Check your insurance policy to see if it's covered. In general, dental is considered a "luxury" item and is not included in many health care covers. Our personal cover here in HK only includes routine dental check-ups, routine cleaning and other general dental work (whatever that means!) So, I'd say in many cases, most dental problems are a personal financial liability.
You can choose to be a generous employer and foot either part or all of the bill, depending on how large it is.