By all accounts, Tooth Fairy is Dwayne "The Rock" Johnson's last family film for a while, which means that yours truly and the rest of the fans of The Rundown will hopefully soon see this decade's definitive action star soon kick ass again. As heir apparent to the likes of Schwarzenegger and Stallone both in terms of physique and personal charm, he has understandably detoured into projects that introduce him to different audiences -- as they did. But because of the rabid energy of contemporary fandom, 360 degree stardom seems more threatening now than it did then, if only because it takes our heroes away from us and gives them to someone else, at least temporarily; meanwhile, Johnson's particular efforts to curry fandom from the pre-teen set have thus far been lackluster at best, even if there's something strangely charming about him gamely sending up his own tough-guy image.

Tooth Fairy is the latest in his recent line of family comedies, and like its predecessors, it's a mediocre but largely inoffensive chapter in Johnson's crusade to charm kids. He plays Derek, a hockey player sentenced to serve time as a real tooth fairy after attempting to crush the imagination of his girlfriend Carly's (Ashley Judd) daughter. Slowly discovering the value of wondering "what if," Derek slowly blossoms into a buff barterer of bicuspids, but finds his own dreams dissolving when a prodigious newcomer named Mick (Ryan Sheckler) threatens to overshadow him out on the ice. Ultimately, it takes a domineering full-time fairy named Lily (Julie Andrews), a wannabe tooth–taking pencil-pusher named Tracy (Stephen Merchant), and the fairies' Q-like inventor Jerry (Billy Crystal) to push, prod and provoke Derek into becoming the best tooth fairy possible, hopefully in the process inspiring him to excellence elsewhere.

Johnson doesn't really have a great deal of subtlety to offer roles like the ones he's playing here and in his two previous family adventures, The Game Plan and Race to Witch Mountain. But it's obvious how hard he's trying to make each movie's low-"high" concept work, and he has noticeably improved as an actor, if only in the sense that his mugging seems slightly less forced. That said, Johnson nevertheless has all of the makings of a megastar, particularly in that he manages to effortlessly charm no matter how hard he is actually working, and carries a presence that's undeniable, even in stuff you wouldn't want to see him in (such as this).

Although the movie is by no means imaginatively directed, Michael Lembeck (Santa Clause installments 2 and 3) keeps the story going at a breezy enough clip that you almost don't have time to notice how silly Johnson and his fairy cohorts seem. Further, the effects in the film are all convincing enough to keep at least pre-teens satisfied; the sequence in which Derek infiltrates a bedroom by shrinking to six inches tall looks pretty terrific, and the rest of his parlor tricks -- including invisibility and "amnesia dust" -- are all executed with dexterity and, relatively speaking, a degree of grace.

The rest of the cast, perhaps unsurprisingly, is equal to Derek's one-dimensionality. Ashley Judd, who hasn't "starred" in a movie since 2004's De-Lovely (and rightly so), is all immediate outrage and forgiveness as Carly, Derek's love interest; Sheckler offers nothing but youthful arrogance as Mick, Derek's replacement as the star of the hockey team; and even the great Julie Andrews does little more than provide requisite, ready-to-melt consternation as Derek's warden in tooth fairy land. Only Stephen Merchant, late of Ricky Gervais' "Extras," infuses Tracy with something slightly more substantive, turning an ambitious nebbish into a surprisingly quick and self-aware counterpart to Derek's entitled obliviousness.

Needless to say, Tooth Fairy isn't a movie made for anyone other than that sweet-spot family crowd, which means that most criticisms of its execution will fall on deaf ears or otherwise be irrelevant. But again, its greatest accomplishment may be to exhaust Dwayne Johnson's interest, however temporarily, in donning tutus and shepherding pre-pubescent kids through the rigors of adolescence. In which case, as already de-fanged entertainment, Tooth Fairy is effective and harmless, but nothing fans of The Rock (much less Dwayne Johnson) will want to sink their teeth into.