Nanomechanical properties of kidney stones, gallstones and oral stones compared with tap water scale by depth sensing indentation

This article focuses on a description of research performed to identify structural and mechanical properties differences between calculi in stones, such as gallstones, kidney stones, dental tartar, and saliva gland sialolite, were analyzed and compared with tap water stone, in order to set interrelations. In this study, biological hard pebble-like structures were analyzed and compared among them using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), and Atomic Force Microscopy (AFM). In addition, Nanoindentation was used to obtain values as example in kidney stones the in; stiffness S = 27,827 ± 620 N/nm elastic modulus E = 27.3 ± 4.5 GPa, hardness H = 1.5 ± 0.5 GPa. Samples with the highest amounts of calcium and magnesium oxides were; Tap water stone (39.60%), followed by dental tartar (39.40%), saliva gland sialolite (29.20%), kidney stones (27.70%), and lastly the gallstones (0.30%). Kidney stones showed in particular, whewellite and kaoulinite crystallographic phases, that confers characteristics of greater crystallization with respect to the other stones. Kidney stones positioned in the major hardness stone in human body with 1.5 GPa. In general, samples with the highest amount of calcium oxides, also showed the highest mechanical properties of H and E. Microstructural characteristics and nano-hardness of tap water stone from drinking water where similar to those of dental tartar and saliva gland sialolite, more research still required to associate health concerns and tap water scale derived from drinking water known as hardwater. [Display omitted] •Nanomechanical properties in gallstones, kidney stones, dental tartar, and saliva gland sialolite.•Kidney-stones showed whewellite and kaoulinite crystallographic phases.•Microstructural characteristics of tap-water-stone from drinking-water where similar to saliva gland sialolite.•Even though the calcium carbonate CaCO3 was present in all the samples.•It is important to understand the composition and mechanical-properties of these stones in the body.