“The wide range of recommendations we found is likely due to the lack of strong evidence suggesting that one method is conclusively better than another,” said lead author John Wainwright in a University College London press release. The discrepancy is problematic, Wainwright said, because it leads to distrust in dentists and their profession. “For something most people do twice a day, you would expect dentists to send a clearer, more unified message to their patients on how to brush their teeth,” said Wainwright, who now works as a dentist.