Dental Simulation Technology

Introduction :

One of the most important skills for any dentist is the ability to prepare and restore damaged tissue resulting from carious lesions. The development of this skill requires mastery of two components: knowledge of the concepts of the procedure and the dexterity to perform it. Instruction regarding the concepts of cavity preparation and demonstration of techniques can be offered by faculty in large group sessions. However, the performance component requires a situation in which students can repeatedly practice the application of the knowledge imparted by the instructor. In the past decades, educators have come to realize that the clinical arena may not be an optimal environment for dental education. There are a number of reasons for this. Technical skills are increasingly complex due to advances in knowledge, materials, and technology. In parallel with the technological advances, financial restraints have increased the pressure for high patient turnover at dental school clinics, leaving less teaching time available to instructors and students. Finally, concerns over patient safety have led to a decrease in the acceptance of having students practice new skills on patients.

Simulation coupled with technology, is most identified with the field of aviation but in recent years, simulation using advanced technology has become prominent in the health care field. Dentistry has also been investigating the extended use of simulation for its training, especially in the area of preclinical training. Factors that appear to be driving the interest are a desire to provide a smoother transition for students into the clinic, to support and reinforce ergonomics, to broaden the students’ preclinical experience by including additional models mimicking real patient conditions, to offer practice for students in the documentation of care, and to improve the delivery of supporting material such as demonstrations, diagrams, manuals, etc.

Lichtenthal of University of Columbia school of Oral and Dental Surgery states that about 11 of approximately 65 dental schools in Northern America have adopted at least some form of dental simulation technique in their curricula. The technologies that are currently in use include the following:

DentSim®:

The units by DenX Ltd. are by far the most developed, and the most evaluated. It has been available since 1997. The unit consists of a simulated patient or manikin with head and dentoform, dental handpiece and light, infrared camera, and two computers. The manikin head and handpiece contain infrared emitters that allow the infrared camera to detect their orientation in space. As a student prepares a tooth in the manikin head, the computer can formulate a virtual image of the tooth being prepared in the computer. The virtual tooth can then be compared to the ideal preparation approved by the faculty, and abundant, detailed visual feedback can be given, including a grade. The unit can evaluate the process of the preparation and not just the end product.

Image Guided Implantology (IGI):

The IGI unit is in the last stage of development by DenX Ltd., and is specifically directed toward the teaching, diagnosis, treatment planning, and placement of implants. It uses the same technology at the DentSim® unit, but a virtual reality composite of an individual patient can be obtained by entering the patient’s CAT scan into the unit. Diagnosis, treatment planning, and virtual trial surgery of placing implants can then be done on the virtual patient. The exciting and unique ability of this unit is that the developers have included a registration device that can be used at the time of the surgery and allows the patient and the virtual patient image to be coordinated during the actual surgery. It is anticipated that simulators with this type of advanced technology will encourage, easier, more thorough training in the area of implant placement in dental schools and in the private practice arena. The additional support of this technology during implant placement surgery is an added and exciting benefit.

Virtual Reality Dental Training System (VRDTS):

This type of virtual reality training system is being developed by Novint® in collaboration with Harvard School of Dental Medicine. This unit, still very much in the developmental stage, consists of a desktop workstation, a phantom desktop haptic (referring to sense of touch) interface, and dental simulation software. The software includes simulated dental instruments (low speed drill, an explorer, two carvers, a carrier, and a packer), amalgam material, and a juvenile molar including enamel, dentin, caries, and pulp materials. Visual aids such as zoom magnification and cross-section modes are included. The dental instrument, tooth and decay are displayed as virtual simulated images on the monitor when the haptic device is held in the air. By moving the interface device, the operator can control the selected dental instrument and prepare or restore the juvenile tooth simulated on the monitor. This devise holds the promise of actually restoring teeth. The unit has one disadvantage, however, in that it does not enforce or support correct positioning or hand finger rests since the student holds the interface in the air. Iowa Dental Surgical Simulator (IDSS): The IDDS unit is also in its early stages of development, but it focuses more on tactile skill development and less on psychomotor skill development. It consists of three hardware components: the computer, a monitor, and a force feedback device with software. Participants interact with the computer by grasping a joystick or explorer handle attached to the force feedback device. Teeth are displayed on the monitor, and the student can manipulate the joystick or explorer in such a way as to “feel” enamel, healthy dentin, and carious dentin. Different haptic responses are received when the joystick or explorer is manipulated over the appropriate areas of the tooth. There are obvious benefits of expanding haptic technology to include other tactile sensations important to dentistry such as the sensation of drilling into enamel, healthy dentin, and carious dentin.

