Terahertz waves, the electromagnetic waves in the range of 0.1 to 10 THz, has the advantages of being damage-free, causing no ionizing radiation injury, and being capable of recognizing the fingerprint spectrum of molecular characteristics, thus holding encouraging prospects for wide applications in the field of biomedicine. Terahertz spectrum can be used to identify and characterize biological structures of different levels, from biomolecules such as proteins to cells and tissues, through the spectral signals and/or restored images of the samples. Herein, we summarized the current stomatogical application of and research progress in terahertz spectroscopy and imaging in dentistry, reported the latest research findings, strengths and limitations from three perspectives, tooth anatomical structure, the extent of caries progression, and oral soft tissue, and suggested possible directions for future exploration.