It's a wall of text that has John talking about an upcoming convention.
Panel 1: It's the end of another day at the office; Jean hopes that Doctor P has a good time at the dental convention. John promises that he will.
Panel 2: AS he puts some paperwork in his briefcase, he mentions that there'll be new products and inventions that he'll need to check out and a couple of speakers that he wants to hear.
Panel 3: He boasts that he always comes back from those things with a renewed interest in his profession and a real incentive to work.
Panel 4: As he is about to get in the elevator, he thought-bubbles that when he closes the practice for a few days, he has to work like mad to catch up.
Summary: I remember a Sunday strip that had Elly go into hysterics because John was stuck in traffic; I can well imagine the misplaced paranoia about the impossible prospect of John's cheating and infantile hand-wringing Elly will be doing for the next few weeks.