Optical Sensor to Monitor Bacterial-Mediated Acidogenic Profile of Saliva

Optical sensor offers advantages such as portability, ease of operation and allows detection of various biochemical parameters rapidly and quantitatively. Objectives: The aim of the study is to evaluate the ability of a visible light based spectroscopic sensor system to monitor the bacterial-mediated acidogenic profile of saliva resulting from the bacteria-sucrose interaction. Methods: Experiments were conducted in two stages. In stage-1 designing and characterization experiments were conducted to standardize the optical sensor. In stage-2, clinical experiments were carried out on stimulated saliva samples obtained from children of age group less than 6 years. The bacterial-mediated acidogenic profile was monitored at hourly intervals using a photosensitive pH indicator for a total period of 180 min. Microbiological assessment of the saliva samples were carried out using the commercial chairside tests (Dentocult SM and LB). In addition, the shifts in the pH of saliva-sucrose samples were recorded using a pH meter. Results: The absorption spectra obtained from the optical sensor showed peak maxima at 595nm, which decreased as a function of time. The Dentocult SM results obtained categorized the patients into high and low caries risk category. The bacterial-mediated acidogenic profile monitored using the optical sensor was significantly different between the high and low caries risk groups (p=0.003). A strong positive correlation was also observed between the rate of decrease in the absorption intensity measured using the optical sensor and the decrease in pH measured using the pH meter (r= 0.93). Conclusion: The optical sensor used in this study presents a sensitive and rapid chairside approach for the quantification of the acidogenic profile of saliva. Funding: NUS, ARF-2006-R-222-000-020-112