There are a few gum brushes on the market that you can use. A relatively new dental product, gum brushes resemble toothbrushes, although their heads are generally smaller and the bristles are much softer and thicker. They cost roughly $5 to $10 and may be easiest to find online. Gum brush proponents say toothbrush bristles are designed to remove plaque from teeth, not massage gums, so you shouldn't use a toothbrush to massage your gums. Further, since the major cause of gum recession and injury is brushing too hard, using a toothbrush to massage your gums can actually be harmful [source: Earthority].
Additionally, there are gum brushes for infants, which are typically designed as a combination teething ring-gum brush to stimulate infants' gums as they chew on the piece [source: Baby Center]. Since massage is a recognized practice for developing healthy gums (and it's recommended to wipe infants' gums clean before teeth emerge to help rid the mouth of bacteria), it seems gum brushes can be helpful at any age.
It can be difficult to find gum brushes, however, and even dental professionals often don't know much about them. Some believe gum brushes may be more of a marketing ploy than a truly beneficial device. Others believe they may be helpful but are so new they haven't been popularized yet.
Bottom line: Good oral hygiene is very important, and massaging your gums is helpful. Use your fingers, your toothbrush, a gum brush -- whichever you prefer. Just make sure you're doing the massaging gently.