25 February 2020

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Materials for digital dentistry: classification and clinical features

Lorenzo Breschi

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CAD/CAM technology has been used in industry for long time and has increased in popularity over the past years in dentistry from making impressions, casts, provisional and final restorations. The digital process is usually time efficient and eliminates the need for impression materials, and in most cases, allows the delivery of the final product in a single appointment.
Today, the dental market proposes several CAD/CAM systems and, for that reason, it is crucially important for the restorative team to understand the spectrum of digital materials that are available in order to ensure the optimal treatment outcome for the patients.

A recent review from Prof. Sulaiman published on the Journal of  Esthetic and Restorative Dentistry at the beginning of the current year and entitled “Materials in digital dentistry-A review” described in details the materials utilizing CAD/CAM technologies, their properties and accuracy compared to conventional methods and materials used in restorative dentistry. 

The author divided the materials into subtractive (SM) and materials produced by additive manufacturing (AM).

Talking about SM,  Sulaiman explained that, usually, they involve milling of the designed volumetric shape from a presintered or sintered material using a milling machine that performs either in a wet or dry condition, that moves in defined paths and is referred to as 3‐, 4‐, 5‐axes milling systems. These systems could be either laboratory or chairside. The subtractive materials described in the paper include wax, poly(methyl methacrylate) (PMMA), composite resins, high‐performance polymers, metals, and ceramics. As regard the second category, the one produced by additive manufacturing, it employs 3D printing, a recent and emerging technology that has gained a lot of interest in the dental field due to its wide‐range capabilities for providing surgical guides, temporary restorations, occlusal splints, bite‐guards, scaffolds, and orthodontic appliances.

Indeed, AM allow the production of pieces by adding materials (composites, metals, and ceramics) layer‐by‐layer, based on a computerized 3D model. 

The review concluded that CAD/CAM technology has changed the way dentistry is practiced, and care is delivered. In particular, laboratory and chairside milling units are described as more versatile and capable of milling multiple materials with properties that may ensure a long-term clinical success. On the other hand, additive manufacturing is a good alternative and a promising manufacturing method of dental restorations and appliances. To be more precise, the additive techniques allows for fabrication of more sophisticated build structures without excessive force and much less non-recyclable waste when compared to SM techniques

However, beside these positive aspects, AM have a shorter track record of clinical evidence compared to SM materials.

For additional informations: Materials in digital dentistry-A review.