Modern prosthetics has undergone noticeable changes compared to the methods of restoring teeth that were used in the last century. Today, new, more aesthetic and durable materials, soft and comfortable prostheses are appearing on the market. In addition, the technologies for manufacturing structures for prosthetics are also changing. If earlier a dental technician could only make a prosthesis manually, today computer modeling and robotic production are actively used. And one of these methods is CAD/CAM technology for creating dentures.
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List of modeling programs to help the dentist
There are many CAD systems for 3D-designing teeth for the purpose of their subsequent manufacture. The most popular:
- Denta Pro;
- Dental Cloud;
- Dental Software;
- 1C: Dental clinic.
But technological progress has a positive impact on the development and implementation of new software, and therefore AutoCAD, ZWCAD and other design programs and visualizers are being improved, developed and become reliable assistants to dentists and dental technicians.
Description of CAD/CAM technology
CAD/CAM technology (read – “CAD/CAM”) applies not only to orthopedic dentistry, but also to mechanical engineering, to any field where high-precision modeling and production are required. In its full form, its name sounds and stands for as follows:
- CAD is Computer-Aided Design (using computer modeling or design),
- CAM is Computer-Aided Manufacturing (using computer technology to manufacture a product).
CAM systems process various materials – ceramics (conventional and hybrid), metal dioxides (zirconium and aluminum), titanium, cobalt-chromium alloy, steel, wax, plastics, etc.
CAD CAM is a unique modern technology for the production of dental prosthetic products using panoramic 3D computer modeling and further manufacturing of the prosthesis on milling electronic equipment.
The method is fundamentally different from standard production technologies with a manual method of higher accuracy of finished products, production speed and ease of operation.
The procedure includes the following steps:
- diagnostics using a computer;
- panoramic modeling of the system;
- production of the prosthesis;
- installation of the structure.
The main purpose of CAD CAM is the processing of high-strength materials and the manufacture of high-quality prosthetic structures that do not cause discomfort and have high aesthetic characteristics.
What is CAD and CAM?
- CAD-Computer-Aided Design (from English. computer assistance in design, modeling). After scanning the oral cavity, the model is created in a virtual space on a special software. As a result, the crown fits perfectly in size.
- CAM-Computer-Aided Manufacturing (from English. computer assistance in production). The data about the modeled product is transmitted to the CNC machine, where the crown is automatically turned out.
In the traditional production of crowns by casting, the patient experienced discomfort when creating impressions, and there could be situations when the crown did not exactly fit in shape. In addition, the production time of the prosthesis took an average of 2-3 days, during which the patient remained with open, sharpened teeth.
CAD/cam crowns are not only more accurate and more perfect than their cast-made sisters, but they are also produced much faster – the number of visits to the dentist is reduced to one. At the same time, the patient can personally observe the manufacture of the prosthesis, and it looks impressive.
Before the appearance of the innovative principle, casting was considered the best option, but there was also a method of soldering and stamping, as well as sintering and superplastic molding. At all stages of the methods, the possibility of deformation, difficult to predict shrinkage, inaccuracies in fitting and similar problems that are leveled by the computer method were not excluded. Such problems could previously cause inaccuracies in the casting of blanks, their molding and fitting, non-compliance with the technology, such as overheating of the material.
If the original CAD/CAM if it was implemented in dentistry due to volumetric modeling of a fixed structure, which was created by milling with an accuracy of up to 10 microns, now science has made a big step forward. Expensive milling cutters and blocks made of hard-alloy materials had to be used in the implementation of the technique. Naturally, the cost of the method was very high, but it was possible to optimize it a little with the introduction of volumetric printing techniques into the everyday life of the expert community. Within the framework of dentistry, doctors have the opportunity to create shapes with any geometry of the external and internal surfaces. At the same time, the method is currently divided into several separate directions:
– printing with wax; – polymers; – metal alloys; – ceramics and gypsum.
The first direction implies a thermal effect that melts the wax, the shape is projected by drops. In fact, the method is considered more perfect, but requires the use of casting, which retains its disadvantages. Due to the high error when creating the casting, the accuracy of modeling the component practically loses its meaning.
The second direction is convenient because it allows you to create collapsible models of an entire jaw based on plastic, bearing systems made of ash-free raw materials and high-quality prostheses, including removable ones. The method is divided into two subspecies: thermal printing and light polymerization. The first option is good for ash-free raw materials, thermoplastics, and the second-frames, crowns made of ash-free raw materials, polyurethane or acrylates.
