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In the last decade, 3D virtual models have been used for educational purposes in the health sciences, specifically for teaching human anatomy and pathology. These models provide an opportunity to didactically visualize key spatial relations that can be poorly understood when taught by traditional educational approaches. Caries lesion detection is a crucial process in dentistry that has been reported to be difficult to learn. One especially difficult aspect is linking clinical characteristics of the different severity stages with their histological features, which is fundamental for treatment decision-making.
This project was designed to develop a virtual 3D digital model of caries lesion formation and progression to aid the detection of lesions at different severity stages as a potential complement to traditional lectures.
Pedagogical planning, including identification of objectives, exploration of the degree of difficulty of caries diagnosis–associated topics perceived by dental students and lecturers, review of the literature regarding key concepts, and consultation of experts, was performed prior to constructing the model. An educational script strategy was created based on the topics to be addressed (dental tissues, biofilm stagnation areas, the demineralization process, caries lesion progression on occlusal surfaces, clinical characteristics related to different stages of caries progression, and histological correlations). Virtual 3D models were developed using the Virtual Man Project and refined using multiple 3D software applications. In the next phase, computer graphic modelling and previsualization were executed. After that, the video was revised and edited based on suggestions. Finally, explanatory subtitles were generated, the models were textured and rendered, and voiceovers in 3 languages were implemented.
We developed a 6-minute virtual 3D dynamic video in 3 languages (English, Spanish, and Brazilian Portuguese) intended for dentists and dental students to support teaching and learning of caries lesion detection. The videos were made available on YouTube; to date, they have received more than 100,000 views.
Complementary pedagogical tools are valuable to support cariology education. This tool will be further tested in terms of utility and usability as well as user satisfaction in achieving the proposed objectives in specific contexts.
Dental caries is one of the most prevalent chronic diseases worldwide [
Dental caries are detected by recognizing the signs and symptoms involved in the abovementioned process [
Several caries classification and detection methods have been developed to assess different stages of caries lesions [
Based on this, the ICDAS Foundation designed an e-learning program to universalize and spread the use of their system [
3D animation models can show spatial and dynamical relationships from almost any angle; this can provide information that may be difficult to acquire using traditional static learning resources [
Thus, the aim of the present project was to develop a digital, dynamic, and virtual 3D model of the formation, progression, and detection of caries lesions at different stages using the ICDAS at the Virtual Man Project Laboratory to complement traditional teaching resources.
The Virtual Man Project developed at the Telemedicine Discipline, School of Medicine, University of Sao Paulo, Brazil.
This descriptive study was developed in collaboration with the Discipline of Telemedicine (School of Medicine), the Teledentistry Centre, and the Department of Pediatric Dentistry (School of Dentistry) at the University of Sao Paulo, Brazil. The study was approved by the Ethics Committee of the Dental School (protocol 206.345/2013).
This phase comprised the initial steps to develop a learning object oriented toward the detection of caries lesions based on their developmental stages and the differences among their clinical characteristics. In this phase, we discussed the objectives, the topics to approach, and the best methodologies for knowledge transmission. Firstly, a team of experienced lecturers and researchers in the area of cariology was formed to discuss the learning object purpose, key topics representing the minimum skills a dental student should develop in this field as a future dental practitioner, and the possibility of using technology to achieve the proposed goals. Sources such as the First Consensus Workshop on the Development of a European Curriculum in Cariology [
As a second step in the previous study, we assessed the degrees of difficulty of caries detection–related learning topics perceived by dental students and lecturers [
First, images of clinical and histological caries lesions were acquired to include them in the learning object as complementary supports. To that end, an examiner trained in the ICDAS criteria selected a sample of human teeth (N=12) with different caries lesion severity stages on occlusal surfaces (scores 0-6) from the Human Teeth Bank of the Dental School, University of Sao Paulo. Clinical images of these lesions were then obtained with a digital camera (DS126151 EOS Digital Rebel XTi, Canon) with a macro lens (EF 100mm 1:2.8, Canon). Then, the teeth were fixed with the crown exposed to Eppendorf tubes using utility wax and transparent acrylic resin. Longitudinal sections (100 micrometers) were made at the center of each lesion using a cutting machine (IsoMet 1000 precision sectioning saw, Buehler) with a diamond grinding disc (Extec 12205). The histological sections were analyzed under a stereomicroscope (M80, Leica), and the images were captured and processed with a digital camera (DFC 295, Leica) and QWin Plus software (Leica). This material was saved in digital files until its inclusion in the learning object.
A technological plan structure and interactive tele-education strategies were developed in partnership with a multidisciplinary team composed of cariology experts, digital designers, journalists, and tele-education strategists. This phase was carried out at the Virtual Man Project Laboratory using dual Pentium 4 graphic workstations (Xeon HT) with 4 gigabytes of RAM, a professional video board, tablets, the 3D Studio Max program (AutoDesk, Inc), and Photoshop and After Effects software (Adobe, Inc).
