The best way of thinking of 'RSD' is that it like having an extremely thorough descaling, but you will usually be given a local anaesthetic first. This allows your dentist/hygienist to thoroughly clean out the periodontal pockets around the teeth, without you feeling any pain. Without a local anaesthetic, the procedure would normally be quite uncomfortable. Depending on the severity and distribution of the problem, only a couple of teeth may be treated, or more often, up to half of your mouth in a session. You may have some post-op sensitivity for a few days, and keep up the oral hygiene afterwards. Hope all goes well.