Start With the Bristles
You can narrow down a lot of your choices by deciding which bristles are best. Which you should choose does not depend on the strength of your gums and teeth but rather how hard you brush. If you are a very vigorous brusher who pushes hard, you want to pick a softer bristle.
As a general rule, soft bristles are always better, as hard and stiff bristles can actually damage your gums and enamel. Because of this, if you’re unsure of which you prefer, pick a soft bristle and then work your way up to medium or hard if needed.
In addition to the bristle hardness, some toothbrushes might come with special bristles. Some bristles will be at varied lengths to ensure that each crevice in your teeth is being covered. Some might have a blue strip down the middle that starts to fade as your toothbrush wears out so you know when it’s time to replace it. Still more might have rubber bristles along the edges to massage your gums. Even more might have all these qualities or none of them.
A Perfect Fit
By this time, you should have narrowed down your toothbrush selection by quite a bit. Your next narrowing factor is size. The most important part of size is the size of the toothbrush head. If you have ever used a smaller or larger toothbrush, you know that the wrong size toothbrush can just feel weird in your mouth.
The best size is one that feels comfortable and, more importantly, is able to reach all your dental surfaces. You don’t want it to be too small so you have to exert extra time to cover your whole mouth, but you also don’t want it to be too big to get into the back of your mouth. An average size is ½ inch wide and 1 inch tall.