This is what we found on Wikipedia regarding the Loose Tooth:

Tooth mobility is the horizontal or vertical displacement of a tooth beyond its normal physiological boundaries around the gingival (gum) area, i.e. the medical term for a loose tooth.

Tooth loss implies in loss of several orofacial structures, such as bone tissues, nerves, receptors and muscles and consequently, most orofacial functions are diminished. Damage to the supporting tissues of the teeth may progress to necrosis of the alveolar bone, resulting in tooth loss.