The design and testing of a force feedback dental simulator

Virtual reality and haptics in dental education: Implementation progress and lessons learned after a decade

INTRODUCTION

The search for alternative training environments in dentistry responded mainly to scarcity and lack of standardisation of training material and non-availability of specific clinical procedures. The development of haptic virtual reality (VR) dental trainers provides a platform where irreversible procedures can be safely and unlimitedly practised. The aim of this study was to assess the educational implementation of these devices and evaluate schools' satisfaction.

METHODS

Dental schools that were using haptic VR dental trainers, were approached. The Dental Trainer User Inventory (DTUI), addressing the educational implementation and users' satisfaction, was developed and distributed.

RESULTS

Twenty-seven schools completed the DTUI. The total number of VR dental trainers available varied from one to 42 devices with a mean of 7 devices. The dental trainer was mostly made available from the first year (63.0%) of the undergraduate program, but it was mostly integrated into the curriculum by the third year (70.4%). Curricular integration was reported by 18 schools (66.7%), while nine schools (33.3%) indicated that they had not yet achieved integration. Twenty-one schools (69.4%) were 'satisfied' or 'very satisfied' with the devices, while two schools (7.4%) were dissatisfied and six schools (22.2%) were neither satisfied nor dissatisfied.

CONCLUSION

VR haptic dental trainers are implemented in multiple dental programs and are also being used for educational research and clinical training. Even though curricular changes and teachers' acceptance remain a challenge, most schools are satisfied with VR haptic dental trainers and would recommend the device to other schools.

Haptic and Force Feedback Technology in Dental Education: A Bibliometric Analysis

The haptic and force feedback technology has received an increasing attention in dental schools due to its effectiveness in psychomotor skill training. However, the bibliometric analysis on haptic and force feedback technology in dental education is still scarce. Therefore, the aim of this study was to perform a bibliometric analysis of the development of haptic and force feedback technology and its changing trends in dental education. From 1 January 2001 to 30 November 2022, all papers published on haptic and force feedback technology were searched from the Web of Science Core Collection database. These data were then entered into Apple Numbers for descriptive bibliometric analysis and visualized using VOSviewer software. A total of 85 articles were retrieved following the inclusive and exclusive criteria. The results demonstrated that USA and China exhibited the most publications. The combination of correspondence author and author co-citation analysis identified the more prominent authors in this research field. The top-cited and the average citation count per year ranking led to different views of popularity. A significant increase in the number of haptic and force feedback technology publications were found in the last two years. Virtual reality is the main keyword that indicates more new integrative applications currently underway. Taken together, this study provides a detailed bibliographic analysis of haptic and force feedback technology in dental education to indicate representative authors, literatures, keywords, and trends. These detailed data will help researchers, teachers, and dental students as a very useful information when trying to make haptic and force feedback technology more prevalent in dental education in the near further.

A 3D Model of the Jaw Applied to Paediatric Dentistry

As education and knowledge are adapted to new education systems, as per the Bologna Plan, new technologies are required for educational support. In dentistry, the creation of virtual simulators can advance understanding in areas like anatomy. With this aim, a three-dimensional virtual model of the maxilo-mandibular system was created, based on a real infantile specimen. Once this model was developed, we applied this virtual structure to a teaching tool in a dentistry subject.The main objective of this project is the creation of a virtual model of the jaw, based on a real and infantile subject that serves as an educative tool in the scope of Paediatric Dentistry Anatomy. The secondary aims were to evaluate this model as an educational tool in a paediatric dentistry subject. For the main objective we obtained tomographic cuts of the craniofacial skeleton of a three-year-old girl that were transcribed to the program Amira 5.3.0. On the cuts, we segmented and named all the mandibular structures: jaw, temporary teeth, and permanent teeth. For the secondary aims we developed virtual clinical cases based on this mandibular model and gave a questionnaire to 29 dentistry students in order to evaluate the tool. A total of 512 cuts were obtained in sagittal and coronal planes and 309 in the cross-sectional plane of a thickness of 0.625 mm. In different colours, we segmented the total 25 structures to generate a three-dimensional mandibular model. For the questionnaire, the results of the students’ satisfaction of the tool were high, with an overall score of 8.5 out of 10. The educative system based on the Bologna Plan is a reality. The self-training based on test and error, is a strategy of extreme utility for the student. With an interactive model, the student is able to value his knowledge instantaneously, and the presence of a professor is not essential at all times. Through this real model, we have described the anatomical study of temporary teething, as well as its interactions with the developing permanent dentition, in a three-dimensional form. The students’ satisfaction of the teaching tool was high.

