Projects per year
Aim: To characterize multiscale interactions between high intensity focused ultrasound (HIFU) and dentin collagen and associated matrix-metalloproteinases; in addition, to analyse effect of HIFU on bacterial biofilms and biological properties. Materials and Methods: Dentin specimens were subjected to 10 or 20 s HIFU. XPS-spectra were acquired and TEM performed on dentin slabs. Collagen orientation was performed using Raman spectroscopy. Calcium measurements in human dental pulpal cells (hDPCs) were carried out after 7 and 14 days. For macrophages, CD36+ and CD163 were analysed. Biofilms were analyzed using CLSM. Tandem Mass spectroscopy was performed for detection of hydroxyproline sequences along with human MMP-2 quantification. Results: Phosphorous, calcium, and nitrogen were detected in HIFU specimens. TEM images demonstrated collagen network appearing fused together in HIFU 10 and 20 s specimens. Band associated with 960 cm-1 corresponds to stretching ν1 PO43-. Control specimens showed intensive calcium staining followed by HIFU 20 s>HIFU 10 s>HIFU 5 s specimens. Macrophages in HIFU specimens co-expressed CD80+ and CD 163+ cells. CLSM images showed HIFU treatment inhibiting bacterial growth. SiteScore propensity determined effect of HIFU on binding site with higher DScore representing better site exposure on MMPs. Conclusion: Multiscale mapping of dentin collagen after HIFU treatment showed no deleterious alterations on the organic structure of dentin.