Bioimpedance spectroscopy and spectral camera techniques in detection of oral mucosal diseases: a narrative review of the state-of-the-art.

Oral mucosal diseases are common health problems that reduce overall wellbeing and increase the risk for several systemic diseases. Due to the limitations of present diagnostics, new non-invasive methods are needed for reliable, affordable, real-time screening and follow-up of oral mucosal lesions. Bioimpedance spectroscopy, spectral camera imaging and other optical methods are promising novel techniques to detect abnormal changes in oral mucosa. In this review, the current status of bioimpedance spectroscopy and autofluorescence utilising spectral camera techniques in the assessment of oral mucosal health is critically evaluated. Scientific publications related to bioimpedance spectroscopy were surveyed using PubMed and Scopus databases. Search was done using a combination of terms "oral mucosa", "oral cancer", "squamous cell cancer", "tissue", "electrical impedance measurement" and "bioimpedance spectroscopy". Publications related to spectral cameras were searched from PubMed with a focus on autofluorescence utilising spectral camera techniques. Search was done using terms "autofluorescence", "oral disease" and "VELscope" publication date restricted from 2008 to date. In this review, we also discuss the future trends and strategies such as combining different methods, e.g. spectral cameras and bioimpedance spectroscopy that could represent a unique multimodality in vivo tool for providing complementary information on the health status of the oral mucosa.