Senior Principal Scientist Colgate Palmolive, United States
Introduction:: Intraoral microvascular mapping using capillaroscopy is a powerful diagnostic tool that can provide valuable information for the early detection and monitoring of various oral diseases. Microcirculation plays a crucial role in maintaining the health of oral tissues, and any disruption to this system can lead to the development of pathological conditions. Capillaroscopy allows visualization of the microvasculature of oral tissues, which can provide detailed information about blood flow and microvascular abnormalities. This information can be used to diagnose and monitor various oral diseases, such as oral cancer, periodontal disease, and oral mucosal lesions. Moreover, capillaroscopy can assist in selecting appropriate treatment options by providing a detailed view of microvascular changes associated with the disease. In this article, we present the design and development of a low-cost, compact intraoral handheld capillaroscope based on cross-polarized optics and demonstrate its diagnostic capability for intraoral microvascular mapping applications.
Materials and Methods:: The intraoral handheld capillaroscope is based on an off-the-shelf USB camera that offers an adjustable magnification range of 50X to 500X. The optical design of the microscope is modified to a cross-polarized optic by integrating a pair of linear polarizers. A miniature ring-shaped polarizer is placed in front of the ring LED illuminator, and another circular-shaped polarizer/analyzer is placed in front of the camera lens aperture such that their optical axes are perpendicular to each other. Fig. 1 (a) illustrates the schematic diagram of the handheld capillaroscopy system. The forward-viewing optics of the system can image the anterior oral cavity of human subjects with a spatial resolution of ~5μm and a field of view of 5mm². To quantitatively analyze the microvascular map and blood volume, the RGB channels were separated, and the green channel was subtracted from the red channel to highlight the gingival bleeding. The image was then thresholded, and the gingival bleeding was quantified using pixel counting.
Results, Conclusions, and Discussions:: In order to demonstrate the feasibility of the designed handheld capillaroscope, we imaged the buccal marginal gingival area of a healthy human subject. The left image on Fig.1 (b) shows the original marginal gingival capillary map in cross-polarized mode and the right image on Fig.1 (b) shows the cross-polarized mode with enhanced contrast. To show the capability of the system for micro-bleeding detection and quantification, we induced gingival abrasion by controlled brushing with a toothbrush with untapered bristles. Fig.1(c) shows the induced gingival micro-bleeding with Fig. 1 (d) displaying the results of micro-bleeding quantification. In conclusion, we have successfully developed and demonstrated a compact handheld capillaroscopy system for intraoral soft tissue diagnostic application. Our system provides high-resolution images of the capillary network in the marginal gingival area, allowing for the detection and quantification of micro-bleeding. This technology has the potential to aid in the early detection of periodontal disease and other oral soft tissue disorders. The portability and ease of use of our system make it a promising tool for use in both clinical and research settings. Future work will focus on further improving the image quality and developing automated analysis techniques to enhance the diagnostic capabilities of the system. Overall, our study presents a significant step forward in the field of intraoral diagnostic imaging and holds promise for improving oral healthcare outcomes.
