So I receive feedback from a proofreader and it says: “In Polish there is no dot after dr” (an abbreviation for “doctor”). Yes, of course there isn’t, but not in a sentence like this “Proszę poinformować dr. Piotra, że przyszedł pacjent”. Why? Because when a word ends with a letter which is different from the last letter in a non-abbreviated form, we use a dot. In my example, the full word is “doktora”, so a dot is justified.