Computer science in orthodontics
We can already say that the 21st century is the digital century. The phenomenon has invaded all sectors, and dentistry is no exception: providing information to dental practices is a reality that is becoming increasingly commonplace. Thus, who could have foreseen the possibility of systematically using 3D imaging in dental practices a few years ago? At the same time, new information and communication technologies (NICTs) are taking over from traditional methods, opening up exciting prospects for the future.
2/Definition.
Computer science, a contraction of information and automatic , is the “science of automatic and rational processing of information as a support for knowledge and communications. Automatic processing of information requires capturing information through input devices, transmitting this information through transmission lines, storing it in memories, processing it in a processing unit using software and, finally, returning it to the user through output devices” (Le Petit Larousse, 2008).
The main machine dedicated to the transport and processing of information is the computer. In practical terms, it transforms, through the processing that has been defined for it and that it applies, input data into output results.
In a computer, all information is coded in the form of bits ( binary digit ), an elementary unit of information which can only take, as its name indicates, 2 distinct values (0 or 1). Subsequently, these bits, embodied by electrical signals, will be transferred, memorized, logically composed in the processing circuits of computers.
3/Programs/software.
3.1/Operating system.
A computer, without instructions, is of little use. The instructions are contained in programs called software . Among these programs, there is one that is essential to the functioning of the computer. This is the operating system, “software managing a computer, independent of application programs but essential to their implementation.” (Le Petit Larousse, 2008).
We can cite:
- MS-DOS: old Microsoft operating system;
- Windows NT, XP, Vista…;
- Mac-Os: operating system for Macintosh computers;
- Linux, Unix…;
3.2/Application Software.
The success of microcomputers came about when software was developed to create useful applications. Application software allows computers to perform a variety of tasks:
- word processing ( Microsoft Word® ),
- spreadsheets ( Microsoft Excel® ),
- drawing, photo editing ( Adobe Photoshop® ).
3.3/Specific application software for dentistry.
These only meet the needs of a dental practice, and nothing else. They will be developed in the next section.
4/Applications of IT in dentistry.
A dental surgeon’s working time can be divided into administrative time, accounting time, and clinical time. The first two phases are both time-consuming and tedious. And this is where IT proves to be a valuable aid. Indeed, it performs repetitive tasks effortlessly, error-free, quickly, and efficiently. From an entry, generally in the care sheet, the recorded data is processed and transmitted to all the program compartments where it is needed: this is the difference with manual entry, which previously required transcribing the same information several times. In addition, the clarity and standardization of the presentations of the editions facilitate reading for pharmacists, social security, or even the tax authorities.
4.1/Administrative applications.
Administrative time includes maintaining patient records, preparing treatment sheets, documents for mutual insurance companies and other supplementary insurance, prescriptions, quotes, managing “third-party payment” and other deferred payments, following up on unpaid invoices, managing control reminders, etc. It also involves managing the traceability of products used during care and decisions concerning the stock of consumables, investments (renewal and/or new acquisitions of devices, instruments, etc.), ongoing training for practitioners and staff, etc.
Patient File.
There is no formal legislative provision specifying that a Dental Surgeon must keep a patient file, but it is an obligation inherent in the medical contract; case law has established this obligation.
What is its role? A patient’s file gathers all of their medical and administrative information, allowing for comprehensive care. The Dental Surgeon therefore collects not only information relating to the oral sphere, but also all medical data that may interfere with their care.
Thus, office software allows for convenient and automated file management. Data concerning the patient’s civil status, social security information (health insurance codes, mutual insurance companies, CMU, etc., often retrieved from the Vitale card), medical history, and current medications are recorded there, as are treatment plans, comments, quotes, and other correspondence. The dental chart, procedures performed, and fee payments are entered and directly linked to the treatment sheet output.
Medical imaging—most often digital X-rays, but also videos and photographs—is attached.
Prescriptions, quotes, and correspondence.
A number of tasks can be automated using computers.
Prescriptions, medical questionnaires, and other correspondence with fellow healthcare professionals or dental technicians are among them. As such, email exchanges, which are quick and economical, are increasingly popular among professionals.
Reducing and editing prescriptions, based on a drug library established by the dental surgeon, are facilitated by the computer, which recalls, if necessary, drug incompatibilities and the patient’s health problems. Some software programs are interfaced with the Internet, such as Dental-On-Line.
Standard prescriptions (hygiene motivation, premedications, etc.) for redundant and frequent procedures can also be saved in advance; they can simply be edited on demand.
Regarding correspondence, pre-written texts are offered by dental office software:
- letters to colleagues,
- letters to doctors,
- reminder letters,
- control letters,
- certificates…
Appointments.
Aside from the “appointment reminder” function mentioned above, computer-based appointment management doesn’t seem to be perfected yet, or at least it hasn’t yet proven itself compared to the usual, practical and efficient weekly planner. Some software programs have built-in reminders that appear on the day the action needs to be performed, such as “remind the prosthetist” or “assistant’s birthday.” This type of utility, a sort of electronic Post-it®, is found in accounting applications, where it reminds you of the due date for direct debits, for example.