Trade-Off between Task Accuracy, Task Completion Time and Naturalness for Direct Object Manipulation in Virtual Reality

Virtual reality devices are used for several application domains, such as medicine, entertainment, marketing and training. A handheld controller is the common interaction method for direct object manipulation in virtual reality environments. Using hands would be a straightforward way to directly manipulate objects in the virtual environment if hand-tracking technology were reliable enough. In recent comparison studies, hand-based systems compared unfavorably against the handheld controllers in task completion times and accuracy. In our controlled study, we compare these two interaction techniques with a new hybrid interaction technique which combines the controller tracking with hand gestures for a rigid object manipulation task. The results demonstrate that the hybrid interaction technique is the most preferred because it is intuitive, easy to use, fast, reliable and it provides haptic feedback resembling the real-world object grab. This suggests that there is a trade-off between naturalness, task accuracy and task completion time when using these direct manipulation interaction techniques, and participants prefer to use interaction techniques that provide a balance between these three factors.

Technical skill training and assessment in dental education

Highly competent clinical practice requires cognitive, psychomotor and affective skills. Therefore, the ultimate goal of dental education is for practitioners to be competent in all of these domains. While many methods have been introduced to assess knowledge and non-technical skills, it is still very difficult for educators to assess technical skill. Assessment methods for technical skills are still not well established because it is very difficult to assure objectivity, validity and fairness. Nonetheless, technical skill is especially important in dental treatments, along with knowledge and attitude. The aim of this review was to summarize the methods of technical skill training in dental education and how they are assessed. This is a literature review. We searched PubMed MEDLINE using terms related to technical skill training and those assessment as of June 2020 and reviewed them. There have been many reports introducing methods of technical skill training and assessment, including the use of digital technology. However, no single assessment method had demonstrated validity of it. Technical skill training is very important in dental education and there are various ways of learning. The validity of current assessment methods is limited; therefore, a combination of several methods may achieve the best results.

The utility of haptic simulation in early restorative dental training: A scoping review

BACKGROUND

Haptic dental simulators are becoming increasingly available in dental schools around the world; however, there is a paucity of evidence on their pedagogical effectiveness particularly in early dental training for the acquisition of the highly specific fine motor dental skills.

METHODS

A scoping review was performed to broadly map the available evidence and to detect knowledge gaps on the utility of haptic dental simulation in early dental training. The review is reported using the PRISMA-ScR guidelines. Eight bibliographic databases were searched: Web of Science, Scopus, MEDLINE via PubMed, Cochrane library, CENTRAL, ERIC, IEEE Xplore, and TRIP. Charted data were reported by clustering results according to study characteristics, research themes, research purpose, and type of validity evidence identified.

RESULTS

The review process resulted in the inclusion of 36 studies published between 2009 and 2020. The majority of the studies were cross-sectional in design with short-term evaluation data. Of the studies included, 64% investigated commercially available haptic simulators, while 36% investigated experimental haptic simulators. The research themes identified were skill acquisition and transfer, task-specific haptic training, trainee level discrimination, feedback, subjective user evaluation, performance prediction, and human factors in haptic training.

CONCLUSION

Short-term evaluation evidence from reviewed studies indicates the usefulness of the haptic simulators in early dental training. They complement the existing phantom head simulators by offering qualitatively different features. Further empirical research is needed to investigate the long-term impact of training with haptic dental simulators, to improve the availability of validation evidence and to enhance the results generalizability.