Advantages of using Dental Simulation Technique:

•	Reinforcement of concurrently learned dental concepts – students can apply biologically sound concepts from the freshman dental anatomy and cariology courses to a simulated clinical experience. •	Correct ergonomic positioning – incorrect operator and/or patient positioning can result in blocking the camera from reading the LED sensors. When this happens, a warning signal prevents the user from continuing. This encourages the students to practice good ergonomic habits. Accommodations are also available for left-handed students. •	Correct use of dental instruments – students learn how to correctly use the high-speed handpiece, rotary cutting instruments, mirror, explorer, and periodontal probe during the first semester of dental school •	Psychomotor skills – training in direct and indirect vision and spatial orientation in a timed setting are incorporated very early into the dental curriculum with VRDS (Virtual Reality Dental Simulation). •	Self- evaluation – students have unlimited, immediate, and objective access to detailed feedback of their work. The imaging available in this system includes 3 – D graphics, cross-sections, measurements, and zoom features. With VRDS, students may view their procedures from a 3 – D perspective. •	Faster acquisition of skills – the research that has been published so far indicates that students attain a competency-based skill level at a faster rate than with traditional simulator units. This can result in a domino effect; i.e., changes in dental curriculum, course sequencing, and perhaps earlier entrance into the pre-doctoral clinic. •	Positive student perception – the majority of courses in the freshman curriculum relate to basic biomedical sciences. Students seem to enjoy the opportunity to have what they perceive as a more dental-related course with VRDS.

Disadvantages of using Dental Simulation Technique:

•	System limitations with the current design – the system is programmed for and evaluates tooth preparations only. Tooth restoration is not included in the program at this time. In addition, hand instrumentation cannot be done. The haptic device will solve that problem in the future. •	Cost – the current units are expensive. The cost of each unit is approximately $70,000. New program softwares are also expensive at about $6,000 each. •	Difficult equipment maintenance and repair – technology-based systems require faculty / staff to be available for training, repair and supervision of the laboratory. The system is made up of components that come from more than one manufacturer. The mannequin head, typodont, and computer system may come from three different manufacturers. Troubleshooting and equipment repair are not difficult, but sometimes must be handled through all of the companies involved, adding to the cost.

Studies Conducted :

LeBlanc et. al. conducted a study at the Columbia University School of Oral and Dental Surgery. Sixty-eight students (forty-four males/twenty-four females) were enrolled in the second-year course of preclinical operative dentistry. Twenty of these students were randomly selected to engage in computerized simulation training (simulator group: twelve males/eight females) in addition to the standard 110 hours of traditional laboratory-based instruction in operative dentistry alongside the control students. This research project was approved by Columbia University’s Internal Review Board, and the students gave signed consent for their performance to be used as research data.

The simulation group improved from a mean score 73.6 percent on the first exam of the year to 78.4 on the fourth exam, which served as a cumulative capstone assessment of the students’ operative skills. The control group (traditional training only) improved from 75.3 percent on the first exam to 76.6 percent on the fourth exam.

Buchanan et. al. conducted studies from 1991 – 2001 to evaluate the DentSim® at the University of Pennsylvania - School of Dental Medicine. All three studies (Study #1 : one unit with 8 pairs of students, Study #2 : two units with 14 pairs of students, and Study #3: four units with 13 students) showed that the use of such simulation technique reduced the need for preclinical laboratory hours were by 23 percent; the number of students receiving 80 percent or higher increased by 26 percent; the failure rate for waxing technique exams decreased by 30 – 50 percent; and students failing the course and requiring remediation decreased by 50 percent. The studies showed that students learn restorative procedures faster with DentSim®; student skill developed by DentSim® is equal to or better than traditional methodology; students ask for more evaluations, and students are more efficient as a result of the usage of dental simulation technology. According to Buchanan, the use of such technology also showed that only 20 percent of faculty time was needed compared to the traditional laboratories, which was supported by another study done at Columbia University School of oral and Dental Surgery.

Other Potential Uses :

The NIDR Micro simulation Dental Model: Researchers have been at work to identify new scopes for the use of Dental Simulation technique. For example, a micro simulation model of dental conditions and dental service utilization was developed by the National Institute of Dental Research (NIDR) in collaboration with Cornell University and the University of Michigan. This model allows simulated data to be tabulated and analyzed. A specific tooth can be followed from eruption to first caries, to restoration, to loss and replacement. The same model was also used to assess the potential impact of reductions in the percentage of Americans with dental insurance, in universal dental insurance coverage for children and in fees paid to dentists for their services. The model predicated that reductions in dental insurance coverage would reduce per capita dental expenditures, but that the impact would not be large. Fee reductions had the greatest impact on dental expenditures of any change simulated by the model.

