Imagine a company whose everyday workflow includes laser cutters, three-dimensional printers and three-dimensional scanners, X-ray tomographs, CAD , composite materials, automatic CNC machines , an optical and biochemical laboratory, and even its own assembly of specialized hardware devices. It is widely implemented inline data processing in real time, using 3D printing, doing bioengineering and programming FPGAs , there are networks storing terabytes of data, datamining, and even a little artificial intelligence. Submitted? Now try to guess what this company can do. I must say that this is not space, not aircraft, or even automotive.




The Align Technology company is engaged in ordinary dental care. Surprisingly, modern technologies of dental treatment are perfectly transferred to the digital stack and are ideally combined with three-dimensional scanning of the teeth, the design of their treatment and the printing of dentures and devices for their treatment. The practical implementation of this stack naturally gradually pulls the whole list of technologies described above. Generally, after working in our company, you begin to be especially acutely aware of how much the world in which we live is changing: the teeth of a patient who has come to the US to the orthodontist patient today are often routinely scanned by the doctor or nurse, the digital cast flies over the Web to another The country has a data center where a model of its jaw is created in a semi-automatic mode, and according to the instructions and under the supervision of a doctor, the future treatment is designed in steps. The resulting "drawings" fly over the Network to a third country, where, at a special factory, the robot makes the necessary device for treatment, and this device is sent by mail back to the doctor and installed in the mouth of the patient who came to the second appointment. True life of ordinary dentists, therapists, with whom we often encounter has not changed much: to automate the drill is still not easy :), but the manufacture of dental crowns, implants and braces to correct the position of the teeth is rapidly moving to the "figure."
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Unfortunately, Russia has hardly touched this process so far and when we mention at interviews that our company is engaged in medical equipment and services for dental treatment, our interviewees often frown in surprise, obviously believing that there is nothing more interesting than keeping electronic patient cards in such business can not be. Therefore, to attract interest to our subject matter, we decided to talk a little about how far digital technologies have gone here and how interesting things we have to do because of this.


In general, work in our company can be divided into five areas:

1. Scanning of teeth and bite (own 3D-scanner or scanning of usual orthodontic impressions on a tomograph)
2. Modeling a person's jaw, searching for and correcting orthodontic problems, designing a treatment for forming a beautiful smile and correcting bite
3. Making unique devices for treatment for each individual patient
4. Datamining and research to track how efficiently our devices work and improve them
5. The infrastructure that supports this entire system is a single network that stores patient data, sends them between stations, is responsible for mail delivery, billing, etc.

Alainers

The company's flagship product is the so-called "alyner". Generally speaking, in terms of domestic medicine, this product should be called "orthodontic cap ", but the English-language "alayner" in my opinion sounds simpler and better. Kapa is a special device that is worn on the teeth like a sheath (I have come across the capacious term “headrest”).



In pre-digital orthodontics, mouthguards were made of silicone or plastic using plaster models of teeth and used to apply drugs to teeth, protect teeth in sports, and to fix the teeth in a certain position after orthodontic treatment. Alain invented a “power” mouthpiece, which not only fixes the teeth in one position, but moves them to the desired direction. To achieve this goal, a digital model of teeth and jaws is built, the desired final position of the teeth is determined and the trajectory of its movement is calculated for each tooth. The output is a series of very small movements of the teeth, which begins with the current position of the teeth, and ends with an ideal one. For this series, caps are made of a special transparent composite material, each of which corresponds to one small step in the movement of teeth. Each cap is made of a transparent elastic composite material and corresponds not to the current, but to the next position that the teeth should occupy. Since it is not too different from the current one, such a cap can still be put on, but at the same time it stretches and starts pressing on the teeth until they move and take the desired position. This, in fact, is the alayner.



The “old-time” alternative to the Alainers was to stick curved steel wire to their teeth through special locks — familiar to some braces. The principle of operation there is similar, only in the form of an elastic element is not plastic molded teeth, but glued through a special fastener curved steel wire. Compared to modern braces, alainers work somewhat slower (steel is capable of developing greater effort than plastic, even composite), but they are an order of magnitude more comfortable treatment option:

• There are no foreign objects in the mouth resting on the cheek or tongue.
• The aligners worn on the teeth are invisible, they are almost impossible to see even at close range (which they beat in the trade mark )
• They can be removed and put back at any time, which greatly facilitates eating and brushing your teeth.