Simulation training for ceramic crown preparation in the dental setting using a virtual educational system

OBJECTIVES

The aim was to evaluate the effectiveness of a pre-clinical training of ceramic crown preparation using the Virtual Educational System for Dentistry.

MATERIAL AND METHODS

Fifty-seven dental students were recruited to prepare a ceramic crown under the guidance of the Real-time Dental Training and Evaluation System (RDTES) in order to collect pre-learning data. They participated in the online virtual learning course independently on the Virtual Learning Network Platform (VLNP). One week later, the students were invited to complete their post-learning crown preparation with the RDTES. A questionnaire survey explored students' perceived benefits or drawbacks of the virtual educational system. Students were allocated into Group A (n = 15), B (n = 24) and C (n = 18) based on their pre-learning performance. Differences of assessment results amongst different groups were evaluated by ANOVA and Kruskal-Wallis tests. The pre- and post-learning assessment results in all groups were compared using paired t tests or Wilcoxon signed rank tests.

RESULTS

The error scores for four assessment items (instrument selection, preparation section, preparation reduction, preparation surface and profile) and total score of outcome assessment after the virtual learning were significantly different with those before the virtual learning (P < 0.05). There were significant interactions between time and student group in the mean scores of process and outcome assessments (P < 0.001), except for the assessment item "damage of adjacent teeth."

CONCLUSION

The application of a Virtual Educational System for Dentistry with the VLNP and RDTES in pre-clinical operative training helps students improve their clinical skills.

Haptic Rendering of Diverse Tool-Tissue Contact Constraints During Dental Implantation Procedures

Motor skill learning of dental implantation surgery is difficult for novices because it involves fine manipulation of different dental tools to fulfill a strictly pre-defined procedure. Haptics-enabled virtual reality training systems provide a promising tool for surgical skill learning. In this paper, we introduce a haptic rendering algorithm for simulating diverse tool-tissue contact constraints during dental implantation. Motion forms of an implant tool can be summarized as the high degree of freedom (H-DoF) motion and the low degree of freedom (L-DoF) motion. During the H-DoF state, the tool can move freely on bone surface and in free space with 6 DoF. While during the L-DoF state, the motion degrees are restrained due to the constraints imposed by the implant bed. We propose a state switching framework to simplify the simulation workload by rendering the H-DoF motion state and the L-DoF motion state separately, and seamless switch between the two states by defining an implant criteria as the switching judgment. We also propose the virtual constraint method to render the L-DoF motion, which are different from ordinary drilling procedures as the tools should obey different axial constraint forms including sliding, drilling, screwing and perforating. The virtual constraint method shows efficiency and accuracy in adapting to different kinds of constraint forms, and consists of three core steps, including defining the movement axis, projecting the configuration difference, and deriving the movement control ratio. The H-DoF motion on bone surface and in free space is simulated through the previously proposed virtual coupling method. Experimental results illustrated that the proposed method could simulate the 16 different phases of the complete implant procedures of the Straumann® Bone Level(BL) Implants Φ4.8–L12 mm. According to the output force curve, different contact constraints could be rendered with steady and continuous output force during the operation procedures.

Computer simulation and virtual reality in undergraduate operative and restorative dental education: A critical review

The primary aim of this review was to synthesize the literature for studies investigating the use of computer simulation (CS) and virtual reality (VR) in undergraduate dental education in operative and restorative dentistry. The secondary aim was to list best practices that maximize the simulation experience in dental education. A literature review of the PubMed and ERIC databases was conducted using the search terms "Dental AND Simulator," "Dental AND Virtual reality," and "Simulation AND Dental education." Studies in English language were categorized into 1 of 5 themes: Manual dexterity and cavity preparation, light curing skills, simulation perception and experience, predictability, and simulation model development. Main practices of simulation education indicated in the McGaghie et al. critical review published in 2010 were used as a reference to identify common practices for dental simulation. Thirty nine of 579 identified abstracts met the inclusion criteria. Skill acquisition and feedback were the two most frequently investigated parameters found in the review. CS was efficient in teaching cavity preparation and light curing skills. Feedback and deliberate practice were among the best practices that should be emphasized in order to enhance the efficiency of the CS and VR simulation exercises. The use of CS is effective in teaching operative skills (such as light curing and cavity preparation) reliably; whereas, the use of VR in undergraduate curricula is debatable. To achieve the maximum benefits of the simulation exercises, emphasis must be given to the timely feedback and deliberate practice approaches.