4.2/Accounting applications.
Accounting time involves maintaining income and expense books, accounts, amortization schedules, income tax returns, etc. For some, accounting requires a second software program or the use of an accounting firm. The office software only ensures the maintenance of the income book (recording the date, patient name, amount, and payment method) and the expense book (entering the date, recipient, amount, payment method, and description).
4.3/Clinical applications.
After having explained the contributions of IT in the administrative and accounting fields, let us look at its clinical applications in the chair.
Digital radiology.
Digital radiology now offers practitioners the ability to take all kinds of images, from retroalveolar to 3D, right in the office. Immediate image acquisition, a significant reduction in the doses of ionizing radiation received by patients, and ease of image storage and transfer have been key reasons why many dental surgeons have adopted digital radiology. Furthermore, it is an effective tool for patient education: explaining and showing a curious lesion to the patient is much easier on a screen than on a 4 cm x 3 cm retroalveolar image.
Digital photography.
The advantages of digital photography are numerous: instant results, immediate assessment, visualization on different media, image enhancement via software, etc. In dentistry, digital photography has its place. It is useful in areas such as patient education, prevention, communication between the medical team and the patient, prosthetics, but also in order to collect as much information as possible for maintaining medical records.
Video imaging.
The main areas of video use are patient education and motivation, therapeutic or aesthetic preview, documentation of clinical cases, and, to a lesser extent, diagnosis (cracks, fissures, etc.).
Surgery.
Computer-assisted surgical procedures (CASMP) are now a clinical reality: in oral implantology, of course, and perhaps soon in other fields, such as periapical surgery, for example.
The Nobel Guide system.
The Nobel Guide system developed by Nobel Biocare is a planning software program that simplifies implant placement.
The Cad-Implant system.
The Cad-Implant system is broadly similar to the previous protocol but has some differences.
5/CONTRACT OF COMPUTER ASSISTANCE IN ORTHODONTICS.
Today, the development of computer science allows us to glimpse the possibility of working systematically and flexibly on three-dimensional images. This new technique is a real alternative to traditional casts. Indeed, in addition to the 3D reconstruction of the craniofacial complex, it allows us to transform traditional “gypsotheques” into virtual gypsotheques thanks to the digitalization of orthodontic models. This gives us the possibility of quickly obtaining documentation material and a remarkable saving of space and time.
There are numerous software programs allowing the use of digital models, which are increasingly effective in assisting with diagnosis, also allowing us to simulate and visualize the results of your treatment plan. In addition, other applications such as bracket placement and the individualization of multi-band appliances are available.
5.1/Three-dimensional representation of dental arches and applications:
The digitization of dental arches is a way of archiving study models, thus making it possible to produce a durable image, without the risk of loss or damage to the original models.
In addition, this storage is easy: if a model requires 5 MB of space, a CD-ROM can then contain between 130 and 145 study models. A 60 GB hard drive can therefore contain 12,000 study models. Thus, thanks to the digitization of study models, it is no longer necessary to provide storage space, which can reach several cubic meters each year.
Diagnosis and treatment.
Thanks to new advances in 3D scanning, there is now software that allows for highly accurate examinations of study models, saving time. This software will be described later. This allows treatment plans to be simulated, such as the closure of spaces after extractions. This will help the orthodontist make a diagnosis and implement the most appropriate treatment plan for the case.
Likewise, thanks to scanning, arches and brackets can be custom-made; this aspect will be developed later.
Communication.
The scanning of dental arches will allow the orthodontist to easily learn about and discuss patient treatment plans with other healthcare professionals. 3D recordings can be easily shared with other colleagues via the internet, saving time and effort in implementing the treatment plan. It is no longer necessary to meet with people in person.
Communication between the orthodontist and their patient is also simplified. Thanks to software, the practitioner can simulate treatments such as the closing of interdental spaces following extractions, for example. This makes explanations easier because the patient sees better what is going to be done and therefore better understands the proposed treatment plan . We all know that a patient who understands what is going to be done will be much more cooperative and attentive to the orthodontist’s prescriptions. Simulating and showing the patient allows you to reassure them and give them confidence for a better final result.
5.2/The different software for three-dimensional casts
OrthoCad®: diagnostic tools:
Measurement of overjet and overlap.
The possibility of making cuts, mentioned above, will facilitate the measurement of these two parameters.
Measurement of the arch length.
These measurements are made using automatically generated arches that can be modified at will.
The adjustment is made using reference points located on the arches.
Mesio-distal measurement of the teeth.
Virtual calipers and zoom allow for very precise adjustment of each measurement.
Mesio-distal measurements are taken on each tooth and listed in a Table.
Calculation of the difference between available space / required space.
The required space corresponds to the sum of the mesio-distal diameters of the teeth, and the available space is calculated using the virtual arches described previously.
This sum is positive when there are diastemas and negative in the case of crowding.
Bolton analysis.
Bolton analysis allows a comparison to be made between the mesiodistal width of maxillary and mandibular teeth, the calculation of the Bolton index is carried out automatically.
