Deductions & credits

You can deduct your dental insurance if you're itemizing and if you didn't pay for it pretax which means that your employer didn't take the insurance premium out before taxes were deducted on its earnings.  The same goes for medical.  But, in most cases the employers do not take the taxes out of those earnings, thus you are getting a break and then you cannot deduct the premiums since you can only get one break.  (If you pay for it without going through your employer, you can deduct it.)