14.1 Introduction

In the present day, it is impossible to imagine daily life without digital technology. Every aspect of our lives is dependent on digital support, from computers to mobile phones. One of the milestones considered in the medical field is the introduction of 3D radiological techniques such as CBCT in dentistry. Other digital advancements used in dentistry are CAD/CAM, intraoral scans, digital shade selection, etc. all of which have been covered in detail in this book. All this digital information facilitates data availability and storage and can further be utilized to create a special computer-simulated patient casts, the so-called virtual patients. In one sense, virtual patients can be considered digital simulations of real human beings and their findings [1].

This chapter will provide the reader with information about virtual reality and its more recent variant, augmented reality along with the differences between them, clinical applications of these techniques and their advantages and disadvantages. Future prospects will also be discussed briefly.

The reader must keep in mind that the purpose of this chapter is not to give detailed information behind the principles of information technology and knowledge; rather, it is designed to give an overview of the newer terms such as virtual patient (can also be referred to as the digital patient), augmented reality and its application in the field of dentistry. For more information about the background of the described technologies and their widespread use in other areas, the reader is referred to the existing literature of information technology, health informatics, medicine and physics.

14.2 A Virtual Patient

The idea of a virtual patient can be explained by dividing it into three main parts. The first part concerns with the concept of creating a database with patient’s medical and dental information/history popularly known as electronic health records (EHRs). EHRs are a part of teledentistry, which can be defined as “the practice of using video conferencing technologies to diagnose and to provide advice about the treatment over a distance”. It combines telecommunications and dentistry, with the exchange of information, both clinical data and images, over remote distances for consultations and treatment options [2]. Teledentistry, patient care and education can be delivered as live video (synchronous), store and forward (asynchronous) and remote patient monitoring (RPM) [3].

It aids in distant learning via web-based self-instruction and interactive video conferencing in addition to interprofessional communications where the specialist observes the procedure in one part of the world and, in the other part, another dentist makes a digital project of complete implant and prosthetic construction and route the direction for the placement of implant or extraction of wisdom teeth through navigation.

OrthoCAD and models are two popular systems that help orthodontists achieve success with distant patient’s treatments [4]. Another advantage of teledentistry is that these cumulative audio/visual data or live consultations can reduce fear and anxiety among children and people living in rural areas.

Electronic health records with standardized diagnostics and universally accepted data formats help in collecting data from different clinics. These data can vary from routine treatment to specific surgeries. These cumulative data not only minimize storage space but also help further in research especially diagnosing rare diseases. An example is the universal dental diagnostic coding system (the Standard Nomenclature for Dentistry (SNODENT)) [5].

The second part is digitally connecting diseases with their symptoms, EHRs and treatments. Thus, while electronic case scenarios can be created for education and training purposes, this information can be used as a source for research as well. Lastly, the third part comprises a 3D computer-based reconstruction of human body parts, for example, head, neck or even the entire human body.

From a dental perspective, this 3D visualization is very significant as it is based on previously captured digital dental findings such as CBCT radiographs and facial and intraoral 3D scans. The digital assembly of all this information requires the presence of an ordinary analogue (non-digital) information transformed to digital information. A specially developed software is then used to bring these data together and to create a digital simulation of a patient—a virtual patient.

14.3 Understanding the Difference between “Virtual Reality” (VR) and “Augmented Reality” (AR)

Virtual reality (VR) or “near reality” technology is defined as a method by which, an environment is three-dimensionally simulated, giving the user a sense of being inside it, controlling it and personally interacting with it [6]. It uses artificial scenes that are computer generated with no connection to reality. The user is exposed to a realistic multidimensional visual stimulus which creates a virtual environment for the assessment of various anatomical regions of the body for the diagnosis, planning and surgical training [7]. This is experienced via head-mounted goggles and wired clothing.

The concept of virtual reality requires the development of specialized software to manipulate the recorded 3D images of the dental and orofacial morphology. Four main types of 3D imaging systems that are currently in use and essential for virtual planning are cone-beam computed tomography (CBCT), laser scanner, structured light scanner and stereophotogrammetry [8].

