Periodontal probe based on the fluorescent fiber position sensor

The paper presents a photonic smart-probe, based on a fluorescent fiber, dedicated for the point-of-care periodontal examination. Globally, periodontal diseases are prevalent both in developing and developed countries and affect about 20-50% of global population. The handpiece of the pressure sensitive periodontal probe should provide the accurately measurement of the depth of a pyorrhea pocket in a human or animal gum. Clinical attachment level (CAL) is the new gold standard for the diagnosis and monitoring of the periodontal disease. CAL has stimulated the recent introduction of novel periodontal probes. For point-of-care, a general dental practitioner usually uses low-cost first- or secondgeneration probes. They would require a low-cost smart-device (at least third-generation level), for accurate quick test results, light weight and easy to use, to avoid the wrong measurements. The proposed device is based on fluorescent linear optical fiber position sensor, adapted to the second-generation probe system. A modified surgical caliper with periodontal probe attachments, transforms the unit depth (mm-scale) of the probe into the cm-scale (according with the excitation length of the fluorescent fiber). The end of the fluorescent fiber is placed on the caliper scale and a SMD blue led attached to the caliper mobile arm is slid over the fluorescent fiber. The movable arm range is proportional with the mm depth of the periodontal probe into the gum. The T-Flame OceanOptics mini-spectrometer is used for signal processing. Lateral coupling of the excitation led light into the fluorescent fiber at different positions produces the emission spectral shift. Thus, the result of the energy transfer process changes for different lengths of the led excitation of the fluorescent fiber (at cm scale), as an overlap of the emission and absorption spectra of the PMMA co-doped fiber.