Liquid enamel is:

Saliva is also called 'Liquid enamel' as it is a rich source of various minerals. The amount of saliva secreted normally is 5 ml/ 5 min i.e. 700-800 ml/ day. The quantity of saliva may influence caries incidence as is especially evident in cases of salivary gland and xerostomia in which salivary flow may be entirely lacking, with rampant caries as the typical result. The average unstimulated flow rate of saliva is about 0.3 ml per minute.