Augmented reality (AR) is a variant of VR, an emerging technology. It was first developed by Ivan Edward Sunderland in 1968 with a binocular system “kinetic depth effect” made of two cathode-ray tubes. It wasn’t until 1991 that the definition of “augmented reality” was first described by Tom Caudell of the Boeing Company as “a technology that superimposes a computer-generated image on a user’s view of the real world, thus providing a composite view” [9, 10] (Fig. 14.1). AR is to “virtualize” the virtual image into the real space, creating a completely virtual space around the user’s eyes to replace the real space. Thus, it combines virtual reality with a 3D real environment specific to an individual patient to achieve an integral image, using semi-transparent glasses, to augment the virtual scene with the real one [11]. Hence, the user feels in the real environment instead of being engaged in a computer-generated world (like in VR).

Virtual reality can either be interactive (user can modify the virtual environment) or immersive (sense of being in a non-real virtual environment). Based on the level of presence experienced by a user, virtual reality technology can be further classified into immersive and non-immersive virtual reality.

Immersive reality experience includes interaction and involvement of the user within the virtual environment to create a sense of being “present” in the environment. It combines virtual reality with the added characteristics of the captured environment to provide the operator with the sense of being in the scene, able to visualize the recorded image in 3D, 3D audio direction and interact using a wearable device that detects eye movements and tracks leap motions of the hands. The user is detached from the real world and gets a feeling of being completely surrounded by a virtual computer (psychophysical experience). Non-immersive virtual reality involves computer-generated experiences on a desktop, while the user interacts with a mouse, in a virtual environment [12]. Immersive reality is similar to augmented reality but the user is interacting with a digital 3D world recreated through 360° real records. The 360 records recreate the continuity of the surrounding with no interruptions.

Augmented reality is commonly confused with virtual reality since both have many components in common, in spite of the completely different outcome. Virtual reality, as explained, is a virtual immersive environment where the user’s senses are stimulated with computer-generated sensations and feedbacks and generates an “interaction”. Augmented reality, on the other hand, generates an interaction between the real environment and virtual objects.

For example, a virtual reality system would be a head-worn helmet stimulating navigation inside the human body and permits the user to explore it on the base of virtual three-dimensional reconstruction. A similar example with the augmented reality would permit the user to directly observe a human body and to see virtual objects on it, or through it as the anatomy of the body was superimposed [9, 10]. Another way of explaining can be in surgical trainings and procedures.

The 3D acquired images of the head and neck region will provide a platform for education and training, whereas the recorded images can also be superimposed into the patient for a surgical procedure to be carried out in an environment of augmented virtual reality.

The use of AR (with the use of special glasses and an integrated screen) is a fairly new development in the field of medicine and dentistry. However, substituting virtual reality with augmented reality means to superimpose virtual objects to the reality in a precise and reproducible way keeping in mind, the dimensions of space as well as the users and patient’s movements. This is still a controversial topic as it is highly affected by the system used. The most commonly used systems are head-mounted displays and half, silvered mirror projections, both of them are valid systems for augmented reality and different settings as described by Azuma et al. [9].

14.4 Uses of VR

14.4.1 Education and Training (Preclinical and Clinical)

Historically, dental education has been restricted to phantom heads and artificial teeth mimicking different case scenarios. Nowadays, virtual 3D simulators are available (Fig. 14.2). This virtual environment comprises of one visual display on which a mouth or even an entire patient’s head is projected. These displays can be integrated into special eyewear in order to enhance the perception of reality and haptic input devices can be utilized to provide the user with the opportunity to receive feedback in terms of tactile sensations. A study done by Buchanan concluded that students trained with virtual reality simulators learned faster, practised more procedures per hour, accomplished the same levels of competence as traditional preclinical laboratories and requested more evaluations through the computer thus reducing instructor-student evaluation time [13].

