A new prototype device paves the way for pinpointing the exact location of increased acidity in the oral biofilm and therefore where caries is most likely to develop. The optical pH monitor, called O-pH, provided impressive results in monitoring oral biofilm pH levels and even influenced the career path of one of its developers. Dental Tribune International (DTI) was able to speak with the principal investigators, Dr. Eric Seibel, a research professor of mechanical engineering with affiliations in the department of electrical and computer engineering, bioengineering, and oral health sciences. dentistry at the University of Washington, and Ph.D. student Manuja Sharma on the development of the O-pH device, its potential, and the motivation for the project.
Ms Sharma, Previously reported DTI on the new prototype optical pH sensor O-pH. How did developing braces as an electrical and computer engineering PhD student influence your studies and the career path you are aiming for?
Sharma: On a personal level, my research motivated me to work in health diagnostics in order to design and develop sensors to study signals and parameters of the human body that are still unexplored. During the development of O-pH, I had the opportunity to interact with dentists, chemists and other engineers and understand what it takes to build a prototype and deliver it to the clinic. I am sure that these skills and experiences will be extremely valuable in my future career.
Dr. Seibel, the study mentioned that previous attempts to measure the pH of dental biofilm used electrodes or pH strips. How did your team find the revolutionary concept of using photodiodes?
Dr Sebel: My dentist colleagues challenged me to predict where cavities might occur in the mouth, which led me to measure pH, not outside of the oral biofilm, bathed in saliva, as do pH electrodes or paper pressed against the biofilm, but all the way through the biofilm. This requires a pH-sensitive dye that only permeates the extracellular matrix in order to get an accurate reading of the pH that surrounds the enamel.
Sharma: The low-powered blue light causes the dye inside the syringe to fluoresce, then that dye on a set of artificial teeth mimics how the device works in the mouth.
The O-pH device uses low power blue light and a special dye to cause oral biofilm to fluoresce in areas with higher levels of acidification. (Photo: Manuja Sharma, University of Washington)
Case study using a multi-mode scanning fiber endoscope (mm-SFE) for pH detection. Subject had not received professional cleaning in over seven months and had skipped brushing for five days prior to the exam. (a) Image of interproximal dental biofilm with pH heat map. (b) The pH heat map after the sugar rinse. (c) The difference between resting pH and falling pH. (d) The protocol used for testing with mm-SFE. The fluorescein is rinsed out instead of being applied to each tooth surface using a blunt hypodermic needle. (e) The mm-SFE pH probe. (f) Stephan’s curve, red line indicating average pH obtained using images at each stage of resting pH and falling pH. (Image: University of Washington)
PhD student Manuja Sharma is studying electrical and computer engineering; she found that her work on the O-pH device oriented her towards the development of medical diagnostic devices. (Photo: Manuja Sharma)
Dr. Eric Seibel is a Research Professor of Mechanical Engineering and an Adjunct Research Professor of Electrical and Computer Engineering, Bioengineering, and Oral Health Sciences at the University of Washington. (Photo: Eric Seibel)
During your research with O-pH, have you identified any other possibilities for further research other than studying different levels of sucrose concentration?
Dr Sebel: We searched for a dental app that would help guide a teen undergoing orthodontic treatment, or their parent, in applying a prescription fluoride varnish at home to areas identified as most at risk for cavities by O-pH. This concept was tested in surveys of pediatric dentists in Washington State and featured in a poster that Ms. Sharma co-authored.
What is the next step for this product, and what would it take to make it widely available for use by practitioners?
Dr Sebel: We hope to work with dental device manufacturers to conduct clinical studies with variations of the O-pH device, such as the image-based device, the Multimodal Scanning Fiber Endoscope, used in the study. case described in our recently published article. An imaging system that maps oral biofilm pH should be able to obtain a more robust measurement over time. For example, a series of panoramic pH images of biofilm coating enamel surfaces can be compared to the next set of panoramic images obtained six months later. Over time, this measurement of biofilm pH prior to biofilm removal in the dental office can become a quantitative and spatial monitoring system of enamel health.
The two researchers said they could envision a smaller version of their O-pH device being used at home to help dental patients see biofilm and monitor acidification in their teeth, perhaps in conjunction with an app. such as that mentioned earlier by Dr. Seibel.