Raw butter is nutritionally superior to pasteurized. The only difference in production is that it has not been pasteurized, processed, cooked, etc.
(The butter you buy in supermarkets generally has been processed and pasteurized, destroying anything in it that might be good for you)
In terms of tooth health, this is significant because pasteurized dairy tends to be acid-forming where as raw dairy can be very easily digested.
You generally find raw butter at a local dairy farm, or in some health food stores and food co-ops (member-owned grocery stores).