In addition, the traditional applications of cap-protection of teeth do not disappear anywhere (while braces significantly increase the chance of caries) and the possibility of passing treatment of teeth with drugs (some, for example, combine the treatment with airliners with teeth whitening). So, Invisalign is now a well-known and well-known brand in the USA, and although braces are also not standing still (there is a development towards greater speed of treatment and translucent or braces located on the side of the tongue), Aline has been very successful for several years now bites off more and more market share of orthodontic services. In my opinion, ultimately, over time, the aligners will become the most massive system for correcting the position of teeth in the world (this is not the case now), since they have another fundamentally important advantage: in contrast to bracket-systems, (relative) non-professionals can use them. Fastening and correction of braces is a kind of art requiring special training and knowledge, and at least in the West, people owning this art are few and form a kind of elite in the dental industry. And where the elite is, there is the corresponding salary, treatment by a specialist orthodontist today in the US is much more expensive than the same (in time) amount of services from a dentist-therapist. The treatment with a-liners theoretically allows all this wisdom to “outsource” our company - it will be enough for the doctor to send us pictures of the patient's teeth, and we will design all the treatment ourselves. The patient will only have to receive their individual and numbered dates by mail and start carrying them. So far this is not yet fully possible, but we are working on it :).



Where is the high-tech, you ask? A high-tech in this little phrase about the need to model the patient's teeth and calculate the trajectory of their movement. Today, to solve this problem, we have a whole special plant located in Costa Rica, where in a huge room the size of a stadium several hundred special technicians work in the CAM system developed by us. At the dawn of the company's formation, our software was very similar to ordinary 3D modeling packages, and the technicians manually cleaned the models sent to us from “garbage”, “cut” their teeth and designed movement through keyframes familiar to many in 3D animation. And designing a treatment for one person could then calmly take a whole day. Or two, since the orthodontist does not always agree with the treatment option offered to him and the technicians often have to modify the treatment plan several times until he completely suits the specialist. But since then, many years have passed and the “ordinary” 3D system has long evolved into a very specialized package that works an order of magnitude faster and has rich functionality for a variety of “special cases”. Not far from the developers of the CAM system, there is a special department of biomechanics that examines the mechanics of the interaction of teeth with aligners and tries to think of ways to improve this interaction (for example, by adding internal projections to the cap or, conversely, hooks on the teeth). Once we were able to treat only simple cases, today - almost any.



A little apart from the CAM-system is the physical production of alayner. The process of transformation of the model calculated in the CAM system into the plastic delivered to the patient is an extremely high-tech process and begins with 3D printing of a unique mold using stereolithography technology. Today, 3D-printing is no surprise, but 15 years ago when the company was just beginning, Aline had to create one of the largest and most advanced industries of its kind in the world. For each patient we need to produce from five to six to several dozen unique molds, one copy for each of the stages of treatment. Daily production exceeds 50 thousand molds per day, and each of them has to be supplied with a machine-readable QR-tag in order not to confuse them with each other. Manufactured molds are sent to an automatic line where robots print an aligner from a special composite material from each form, cut its edges on a CNC machine or (in a new system to be developed) with an industrial laser and grind the surface.



The resulting products are automatically sorted, packed in individual boxes, in an understandable way for the patient, signed and assembled into kits ready for shipment by mail. And the functioning of this whole process is provided by a number of specialized software products. One of these products creates input models for industrial 3D printers and optimizes them for printing, packing a hundred different models tightly on one large pallet. The other one controls the laser cutter, which cuts off the edges of an A-liner printed on the mold. The third one, through QR codes, tracks the produced tens of thousands of alayers and sorts them for packaging and mailing to the customer.
However - all this deserves a separate story. And now I would like to briefly say about

Scanning

Once upon a time, when we were just starting out, the only option for the doctor to “scan” the teeth was to take an impression from these teeth. The traditional orthodontic process meant that special clay was poured into a special form, the form was tightly put on the teeth, after which the resulting imprint was filled with plaster. Further along this “physical” model it was possible, for example, to mold a model of a future dental crown from wax, remove the resulting wax model from a plaster mold, place it in the sand and pour metal, then break the mold, process the molded part with a file, put a layer of ceramic on it , burn in a special oven and paint manually with special paints and brushes. Crowns from metal-ceramic in most Russian dental clinics are still produced in this way. This is an amazing and very artistic process, and at the same time completely, right up to the very last step, manual. But for the production of aligners in the 99th, a three-dimensional digital model was required and, moreover, a high-precision one — an error of even 1/5 mm could seriously spoil the treatment. Fortunately, it was not necessary to reinvent the wheel - X-ray tomographs, as it turned out, do an excellent job with this task. A special installation with a rotating platform makes several hundreds of X-ray images from different angles “to the light”, and a special software then restores the 3D model from these images. Over time, we switched to our own software for tomography, and today, for example, to scan such an imprint, you do not need to pour gypsum into it - the scanner scans the original imprint directly and automatically calculates the model from it.



