Help. They can help but be gentle with them. Soften the end first by gently biting on it. Angle up toward the gums and between the teeth. Should not be painful done properly.
Both. If used well they can help dislodge food, but too many people force them into locations they don't belong and cause trauma to the gingival tissues causing inflamation and swelling and posibly break a piece off in the tissue and then can get a gingival abcess.