No one will see it back there! So, why should I replace my missing back teeth?
Well, it turns out your dental health is highly correlated with whether or not you make the decision to replace your missing back teeth.
When a back tooth is removed it is kind of a “two for one” deal. Teeth that touch together, when you shut your mouth to chew, are “biting partners.” Like many partnerships, the loss of one partner affects the other. With no biting partner, the opposing tooth is not useful and chewing power is diminished. If the “back tooth” is a first molar, or a tooth ahead of the first molar, it will present as a “black hole” in your smile. No one wants their appearance to be swallowed by a black hole.
Teeth erupt until they hit something. Making sure teeth touch is the principle behind “teething” and the reason children’s teeth come in at the same time.
With nothing to touch, a superfluous tooth continues erupting. The resulting contact relationships (or lack thereof) of adjacent teeth allow for the formation of food traps.
The biting movement causes you teeth to move up and down a little bit. This process wears the contacts between them. However, over the course of your lifetime, your teeth stay together (usually). So, how does this happen?
There is a mechanism to move teeth forward (for molars) or backwards (for canines and premolars) to keep the contacts tight. With no tooth ahead of the last molar, it starts to move forward.
With the last molar tipped forward it becomes hard to clean the mesial. (the part of the tooth closest to the center of the mouth) Plaque and calculus accumulate at the gum line and cause periodontal pocketing. When this pocketing reaches the end of the root, abscesses (cavities filled with pus) form. This is painful and usually leads to extraction of the infected teeth.
With the posterior teeth gone the same process starts again on the more anterior teeth, with the premolars drifting distally (toward the back if the mouth).