The Virtual Articulators: A Review

Dr. Vaishali Chuniyani; Dr. Rakshit BM; Dr. B. Mamatha

ABSTRACT

The latest breakthrough in the world of articulators was the introduction of the VIRTUAL articulators in 2003. This system not only simulates the temporo-mandibular joint movements in the modelling software by viewing it on the computer screen, but is also the only system that allows the dental technician to take the measurements of his/her own articulator, to scan it and to add these data to the software database. The articulator dimensions are faithfully saved in the software so as to be able to virtually articulate the models.These virtual articulators marked a groundbreaking leap in dental practice, seamlessly integrating virtual reality technology to replace traditional mechanical articulators. This review emphasizes VAs' evolving role in digital dentistry offering streamlined procedures, reduced errors, and improved occlusal analysis. , Therefore improving patient outcomes.

Keywords:

Virtual Articulators(VA), Digital Dentistry, Mathematically simulated (MS) ,Completely adjustable (CA), CAD CAM Systems

INTRODUCTION

Digitization has become an essential aspect of modern prosthodontics, with greater part of the of treatments being based on digital technology 1.Digitization has become part and parcel of the contemporary prosthodontics with most of the procedures being carried out with the digital techniques presently and the probability of most in near future.Thus digitization has modified the conventional procedures.

Digital dentistry has revolutionized the field of dentistry, transforming the way dental care is delivered. By leveraging advanced technologies, digital dentistry enhances the accuracy, efficiency, and customization of dental treatments. By embracing these digital technologies, dentists can deliver high-quality, precise, and customized treatments, ultimately improving patient outcomes.There is endless scope of digitization and technology in prosthodontics- let it be in the clinical and lab procedures , one such use is --use of the virtual articulators(VA)

This review emphasizes VAs' evolving role in digital dentistry offering streamlined procedures, reduced errors, and improved occlusal analysis. By incorporating patient-specific data and enabling fully digital workflows, VAs optimize clinical decision-making and improve patient outcomes marking a shift towards more efficient and precise dental care.

Articulators are mechanical devices that represent maxilla, mandible and temporo-mandibular joints (TMJs).they are broadly classified into two cateogories (a)Mechanical Articulators (b) Virtual Articulator

Mechanical articulator : “It is a mechanical instrument that represents temporomandibular joints and jaws, to that maxillary and mandibular casts may be attached to simulate some or all mandibular movements”. (GPT 9)

A virtual articulator is an advanced digital tool designed to simulate the movement of the jaw, enabling dentists to analyze and evaluate occlusion (the contact between teeth) in a highly accurate and efficient manner. Also called as `SOFTWARE articulators`.

The concept of virtual reality is based on electronic technology, built on computers that have been connected to the near future of dental practice and dentistry. The virtual articulator is an example of virtual reality-based usage in restorative and prosthetic dentistry that considerably decreased the drawbacks of the MA through modeling of collection of the data, which allows analysis of static and dynamic occlusion as well as jaw relation of the patient. Therefore Virtual articulators are software tools that use virtual reality technology to improve healthcare outcomes 2.

Virtual articulators (VAs) allow a complete occlusion analysis using dental models that replicate all mandibular motions in static and dynamic scenarios. VA when executed in addition to other software enhances treatment planning and patient education.VAs are additionally useful as an educational instrument to demonstrate the patients' different treatment alternatives. Szentpetery described the first virtual articulator software in the late 1990s, while Bisler et al. from Germany launched the first VA in 2002 at the University of Greifswald 3,4,5.

VIRTUAL ARTICULATOR WORKFLOW

MECHANISM OF VIRTUAL ARTICULATORS :

The processes involved are ⁶:

1. Data Collection:

3D scan of the teeth and jaw.

By using an intraoral scanner or scanning dental impressions or plaster models using a model scanner.

The movement of the jaw was analyzed using Jaw Motion Analyzer (JMA), which captures dynamic elements of occlusion and masticatory functions.

Ultrasonic Sensors are strategically placed on the patient’s jaw and a headbow is used to capture movement in multiple dimensions.

The system tracks rotative and translational jaw components (e.g., lateral, protrusive, and retrusive movements).

2. Building a 3D Model:

STL or XML files.

The software creates a digital 3D model of the teeth and jaws.

Using information from the jaw movement tracker, the virtual articulator starts simulating real-life jaw motions—opening, closing, or moving side to side.

3. Simulating the Movements:

The Motion Analyzer Tool recreates how the teeth meet and move against each other as the patient chew or speak.

Using the softwares like VXscan, DentalCAD, DentCAM, dentists can adjust settings like bite pressure during occlusion to identify areas where excessive or uneven pressure occurs and ensure proper occlusion without any unwanted interference and angular movement for simulating realistic and individual jaw movements

thus creating an accurate digital copy to ensure that the teeth occludes correctly and do not interfere with each other which is important for proper function and comfort.

4.Checking and Adjusting:

The software highlights areas where the teeth may not meet evenly, allowing the dentist to visually identify any discrepancies in alignment.

Adjustments are made by virtually modifying the bite, tooth angulation, or positions in the software.

This helps to fine-tune the occlusion (bite relationship) before any physical work is done, ensuring a more favorable outcome. The best part is they can make adjustments right there all in the digital model and avoiding the hassle of dealing with physical impressions.

5. Treatment Planning:

Based on the data gathered from this digital process, the dentist can precisely plan treatments like crowns, bridges, or braces, ensuring they are adapted to fit the natural function of the teeth to maintain the occlusion
This level of customization helps improve the fit and effectiveness of the dental work, minimizing the need for adjustments and enhancing overall treatment outcomes.

