Specialized Probehead for MRI in Qualitative and Quantitative Caries Detection

X-ray based visualisation techniques were for many years the only way to assess structure and state of the human teeth. MRI has been used in the research of the healthy and decayed teeth during last decade. Recently, MRI was used for estimation of the facial bone structure, in preparation to implantation, and tooth structure. Objectives: The aim of this work was to investigate potential of MRI for detection and estimation of the caries on the level of laboratory non-clinical tests. Methods: Measurements were done in MR Tomography Lab INP with the use of special designed probehead containing the homebuilt, unshielded gradient system, high-pass birdcage coil and handling system for small objects for the 4.7 T research MRI system, equipped with Maran DRX console. Prior to the investigation, one randomly chosen, extracted, decayed, human tooth was degassed to minimize magnetic susceptibility artifacts. High intensity signal from water penetrated into the porous decayed regions of tooth, contrasted with lack of signal from mineralized tooth tissue, allow for visualisation of the presence and extent of caries. The existing caries volume was measured. Results: A single measured volume was 15.6 mm³. Conclusion: Presented results show possibility of MRI volume measuring and imaging of the caries in teeth. The challenges in transferring MRI technique into in vivo conditions in present stage are: slow data collection and lack of dedicated hardware.

Supported by Grant no. 2 P05C 054 26 from Ministry of Science and Informatization of Poland.