Martin S. Spiller, DMD, Family Dentistry in Townsend, MA
The short answer is NO! The removal of any tooth has consequences, some of which are important enough to cause you to seriously consider replacing that tooth with a removable or fixed alternative. If it's one of your top front teeth, then esthetic considerations will probably cause you to want to replace it. But even then, if you don't care about how you look, leaving the space will not kill you. The x-ray below shows what happens to the adjacent teeth if a first molar is extracted when a patient is very young. There IS tilting of the teeth and a small collapse of the occlusion, but it is not especially obvious when you look at the teeth in the mouth.
I am going to guess that at least a third of my adult patients have lost back teeth in the past and have never had them replaced. A vast majority suffer no major problems eating, speaking or esthetically (The way they look). On the other hand, a few, especially some women, tend to develop the joint problems, headaches, neck aches or ear aches typical of TMJ. If they use a lot of sugar, they are more prone to ectopic decay (explained below). In addition, many of these people who later want to repair the damage caused by the loss of the tooth find that repair is much more expensive because of the movement in the adjacent and opposing teeth.
The removal of any tooth will always cause destabilization of the remaining teeth and over a period of years, every tooth in your mouth will move in response to its loss, at least a little. The amount of movement depends upon several factors:
Your age: The younger you are when the tooth is removed, the more quickly and severely the rest of your teeth will move in response.
The position of the tooth in the mouth: The loss of any back tooth (the canine tooth and behind) will have a greater effect on the movement of the remaining teeth than the loss of a front tooth. The removal of the last tooth in the arch will not effect the position of any tooth in front of it. It may, however allow hypereruption ("extrusion") of the tooth above or below the missing tooth if that tooth does not make contact with a tooth in the opposite arch. Finally, the majority of the movement in the remaining teeth happens on the same side as the missing tooth. Teeth on the opposite side of the dental arch are effected, but not nearly as much.
Bruxing (grinding or clenching the teeth): If you brux your teeth, then the movement is more severe and happens more quickly than if you do not brux.
The image to the right shows the effect of the removal of a lower first molar.
Note that the tooth behind the space has leaned forward into the space vacated by the extracted first molar. This movement tilts the biting surface of that tooth downward and therefore allows the tooth directly above the space (the top first molar) to begin to extrude down. Because of the way this tooth is shaped, the downward movement of the top first molar opens up some space between itself and the teeth on either side of it. This newly created space allows the adjacent teeth to move and tilt as well causing a discrepancy in the curvature of the arch form. The image on the left shows a fairly typical situation in which an upper first molar was removed, probably before the age of twelve. The upper second molar has tilted forward closing the space vacated by the extracted first molar. At the same time, the misaligned biting surface on the second molar has caused a similar discrepancy in the position of the lower second molar. Less apparent in this image is the decrease in "vertical dimension" (the space between the top and the bottom jaws) on that side. This produces a misalignment in the position of the ball joint of the lower jaw leading, in some cases to TemporoMandibular dysfunction.
1. It stimulates bruxing which leads to TMJ.
2. It tends to "collapse the occlusion" ( decreases the vertical dimension) which means that the Jaw on that side must close a bit further in order to get the teeth to touch. This pushes the ball joint of the jaw further into its socket causing injury to structures within the joint.
3. The tilted angles of the biting surfaces means that biting forces are no longer parallel with the long axis of the tooth (straight up and down the root of the tooth. This puts extra pressure on the bone which supports the tooth and tends to cause loss of the bone. This is a localized form of gum disease that over a period of years may ultimately lead to the loss of the tilted teeth.
4. The tilted and extruded position of the teeth place the contacts between these teeth and the adjacent teeth in unusual positions. The contact between the teeth is the place where decay is most likely to occur because it is a place where plaque tends to build up. Decay in unusual positions on the teeth is called "ectopic caries", and it is generally quite difficult to repair without striking the nerve. When this happens, it becomes necessary either to extract the tooth or to perform a root canal procedure in order to avoid a toothache.
5. It makes it more difficult and expensive to replace the missing tooth later due to the poor position of the surrounding and opposing teeth.
Note that the loss of a back tooth, even if there are more teeth behind the space, does not always lead to the leaning and extrusion of the remaining teeth. If all of the teeth adjacent to the extracted tooth, as well as all teeth in the opposite arch make firm, stable contact with teeth in the opposing arch, and as long as at least half of the occlusal table (the top, chewing surface) is in stable contact with teeth in the opposing arch, then there is little likelihood of major tooth movement. This is especially true if the patient does not tend to have bruxing (grinding and clenching) habits.