precise manipulation of filler architecture at the nano scale.

New material, different properties
Available for CEREC and E4D Systems, Lava Ultimate CAD/CAM restorative contains a proprietary blend of three fillers: zirconia and silica nano particles agglomerated into clusters; individually bonded silica nano particles; and individually bonded zirconia nano particles. The material contains about 80% (by weight) of this filler blend, which reinforces a highly cross-linked polymeric matrix cured using a 3M proprietary manufacturing process.

The result is a material that has different properties than feldspathic glass ceramic and composite materials. This new material offers higher flexural strength and fracture toughness, which results in long-term durability. It also maintains a polish well over the long term. The block is offered with a 10-year warranty, a testament to the rigorous testing and development performed prior to the introduction of this new class of material.

Lava Ultimate CAD/CAM restorative needs no firing and is easy to mill, helping dentists maximize the productivity of their in-office restorative systems. With this new material, clinicians only need to polish for a few minutes to achieve an enamel-like luster. The material is available in eight shades, with both high and low translucency options, giving dentists the palette necessary to closely match the esthetics of the patient’s dentition.

The material is not brittle, adding to its easy milling capability, even for challenging structures. Dentists can achieve better edge quality with Lava Ultimate restorative than with glass ceramics. It also allows for easy adjustments, as well as the ability to build-up and reseal restorations. For procedures such as endodontic treatments, the dentist can gain easy access to the root, after which the material can be resealed with a light-cured restorative.

As dentists know, time is of the essence in the operatory, and saving time with a chairside CAD/CAM system is an important way to maximize the value of their investment. The average time it takes to finish, polish and seat a crown with this block material is just 10 minutes. Eliminating the sintering process is a significant time saver, and makes use of an in-office CAD/CAM system even more patient-friendly.

The material is suitable for use with crowns (including implant-supported crowns), onlays, inlays and veneers. As the following implant crown case demonstrates, the material can be used in challenging areas such as the second molar, and also blends very well esthetically alongside ceramic restorations.

Clinical case
Step 1: Provisional restorations were in place preceding final restoration with the CEREC AC Chairside system (Fig. 1). 

Step 2: At the final restoration fabrication appointment, shade A3 of Lava Ultimate CAD/CAM Restorative was selected.

Step 3: The CEREC wand was used to capture a direct digital impression in the patient’s mouth.

Step 4: The CEREC software converted the scan into a 3D representation, and the system was used to design the final restoration (Fig. 2).

Step 5: Once the correct contours, occlusion and proximal contacts were realized, the restoration was milled in the CEREC machine with Lava Ultimate CAD/CAM restorative.  

Step 6: The restoration was tried in to confirm its fit, then polished to a high gloss.

Step 7: The crown was silanated and then filled with 3M™ ESPE™ RelyX™ Unicem 2 Self-Adhesive Resin Cement.

Step 8: The crown was seated in place (Fig. 3). The final result matched closely with the oven glazed Empress CAD restoration on the adjacent first molar, with a nearly indistinguishable appearance (Fig. 4).

Ideal for implants
Twenty-five years ago, the restorative trend for implants was to use a resin veneer over a coping for the final restoration. Many dentists preferred this method because ceramic does not have a very forgiving effect on periodontal structures. However, use of a more shock-absorbent material, the resin nano ceramic, gives dentists a durable but gentle option for implant restoration (Figs. 5-7).

Additionally, the time-savings made possible with this material might allow cost-savings for patients in the typically expensive implant procedure. With easy handling, time-savings and shock absorbency, Lava Ultimate CAD/CAM restorative is an attractive new option for in-office CAD/CAM restorations, particularly implants.

References
1. D.J. Fasbinder, Clinical Evaluation of CAD/CAM-Generated Composite Inlays: Ten-Year Report, IADR 2011, Abstract 37