The Siberian Husky is not a one-person dog. Nor is he a guard dog. He might let you know someone is around, but he has no concept of protecting you. The Siberian is a friendly and gentle dog who is not overly suspicious of strangers or aggressive toward other dogs.
The short answer is yes, it's entirely possible to have RA in your jaw-RA affects joints and your jaw is a joint. In my personal experience, I find jaw pain one of the most difficult to cope with, it's as if it permeates everything, making it impossible to ignore.
Tooth decay can affect your body. At first your tooth may be sensitive and you may avoid eating certain foods which would affect your nutrition. Left untreated the decay can cause pain in the tooth leading to a loss of concentration and loss of sleep at night which can affect your performance at work and at school. The decay can also cause the tooth to abscess leading to an infection. The infection can spread throughout your body causing flu like symptoms.