A review of haptic simulator for oral and maxillofacial surgery based on virtual reality

INTRODUCTION

Traditional medical training in oral and maxillofacial surgery (OMFS) may be limited by its low efficiency and high price due to the shortage of cadaver resources. With the combination of visual rendering and feedback force, surgery simulators become increasingly popular in hospitals and medical schools as an alternative to the traditional training.

AREAS COVERED

The major goal of this review is to provide a comprehensive reference source of current and future developments of haptic OMFS simulators based on virtual reality (VR) for relevant researchers.

EXPERT COMMENTARY

Visual rendering, haptic rendering, tissue deformation, and evaluation are key components of haptic surgery simulator based on VR. Compared with traditional medical training, virtual and tactical fusion of virtual environment in surgery simulator enables considerably vivid sensation, and the operators have more opportunities to practice surgical skills and receive objective evaluation as reference.

Effectiveness of the Multilayered Caries Model and Visuo-tactile Virtual Reality Simulator for Minimally Invasive Caries Removal: A Randomized Controlled Trial

This work presents the multilayered caries model with a visuo-tactile virtual reality simulator and a randomized controlled trial protocol to determine the effectiveness of the simulator in training for minimally invasive caries removal. A three-dimensional, multilayered caries model was reconstructed from 10 micro-computed tomography (CT) images of deeply carious extracted human teeth before and after caries removal. The full grey scale 0-255 yielded a median grey scale value of 0-9, 10-18, 19-25, 26-52, and 53-80 regarding dental pulp, infected carious dentin, affected carious dentin, normal dentin, and normal enamel, respectively. The simulator was connected to two haptic devices for a handpiece and mouth mirror. The visuo-tactile feedback during the operation varied depending on the grey scale. Sixth-year dental students underwent a pretraining assessment of caries removal on extracted teeth. The students were then randomly assigned to train on either the simulator (n=16) or conventional extracted teeth (n=16) for 3 days, after which the assessment was repeated. The posttraining performance of caries removal improved compared with pretraining in both groups (Wilcoxon, p&lt;0.05). The equivalence test for proportional differences (two 1-sided t-tests) with a 0.2 margin confirmed that the participants in both groups had identical posttraining performance scores (95% CI=0.92, 1; p=0.00). In conclusion, training on the micro-CT multilayered caries model with the visuo-tactile virtual reality simulator and conventional extracted tooth had equivalent effects on improving performance of minimally invasive caries removal.

Survey on multisensory feedback virtual reality dental training systems

Compared with traditional dental training methods, virtual reality training systems integrated with multisensory feedback possess potentials advantages. However, there exist many technical challenges in developing a satisfactory simulator. In this manuscript, we systematically survey several current dental training systems to identify the gaps between the capabilities of these systems and the clinical training requirements. After briefly summarising the components, functions and unique features of each system, we discuss the technical challenges behind these systems including the software, hardware and user evaluation methods. Finally, the clinical requirements of an ideal dental training system are proposed. Future research/development areas are identified based on an analysis of the gaps between current systems and clinical training requirements.

