We have seen previously that the causes of lack of dental height can be quite varied: sinking of the teeth caused by pressure, due to stress on porous bones; congenital boney malformations; wearing away of the surface enamel; poor orthodontic work, and so on.
These are the most common causes that contribute to a lack of dental height.
In picture 59 the lack of dental support is on the left maxillary arch. Thus, the skull, in accordance with simple physical and biomechanical laws, tends to sink just at this point. During such a sinking the skull alters its inclination in relation to the jaw.
As can be seen in picture 59, the left masseter muscle becomes shorter, requiring the lower and upper jaws to meet. In fact, as we have seen previously the skull sinks for two reasons: the force of gravity and muscular tension in the masseter.
In effect, it would be more correct to say that the masseter forces the teeth to occlude until there is pressure created in the upper and lower teeth to support the skull. This pressure, according to Newton’s Third Law, is called the “reaction force”.
Thus, as we have seen, the left masseter and temporal muscles contact. As a result, the right masseter and temporal muscles become longer. In picture 59 the left-hand muscles and the right-hand muscles are indicated by red and yellow arrows, respectively.
This is a concrete example of how compensation in the musculature comes about. These compensatory measures can be verified in practically the entire body. In fact the entire body is destined to adapt to the new configuration imposed by the sinking of the skull.
It is in this way that the process begins which leads the skull to lose its own center of gravity and to abandon symmetry.