As always, it would be nice to read between the lines, to become enchanted by the brilliant subtext... except there really isn't any. Apart from some snazzy soundtrack music and loads of already-passé bleach-bypass cinematography used to telegraph meaningless flashbacks (and one -- count it, one -- surreal giggle), the movie's single ace is a woefully recycled dog-eared card. As Slater, an irritable trumpet player who loathes dentists and pretty much everyone else, Denis Leary punches the clock, clad -- hint-hint! -- in Brad Pitt's duds and shades from Fight Club, to inform David that he needs to stop being such a wussy-ass wuss (my term, not his). Although Slater is established as a real person, the movie milks his character's spontaneous appearances and fantasy advice sessions to David for all they're worth, which is about a dime. We've been here before, perhaps with no more depth but with a lot more punch. This critic didn't think it would be possible to miss David Fincher so much (or at all).
Which isn't to suggest that Rudolph has completely lost his mind or anything. The movie is competent and watchable. But so is the Weather Channel. All we get here by way of a plot is that humble David suspects outgoing Dana of having an affair, most likely after spying her with the overtly cuddly music director for the local opera in which she enthusiastically performs. Thereafter, David meanders through his life being an acceptable-if-flawed father to his three daughters (Gianna Beleno, Lydia Jordan, and Cassidy Hinkle) while allowing Leary's leery Slater to coach him, unsuccessfully, on the coarser points of being a complete bastard.
The best thing about Dentists is Leary, and if you want to watch him bugging the shit out of an American family (and vice versa), skip this and rent The Ref.