Six Degree-of-Freedom Haptic Simulation of Probing Dental Caries Within a Narrow Oral Cavity

Haptic simulation of handling pathological tissues is a crucial component to enhance virtual surgical training systems. In this paper, we introduce a configuration-based optimization approach to simulate the exploration and diagnosis of carious tissues in dental operations. To simulate the six Degree-of-Freedom (6DoF) haptic interaction between the dental probe and the oral tissues, we introduce two interaction states, the sliding state and the penetration state, which simulate the exploration on the surface of and inside of the caries, respectively. Penetration criteria considering a contact force threshold are defined to trigger the switch between the two states. By utilizing a simplified friction model based on the optimization approach, various multi-region frictional contacts between the probe and carious tissues are simulated. To simulate the exploration within the carious tissues for diagnosing the depth of the caries, a dynamic sphere tree is used to constrain the insertion/extraction of the probe within carious tissues along a fixed direction while enabling simulation of additional contacts of the probe with neighboring oral tissues during the insertion/extraction process. Experimental results show that decays with different levels of stiffness and friction coefficients can be stably simulated. Preliminary user studies show that users could easily identify the invisible boundary between the decay and healthy tissues and correctly rank the depth of target decays within a required time limit. The proposed approach could be used for training delicate motor skill of probing target carious teeth in a narrow oral cavity, which requires collaborated control of tool posture and insertion/extraction force, while avoiding damages to adjacent healthy tissues of the tongue and gingiva.

Development of three-dimensional patient face model that enables real-time collision detection and cutting operation for a dental simulator

The virtual reality (VR) simulator is a useful tool to develop dental hand skill. However, VR simulations with reactions of patients have limited computational time to reproduce a face model. Our aim was to develop a patient face model that enables real-time collision detection and cutting operation by using stereolithography (STL) and deterministic finite automaton (DFA) data files. We evaluated dependence of computational cost and constructed the patient face model using the optimum condition for combining STL and DFA data files, and assessed the computational costs for operation in do-nothing, collision, cutting, and combination of collision and cutting. The face model was successfully constructed with low computational costs of 11.3, 18.3, 30.3, and 33.5 ms for do-nothing, collision, cutting, and collision and cutting, respectively. The patient face model could be useful for developing dental hand skill with VR.

iDental: A Haptic-Based Dental Simulator and Its Preliminary User Evaluation

Performance evaluation is indispensable for a surgical simulator to become acceptable. A haptics-based dental simulator (iDental) has been developed and preliminary user evaluation on its first-generation prototype has been carried out to gain the knowledge. Based on detailed requirement analysis of Periodontics procedures, a combined evaluation method including qualitative and quantitative analysis was designed. Construct validity was used to compare the performance difference between two groups of participants (faculty members and dental graduate students). These participants were required to perform three periodontal examination and treatment procedures including periodontal pocket probing, calculus detection, and removal. From the evaluation results, we found that penetration between tool and teeth or cheek will greatly decrease the fidelity of the simulation, therefore, it is necessary to utilize 6-DOF haptic device with both force and torque feedback in dental simulator, and accordingly it is needed to extend point-based rendering to 6-DOF haptic rendering of multiregion contacts. Furthermore, several other key research topics that will enable haptic technology to be effective in a practical dental simulator were identified, including simulation of deformable body such as tongue and gingival, and simulation of occlusion of tongue and cheek on teeth, etc.

Evaluation of a dental model for training veterinary students

Periodontal disease has deleterious effects on an animal's health and potentially serious implications for its welfare. Consequently, veterinarians frequently perform routine periodontal treatment in small-animal practice. One would therefore assume that small-animal dentistry would constitute a core component of a veterinary curriculum. However, most practitioners received little or no formal training in dentistry during their veterinary degrees, and the amount of instruction students currently receive is variable, often with limited opportunities to practice. At the Royal Veterinary College, a prototype dental model was developed to address the lack of practical training; it was made using ceramic tiles, silicone sealant, and grout to emulate teeth, gingiva, and calculus, respectively. A study was conducted with third-year veterinary students to compare the outcomes of learning to perform a professional dental cleaning using a model (group A) or a video (group B). Performance was assessed using an objective structured clinical examination. Students in group A scored significantly better than those in group B (p<.001). All students also completed a questionnaire evaluating attitudes toward the use of a dental model in learning dentistry-related skills. All students identified a model as a potentially valuable learning tool to supplement existing teaching methods and facilitate the acquisition of small-animal dentistry skills. The dental model has the potential to equip students with useful, practical skills in a safe and risk-free environment.

