In recent decades, we have seen the development of numerous imaging modalities that have revolutionized dental and medical diagnosis. Optical Coherence Tomography (OCT) is one among them. OCT is mainly used in ophthalmology and it also represents a major advancement in imaging in dentistry, due to its ability to provide detailed characterization of dental microstructure, enabling the dentists to make earlier and more accurate chairside diagnosis of oral disease. OCT is a noninvasive diagnostic imaging modality which enables invivo cross- sectional, 3 dimensional, and tomographic visualization of the internal microstructure in biological systems. This poster is presented as review about the history, principle and its application in dentistry and especially in Oral Medicine for early screening for precancerous lesions and oral cancer. Keywords: Optical Coherence Tomography (OCT), dental imaging, chair-side diagnosis, noninvasive diagnostic imaging