decay:
    destruction of tooth structure caused by acid produced by bacteria
deciduous teeth:
    baby teeth
dentin:
    hard, living inner layer of a tooth (the layer immediately under the outer enamel layer)
dental implant:
    a (usually) titanium cylinder surgically placed in the bone of the upper or lower jaw to replace the root of a missing tooth
dentition:
    your teeth and how they are arranged in your mouth
denture:
    a removable set of artificial teeth

denturism:

    the production and sale of dentures by non-dentists
diastema:
    the space between front teeth