Making a good first impression is important in life and particularly important in dentistry. Having to take a second one is a waste of material, time, and can upset a patient. Even if you are, or have an assistant that is one of those gifted impression sommeliers that can somehow capture every vestibule perfectly without breaking a sweat, there’s plenty of other potential problems that are outside of your control. Many impression materials are messy and can be uncomfortable for patients, they generally don’t taste too great, and can be prone to some level of distortion.
Through innovation in materials and technology, more seemingly dependable and streamlined solutions have been introduced to address some of these pitfalls. The most recent — and arguably one of the most intriguing — innovation is the dental scanner, which has the potential to eliminate the need for conventional impressions altogether. It does this by scanning everything from single crown preps to full arches at an accuracy of 20 microns for intraoral scanners and up to 6-7 microns for extraoral scanners—they even have color matching capability. Once the scan is captured, the image is converted to an STL file which can be exported and 3D printed for use as a master cast, surgical guide, or even an RPD. We’re going to explore this tech a little more in depth to get a basic understanding of what goes on behind the scenes when you take a scan.
STL is the native language of stereolithography and interpreted by CAD software that are used to design models for 3D printing. There is some debate as to what the acronym stands for, however, it is normally thought to represent either standard triangle language, stereolithography language, or stereolithography tessellation language. STL files are, at their core, a list of coordinates for triangles in 3D space and are exported in one of two formats, binary or ASCII. These triangles are told exactly how and where to sit in 3 planes and when put together they can make anything from a simple square to an entire tooth.
So, why does any of this matter? Well, if you plan on eventually jumping into, or simply exploring, the amazing world of scanners, 3D printers, and CAD programs, you’ll need to understand which systems work together best and STL files are at the core of these integrations.
There are a plethora of CAD programs used to ready STL files for printing; Meshmixer, Blender, and 3Shape are just a few examples. Overall, they are all relatively powerful programs that boast a wide range of functionality and integrate with many 3rd party scanners. However, these integrations are not all equal, not all the systems are open, and this needs to be taken into account when considering them. A scanner system that will allow you to export your STL files and use them as needed is generally the most flexible and powerful option. An open system allows you to export the STL files and use them as you see fit. This can be in printing, milling, or even sending the files to a lab that will print them for you.
Digital scanners open up a new realm of possibilities in the dental field. Although they are not yet at their full potential, they are improving every day. Most recently, a company out of Germany introduced a machine that can accurately scan soft tissue. This future may at times seem far off, but it is fast approaching and an understanding of the technology behind innovations such as digital scanners, is integral to ensuring the highest quality of care for our patients.