I've worn orthodontic braces twice, as a teenager and as an adult, so I know the importance of wearing a retainer. A few years ago, after I had strep, I figured I should boil my retainer because the doctors always tell you to toss your toothbrushes and lipgloss midway through antibiotic treatment for strep. Wrong! Boiling a retainer causes it to shrink and then it doesn't fit properly. And, the longer you wait to get a new retainer made, the more your teeth will move. My new dentist told me the best way to clean a retainer is to use effervescent denture cleaner tablets. (Why didn't my orthodontist tell me that?) I'm still wearing my retainer six years after my braces came off, and I've been through three retainers. Without a retainer, my teeth still shift, so I guess I'll be wearing one for life.

According to my dentist, yes you can wash your toothbrushes in the dishwasher. Still, you should change toothbrushes every three months and after you've had a cold, strep, or other illness.