Abstract
Objective:Bacteria in the dental biofilm produceacid after consumption of carbohydrates which if left unmonitored leads to caries formation. We present O-pH, a device that can measure dental biofilm acidity and provide quantitative feedback to assist in oral health monitoring.Method:O-pH utilizes a ratiometric pH sensing method by capturing fluorescence of Sodium Fluorescein, an FDA approved chemical dye. The device was calibrated to a lab pH meter using buffered fluorescein solution with a correlation coefficient of 0.97. The calibration was further verified in vitro on additional buffered solution, artificial, and extracted teeth. An in vivo study on 30 pediatric subjects was performed to measure pH before (rest pH) and after (drop pH) a sugar rinse, and the resultant difference in pH (diff pH) was calculated. The study enrolled subjects with low (Post-Cleaning) and heavy (Pre-Cleaning) biofilm load, having both unhealthy/healthy surfaces. Further, we modified point-based O-pH to an image-based device using a multimode-scanning fiber endoscope (mm-SFE) and tested in vivo on one subject.Results and ConclusionWe found significant difference between Post-Cleaning and Pre-Cleaning group using drop pH and diff pH. Additionally, in Pre-Cleaning group, the rest and drop pH is lower at the caries surfaces compared to healthy surfaces. Similar trend was not noticed in the Post-Cleaning group. mm-SFE pH scope recorded image-based pH heatmap of a subject with an average diff pH of 1.5.Significance:This work builds an optical pH prototype and presents a pioneering study for non-invasively measuring pH of dental biofilm clinically.
Highlights
IntroductionCommonly known as tooth decay, is the most prevalent health condition affecting 2.3-3.5 billion people globally [1], [2]
Chronic caries in teeth, commonly known as tooth decay, is the most prevalent health condition affecting 2.3-3.5 billion people globally [1], [2]
Similar to a visit to a general physician where measurements like heart rate, blood pressure, and blood work provide a baseline quantitative information, dentistry could benefit with quantitative measurements of the risk factors that are directly correlated with caries formation and can be safely monitored over time to understand the status of oral health
Summary
Commonly known as tooth decay, is the most prevalent health condition affecting 2.3-3.5 billion people globally [1], [2]. Visualization and tactile inspection is a standard procedure to evaluate dental surfaces These techniques are the only gold standard for detecting early caries at occlusal (biting) and smooth surfaces (Fig.1(a)), while bitewing Xrays (Fig.1(b)) are the diagnostic tools used for caries at interproximal (in between teeth) regions. Lesion activity is determined by surface roughness and appearance whereas lesion depth is confirmed using X-rays. These dental tools and procedures provide patients with lagging, non-quantitative feedback assisting inadequately in prevention of new caries or in evaluating site-specific risk of caries development. A leading indicator, a terminology commonly used in occupational health systems [5], provides pro-active, predictive risk assessment unlike lagging tools that assess information after an event has already occurred, in our case, after a carious lesion has formed. The current adjunct diagnostic tools are focused on measuring the presence of the disease, rather than assessing the risk of developing active caries
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