Does using a soft toothbrush lessen gum disease and back tooth decay?

Less inflammation.: The best toothbrush is probably a soft toothbrush, because it does not damage and inflame the gums. It also is unlikely to damage the tooth enamel where another toothbrush would.

Toothbrush: Proper brushing and flossing technique will lessen periodontal disease. Have your dental hygienist demonstrate the proper technique. Soft brush is ideal.

Good oral hygiene: Good oral hygiene begins with a use of soft bristle toothbrush. Good oral hygiene will prevent and help lessen the incidence of gum disease and tooth decay. Soft bristle brush allows for better cleaning due to higher number of bristle in the same surface area to do the brushing. Soft bristle helps to avoid gum tissue injury which may lead to gingival recession and cervical tooth wear.

Yes: Yes, brushing and flossing will decrease risk of periodontal disease, tooth decay and oral and tooth pain.

Soft t'brush best for removing bacteria. But naif you already have infected gums and/or teeth, they will require definitive treatment. Brushing alone will not cure existing infections. Please see a Dentist before this gets worse. You cannot do this alone.