Though much of this film by Abbas Kiarostami is a straightforward lecture about dental hygiene delivered by a dentist facing the camera, it still manages to be persuasively Kiarostami-esque in its description of young Mohammad-Reza’s life at home and school before he falls prey to tooth woes. (Kiarostami found the boy having a tooth removed, then filmed the earlier parts of the story later.) That some audiences find the film hilarious testifies to the humor that can accompany great discomfort.