In principle, the first two methods are similar to an inkjet printer, but the material is applied in three planes. Shrinkage is not observed at the same time due to the application of the composition by microscopic drops. With the exception of the simplest methods that do not give high accuracy, the SHS method (selective thermal sintering) is used in dentistry, which is divided into the inkjet and stereolithographic method (MJ and SLA, respectively).
Light polymerization is interesting because the raw material does not need to be heated, since it is initially liquid. Its solidification occurs under the influence of light of the blue spectrum.
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The stereolithographic technology is carried out in a bath with a liquid composite in which the object is repeatedly immersed. The curing takes place in stages, in layers and takes as much time as it takes to create a specific object. The technology is good for high accuracy, resolution, smoothness of the finished sample. However, you can work with only one color, some of the raw materials that are not used for the prosthesis become unusable in the process, which increases the production costs. Similarly, the price increases due to the small resource of the bath and the laser.
The third direction, that is, metal printing, implies the melting of the prepared material at a small point, which occurs due to the beam. There are several methods:
— direct deposition with the abbreviation DMD; — deposition using an LDT laser; — deposition with the participation of similar LCT equipment; — free — form production of LFMT; — deposition using an LMD laser beam; — fusion using an LMF laser; — sintering of a selective format using an SLS laser; — direct sintering of DMLS; — selective melting of SLM; — focusing using an LC laser;-melting using the electron beam method of EVM; — selective sintering SHS.
Each of the directions has its own specific features, positive and negative sides. The final choice of the technique depends on the technical equipment and the situation of a particular patient.
The fourth direction involves the use of gypsum or ceramics. According to the release technology, the technique has a lot in common with SLS, with the difference that the work is not carried out by a laser, but a binding component acts as a catalyst. In this form, a special glue acts, which interacts with the particles of the material. However, in dental practice, only the principle of working with ceramics has found application, and gypsum has given way to composites that surpass it in many parameters. Ceramics, in turn, is promising for creating frames, bridges and crowns.
It is important to remember that not in any clinical situation, an expert will be able to take advantage of the advantages of volumetric printing when creating products. In some situations, the best result can be obtained with the use of classical technology, which is not so bad given the significant cost savings.
What is CAD/CAM/CAE?
Often, together with the abbreviation CAD/CAM 1 (or instead of it) , you can find such a name as CAD/CAM/CAE technologies. Here CAE means “Computer-aided engineering” and is a system of engineering analysis in design. This program is combined with CAD/CAM and helps to solve more complex problems when creating prosthetic structures. The engineering component allows us to evaluate the performance and strength of a computer model to which conditions similar to real ones are applied. For example, you can simulate the closing of the jaws under pressure or the act of chewing and see how the whole system will work.
What does a computerized system consist of?
The following items are included in the CAD/CAM kit from any manufacturer:
- 3D scanner: it can be a small intraoral scanner, i.e. it takes data directly in the patient’s mouth (and you do not need to go through the not very pleasant procedure of taking ordinary impressions from the dentition). There are also more massive laboratory scanners (they scan a model made according to a physical classical cast of the jaws),
- specialized software( software), a computer and a monitor for a dentist or dental technician: digitized casts are loaded into a program where a virtual sample is created. If desired, the patient can choose the color and shape of the future teeth at this stage, and “try on” a smile using the Digital Smile Design program,
- milling machine: it can be several machines with different functions and capabilities at once – in some you can make single crowns or veneers, and in others you can make a prosthesis for the entire jaw on a metal or zirconium dioxide base. The machines receive all the data directly from the computer, and the participation of a dental technician in the manufacturing process is almost not required.
Some manufacturers, in addition to the above equipment, offer to supplement the CAD/CAM system with automated ovens for baking blanks, hoods, etc. Interestingly, the virtual model of the prosthesis made of zirconium dioxide is created by about 20% more, because after milling and during baking at 1700 degrees Celsius, the product will “shrink” by the same 20%. Of course, the exact “enlarged” dimensions are determined in a computer program, but with the participation of a laboratory assistant, in order to avoid mistakes.
CAD / CAM systems can be of closed and open types. In the first case, all the components of the complex are combined only within their own brand or model. And open ones are able to integrate with third-party programs and equipment.
The main features of the Cad Cam.
CAD / CAM includes two components, namely the design (Computer-Aided Design) and the production of the model (Computer-Aided Manufacture). Everything happens using computerized machines and scanners that help to collect information on the necessary positions of the oral cavity, process it and translate it into ready-made structures. Naturally, the role of a specialist in this process is far from the last, since it is necessary to control and make improvements to the received data. After converting the collected information and creating a three-dimensional model, the expert analyzes and adjusts it to the specific conditions of the patient. The processed file is transferred to the machine. The most modern solutions in terms of technical equipment are able to perform tasks with a complete analysis of the quality of the structure of the materials used.