6.Data Exportation for CAD/CAM Fabrication CAD Integration:

After occlusal refinements, the final model is exported in compatible formats (e.g., STL, XML) for integration into CAD/CAM systems, where restorations are fabricated based on the individualized occlusal plan established by the virtual articulator

Virtual articulators (VAs) are majorly classified into two following types 7 :

(a) Mathematically simulated (MS)

(b) Completely adjustable (CA).

	Mathematically simulated articulators	Completely adjustable virtual articulators
Designed by	Szentpetery	Gaertner and Kordass
Basic units	Does not require extra units; depends on mathematical simulation of articulator movements	Head stabilizer, sensor pen, transmitter, sensor for lower jaw, receiver, bite fork
Measures	Protrusion, retrusion, condyle angle, laterotrusion, Bennett angle	Calculates waves of the receiver and transmitter microphone via the triangulation method to locate the areas of patients’ mandible
Reproduction	Enables dentist to replicate the motion of an MA, which makes it a fully adjustable 3D VA	It records and reproduces the highly specific mandibular movements employing a computerized jaw recording device known as jaw motion analyzer
Drawback	The biggest drawback is that it functions as a mean value articulator and it is impossible to expect movement course of each individua	Special instruments, like a lower jaw motion-tracking system, are required. It lacks a standardized virtual format for storing lower jaw movement. As a result, this system is incompatible with a few virtual articulator software packages
Example	Szentpetery’s virtual articulators and Stratos 200 (Amherst, NY: Ivoclar Vivadent)	Stratos 300 and SAM2 (Gauting, Germany: SAM Prazisionstechnik GmbH)

The completely adjustable VA uses digital tools and accessories to replicate the exact pattern of motion of the mandible.
The primary indication for the CA VA type relates to complicated circumstances in which it is necessary to evaluate the occlusal plane's morphology during mandibular motions to prevent interferences with excursions7.
The exact movement pattern of the mandible is recorded using an electronic jaw registration system called Jaw Motion Analyzer.
The MS type is an average value articulator; it is necessary to alter other settings to replicate mandibular movements.
The primary clinical indication for the MS type pertains to situations where the prosthesis's occlusal morphology can be planned only by replicating the relationship between the arches7.
Virtual articulators use mathematical simulations to accurately mimic the movements of traditional mechanical articulators, which are tools used by dentists to study jaw motions.

NECESSITY OF VIRTUAL ARTICULATORS

The capacity of a mechanical device to imitate the differing characteristics of biological systems, i.e., the constantly changing circumstances of jaw motions and dependent features, is restricted.
The casts cannot accurately capture the dynamic circumstances of occlusion within the mouth.
Many issues with the procedure and dental materials reduce the precision of reproduction. These issues can include the following: the changing shape of registration materials such as heat-sensitive waxes, inaccuracies in cast repositioning into bite imprints, articulator instability, and the proper alignment and maintenance of the MA.
Because of these issues, the replication of dynamic, excessive contact appears to be less reliable. These issues can be overcome by replacing the MA with a virtual articulator.

PURPOSE OF VIRTUAL ARTICULATORS:

Accurate Bite Analysis: Virtual articulators give dentists a detailed, 3D view of how a patient’s upper and lower teeth come in contact fit together. With this level of precision even minute issues that might be missed with traditional methods can be detected.
Better Treatment Planning: Virtual articulators serve as a highly accurate guide when designing dental restorations, such as crowns, bridges, and implants ensuring a more comfortable and functional fit of the prosthesis8.
Improving Results: virtual articulators allows dentists to identify potential issues, like improper bite or interference between teeth, and being able to make adjustments based on the simulations leading to more effective treatments and better long-term outcomes for the patient8
Saves Time: Traditional methods of diagnosing bite problems and planning treatments often involve taking physical molds and making repeated adjustments. Virtual articulators streamline this process by providing instant, accurate data. This reduces the time needed for diagnosis and treatment planning, and cuts down on follow-up visits for corrections or refinements7
Clearer Communication: Virtual articulators are advanced digital tools that generate precise 3D models of a patient's bite, allowing the dentist to assess and analyze dental and occlusal problems like cavities, cracks, misalignment, overbite or crossbite with greater accuracy. These visual representations help dentists effectively communicate the nature of the problem and treatment options, offering a clear understanding for patients and improving the overall treatment planning process9

ADVANTAGES

It facilitates superior level of interaction among the dentist, dental technician, and patient.
Simulating real patient specific data
It works in combination with cad cam systems to develop the occlusal surface, analyzes gnathic and joint disorders, eliminates manufacturing problems.
It is more time efficient and can even imitate the patient.
It supports in patient education and rehabilitation as well
Acts as a 3D navigator

LIMITATIONS

The casts have to be mounted with gypsum onto the physical articulator using a physical facebow, and then, they must be scanned in this position.
The cost is substantial.
Incompetenct of dental technician in interpreting data acquired from of sensors, scanner, minor changes, integrating motion parameter, and so on can be troublesome
Ethical considerations related to data privacy and security need to be addressed

CONCLUSION

The VA is an accurate piece of software that operates in combination with CAD/CAM systems to replace MA and thereby prevent faults. In dynamic simulations, these systems can be improved by utilizing four-dimensional (4D) technology in the upcoming years. These are the reasons why virtual reality has gained popularity and transformed dental practices. The virtual articulators represent a promising technological advancement in which patients will be more comfortably treated with greater convenience and precision.

REFERENCES

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More References are available on request