GTR:

    (guided tissue regeneration) a new technique for replacing bone tissue lost between roots of teeth
general anesthesia:
    a controlled state of unconsciousness, accompanied by a partial or complete loss of pain sensation, protective reflexes, and the ability to respond purposefully to physical stimulation or verbal command
geographic tongue:
    loss of all usual color and texture of tongue; does not require treatment
gingiva:
    the gums
gingivectomy:
    removal of gum tissue
gingivitis:
    inflammation of gum tissue
gum boil:
    See fistula.