Gum disease is caused by poor oral hygiene that results in plaque calcifying on the teeth close to the gum to form calculus (tartar). This protects bacteria to proliferate in close contact with the gums and causing local inflammation. Should this process not being reversed by means of thorough cleaning and change in oral hygiene habits, this leads to the breakdown of the bone supporting the tooth.
Stages of Gum Disease:
Healthy gums and supporting bone
Plaque forms close to gum
Inflammation of the gum margins--possible bleeding when brushing
Tartar formation
Gum in contact with bone inflamed
Bone starts to break down
Pocket is forming where loose gum surrounds tooth.