A drop-like optical fiber salivary pH sensor: A rapid and real-time detection of periodontal disease

A real-time and rapid detection of salivary pH for periodontal diagnosis is an emerging point-of-care (POC) technology trend. The precise and non-invasive sensitive POC devices, which could be used as chair-side tools to improve clinical dental inspections, are essential for an excellent periodontal diagnosis. In this paper, we report on developing a POC technology based on optical fiber sensors as a promising marker, to the best of our knowledge, to detect the role of salivary pH in periodontitis diagnosis and support dentists’ inspection. The optical fiber sensor based on a drop-like structure was fabricated by bending single-mode fiber (SMF) into a section of a thin capillary tube. In this work, firstly, the performance of the proposed sensor towards different pH levels ranging from 1 to 7 was experimentally investigated. Experimentations showed that the pH sensor responded to various pH levels with a calibration curve sensitivity of −2.075 nm/pH and a high linearity of 0.985. Then, 66 patients were enrolled in this study and divided into two groups according to clinical outcomes: Group A with clinically healthy periodontium and Group B with chronic periodontitis. The real saliva from each patient was collected, and the salivary pH was evaluated immediately using the aforementioned proposed sensor. The experimental results show that Group A and Group B salivary pH mapping ranged from 6.5 to 7.3 and 5.5 to 6.4, respectively. The proposed sensor offers substantial practical benefits, providing a rapid response time of less than 2 s, instantaneous, noninvasive, and easily monitored tool for the early detection and diagnosis of periodontal health status.