Diagnosis occurs in the dental office.  The dental hygienist will inspect the gum and bone health by using a probe (measuring for swelling and pockets in the gums) and an x-rays (measuring bone levels and for bone loss).  The presence of disease and the health of the oral cavity in general is determined at the initial hygiene visit.
Treatment is multifaceted.  If an inflammatory process is determined to be at the initial stage, gingivitis, regular hygiene visits and modifications to home care practices is usually all that is required.  However, if the process has moved on to a later stage where there is notable gum and bone loss, referral to a Periodontist (a specialist in the treatment of gum disease) may be necessary.  In some cases, periodontal surgery is required to assist in resorting good oral health.