Bone drilling haptic interaction for orthopedic surgical simulator

Drilling procedure is widely used in orthopedic surgery to position reduced fractured bones and prosthetic components. However, successful execution of bone drilling requires a high level of dexterity and experience, because the drilling resistance is large and sometimes vibrates violently to difficultly grasp the hand-piece or even break the slender drill. This paper introduces haptic functions that are added to a volume based surgical simulator to simulate the drilling process. These haptic functions compute drilling forces and torques based on reliable metal removing theorem. Therefore, accurate prediction for the drilling process can be obtained to provide effective surgery training and rehearsal. A simulation example of screw and plate surgery for positioning the hip trochanter fracture illustrates the practicality and versatility of the proposed method.

Visual field magnification and touch perception when exploring surfaces with the index finger and a rigid instrument

OBJECTIVE

The aim of this project was to compare texture discrimination when both touch and vision were perturbed.

BACKGROUND

Texture discrimination is important in the workplace. How textures are identified with the finger and with instruments when vision is magnified with lenses or video cameras is unclear.

METHOD

Sandpaper was explored with the index finger or a metal instrument (hemostat), using normal or magnified vision. The forces generated during exploration were measured, and participants rated surface roughness.

RESULTS

With the finger, the perception of roughness was unaffected with magnification; with the instrument, magnified surfaces were perceived as rougher (p < .05). Forces during finger exploration were unaffected by magnification; forces with the instrument increased under magnification (p < .05).

CONCLUSION

Visual characteristics of the working field can influence the exploration and perception of materials. With the finger, mechanoreceptors that directly detect textures are activated, and with the instrument, receptors sensitive to vibrations are stimulated.

APPLICATION

The higher forces produced when using instruments under magnification could lead to material damage. Attenuated perception of texture when exploring with tools may lead to difficulty in accurate touch perception. This could create problems in industrial tasks such as grading wool or identifying surface imperfections on manufactured materials, as well as in clinical settings such as dentistry or surgery in which instruments are used during tissue identification.

Cutting on triangle mesh: local model-based haptic display for dental preparation surgery simulation

A new method to realize stable and realistic cutting simulation using an impedance display haptic device and microcomputer is presented in this paper. Material removal or cutting simulation is a critical task in dental preparation surgery simulation. In this paper, a piecewise contact force model is proposed to approximately describe the cutting process. Challenging issues of minimizing the difference between the cutting simulation and haptic contact simulation are analyzed. The proposed contact-based simulation method is developed for a one-dimensional cutting task and can be expanded to three-dimensional cases. Local model-based multirate simulation cutting architecture is proposed and force control of the haptic device is decoupled from the cutting simulation loop, which can both ensure high fidelity of dynamical simulation as well as maintain stability of the haptic device. The cutting operation is realized using spherical and cylindrical shaped tools. An experiment based on the Phantom desktop proves that fidelity in one-dimensional cutting can be realized and stability in three-dimensional cutting can be ensured using the force-filtering method.

Biomedical informatics training for dental researchers

Dental researchers collaborating closely with biomedical informaticians have achieved many advances in oral health research, such as in mapping human genetics and addressing oral health disparities. Advances will continue to increase as dental researchers and biomedical informaticians study each others' disciplines to increase the effectiveness of their collaborative research. The combined skills will greatly increase the effectiveness of dental research. This manuscript summarizes the core of biomedical informatics curriculum (biomedical informatics knowledge, data management, and software engineering) for dental research. It also summarizes the obstacles that must be overcome for all dental research students to receive the training in biomedical informatics they require. These issues are: a lack of biomedical informatics faculty, a lack of biomedical informatics courses, and a lack of accreditation standards. Last, intra- and inter-institutional collaboration solutions are described.