It is interesting, by the way, that then it was far from the only possible way of high-precision digitization - for example, our colleagues from the company Cadent Technologies, which later became part of Alayn, in about the same years they put a model cast from white plastic into a black mold, cut it in layers "Brick", photographed each layer and reconstructed the model from the resulting stack of images. But X-ray tomography eventually took root better and continues to scale well to this day. But it seems that pretty soon it will also go into oblivion, and the reason for this is the appearance of special digital 3D scanners for teeth.



What is a modern 3D scanner? Usually, with these words, everyone imagines one of the low-cost systems based on structured lighting and triangulation: a special projector or laser projects a strip, grid or point onto an object, and a computer creates a model by how one or more cameras see this projection on the object. But human teeth can not be placed on a rotating stand, and even with a place to place the scanner in the mouth, frankly, sparsely. Add to this two more cheerful circumstances: the person’s mouth is very wet (almost everything is filled with saliva), and human teeth, although this is not obvious at first glance, are also translucent. And now try to create a scanner that works in such conditions and produces a model of teeth at the exit with an accuracy of 0.02 mm locally and up to 0.25 mm on the scale of the entire jaw. We managed to do this for the first time about 7 years ago by the Israeli company Cadent, five years ago we bought it, and for the last three years iTero scanners have been the fruit of the joint work of the Israeli and Moscow Alayn teams. Today the company is engaged in a full scanner development cycle. There is an optical laboratory where a unique scanning scheme was invented, specialists involved in designing hardware, a special clean room for assembling it, and, of course, dozens of programmers writing code from firmware and drivers to application software that transforms raw data in real time. »The data in the 3D-model, cleans it from the" garbage "and allows you to edit it immediately. Today, such a scanner is the most complex and high-performance system I have ever worked on, and I don’t think I’ll lie if I say that our scanner still firmly holds the leading position on the highly competitive market. .



Did I mention above that aligners are a technology that revolutionizes bite treatment? Similarly, dental scanners are a technology that revolutionizes, perhaps, a good half of dental practices, and this will happen literally in front of you and me. The first generation of 3D scanners was losing heavily on traditional “fingerprints” in time, since the impression from the teeth can be easily taken in 5-10 minutes, and it took 10-30 minutes to scan the same patient, and sometimes even more. But today, the second generation of 3D dental scanners is entering the market, and it is already working fast enough to easily fit in 5-10 or even 3-5 minutes. Prices also fell: if yesterday scanners cost 40 thousand dollars and more, today they cost 20, and some simple models even 10 thousand. In this digital impressions

• Much more precisely - if in the old technology the crown had to be “doped with a file” at the place of installation, then crowns made from digital models ideally stand up the first time (and, I will add, as a result, they serve longer), the junction of the crowns and teeth is more dense and there are less caries )
• It is much more convenient to store and search (in some cases casts oblige to keep the law and whole cabinets are allocated for them)
• Allow you to organize a convenient "case history" - show how a patient's teeth wear out and change over time.
• Provide instant transfer of data between doctors (or, for example, to us for the production of alyner)
• Comfortable for the patient (well, at least our scanner :))
• They serve as an excellent visualization (on the screen you can examine in detail the tooth model enlarged hundreds of times from various sides, which contributes to the quality of its processing)

Well, from the pros, of course, reducing the number of consumables. The cost of materials for one print in the USA today is about $ 30, while the cost of a digital scan can be almost free. True, in our iTero we didn’t completely eliminate consumables for purely hygienic reasons: before each scan a special disposable sterile pad is put on the scanner.



It is interesting that many clinics today successfully combine the use of ultra-modern dental scanners with the good old manual process of making dental crowns using a plaster model. In this case, only the plastic model of the teeth is not produced by 3D printing (additive method), but is cut out from blanks by robots — CNC machines. This process is longer and more energy-intensive than 3D printing, requires a lot of maintenance costs (say the same replacement of cutters), however, it is not yet possible to abandon it because of the higher demands on the accuracy of the model. The plastic a-liner can be deformed by fractions of a millimeter when put on the teeth, but the metal crown should fit perfectly. However, it seems that even with the “digital” process the good old “dental laboratories” do not have long to live, because with no less success CNC machines grind not dental models, but immediately designed dental crowns of special zirconium material. Since the dental crowns are small, the robots “sharpened” for the production of crowns on digital models today resemble ordinary office MFPs in size and easily fit right in the dental office. Traditional couple of days of waiting crowns in clinics equipped with similar equipment are reduced to only 15-20 minutes. The only deterrent here is the high price of such devices, which starts from 40-60 thousand dollars, but in the newly emerging clinics it is partially balanced by the lack of need to purchase equipment and facilities for a traditional dental laboratory. But the advantages of the “numbers” are so obvious that, most likely, very soon this equipment, like dental scanners, will become mainstream.

However, by virtue of the overgrown volume of the article, more similar about scanners and printing, also another time. Subscribe to our hub, and we will tell a lot of interesting things and even share some production secrets :).