Lawrence.com

Good oral hygiene can be important to the body as a whole. The mouth can contain all kinds of cancers, and there are links between gum disease and heart problems. Still, despite the importance of their work, there's something about dentists that makes it hard for people to take them seriously.

Writer and first-time director David Atkins (who previously penned "Arizona Dream") capitalizes on this quandary in "Novocaine." As with dentistry, the stakes in the flick are life and death, but there's an eerie mocking laughter throughout.

Atkins sets up an offbeat tone almost immediately by casting "Wild and Crazy" comic Steve Martin as Frank Sangster, the film's only normal character. Martin is more than up to the job (having convincing dramatic turns in "The Spanish Prisoner" and "Leap of Faith"), but there's still something appropriately off about watching him play a straight role.

It's obvious that Frank is headed for trouble because he has a thriving dental practice and is about to marry Jean (Laura Dern, "Focus"), his gung-ho hygienist. Frank's prosperity begins to decay like an infected molar when he starts looking after a Goth-dressed patient named Susan (Helena Bonham Carter). Susan has a tooth that needs attention, but it's quickly apparent she's more interested in scoring drugs than she is in getting her mouth fixed. Feeling a combination of pity and lust, Frank ignores his better judgment and writes her a prescription. He even takes her up on an offer to use the dental chair for something other than a cleaning.

Frank quickly regrets his decision when some of the stiffer pain medications from his office turn up on the street in the hands of junkie teen-agers. Soon the dentist finds himself having to explain his indiscretions to Jean and eventually defending against charges of dope peddling and homicide.

The blessing and the curse of "Novocaine" is that the storyline veers wildly from sequence to sequence and even from genre to genre. Every now and then Atkins (working from a story he wrote with Paul Felopulos) pulls out some jaw-dropping surprises. (Keep an eye out for an amusing cameo by Kevin Bacon and a stuffed animal later in the flick.) This "anything goes" attitude makes "Novocaine" a disorienting fascination at its best moments.

Conversely, many of the later plot twists are as forced as a bad set of dentures. The result is that many of the final revelations don't startle like Atkins probably intended. When the actual motives of some of the characters come to light, they don't seem true enough to the protagonist (or the audience) to really work.

Fortunately, the big-name cast usually manages to get around these shortcomings. Bonham Carter may be rehashing her dour character from "Fight Club," but she tempers the cynicism with an oddly convincing sweetness. Dern is a believable martinet and makes a viewer nervous about taking a filling. Martin stands out nicely as Frank and handles playing a straight role so well that one almost forgets his energetic performance as a sadistic dental practitioner in "Little Shop of Horrors."

With the talent involved, "Novocaine" never becomes quite as numbing as its title implies, even if some of the contrivances make one wonder if the treatment is essential.