There's a central decision at work in Teeth that kind of hobbles the pic's whole point. You've got a movie all about ancient mythical vaginal angst and the ways in which modern society perpetuates and internalises womens' fears of their own bodies so as to make them sexually malleable by men; so far so good. The central device is well-explored as a metaphor for internalised gynophobia and the less pure implications of the abstinence movement, and it's done in a way that breezily veers between Dawson's Creek teen drama and b-horror. This is nice.
But the movie sets itself up for a payoff that's not delivered, and does so in a way that threatens to make it the exact thing it sets out to undermine: a gynophobic, guilt-ridden romp through the tropes of misogyny.
Dawn's mutated (or "evolved", as the movie strongly hints) genitalia is never revealed to the audience; there are plenty of severed dicks, which is nice, but the terrifying agent of their severing remains secret, sacrosanct. It gets talked about plenty, in a perplexing scene that posits Dawn's sex as part shark, part lamprey and all mysterious, but this is just a wasted subplot that doesn't go anywhere. Similarly, the metaphor of stickered-over anatomy textbooks is a subplot that ought to move toward even Dawn getting a look at the mysterious organ, but as far as we know, she ends the movie as clueless as we are.
Lichtenstein justifies this by saying he "didn't want anything ugly associated with the character" and wanted her to remain "innocent"; one can't help feeling that in a movie about vaginal anxiety and the complicity of modern society in perpetuating same, a 52-year-old dude's hesitations regarding "ugliness" are hardly helpful. If you think the vagina has latent potential to be "ugly" and be tied up in questions of "innocence", maybe you're not the best person to make a movie about it. In a movie where gaze power yadda yadda yadda, to work your way through several subplots about how the worst thing about modern attitudes to the vagina is our unwillingness to talk about it then yourself lace your movie with innuendo and clunky visual punning is hardly breaking down boundaries.
About the best way Dawn's latent danger is foreshadowed is in a way that's never alluded to, but hopefully deliberate: though pretty much everyone in the movie wants her, and are willing to employ all sorts of trickery and coercion to get into her pants, nobody ever just tries going down on her. If this is intentional it's nice, because usually cinematic endorsements of cunnilingus are pretty gross. Is that Teeth's greatest achievement? A sly, subversive fable about eating pussy before it eats you? Put that way, even this doesn't seem like such a great thing, does it?