Columbo complains to Wesley that he has a "sensitive tooth on the left", as he chews his bagel on the right and holds his hand to his painful jaw - on the left. But when Columbo goes to the dentist, the dental work is done to a tooth on his right. And afterward, at the outdoor café, Columbo holds his hand to his painful jaw - on the right.
When Columbo explains his suspicions to the dentist at the race track, the dentist orders Columbo a Scotch. Just as they part the glass of Scotch changes positions between Columbo's hands and the little table a few times.