Calcium phosphates are excellent biomaterials for hard tissue regeneration and replacement. Recently, nano hydroxylapatite (HAp) has been intensively studied as remineralization agent for tooth enamel protection and remineralization. In this research, we developed a model toothpaste composition, determined viscosity and investigated weather differently processed – spray-dried (spCDHAp), lyophilized (lyoCDHAp), wet precipitated (paste-like consistence, pCDHAp) – calcium deficient hydroxyapatite (CDHAp) affect remineralization of bovine tooth enamel. Components of model toothpastes were CDHAp, 2-hydroxyethylcelluloce, glycerol and water. Viscosity of toothpastes varied from 2.5 to 40 Pa∙s. Model toothpastes with 20 wt% CDHAp showed thixotropic behaviour, thereby we examined them as potential tooth remineralization pastes. After in vitro remineralization, changes in enamel surface were detected; neither the texture of demineralized surface nor bundles of HAp crystals were observed. It was suggested, that a new calcium phosphate layer was formed on the enamel. In conclusion, CDHAp is very promising material for enamel regeneration, but different pre-treatment of CDHAp (resulting in different morphology of agglomerates) did not lead to distinctive remineralization results.