Initial research for using VR and AR in dental education was conducted by Kim et al. They proposed a dental training system with a multi-modal workbench providing visual, audio, and haptic feedback. Haptics is the science of studying the sense of touch [14]. This system used volume-based haptic modelling which represents a tooth as a volumetric implicit surface and permits the drilling of a tooth. However, it is limited to a spherical tool [15]. Wang et al. developed a simulator that allows probing and cutting of a tooth model, but the virtual tool implementation was limited to a spherical shape, as with Kim et al.’s 2005 system [16]. These studies were considered incomplete.

Haptics offers an additional dimension to virtual reality or 3D environment. In combination with a visual display, haptic technology can be used to train people for tasks requiring hand-eye coordination, such as surgeries in dentistry. It creates the illusion of substances (teeth, alveolar bone, instruments, hand-pieces, burs, implants) and force within a simulated virtual world of the oral cavity. The haptic devices provide force-feedback of the virtual dental operative instruments as they come in contact with the virtual teeth and alveolar bone giving the operator a perception of manipulation of objects using the senses of touch and proprioception [14].

New technologies being developed, include “haptic” (sense of touch) and “virtual lab environments” into the simulation exercises increase motor skills and student efficiency as well as reduce the faculty time required [17].

Virtual reality for dental education holds the promise of merging educational ideas and technological capabilities thus allowing for successful use of technology in higher education; reshaping teaching and learning experiences. However, the author recommends that virtual simulation cannot solely replace the traditional teaching methods of interactive human lectures. Blended learning designs in the form of virtual reality units along with instructor teaching/feedback should be incorporated into dental education to make full use of the laboratory training time and improve fine motor skills.

14.4.1.1 DentSim

One of the first computerized dental training simulators is the DentSim [18] virtual reality system for teaching restorative dentistry. The DentSim™ units comprise a phantom head, a set of dental instruments, infrared sensors, an overhead infrared camera with a monitor and two computers.

It enables students to practise clinical procedures on a simulated patient with on-screen visual tracking of the procedure concerned, real-time feedback and evaluation of their performance (Fig. 14.3). Studies on this indicate that it is effective in enabling students to work without the need for a supervisor to assess their performance critically, and to monitor their performance [19, 20]. This ability to mimic real-life situations allows students to train independently and enhance clinical skills, thus reducing training costs. A study by Jasinevicius et al. [21] reported that using virtual methods decreased faculty time by fivefold when compared to traditional preclinical teaching methods.

14.4.1.2 PerioSim^©

PerioSim^©, is a virtual reality simulator, for training in periodontal procedures and developed by Luciano. It allows the students to visualize a virtual human mouth, including teeth and surrounding gingival soft tissue, and develop skills of how to examine and detect periodontal disease in a haptic environment, without the need of preparation of teeth surfaces, with virtual dental instruments. It has the advantage that it does not require tooth surface alteration, but the disadvantage that tactile sensations for the gingival tissues are not realistic [22]. A study by Steinberg et al. [23] concluded that the device can help students develop necessary tactile skills and recommended its incorporation in dental schools. However, it was found that the realism of images of instruments and oral structures as well as the realism of tactile feedback had some limitations that needed further enhancement [23, 24].

14.4.1.3 MOOG Simodont Dental Trainer

This is a simulation unit without the need for a physical phantom head. Moog Simodont Dental Trainer combines Moog’s expertise in haptic technology and ACTA’s (Academic Center for Dentistry in Amsterdam) experience in dental education to help students practice more efficiently and learn faster. The system consists of a display projecting the mouth and teeth of a virtual patient as a stereo image on a mirror right above a haptic handpiece (Fig. 14.4). The system consists of a display projecting the mouth and teeth of a virtual patient as a stereo image on a mirror right above a haptic handpiece. Special stereoscopic glasses help in creating spatial illusions that enables the user to apply a physical drill handle as typically done on real patients, thus creating the illusion of a real dental experience. These haptic devices while providing various dental procedures including diagnosis and treatment planning, cavity preparation, and crown and bridge preparations, also provides different haptic feedbacks depending on the material being prepared virtually (e.g. enamel, dentin, or pulp) [25, 26].

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