Rot and decomposition are words for decay. Another word for tooth decay is cavity. Cavities happen as a result of the production of acid by bacterial fermentation of food debris accumulated on the tooth surface.
rot
produce and decay
ancient, archaic, antediluvian, antique, antiquated,decay.
elder,ancient, archaic, antediluvian, antique, antiquated,decay.
perversion, decay decline, degradation, downfall, dissolution, regression
The dead deer started to decay.
Francium-223 decay to radium-223; each isotope have another type of decay.
물러서!
rot
Transmutation, which is the change of atoms from one element to another.
"if you don't take good care of your teeth, they will decay"
That would be radioactive decay.