The materials that dentists use in CAD/CAM machines have changed over the years. Digital dentistry and CAD/CAM has changed the restorative work. Over the past few decades, the materials they use in their machine have changed, too.
But how are they different from traditional indirect materials?
Here’s what you should know:
The most significant difference is the effects of the manufacturing process on the fabric composition. According to the American Dental Association, the improvements in materials, alongside advancing technology of CAD/CAM systems, contribute in no small thanks to clinical success. The fabrication method of those materials enhances their reliability when used for restorations. In other words, the manufacturing process of the blocks leads to a uniform “dense, high-quality material.” Traditional materials are produced by hand. So, although ADA says the restorations from traditional materials also are top quality, they could have less “reliability” regarding mechanical and esthetic properties because they weren’t mass-produced. For instance, once you examine a cross-section of block vs hand-built (traditional indirect) material, there are pores in hand-built.
Furthermore, when comparing the blocks of several manufacturers from the time (2006), the blocks had “fine-particle-sized microstructure,” which helped them in many areas, including:
- Resistance to machining damage
- Improvement of mechanical properties
- Reductions of polishing time
- Increased “wear-kindness” of the finished restoration
Some Pros and Cons of the Digital Material Types:
Digital dental materials all have their features and related benefits, also as some drawbacks. For permanent restorations, RPD Dental Lab has roughly categorized the digital materials into four material types:
Resin-based materials (composites)
The resin-based materials are mostly an equivalent composition as composites used for direct restorations. They contain glass or ceramic fillers during a resin matrix. The benefits of resin-based material are suited explicitly for in-office milling. Resin-based materials don’t have the strength of ceramics, and that they have a less reliable bond.
Porcelain/leucite based materials have a number of the benefits of ceramics built-in. They not only have an identical bonding ability and high esthetics but also don’t require crystallization during a furnace. However, they need an obstacle, too. These materials don’t have the strength of lithium disilicates.
Lithium disilicate materials
Lithium disilicate because of the “workhorse material for CAD/CAM dentists.” Lithium disilicate may be a high-strength ceramic material that has the benefits of ceramics (e.g., esthetics, “bondability”) but with a way higher strength than porcelain.
The newest addition to the family of in-office CAD/CAM materials is zirconia. Zirconia may be a durable polycrystalline material (contains no glass) and utilized in many everyday materials, from dishes and servers to lighting and more. This material requires different process steps than all other materials. It’s milled dry in a chalky form. It’s then sintered during a special furnace that has got to achieve a temperature much above the furnace wont to crystallize lithium disilicate. The disadvantage of those materials is that they do not have the esthetic properties of lithium disilicate or porcelain, and there’s less clinical evidence for the bond between zirconia and resin cement.