It is important that a missing tooth be replaced as soon as possible for several reasons. If not treated, the teeth surrounding the gap begin to shift inward, creating a whole chain reaction of bad things. Teeth use their neighbors for support, and, with one missing, they start to fall. This worsens the bite changes in response to the pressure and can eventually result in problems with the entire jaw, e.g. TMJ. The surrounding teeth deteriorate and it is just a matter of time before they, too, are lost.