If your cavity is just at the surface there is a possibility to stop or reverse it with oral care and lifestyle changes incorporating:

Sunlight/Vitamin D

Vitamin C

Omega 3

Iodine

Cloves

Baking Soda

Non-PFOA floss

Goats milk(If you can tolerate milk)

Also avoiding:

Stress

Added sugar

Simple carbohydrates

Acidic foods