Is it possible to totally cure gum disease?

Yes. It really depends on the severity of the disease, and how destructive the patients immune response to the presence of the disease is. The mildest form of gum disease, gingivitis is completely curable. Remove the cause (usually plaque/tarar) and it clears right up. The severe forms involve bone loss. Bone loss is permanent but in some cases bone can be regenerated. Patient compliance is the key.
No cure, sorry. It is a chronic disease, which we can make better and manage, but it usually doesn't go away forever. The only known "cure" is to pull out the involved teeth, but please don't do that if at all possible.
Often. In a healthy individuals with proper oral hygiene and modern periodontal techniques, periodontal health can be restored and maintained for life. With diabetics and smokers, it's problematic. In severe cases of bone destruction, not all teeth can or should be saved, and periodontal health cannot be fully restored long term. That's why early diagnosis and treatment is key.
Yes..but. We can stabilize gum disease, regenerate bone, and get the gum tissues healthy again. I feel we can maintain and keep the disease in check. Totally cure the disease? I know we have maintained patients in our laser periodontal practice close to 29 years. I am not sure it is a total cure, but the innovative laser treatments and advancements do work over the long term.