Dinosaur drama Expensive dentistry sparkles as suddenly gaping mouths release a collective oooomph which bangs around the auditorium a mini-second before the rows of well-dressed goldfish begin to laugh. The audience had just suffered the collective shock of hearing reality spoken on an Australian stage. The shadowing laughter was their relief at finding it wasn’t serious, they were just being amused. Offstage things change but onstage at the Sydney Theatre Company political timidity always rules. Joanna Murray-Smith’s new play, Fury, startled her audience simply by pretending it was about to discuss something real. Twice it seemed we were moving towards…