Before graphical production, a descriptive lecture regarding the caries process and the ICDAS criteria on occlusal surfaces was given to the team members who were not familiar with cariology. Concept descriptions as well as clinical and histological images of caries lesions were shown. Then, an educational script strategy was created to define the sequence in which the topics would appear in the video, emphasizing the most difficult topics (
Presentation
Dental structures (enamel, dentin, pulp)
Dental enamel structure, microscopic view
Dentine structure, microscopic view
Plaque stagnation areas
Demineralization process
Caries lesion formation
ICDAS scores (clinical/histological)
ICDAS scores (histological correlation)
Credits
Graphical computer models (using the Virtual Man Project) of the clinical and histological images and a preview video were promptly generated. A group of experts in the field of cariology who were not involved in the video production reviewed this first version of the video. After that, the video was edited to correct some theoretical and technical inconsistencies. Then, a new version was produced that incorporated all the suggestions; after the team’s approval, this video was rendered and textured. To achieve this, an image synthesis process was performed to generate photorealistic images (geometry, viewpoint, texture, lighting, shading, etc.) from the developed 3D models using computer programs. By this process, a silent 6-minute video was created using the Virtual Man Project (
Scenes of the video produced at the Virtual Man Laboratory. ICDAS: International Caries Detection and Assessment System.
After the graphic design phase was complete, voiceovers were recorded to be played over the video to narrate the dynamic illustrations in an understandable way. Scripts in 3 languages (English, Spanish, and Brazilian Portuguese) were written and revised by native experts. After that, the scripts were adjusted and synchronized with the times and sequences in the video. We engaged a native-speaking narrator from the United Kingdom, Mexico, and Brazil. Each of the 3 narrators received a brief explanation about the video and its objectives together with the script. They were then taken into a recording studio and provided with instructions on how to record the voiceovers. Voice volume and speed tests were performed. Later, the narrator read the script while the voiceover was recorded. If the narrator made mistakes, they were required to start over from the previous paragraph. Repetitions were made when necessary. Finally, the recordings of the scripts were edited and incorporated into the body of the video. The final versions, a 6-minute video in each language, were sent to the scientific board for revision. Minimal corrections and additions were performed at this point (
Frames from the final English version of the 6-minute video about the caries process and the International Caries Detection and Assessment System.
Using the process described in the Methods section, a 6-minute dynamic video was produced in 3 languages (English, Spanish, and Brazilian Portuguese) showing the dental structures, biofilm stagnation areas, caries lesion formation, demineralization process, caries lesion progression, and severity stages of caries lesions on occlusal surfaces according to the ICDAS (
Interest is increasing in developing educational resources using information and communication technology to improve students’ understanding of human body processes [
This project represents an improvement in educational infographics, as it may facilitate and accelerate understanding related to a specific matter [
Part of the pedagogical planning for the development of this learning object was based on the findings of a previous study [
We consider that this tool may have an impact on the theoretical understanding of caries lesion formation and progression and therefore may improve students´ knowledge and grades. This is supported by a study in which students who accessed virtual tools scored higher on assessments than students who did not [
As mentioned, the ICDAS e-learning program is an interactive resource that supports training in the use of the ICDAS criteria for dental education, examination protocols, and scoring systems [
One of our main goals is the dissemination of the produced tool. Open access is an ideal aspect of this process, and the first version of the video is already available on YouTube. However, additional steps should be performed to test the characteristics of the learning material as well as to address copyright issues; these steps are currently in progress. In the phase described in this paper, the authors created a learning object in 3 different languages: English, Spanish, and Brazilian Portuguese. This can be seen as an advantage in terms of dissemination, as these 3 languages have some of the largest populations of first-language speakers in the world [
As a next step to fully address the efficacy of the current learning object, the authors will test this tool in a student population in different contexts and countries. This testing will be conducted to validate and assess the potential benefits, obstacles, and user acceptability of the learning object as a novel pedagogical resource in the area of cariology. Therefore, we will perform a multicenter randomized study involving dental students from different countries with the aim of evaluating the impact of the 3D virtual model as a learning object on the training and teaching of undergraduate dental students to detect caries lesions using the ICDAS; the results of this study will be discussed in a future paper.
We produced a 6-minute virtual 3D video intended for dentists and dental students to support teaching and learning of the caries detection process. We suggest that complementary pedagogical tools, such as the one described here, are valuable to complement education in cariology. This learning object will be further tested in terms of utility and usability as well as user satisfaction in achieving the proposed objectives in specific contexts.
International Caries Detection and Assessment System
This study was funded by the Coordination for the Improvement of Higher Education Personnel of the Brazilian government, which granted scholarships to the MSc and PhD candidates during the conduction of the study. The authors are grateful to Diogo Miranda for his assistance with the voiceover recording and editing process and for lending his voice to the Portuguese version; we are also grateful to Harry Johnson for his participation in the English version. To Kim Ekstrand, Stefania Martignon, and Nigel Pitts, we offer special recognition of their support to make this project a reality.
JSL, MMB, CLW, FMM, and AEH contributed substantially to the concept and design of this study. JSL, MMB, CGZ, CLW, FMM, and AEH designed the study and worked on it from its conception. JSL, MMB, PUM, and AEH were involved in the collection of the data (in the previous study) and of the materials for the 3D model development. JSL, CGZ, and CLW worked on the technical development and editing process of the 3D model. JSL and PUM recorded the voiceovers and drafted the manuscript. JSL, MMB, FMM, and AEH critically reviewed the intellectual content of the manuscript. All authors have provided approval of the final version to be published. JSL is responsible for the integrity of the work as a whole.
None declared.