Number of copies : very few...
In order to be able to purchase it, you needed to be a Japanese dentist surgeon with an officiel license... GC Dental doesn't deal with other people.
Dental IQ-san is a series of informational softwares sold to dentists for them to use in their dental clinics. Patients could use it in the waiting room, or it could also be installed next to the dentist's chair.
There exist several levels (4), released on PC and MAC. Level 1 and 2 were also released on PlayStation.
It is not a hibaihin since it could be purchased from GC Dental corporation (50 000 yen was the catalogue price...) but I think it was too obscure not to be present here!