The incidence of root caries and hyperesthesia in elderly people tend to increase with increasing age. This can be prevented by enhancing the root surfaces against aciduric bacteria. In order to prevent root caries, a chewing gum containing calcified seaweed rich in Ca, Mg, Na, F and P was created. A dentin block was made from the cervical part of the third molar after removing the cementum. The dentin blocks were immersed in remineralizing solution with extract of the gum with or without

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... ied seaweed for 2 weeks. The dentin blocks were immersed in demineralizing solution for 6 hours and acid resistance was evaluated after. Demineralization was evaluated by CMR image, demineralization depth (Ld) and mineral loss quantity ( Z) by image analysis, qualitative analysis by EPMA and the surface structure with the SEM. CMR image analysis revealed that the region immersed in aciduric solution had less quantity of demineralization than the region which was not immersed. A significant difference in Ld and Z of the demineralization area after the aciduric treatment between the solution with calcified seaweed and the solution without aciduric treatment (p<0.05) was observed. Levels of Ca, P and Mg were detected in EPMA except for F. In SEM, the dentinal tubules of the demineralized region without aciduric treatment was enlarged which was not seen in demineralized region after aciduric treatment. The results indicate that the chewing gum with calcified seaweed is effective in increasing dentinal acid resistance. Journal of Hard Tissue Biology 20[2] (2011) p87-92