How can a dentist tell if i am having gingivitis?

Examination & x-rays: A dental exam and x-rays. Pocket probing, bone loss, and most important bleeding gums. Do not try to be your own dentist.

A thorough Exam: You gums should be pink, tight around the teeth and stippled. They should not bleed when you touch them or when you brush. If they are red, swollen and bleed, you likely have gum infection. Only a thorough examination can tell if that gingivitis (gum infection) has become periodontitis (where it spreads to the bone underneath). Get checked out sooner rather than later!

Bleed,color, texture: Gingivitis by definition is the inflammation of the gum. The first sign of inflammation is bleeding, then color change to red or deep red. Gum became swollen, with bulbous appearance with roll, rounded margin. The tip of the interdental papilla becomes blunted. In severe case, exudate, pain, and loss of function may occur (rare but possible such as anug, acute necrotizing ulcerative gingivitis).

Dental examination: He can examine your gingiva and see if there is plaque present; if you gingiva is red and swollen; he can also measure the depths of the tissues around each teeth and that gives an indication of gingival disease, health or periodontal disease.