fresco vs tooth enamel

fresco

noun
  • An artwork made by applying water-based pigment to wet or fresh lime mortar or plaster. 

  • The technique used to make such an artwork. 

  • A cool, refreshing state of the air; coolness, duskiness, shade. 

verb
  • To paint using fresco. 

tooth enamel

noun
  • The hard, mineralised substance that makes up the visible part of teeth. 

How often have the words fresco and tooth enamel occurred in a corpus of books? (source: Google Ngram Viewer )