Brady did not enjoy his first electric toothbrush because he found it was too delicate for his use. Brady sometimes used a wooden toothbrush (though the bristles once exploded in his mouth).
The corner was officially created in H.I. #72: 64 Pairs of Underwear after the family of Grey gave Brady an electric toothbrush which he enjoyed. However, Brady later abandons the use of the electric toothbrush (again).