The hygiene conscious driver was stopped during a police checkpoint that was targeting distracted drivers in Crawford St, between 9.50am and 10.30am.
A police spokesman said the driver who was brushing their teeth was spoken to and educated.
Eight other people were caught using their mobile phone, three people were not wearing their seatbelt and a number of drivers were spoken to about holding vaping devices while driving,
In line with police focusing on motorcyclists this month, a number of motorcyclist were also pulled over and spoken to, he said.