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What Now? What Then?

What Now? What Then?

Scientists at the National Institute of Neurological Disorders in Bethesda, Maryland, have been running up and down the DNA busily identifying genes. It has been predicted that within five years all 50,000 to 100,000 human genes will have been identified. It has even been claimed that a gene has been identified that controls the mastery of grammar. The ethical debate can be expected to heat up as we approach the possibility of controlling all manner of human characteristics through gene modification.

It boggles the mind to think of where this could lead us if pinpoint control of the gene string were used for good or for evil. Remove a gene here, add a gene there, change a gene elsewhere. We might produce perfect human specimens, but according to whose idea of perfection?

There are surely more pressing problems of bodily form and function than orthodontics that might be solved with designer genes. One could recite a litany of hereditary diseases and malformations. Still, a case can be made for genetic control of muscle, tooth, and jaw relations. The first step in orthodontic diagnosis would occur before conception, and it would be entirely different from what we now consider diagnosis to be.

Controlling heredity would certainly go a long way toward solving the nature/nurture controversy--the relative influence of heredity and environment in the etiology of malocclusion. Although the scope of orthodontics might be considerably narrowed if we were to eliminate or sharply reduce bad genetic influences, the specialty would likely become more medical, with an emphasis on behavior-related problems such as habits and stress-related problems such as TMJ disorders. Head and neck pain would be more likely than at present to fall within the orthodontic domain. There is an implication that the secondary diagnosis of environmentally related disorders would include, but transcend, our present concept of diagnosis.

It is unlikely that any orthodontist alive today will see the clinical application of gene modification in orthodontics, but it is far from unlikely that extensive research within the next 25 years will lead to human genetic engineering. For the moment, we can leave it to future generations to resolve the moral and ethical questions that accompany the ability to play God.

Until the time when the dentofacial complex can be perfected genetically, we will continue to depend on force systems to move teeth. Even if we find ways to influence growth and development electrically or biochemically before then, moving teeth is likely to continue to be a significant part of orthodontic treatment.

The professional and commercial participants in the orthodontic field have been ingenious in the development of tooth-moving force systems and materials during the 25 years of JCO's existence. We have used all manner of interferences to oppose or encourage gravity, and to oppose or encourage muscle forces. At times, we have harnessed the force of the jaw muscles themselves. We have approached mastery of tooth movement through appliance systems by taking advantage of the diverse qualities of wires, the fundamentals of force systems, the contribution of bracket design, and the organization of various appliance disciplines. We have used levers, inclined planes, expansion screws, push springs, pull springs, and magnets. Much of this work has been empirical, conducted in individual practitioners' offices; much of it has been due to intensive research in metallurgy and plastics. We have engaged in bioengineering.

Whatever energy source we use--muscles, magnets, elastics, wires--it's still all mechanics, and we will constantly be on the lookout for some better force system. There is a whole field of micromotors that may have the potential to develop enough force to move teeth, and to do it in ways that we cannot envisage now. Combined with radio signals, these machines might be incorporated into devices that look and work much differently from those we now have. It is something to think about, because scientists have already developed a motor with a rotor no bigger than the diameter of a human hair. How much bigger would it have to be to develop a force capable of moving a tooth?

Advances in technology and miniaturization continue to be made at a rapid pace, which makes it almost a certainty that we will continue to see changes in orthodontics. However, tooth movement will remain a major part of our job--at least until genetic engineering changes all the rules in medicine and dentistry.


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