Analysis of a submandibular salivary caluculus showing egg-like structure

Objectives: Salivary calculus is an ectopic calcification of high frequency. It is principally found as pathological calcification in oral consisting of apatite crystal, but it's formation mechanism is unclear. To gain insight into the formation of a caluculus, detailed structural properties were investigated. Methods: Structural propaties of calculus were investigated usingoptical microscope, micro-CT and micro-X-ray diffraction(XRD) non-destructive method. Results: An optical microscope revealed that center part was lump with luster organic content in yellow color, and the outher cruster white cloudy roughwrought, liked an egg structure. By micro-XRD, apatite consisted these two layers, and a difference of a quantity of crystal was recognized. Using micro-CT, three layered structure was recognized with the core part in center. CT-value of each layer was different, and calcification degree was in the order of core, crust and intermediate layer. Conclusion: This salivary calculus had the three layered structure, and indicated that a ratio of crystal to organic content was different in each layer. Generation of three layered structure is studying.