The Health Mouth
A functionally healthy mouth has 28 teeth - 14 upper and 14 lower (not including the four wisdom teeth). Chewing is well balanced and almost automatic when each upper tooth has proper contact and function with the corresponding lower tooth. When teeth are properly aligned, there is minimal strain or irritation on the gums during chewing. Drifting or spreading of teeth does not occur because each tooth supports the other. Oral hygiene is easily maintained.
Companion Teeth
Each tooth has three or four companion teeth: its neighboring teeth in the same arch, and one or two biting partners in the opposite arch. Teeth greatly depend on companion teeth for support and stability.
Tooth loss may have many causes: advanced decay, gum disease, and injuries are the most common. When a tooth loses one of its neighbors or opposing biting partners, the remaining teeth begin to shift in the direction of least resistance. In fact, all teeth begin moving as soon as one of their companion teeth are missing.
Missing teeth can detract from your appearance and make eating and speaking more difficult. The most disastrous effect, however, occurs over longer periods of time due to tooth movement. As can be seen from the left diagram, one lost molar (the first molar or six year molar) has allowed nine nearby teeth to migrate into new and unhealthy positions that actually promote more decay and periodontal disease.
This cycle can be vicious and often unending. Any mouth with missing teeth is very much out of natural balance. Destruction can happen very slowly–often without you even knowing it!
