The Movie is Apossionato? Incest is a theme. The Mother is crazy. The
father is a dentist. Daughter is the object of fathers affection after
flirting with him. The father has allready had an affair with her
girlfriend.Where can I buy it?0

Dear dezzibeagle,

The correct movie title is "Appassionata" (Italy 1974), directed by
Gianluigi Calderone, starring now-famous actress Ornella Muti and
Valentina Cortese.

Here is a short synopsis to prove that it is indeed the movie you are
looking for:
"Two girlfriends conspire to find out how much their youthful
sensuality can disrupt one of their households, headed by a dentist
and his mentally-ill wife. An exemplary instance of the Italian
"middle aged man goes garter belt shopping with his daughter and her
beautiful friend who he is currently having sex with" movie. As good a
seduction scene as one is likely to see set in a dentist's office.
Non-stop incest undertones and overtones."

You can order a VHS of this movie (converted to American NTSC video
norm) from Atomic Cinema. It is the very only source I was able to
locate. The price is $20.00:
http://www.cinebizarre.com/genre_sexploit1.htm

Atomic Cinema's website: http://www.cinebizarre.com/
Atomic Cinema's e-mail : mail@cinebizarre.com

Before ordering, please read Atomic Cinema's terms of service very
carefully:
http://www.cinebizarre.com/main_policy.htm

Source:

Internet Movie Database
http://us.imdb.com/

Search terms used:
"Appassionata " incest
://www.google.de/search?q=%22Appassionata+%22+incest&ie=UTF-8&oe=UTF-8&hl=de&meta=
appassionata "ornella muti" vhs
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=appassionata+%22ornella+muti%22+vhs&meta=
appassionata "ornella muti" dvd
://www.google.de/search?hl=de&ie=UTF-8&oe=UTF-8&newwindow=1&q=appassionata+%22ornella+muti%22+dvd&btnG=Google-Suche&meta=

Hope this helps!
Best regards,
Scriptor