A component of periodontal disease is inflammation, however, it's important to remember that periodontal disease is more than an inflammation of the gums, it is an infection. With that said, we are accustomed to treating infection with antibiotic, however, periodontal disease behaves similarly to the way viral infections work- you can't treat them with antibiotics. Viruses stay in the system and can become active when immunity is low and periodontal disease can behave the same way.
It is unrealistic to expect that a person with periodontal disease could be on antibiotics for the rest of their lives. It would cause more harm than good to have prolonged antibiotics. The digestive system would suffer by the helpful bacteria being destroyed and the person would develop reistance to the antibiotic and perhaps develop infections that no longer respond to antibiotics at all.
Therefore, it makes sense to approach the treatment of gum disease with natural methods that benefit the entire health of the patient. Having a healthy diet and one that includes fish oil makes sense as part of a program to treat gum disease. This would be a great adjunct to professional care to control the disease in combination with the patient learning proper homecare techniques.