According to this principle, crowns and bridges of various scales and degrees of complexity of the layout, telescopic and pharmacological crowns, inlays and veneers, as well as abutments of dental implants are produced.
All technical systems are classified into two groups, namely closed and open. The first option is aimed at using a strictly defined consumable material, the production of which is occupied by a specific company. Open ones are more promising, since they are able to use any raw materials components, regardless of their origin and brand.
How to make and install prostheses using
The stages of creating dentures using CAD/CAM technology are as follows:
- preparation: the dentist performs the sanitation of the oral cavity, removes bacterial plaque and tartar, determines the type of future prosthesis,
- taking casts: for this, intraoral scanning is most often used (it was discussed above). But in some situations, it is impossible to do without classical casts, according to which a plaster model will be created in the laboratory, and then it will be scanned,
- creating a 3D model: next, an orthopedic dentist and a dental technician work exclusively at a computer. First, a three – dimensional image of the scanned “jaw” is displayed on the screen, after which the prosthesis itself is displayed, followed by its virtual “fitting”,
- manufacturing of a dental prosthesis: the data is transmitted to the milling machine, with which the structure is turned out. After that, if it is a crown or a bridge for facing, a coating of natural-colored ceramics is applied, and the product is baked under the influence of high temperatures. Then the structure is ground, polished to give smoothness and shine by the technician in the laboratory.
The result is a dental prosthesis that will perfectly fit the patient and will not cause discomfort both in the first days after installation and after several years of active operation. By the way, the installation itself is carried out in one visit – first the prosthesis is tried on a temporary adhesive composition, and if there are no complaints, then on a permanent one.
Advantages and disadvantages of the method
The advantages of the systems include experts:
- short production time of the product – there is no need to perform the procedure of removing the impression, which allowed the restoration of the dental unit in one visit to the dentist.
- In the process of prosthetics, local anesthesia is recommended and only at the stage of preparing the organ for the upcoming implantation of the structure.
- The exception is the installation of ceramic bridge-like systems of a solid type – they are installed in two visits;
- the ability to see the result in advance on the computer monitor. In addition, the patient can choose the shade that is most suitable in color for natural
- organs and the doctor will choose the detailed shape of the model;
- turnkey work. The use of computer programs and modern innovative technologies made it possible to complete all the manipulations on a turnkey basis where previously only a seal was placed during the first visit.
- The material allows mixing ceramic elements in the necessary concentrations and as a result get their excellent compatibility, hypoallergenic and high service life;
- the frame is quite thin – no more than 0.4 mm, which eliminates the need to grind the teeth, they are only slightly ground, creating a rough relief that enhances the adhesion of materials;
- absence of darkening in places bordering on crowns, which contain metal alloys;
- the ability to qualitatively process the seal and the surface part of the enamel so that they will look whole;
- milling restorations are high wear resistance of crowns, strength and long service life;
- the ability to adjust and customize the system;
- exclusion of errors. Since the human factor is involved at a minimum in the production process of the part, therefore, the probability of error is practically excluded;
- high accuracy at all stages of product manufacturing, which can be provided only by modern computer technologies;
- devices made in this way do not cause physical discomfort, do not cause mechanical injury to the soft tissues of the gum and almost do not deform during operation, unlike analog versions made manually.
The technology also has its disadvantages:
- not every variant of prosthetics can be performed using this method, and the doctor decides individually how justified the use of CAD CAM is;
- in some cases, the finished result may differ from the computer version – the systems may differ in color and look not quite natural;
- the cost of the service is quite high, which limits its use to patients with a low level of income.
Advantages of CAD/CAM technology
CAD/CAM technologies have become very widespread in the world practice due to their undeniable advantages, the most significant of which look like this:
- precision in the manufacture of the prosthesis: it fits perfectly, does not violate diction,
- maximum wearing comfort,
- longer service life of the structure: since the gap between the walls of the tooth and the walls of the prosthesis does not exceed 5-10 microns, bacteria do not penetrate under it, and it does not loosen under pressure,
- the opportunity to work with the most durable materials such as zirconium
- dioxide and aluminium, disilicate lithium Lacanau ceramics, titanium alloys,
- automation of the manufacturing process, elimination of human errors,
- quick recovery process dental prosthesis is possible to spend 1 day – in the morning I came in prepared teeth and made casts, and in the evening returned for a new crown, veneer or tab made by CAD/CAM technology.
