Dental News - 3D printing: Current applications and perspectives

Dr Carlo Mangano

Wed. 11. August 2021

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MILAN, Italy: Digital technologies are rapidly spreading in dentistry. Tools such as intra-oral and laboratory scanners, CBCT, computer-aided design and computer-aided manufacturing (CAD/CAM) software, as well as innovative manufacturing procedures such as 3D printing and laser sintering, are changing the way we treat our patients. Therapies are increasingly personalised, and the tools available allow more predictable results with levels of diagnostic precision and manufacturing accuracy that were previously unthinkable.

Current applications for 3D printing in dentistry have also increased significantly. This is because 3D printing allows for the easy and efficient manufacturing of customised products, which saves on production costs and simplifies the processing of patient image data.

The exciting possibilities of 3D printing

3D printing has opened up many new and interesting possibilities for dentists, particularly in oral surgery, prosthetics and orthodontics. Thanks to this technology, it is now possible to fabricate hollow and extremely complex objects that are impossible to produce through conventional methods, while also saving a considerable amount of material.

3D printing allows for complex models and objects to be produced at speed. (Image: bymandesigns/Shutterstock)

The whole process of dental additive manufacturing can be divided into four main stages:

creating a digital 3D model using software that is able to process intra-oral, facial or computed tomography scans;
slicing the 3D model into many two-dimensional layers;
3D-printing the final product layer by layer; and
post-processing of the printed object.

This basic workflow applies to a range of different printing technologies as well as to a range of materials, including polymers, metals and ceramics.

Speed, accuracy and resolution

The two main 3D-printing technologies used in dentistry today are stereolithography (SLA) and digital light processing (DLP). In SLA, a laser beam in the ultraviolet spectrum is used to cure photoactive resin, whereas DLP utilises a light projector to cure the resin. The two methods therefore diﬀer in the light source used: laser for SLA, against structured light for DLP.

In dentistry, speed is important, especially for large dental laboratories which regularly produce large amounts of dental applications. The DLP technique is faster than SLA because a DLP printer can produce a whole layer at once, whereas the laser in an SLA printer has to move around to complete the layer. However, speed does not automatically mean accuracy. In fact, 3D printers could be likened to an orchestra in that there is never just one single element that determines the accuracy of the object we are going to print. There are a multitude of important factors to consider: the physics of light and its propagation, the chemistry of the resin used and its polymerisation, the electronics of the panels (the liquid crystal display [LCD] in a DLP printer) or of the laser in an SLA printer, the lenses and mirrors, the mechanics of advancement and/or rotation of the system, and of course, the software—the heart of the printer and the harmoniser of the process.

“Surgical guides, indirect bonding trays, aligner bases and study models can all now be 3D-printed using different materials”

One thing that is often used as a selling point for 3D printers is resolution, which is frequently confused with accuracy. The concept of resolution on the vertical z axis can be simplified to the minimum possible advancement in z; unfortunately, the coincidence of this minimum advancement with the minimum thickness of the layer is only ideal, and not yet demonstrated (in fact, the material variable must be considered). Meanwhile, the concept of resolution on the horizontal xy axis is valid only for LCD printers.

In fact, for SLA and DLP printers, one should instead talk about the minimum size of the light source, which ideally, should correspond to the minimum printable size. However, even then, there remain the variables of the material, the machine components and the postcuring procedure. Accuracy and resolution, therefore, are two different concepts that together determine the quality of the print job.

Since 3D printing’s emergence, manufacturers have further simplified the printing process by making 3D printers more accessible and improving the quality of the dedicated software. Printing is not difficult: once you understand how to position the models on the build platform and how to adequately support them to avoid their detachment from the build platform during printing, the procedure is clear.

Dentistry in the next five years

The impact of 3D printing on digital dentistry continues to be very strong—surgical guides, indirect bonding trays, aligner bases and study models can all now be 3D-printed using different materials. The race to be able to print zirconia restorations and complete prostheses has already started. The possibilities are many, and they will grow, together with the development of new materials. It is not difficult to predict that soon every dental office and dental laboratory will be equipped with at least one 3D printer. Thanks to all of this, 3D printing is pushing dentistry towards a definitive digital transformation.

Over the next five years, we will also see an influx of new tools and software as manufacturers and companies continue to invest in research and development. Digital technologies will bring epochal changes to the world of dentistry, altering not only patient expectations of dental care but also the way dental professionals think about and implement therapies. They will be able to use increasingly better performing tools, easier software and, above all, new materials with high aesthetic value that are more compatible with the patient’s health. There will also be predictable clinical protocols, higher quality and lower costs.

Advice to new digital dentists

No clinician should underestimate the key role of digital technologies, ignore them or think that he or she can work without them. Giving up or waiting too long to adopt digital technologies in one’s daily practice would be a great mistake. The development of new technologies happens very quickly—the computational power of computers alone increases by around 50% every year. As a result, clinicians should dedicate time to understanding how to use digital technologies to their advantage and, if necessary, attend training courses as well.

“No clinician should underestimate the key role of digital technologies, ignore them or think that he or she can work without them”

The initial investment can be considerable, in terms of both time and money; therefore, it is important to make the most of it. In order get off to a good start, two machines are key in daily practice: a CBCT unit and an intra-oral scanner. A CBCT unit is certainly a device that increases your diagnostic capacity and simplifies therapeutic planning. Meanwhile, intra-oral scanning technology is now more accurate, efficient and intuitive than ever and simplifies and improves communication with the patient. Above all, these scanners allow for the adoption of a full digital workflow, with advantages both in terms of time and costs.

Clinicians need to address the new challenge by increasing their knowledge and asking for valuable suggestions from those colleagues who started their digital journey a long time ago. Furthermore, they should attend training courses that will help them make correct choices that are not just based on information from the market. The Digital Dentistry Society (DDS) organises events and certified training courses, which are practical and follow a unified format at an international level. Official courses are held by DDS’s certified speakers, who are all internationally recognised clinical experts and researchers.

The quality of the available training will determine the speed with which clinicians change their way of thinking and working to adapt to a fascinating new digital world of intra-oral scanners, CBCT units, CAD/CAM software, milling machines and 3D printers. Waiting too long to adopt or integrate these technologies into the daily workflow could be a dire mistake, especially for young dentists.