Until then, the hopelessness of a five-day family epidemic can be seen as a set piece in "The Secret Lives of Dentists," a compelling, if despairing film about marriage based on a Jane Smiley novella.

The flu incapacitates a family already on the verge of a collapse because of a husband's belief that his wife is having an affair. The dentists of the title are David and Dana, a married couple practicing in adjacent offices. As played by Campbell Scott, who does for quiet cuckolding what he did for cocksuredness in "Roger Dodger," Dr. David Hurst suffers in silence, choosing not to rock the marital boat and risk losing his wife. If he confronts her, David figures, they'll have to do something about it.

As his disquiet grows, David clings harder to the couple's home life, being the good dad to their three daughters. "Daddy's feeling a little complicated," he tells one of them as he tries to hold his family together.

What does the marital story have to do with the pain of the dentist's chair? In voiceover, David makes the point that teeth are corrupted by the life forces; they are stones within flesh and dentists don't trust their patients to take proper care of them.

Director Alan Rudolph gives the outwardly bland David a complex inner life. A scowling patient (Denis Leary in alpha male mode) becomes part of his interior monologue, a leather jacket loudmouth who protests David's continued emasculation. David fantasizes about his wife's midday trysts with whomever it is she might be having the affair with — is it the conductor in the opera company she performs with after-hours? Is it Dana's oral hygienist? David's assistant?

Though humorous at first, these flights of fantasy hurt the film, which nails the realities of meals with the kids, suppressed hopes and Dana's increasing lack of interest in David. Those moments — a child's dinner-table tantrum, Dana's lecture about Greek opera to a barely listening family, one daughter stepping in her sister's fresh vomit during the five-day flu nightmare, are far more interesting than Leary's rants or the amped-up imaginary sequences, which grow tiresome. Leary struts and advises; David's id protests the loss of his manliness. It's pat and it's obvious.

The interjections push the film into "American Beauty" territory, but the effect is a wash. Scott and Davis play their parts so convincingly that the breaks from the film's slow build are at best distracting, at worst, tacky.

David cares for the couple's three daughters as a doting, perfect dad, the kind of TV-ready father who surprises the rest of the family by yelling "Be quiet!" at a screaming kid in the next room. As such, the deck is stacked in his favor. While David is patient, loving and forgiving, Dana is unsatisfied and cold. That she elicits any sympathy is a testament to Davis, who plays her as weary, smart and trapped by her own passionate nature.

The central theme of "Dentists" is not infidelity itself, or the suspicion of it. What the film asks, with ambiguous answers, is whether marriages, like teeth, are strong enough to withstand the cruelties that life inflicts upon them.

There's enough meat and bone here for several films, but "The Secret Lives of Dentists" doesn't trust its material enough to play things straight. The film works nicely when it's brutally honest and attendant to detail. When it veers into fantasy, it's as broad and shallow as an episode of "The Mind of the Married Man."