Toothbrushes are made in two ways: the cheap ones have the bristles put on and then they are cut straight across. The major brand name brushes have each individual bristle made with a rounded edge. If you compare a generic cheap brush with a brand name one under a microscope the difference is dramatic. So what? Well the sharp bristle brushes cause more wear to the teeth especially if the roots are exposed.
I have no financial interest in any company but a few of the major toothbrush brands are Colgate, Oral B, Butler, POH etc. If you are looking at brushes at the store and you see some brands that you recognize from commercials or ads you can be confident that they are good brushes so then you just have to choose the cheapest one. REMEMBER: only use a soft brush.
Manual or electric?
It doesn’t matter. You can do a great job cleaning your teeth and massaging your gums with either one. There is one major difference between the two. With mechanical brushes you let the brush do the work. You don’t scrub. But you also have to move the brush slowly enough so that it has time to unravel to get into the indent between the teeth. If you move a mechanical toothbrush along too quickly you will not do a good job.
There are a few very good mechanical toothbrushes on the market. I have no financial interest in any of them but my recommendation, when asked, is the Oral B. It has a small round head that can get to hidden areas especially when the teeth are crooked. Just buy the cheapest model. You don’t need all the bells and whistles. You just need it to clean your teeth. You definitely don’t need it connected to your phone so that you get a notification about how you brushed.