Development of Quantitative In Vivo Imaging of Oral Biofilm pH to Allow Prevention of Enamel Demineralization

ABSTRACT Dental caries, affecting over 3.5 billion people globally, are characterized by tooth demineralization, typically starting with external enamel and progressing into underlying dentin. If left untreated, caries may result in excruciating pain and tooth loss. Acid produced from plaque-forming bacteria contributes to demineralization of the exterior tooth enamel which accelerates after the pH drops below a threshold value (e.g., pH of 5.1- 5.5) at the enamel surface for extended time periods. Given this, rapid recognition of acid production of biofilms, especially in hard-to-reach locations such as the pits and fissures of occlusal and interproximal regions, would allow dentists to locate early-stage tooth decay and therefore assist the dental practitioner in preventing the development of caries. Although this idea is currently employed via pH meter electrical probes, they are limited in cost effectiveness, accuracy, speed, resolution, and ability to reach crucial high-risk areas such as between teeth and within crevices on the biting surfaces of teeth. To answer the market’s need for improved and rapid early-stage tooth decay detection that may even predict caries and its severity, VerAvanti is developing an acid-measurement technique that relies on pH-sensitive fluorescence dye (sodium fluorescein) that rapidly permeates the extracellular matrix of oral biofilms. By identifying areas on teeth which are more acidic, dentists will be able to identify tooth decay at its earliest possible stages. Through pre-production development and a pilot human subjects study, VerAvanti intends to put forth an Optical pH (OpH) device for dental clinics which will be the first medical or dental imaging product to combine full-color high resolution imaging with exact co-registration pH mapping through the oral cavity at video rates. This project will include the initial pre-product development of the OpH device, and a first human subjects study examining clinical utility of caries detection and prediction, ease of use, and integration into dental clinic workflow. To this end, VerAvanti will first address the actual fabrication of a prototype OpH with pH measurement versatility, full-color imaging, and initial user interface. Building from this, the quantitative accuracy and reproducibility of the OpH device after technical calibrations will be tested in vitro, and the device’s efficiency will be assessed subsequently in a pilot clinical study using up to 12 human subjects. By the end of the project, VerAvanti will have demonstrated that accurate pH measurements and mappings can be acquired easily and quickly by the hygienist, as well as be interpreted by dentists in forming site-specific caries management strategies. This project will establish the feasibility of use of the OpH device in a clinical setting in adults and also propose future implementation for children.