The NIDR micro simulation dental model consists of two modules, CORSIM®  and DENTSIM®. The two modules come with a lot of variables to choose from. Researchers can change the sets of variables to conduct various types of hypothetical research. Crucial policies can be adopted based on the predictions generated by the experiments.

CORSIM®: This module simulates the demographic and socioeconomic characteristics of the U.S. census data from 1960. The two major entities in CORSIM® are the person and the family. For every person in the simulation (alive or dead) there is an associated person record. For every family entity there is a family record. Person records are grouped into families. Every person belongs to a family, and CORSIM® families may contain any number of people (including none).

DENTSIM®: This is a dental module that generates a range of dental variables. The use of dental services and expenditures for these services are modeled at the person level. Data on persons can be aggregated to families. Variables that influence utilization include dental insurance coverage, family income, socio-demographic variables and measures of dental disease.

An Apparatus to set teeth: An apparatus and method have been formulated using the dental simulation technique. It determines the fit of a set of upper or lower teeth in a masticatory system of a patient by generating a computer representation of the masticatory system of the patient using one or more variables (keys). The key can be selected from a group consisting of a molar relationship, a crown angulation, a crown inclination, teeth rotations, teeth contact points, and an occlusal plane. Any other form of variables can also be incorporated on a case basis. The design comes with a feature of optimization. The features can be identified automatically or by a user. The method also includes generating progress reports that can be browsed over a network that can be accessed by the patient and the clinician. The user, which can be a clinician or a patient, manipulates the computer representation of the masticatory system. This new application of the dental simulation technique is still pending patent approval.

Discussion :

The result of the analysis done based on the articles offer valuable insights for the use of dental simulation technology:

1.	Advanced technology simulation is on the verge of dramatically affecting health care education. Specifically, virtual reality-based technology allows for more advanced simulation, thereby setting a new state-of-the-art dental simulation. This new level of simulation, unlike the previous models for simulation labs, has the real potential to influence and modify how we teach. 2.	Dental operatory and virtual reality patient simulators (such as the DentSim® developed by DenX) offer the promise of providing practice in a realistic environment filled with detailed, frequent, and objective feedback. The study mentioned in the articles indicate that the students in the DentSim® simulator group improved their scores significantly more from the first to the fourth examination of the year than did students in a control group who did not receive augmented instruction by the simulator. 3.	Interest in this advanced Virtual Reality Based Technology (VRBT) may be fueled by schools having difficulty in recruiting faculty for preclinical courses, schools looking for ways to reduce costs while maintaining or improving student learning, or schools having difficulty in obtaining sufficient patient pools to address student needs. However, because this simulation technology is involved in the actual evaluation of students, schools are trying to find ways to improve and change the way dentistry is taught. 4.	Simulation technology must be adapted to the needs of individual schools to reach its potential. Many schools perceive the value of virtual reality in competency testing both as part of the curriculum and for the regional clinical boards (for the licensing examination). Preliminary results from Columbia University suggest that this technology may be more helpful with students who are at the lower end of ability in psychomotor skills rather than more gifted students, and the University of Pennsylvania has noted differences in attitude and skill development based on learning styles. Students with learning styles that put more emphasis on learning from individuals appear to have less enthusiasm for this technology. This suggest that this technology may be more helpful for different student groups and allow for individual teaching programs adapted to a student’s ability and learning style. Other areas of potential are in continued competency of practitioners, help with clinical board exams, remediation of impaired practitioners, and continuing education. 5.	The cost of this advanced technology simulation is expected to be substantial, but only the DentSim® advertises a firm price ($70,000 per unit). The cost for units still in development is not yet available. It is hoped and anticipated that, as more and more companies become involved in the manufacture of this technology, costs associated with it will dramatically decrease. 6.	Institutions should be aware of hidden costs and resources must be allocated for on-site staff with technical skills and personnel responsible for maintenance of the units. Additional resources may be necessary for the training of the faculty, staff, and students. The economic impact of this technology is certainly an area that needs further evaluation to help schools decide to purchase equipment in this price range. 7.	Technology related to the presentation of case-based scenarios and technology authoring programs is increasingly available, enabling schools to more easily access and develop electronic case scenarios. The advanced technology simulation may have even greater possibilities if dental education has the vision to couple advanced technology simulators with case-based scenario programs. 8.	In summary, advanced dental technology simulators offer an exciting opportunity for dental educators to review and reconfigure the curricula to meet the needs of the schools and improve student learning significantly. Further evaluation of currently available systems and new systems arriving in the future is critical to expanding this opportunity.

References :

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