Receding gums means a decrease in gum tissue. Unlike gum recession in periodontitis, ordinary recession is not caused by inflammation.

Recession can be caused by a number of factors. If the recession is locally contained (around one tooth) this can be attributed to a defective tooth position – shown here on the upper incisor.
If recession occurs around more than one tooth (as shown in this picture), the reason may be faulty cleaning habits.

If a tooth, as is usually the case, breaks through the middle of the maxillary ridge, then a thick enough layer of bone and gum remains on the outside of the tooth – then there is sufficient circulation (shown by the red dots in the picture).

If the tooth comes through much further out (towards the lip or the cheek), in this area the bone is thinner than usual and circulation is reduced. If the bone base is compressed, for example, due to undue stress on the tooth when biting down (shown as a red arrow in the animation), this may result in poor circulation. Poor circulation results in a poor supply of nutrients to the anatomical area affected, and the bone and gums recede - known as recession.

Aside from increased sensitivity (reaction to cold or heat), the exposed necks of the teeth can be more easily damaged by a toothbrush or cavities, so it is absolutely necessary to get treatment. Treatment should not only include build-up of tissue around the outside of the tooth in order to ensure proper circulation in the tissue, but side factors such as defective tooth position or faulty cleaning techniques must also be changed.