An oral saline solution, or salt water mouth rinse, is used to cleanse and relieve pain associated with canker sores, after oral surgery, and for general mouth pain. Why Salt Water Can Be Better Than Mouthwash Traditional mouthwashes, many of which have alcohol in them, can irritate swollen mucous membranes in the mouth. That's a big reason why dentists suggest using saline solution, also called salt water mouth rinse, to relieve the pain and swelling that comes after a deep