‘X’ marks the spot: Dentistry students sharpen their radiography skills with NUS-developed augmented reality, virtual simulators

'X' marks the spot: Dentistry students sharpen their radiography skills with NUS-developed augmented reality, virtual simulators

There is one question Dr Lim Li Zhen often gets asked by dentistry students who are learning to take X-rays inside a patient's mouth: "Dr Lim, does this look correct?"

Unlike extraoral X-rays, where the film is placed outside the mouth, intraoral radiography requires dentists to position X-ray holders with film behind the patient's teeth.

It is a complex positioning procedure. When the film is placed in the mouth at the wrong angle, it can lead to imaging errors: teeth might not be fully captured in the image or might be overlapping - making it hard to properly diagnose issues such as tooth decay and bone loss around teeth.

Noticing that students were struggling to grasp the technique, Dr Lim devised two innovative tools - iRadiate2D and iRadiate3D - to simulate the X-ray taking process and help them practise their skills.

"Students tend to get overwhelmed when a task has too many steps or components - I break it down into smaller, simpler, and more digestible tasks," explained the Senior Lecturer at the NUS Faculty of Dentistry.

Practice makes perfect

Previously, students learnt intraoral radiography in Oral & Maxillofacial Medicine, Pathology & Radiology (OMS2100)through a lecture and a 45-minute practical session.

But despite having been taught the theory beforehand, they often turned up at practical sessions unsure of how to set up and position the X-ray holders and films in three-dimensions to ensure the X-ray images are clinically useful.

"They had a lot of issues with visualising the end goal, so it made it difficult for them to prepare for the task, which meant that we were not using the practical sessions efficiently," recalled Dr Lim, who graduated with a Master of Science in Oral and Maxillofacial Radiology from the University of North Carolina at Chapel Hill in 2017.

To solve this issue, she worked with Ms Mandi Lee and Mr Eng Teng Chuan, design researcher and design engineer respectively at Keio-NUS CUTE Center, to build iRadiate2D. This interactive web-based intraoral radiography teaching tool helps learners reinforce theoretical concepts at home before they attend hands-on sessions.

Integrated into the curriculum in 2019, this learning tool guides students through setting up X-ray holders, as well as the ideal positions in the mouth for imaging.

Students drag, drop and rotate the holders to align them with the targeted teeth. If their answers are incorrect, they are asked to try again and cannot proceed until they input the correct alignment.

For their innovative use of technology in teaching, Dr Lim and the team received the NUS Annual Digital Education Award (Team category) in 2022 and the Faculty of Dentistry's Excellence in Teaching Award in AY2020/21.

"I enjoyed the convenience of using the website at home and at my own pace," said Silvester Chew Kheng Han, a second-year dentistry undergraduate who took the module in 2023.

"The software takes you through the process step by step, and corrects you throughout, which I found effective in consolidating the content Dr Lim went through in her first lecture," he added.

Hands-on learning

However, there is only so much an interactive website can do. To give students more opportunities for hands-on practice, Dr Lim worked with design researchers from the Keio-NUS CUTE Center, Ms Lee and Ms Tracy Shen, to create a three-dimensional version of iRadiate2D in 2020.

Known as iRadiate3D, it allows students to practise what they have learnt online on a physical model - without the need for an actual X-ray room, specialised equipment and staff supervision. The latter is especially important given the safety concerns associated with handling X-ray equipment, which involves ionising radiation.

There were other logistical considerations. The growing number of students in class meant that there was a need to provide them with options to practise outside of these supervised sessions. Meanwhile, the manufacturers' discontinuation of the manikins currently used in training meant that alternative methods had to be considered.

The setup of the iRadiate3D features a 3D-printed model of a jaw, tongue, and cheek mounted on a stand, along with a phone in front of it. The phone's camera detects the position of the X-ray holder in the mouth and - with the help of augmented reality - displays the corresponding X-ray image on its screen.

Dr Lim first trialled this training simulator with her students in 2021. Since then, the team has not only resolved the technical bugs and glitches in its initial version, but also discovered the most effective way to use it in class.

For instance, she quickly realised that allowing students to use the simulator's "dynamic" mode - which shows them what the X-ray would look like in real-time as they moved the film - made them over-reliant on the tool.

"We do not have this luxury in actual clinical practice," she explained. In the real world, the image is only visible after the X-ray exposure is made. Moreover, the number of X-rays films taken should be kept to a minimum in order to reduce the patient's exposure to radiation.

She now uses the "dynamic" mode only for demonstration purposes at the end of her lectures, while students work with a "static" mode, which shows the X-ray image only after they click the "capture" button.

Rosemary Tan Li Une, another second-year undergraduate, said it gave her a better understanding of how to position the film in a patient's mouth. "The additional practice made performing the actual procedure less daunting," she said.

With the help of iRadiate2D and iRadiate3D, undergraduates are finding it easier to pick up the intraoral radiography procedure. Dr Lim noted that students are now more prepared for lessons, making the sessions more efficient and productive.

Silvester added: "They allow visual learners like me to understand the set-up and conceptualise the content taught during the lectures."

Innovate to motivate

While plans to scale iRadiate3D are in the early stages, its predecessor, the iRadiate2D website, is already being adopted by dental schools overseas, for example in the United States.

Dr Lim is now exploring new ways to teach students how to read X-ray images and make diagnoses better. These innovative teaching methods are a win-win. Students learn better, and as Dr Lim quipped with a smile, "it also keeps things interesting for me".