Label-Free Nonlinear Optical Microscopy: Shedding Light on Oral and Dental Tissues.

Nonlinear optical microscopy (NLOM) enables 3D imaging with submicron resolution, and autofluorescence spectro-microscopy of oral and dental tissues shows promise for enhancing the analysis of both healthy and diseased tissues. We critically reviewed studies involving humans and animals, examining oral and dental tissues in vivo and ex vivo using label-free NLOM. A scientometric analysis was also conducted to assess the 25-year trajectory of NLOM in dentistry. A total of 78 studies from 17 countries were evaluated. Second harmonic generation (SHG) was the most commonly employed technique (83.3%), often combined with other NLOM methods (68%). The primary specimens imaged were the oral mucosa and teeth, with at least 70% of the studies contributing new morphological or biochemical insights and 34.6% generating data with potential clinical applications. SHG and cancer diagnosis were prominent descriptors, reflecting key findings from the most-cited articles. Data indicate that NLOM provides robust and reliable clinical information, particularly for cancer and dental caries diagnosis; however, challenges remain in translating this knowledge into practice. Integrating this technology into clinical devices could advance dentistry by creating noninvasive tools for long-term monitoring with minimal intervention and sample preparation.