Imagin carious human dental tissue with three-dimensional optical coherence tomography

Optical Coherence Tomography (OCT) used in this study, is a new non invasive optical detection technique. The OCT system is based on a Michelson interferometer, that generates a crosssectional image of the teeth with resolution up to 2 microns. The buccal surface from the third molar teeth was used to induce caries like lesions. This surface was coated with an acid resistant nail varnish except a small window. The pH demineralizationremineralization cycling model was used to produce the lesions. This cycle was repeated for 9 days and remained in the remineralizing solution for 2 days. The OCT system was implemented by using an ultrashort pulse laser (Ti:Al2O3@830nm) with 50fs of pulse width and average power of 80mW. The laser beam was focused into the teeth providing a lateral resolution of 10 microns. Image was produced with a lateral and axial scans steps of 10 microns. After analyzing the surface by OCT it was possible to produce a tomogram of dentine-enamel junction and it was compared with the histological image. This OCT system accurately depicts dental tissue and it was able to detect early caries in its structure, providing a powerful contactless high resolution 3D images of lesions. ; Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP) ; FAPESP: 00/15135-9