Overview of popular manufacturers and manufactured models of systems
CEREC and InLab by Dentsply Sirona (USA-Germany)
The American-German concern Dentsply Sirona produces two CAD / CAM systems:
- the CEREC system is the most famous and oldest on the market: we can say that it was with Cerec that the era of CAD/CAM in dentistry began in the 80s of the twentieth century. The kit includes an Omnicam scanner camera (which recognizes not only the color of teeth, but also gums), intuitive modeling software and 3 grinding and milling machines that can sharpen a crown in 4 minutes. CEREC is also equipped with a unique SpeedFire oven, in which the crowns are not only baked, but also glazed,
- InLab system: the manufacturer positions InLab as the most versatile in the world. In addition to scanners and software, the system is equipped with milling machines InLab MC XL (suitable for processing glass ceramics) and InLab MC X5 (in which complex prostheses are made), as well as an inFire HTC speed furnace with high-speed firing of ceramics and synterization of base metals in one processing stage.
DT2/FZ2 by DYAMACH (Italy)
Italian CAD / CAM systems from DYAMACH include a 3D laboratory scanner, software running on Windows OS, and 2 types of compact milling units:
- DT2 (for metal processing): The 5-axis machine is capable of milling single crowns (the base for ceramics), bridges of 3-4 crowns, beams and frames, individual abutments using dry and wet processing. Milling can be carried out continuously, and there is also a fault detection function,
- FZ2 (for processing resins, ceramics and zirconium dioxide): in most characteristics, it is identical to the previous one, but it has one difference – turning without water irrigation is preferred (although it can also be used here).
CAD/CAM system from Zirkonzahn (Italy)
The CAD / CAM complex from the Zirkonzahn company, which produces one of the most popular PRETTAU materials in the world (for veneers and crowns), is able to cope with various tasks in the manufacture of prostheses. This is possible thanks not only to three types of scanners (S300, S600, S900) and a well-developed software package, but also to several types of milling stations:
- M1: compact and high-precision device for the rapid manufacture of small prostheses,
- M2 Wet Heavy Metal and M2 Dual Wet Heavy Metal: more powerful machines that mill various types of materials (ceramics, zirconium dioxide and titanium). It is possible to use wet treatment,
- M4 Wet Heavy Metal: a large-sized station in which it is possible to grind prostheses from 4 large disks at the same time (in which material for extended orthopedic structures is usually supplied),
- M5 Heavy Metal: equipped with a special 6-millimeter drill for greater stability during the milling of extended prostheses. And there is also an ionization option available for working in sterile conditions,
- M6 Wet Heavy Metal: The installation is equipped with the same functions as the previous one, but has a larger capacity. Up to 14 disks of material can be placed in it at the same time, each with a size of 9.5 cm (and their change occurs automatically).
DGSHAPE by ROLAND (USA)
The DGSHAPE system from ROLAND (United States of America) has been produced for about 30 years and includes 3 milling machines:
- DWX-52D: efficient processing of even very strong materials in 5 planes, “smart” software (which tells you when and which cutter it’s time to change), a powerful filter (which does not allow environmental pollution),
- DWC-52DCi: in addition to the characteristics inherent in the previous device, it is equipped with an automatic disk change function with pre-installed prosthetic blanks – therefore it can work 24 hours 7 days a week. And at the end of the work, the device should send an email to the dental technician,
- DWX-42W: In this compact machine, materials (glass ceramics and composite ceramics) are processed under the influence of a humid environment. It is also equipped with an automatic change of milling cutters working in 6 planes. Suitable for the manufacture of single crowns and bridges, with a length of three crowns.
Zenotec from WIELAND (Germany)
The German company WEILAND, which produces the Zenotec CAD / CAM complex, very often improves its components. Today, the company offers modern 3D scanners – intraoral Scanpfosten and laboratory 3 Shape 2000. Zenotec also produces 3 compact milling units:
- mini: despite its miniature size (it fits on an ordinary table), this device is capable of performing any restorations, but in a small amount in one cycle of operation,
- selection: designed for quick and easy processing of acrylic materials (plastics) for prostheses, templates, etc.,
- select hybrid: accommodates up to 8 disks of material, which, if necessary, are changed automatically – so the device can work for a long time without stopping.
CORiTEC by IMES-ICORE (Germany)
The CORiTEC system from the German manufacturer IMES-ICORE is characterized by high quality and includes several modifications of milling machines-CORiTEC one, 150i, 250i, 350i, 650i. The sizes range from compact (portable) to powerful large-sized robotic machines. Moreover, the processing of materials can be carried out in two modes (dry and wet), as well as in several planes (at least four, maximum 11). Thus, absolutely any restorations can be made on this system.