Supplemental. Antibiotics alone will not help much. Gum disease beyond gingivitis has no cure but can be controlled through initial therapy and rigorous oral hygiene followed by frequent maintenance visits ( usually every three months). Surgery may be done to aid long term prognosis. Antibiotics and laser treatment can be used as well to ensure a good long term result.
Application Methods. Antibiotics have long been tried as a means of stopping gum disease. Unfortunately many do not "target" the infected gum tissue in an effective way. There are other means of getting medications to the specific sites like perio-protect trays, which have been shown to be very effective. But you still need to employ good oral home care routines daily as well.
Some. I think hygiene, brushing, flossing and rinses are very important also.