The thing about being attracted to someone, Dr. Frank Sangster tells us, is that “you find yourself doing things and you have no idea why.”

“Novocaine” is all about those things, and the insanity they can lead to. In this rather Hitchcockian dark comedy/suspense drama from writer/director David Atkins, a middle-of-the-road dentist is driven to extremes by the woman he has the hots for, and he’s the subject of a murder investigation, too.

The dentist is the aforementioned Frank, played with quiet befuddlement by the incomparable Steve Martin, who proves himself more invaluable to our collective consciousness each time he appears on the scene. Frank has a successful practice and is engaged to his blond hygienist, Jean (Laura Dern), who is a lovely, all-American gal. Still, he longs for something more — something exciting or different.

Proving the adage that you should be careful what you wish for, Frank is visited by a new patient, Susan Ivey (Helena Bonham Carter), who tricks him into prescribing drugs for her in addition to stealing all the narcotics he has in the office. The problem would be easily solved with a quick phone call to the police, but Frank has unfortunately been mesmerized by the mysterious femme fatale.

We should also mention the worthless brothers: Frank’s (played by Elias Koteas), and Susan’s (Scott Caan), both of whom figure into things later.

That’s how things go in these movies: A normal guy gets drawn into non-normal situations, usually due to a mistake he made that was serious enough to demand attention, but not serious enough to deserve all this.

It’s a modern example of film noir, in many ways, aided by Danny Elfman’s loudly ominous score and the presence of dangerous women and an innocent man whom no one believes. If you can accept the unlikely way Frank gets into the mess — by not turning Susan in to the cops early on — it’s an exciting adventure with more than a few good laughs along the way. (Kevin Bacon is very funny as a self-serious Hollywood actor who “interrogates” Frank while doing research for an upcoming cop movie.)

Bonham Carter and Dern are solid in their very different roles, and Caan is as obstreperous as one expects him to be. Elias Koteas is perhaps under-used as Frank’s brother.

In the end, some of the revelations come a bit too easily, but it leads to a resolution that is delightfully, painfully original. “Novocaine” is unusual, but in an accessible, crowd-pleasing way. And you may never look at your dentist the same way again.

B+ (; R, frequent harsh profanity, some fairly.)