The Tooth Harry 3rd Rock from the Sun : Season 3 Episode 26

Harry drives Nina to the dentist and behaves so sweetly toward her that he ends up stirring her emotions and sparking a romance. At work, Mary has been awarded a place in a promotional video for Pendleton and a jealous Dick takes desperate measures to ensure that he also is granted a place in it. Unfortunately, neither Dick or Mary share the director's vision and end up ruining the video. Meanwhile, Officer Don gives Sally a key to his apartment, hoping that the pair can spend more quality time together; however, he regrets it when she begins to treat the place a little too much as if it is her own.