That is a real word! It is the study of cavities. Today I heard about a new approach in dentistry which involves treating tooth decay in the earliest stages, before the enamel is in need of drilling and filling. This must be the type of problem we have when the dentist tells the hygienist "keep an eye on number 7."
Some dentists think that better brushing and fluoride is all that is needed in this case (oh and not consuming a lot of sugar), but others are using a technique in which mild acid is used to clear out the early decay and a resin is used to fill the holes left behind.
You can read about it here.
I heard about it on the radio this morning and as I was listening I sort of giggled thinking that 100 years from now, the new civilized world is going to gasp at the thought of the barbaric drilling we poor fools endured!