Optical pH measurement system using a single fluorescent dye for assessing susceptibility to dental caries.

Manuja Sharma,Ryan Nguyen,Matthew D Carson,Jasmine Y Graham,Lauren K Lee,Eric J Seibel,Shwetak N Patel,Leonard Y Nelson,Philip A Walczak,Zheng Xu

doi:10.1117/1.jbo.24.1.017001

Abstract

.Sugar-rich diets and poor dental hygiene promote the formation of a biofilm (plaque) that strongly adheres to the dental enamel surface and fosters the evolution of aciduric bacteria. The acid contributes to demineralization of the exterior tooth enamel, which accelerates after the pH drops below a critical value () for extended time periods resulting in the need for restorative procedures. Preventative techniques to alert the dentist and caries-susceptible patients regarding vulnerability to dental decay require a clinical measure of plaque activity. Therefore, there is a need to evaluate the acid production capability of plaque deposits in the pits and fissures of occlusal and interproximal regions. A ratiometric fluorescence pH-sensing device has been developed using an FDA-approved dye and LED excitation. Fluorescein spectral profiles were collected using a spectrometer and analyzed with a spectral unmixing algorithm for calibration over the pH range of 4.5 to 7. An in vivo pilot study on human subjects was performed using a sucrose rinse to accelerate bacterial metabolism and to measure the time-dependent drop in pH. The optical system is relatively immune to confounding factors such as photobleaching, dye concentration, and variation in excitation intensity associated with earlier dye-based pH measurement techniques.

Highlights

Dental plaque formation occurs in a systematic manner, with early bacterial colonizers creating a favorable environment for secondary colonizers.[1]
FL was diluted in phosphate citrate buffer (0.2-M dibasic sodium phosphate, 0.1-M citric acid, pH indicated for each experiment), 0.1-M sodium bicarbonate buffer, or chemically defined medium (CDM) buffer.[29]
We created a test set consisting of different buffer values than those used for calibration in the same pH range

Summary

Introduction

Dental plaque formation occurs in a systematic manner, with early bacterial colonizers creating a favorable environment for secondary colonizers.[1]. Organic acids produced by these bacteria, lactic and acetic acid, have been shown to cause enamel demineralization.[3,4] This demineralization may progress to the clinical diagnosis of dental caries or breakdown of the tooth enamel surface.[8]

Methods

Results

Discussion

Conclusion