If it's a canine that is needing to come out it'll be a costly one, as well if it is molars. Reason being is that they are much more difficult and they take a lot of time to extract them safely. Any tooth brushing, rinsing, dental treats will not be helpful at this point. Unfortunately they are meant as more of a preventative, not a fix.
February is dental health month, as least in Saskatchewan. I am just assuming that most places would have something similar at some point in the year. During this time it is cheaper to have a dental performed.
In response to lindapalm, there is a feline dental food... Hills T/D maybe? I can't remember off the top of my head if it's hills or medi-cal. Some cats seem to have a genetic predisposition to poor dental health. So it may be an ongoing issue, no matter the type of food.
My last piece of advice is go to a clinic that does full mouth xrays with their dentals. If your kitty has teeth that visibly need to be removed there will most likely be more that are in trouble below the gum line. Shop around, you'll find a great variety in quoted price. Most clinics will do complementary dental exams, which is nice