Generally, prepaid medical expenses, including dental costs, are not deductible. An old Tax Court case said that advance payment for medical services to be rendered in the following year are not deductible in the year paid. The only exception is for prepaid of lifetime care from a continuing care facility or nursing home.
The difference between face value of a bond and lower market price, attributable to rising interest rates. On a sale, gain on the bond is generally taxed as ordinary income to the extent of the discount.