Possible measurements on the arches.
At the arch level, three types of measurements can be carried out:
UPAW maxillary intermolar width
LPAW mandibular intermolar width
UCD maxillary intercanine width
LCD mandibular intercanine width
LAAW mandibular interpremolar width
UAAW maxillary interpremolar width
Invisalign®:
Align Technology Inc.® has developed a treatment method called Invisalign®.
This system represents a true technological breakthrough thanks to its aesthetic approach to treating malocclusion. Thus, thanks to 3D imaging and CAD/CAM technology, Invisalign® offers a new concept of “invisible” appliances.
The Invisalign® system was marketed in June 1999, and currently more than half of American and Canadian orthodontists are qualified to use this system. During their training, orthodontists become familiar with:
- the criteria for selecting cases that can be treated by Invisalign®;
- taking impressions with polyvinyl-siloxane;
- the software that allows them to communicate with society via the Internet
5.3/Clinical applications.
Virtual setup.
The software described above for its “diagnostic” function also has a clinical interest. Thus, they allow, among other things, the creation of a virtual setup. This application that we will describe in OrthoCad®, is also available for other software such as Emodels® or Bibliocast® and others.
The creation of computer setups from digital models is based on a Stratith Wire approach: the teeth are connected to the arch via a fixed appliance and their movements are constrained by the mechanical properties of these appliances.
Other possible features of the setup:
Precision of bracket position.
Once the appliance is in place, it is possible to refine the positioning of a bracket. We thus have the possibility of correcting the position of each bracket according to criteria that the software does not have: when there is a crown-root angulation
Arch shape customization.
It is possible to modify and individualize the shape of the dental arches. Thanks to the “Wire Shape Control” function, modifications can be made at will.
Taking into account the third molar.
If the third molars are on the arch, it is entirely possible to integrate them into the setup manually. The software does not ignore them.
Bracket alignment.
The bracket alignment plane can be adjusted to avoid interference between the maxillary and mandibular appliances.
Manufacturing of custom arches and brackets in lingual
Incognito® is the system of lingual brackets and wires entirely individualized, designed according to the treatment plan defined by the practitioner and adapted to the anatomical particularities of the patient. To achieve this result, high-tech processes are used:
-digitalization of the set-up in three dimensions by optical scan;
-integration of manufacturing and positioning systems in a single process;
-computer-assisted drawing and positioning of the brackets. This data is then used for the production of Incognito® locks. This technique has allowed a simplification of the transfers necessary for carrying out the laboratory steps for the manufacture of the brackets.
-computer-assisted manufacturing of the arches, according to the positioning of the brackets, thanks to a robot.
Fabrication of custom arches for vestibular treatment.
As with the lingual technique, there are 3D software programs that allow for the fabrication of custom arches for vestibular treatment. The SureSmile® software allows this maneuver for the vestibular technique. During the computer setup, the practitioner makes the clinical choices for their treatment. Then, this clinical data is transmitted via the Internet to the company Orametrix, which will manufacture arches that conform to the data, using a robot.
Indirect bonding.
The systems described above allow, among other things, the creation of bonding splints. After completing the setup, the practitioner requests the splints online. These will allow the brackets to be positioned in accordance with the clinical data chosen during the setup. The technique for manufacturing the splints is the same as that used in the mouth, the only difference being that it is used in the laboratory on plaster models.
Bonding splints are particularly essential in lingual techniques as in the Incognito system. With Incognito, the bonding technique is as follows:
- reception of silicone gutters;
- checking and degreasing the gutter with acetone;
- intraoral sandblasting (using a sandblaster: 50 micrometer alumina, 3-5 bars) for 3 to 4 seconds per tooth and away from the gum to avoid bleeding. For this cleaning, the patient is protected;
- the teeth are well isolated using a Dry Field and the placement of a Dry Tip in each cheek;
- The tooth surfaces are then prepared using 37% orthophosphoric acid gel;
- Rinsing and drying teeth, placing cotton balls when it comes to the mandible;
- installation of the bonding system on the composite heels and on the faces of the teeth;
- insertion of the gutter which is held firmly. Then removal of the spacer followed by the gutter
- Finally, excess adhesive and silicone residue are removed; the occlusion is checked;
- the gluing is finished and the arch can be put in place;
Future prospects in orthodontics.
The digitization of casts represents a major step forward in assisting diagnosis and treatment. However, the lack of root representation is regrettable. Three-dimensional reconstruction from tomographic slices could be the solution to this problem, but this second technique also has its drawbacks. Indeed, as mentioned previously, this technique has the limitation, on the one hand, of a lack of definition of the crowns and, on the other hand, artifacts are visible when there are metal restorations. Because of this lack of precision in the reconstruction of dental crowns compared to 3D models, this technique cannot replace the digitization of arches. In addition, waiting lists for scanners constitute another difficulty in using it as a routine examination in orthodontics. To overcome these problems, research tends to integrate coronal images from virtual models with three-dimensional reconstructions from tomographic slices. This combination would allow precise visualization of both crowns and roots.
Computer science in orthodontics
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