MANY general dentists, most orthodontists, and virtually all oral surgeons in private practice recommend the removal of all four wisdom teeth whether or not there is evidence of abnormality, impaction, or the likelihood of impaction. Wisdom teeth that cause problems justify removal. Some grow at an angle against a second molar (impacted), causing root resorption or decay. Occasionally a cyst forms from the developmental sac resulting in an ameloblastoma which can become cancerous.

Quite often, an adolescent experiences the pain of teething as the crown of a wisdom tooth penetrates the gum. Teething should not dictate extraction, but extraction may be the best solution if the overlying gum tissue becomes infected repeatedly. Even then, I prefer to do a eulectomy, which simply means the surgical removal of the gum tissue that is either causing the retention or traumatic biting problem.

There are some good reasons for removing some wisdom teeth. To prevent crowding of front teeth or post-treatment relapse is a good reason because wisdom teeth can cause such problems. The rationality of extracting third molars to prevent orthodontic malocclusion is justified but not for the reason some dentists suggest. Third molars occupy space on the dental arch it cannot afford. However, some dentists argue that third molars exert tremendous pressure against second molars and that this pressure is transmitted forward from one tooth to another until the front teeth shift, twist, and overlap.

You do not have to be an engineer to understand the fallacy of this argument. Each dental arch has 14 permanent teeth, not counting third molars, encased vertically in bone, each in contact with the adjacent tooth forming a horseshoe arrangement. It is like having a picket fence with each picket a post buried in the hard-packed earth, each one connected to the next picket, and so on.
In addition, the lower teeth are contained within the outer ring of the upper teeth, which are in turn kept in place by intercuspation, or interlocking with the lower teeth when the jaws are closed, and by the strong musculature of the lips and cheek. In order to exert sufficient force to move these teeth, the wisdom teeth would require, in the least, a firm foothold, but there is none. The developing wisdom teeth are contained within soft, spongy bone filled with bone marrow. The roots lack a strong buttress against which to push all the other teeth forward and out of position. The proposition that third molars cause either initial crowding or relapse of the front teeth is absurd on its face.

If there are no wisdom teeth to blame, orthodontists attribute post-treatment relapse to the continued growth of the lower jaw so that the interior teeth crunch together and overlap to relieve the strain. But there is also a natural tendency for a tooth to move forward, to remain in contact with the tooth in front of it, each side meeting at the midline where the forces on one side are countered and neutralised by the opposing forces. This phenomenon is called the anterior component of force. The teeth are not set in the bone absolutely vertically but are tilted slightly toward the front or midline of the jaw.
As the teeth come together in chewing and swallowing, forces are applied in a forward moving direction. This action is usually sufficient to keep the teeth in tight contact with each other, preventing separation and food impaction. Without it, everyone’s teeth would likely separate. Of course, no system is perfect, and if there is disharmony or imbalance in these structures and forces, if the anterior segment of the arch, especially the lower arch, is too narrow or small, the incisors slip past each other, resulting in the minor overlapping that so many people complain about. The movement is self-limiting and harmless. Minor crowding and overlapping of teeth do not warrant intervention or correction.

As already noted, in addition to the four, third molars, orthodontists frequently prescribe removal of the four first bicuspids, one in each quadrant of the mouth, when the problem is the protruding front teeth. Few people realise that these eight extractions represent 25 percent of their 32 natural adult teeth. It is even more disturbing that dentists who place such emphasis on preserving the natural dentition are so willing to sacrifice one-fourth of it for the sake of appearance.

In fact, enough but not too much additional space push back the anterior teeth (dentists call this process retrusion) can be obtained by removal of only four teeth, the second permanent molars. For this alternative, the child must be 13 or 14 years of age, with normally developing third molars. This approach has the advantage not only of providing enough space for repositioning all the teeth but of permitting adequate room for the eruption of the third molars, thereby reducing the risk of impactions. It also eliminates the open spaces behind the cuspids that often remain after bicuspid extractions and help with the retention of all the flattening of the profile that often happens when bicuspids are removed.

Before subjecting your child or yourself to the sacrifice of one-fourth of the natural teeth, the orthodontist should be requested to consider the alternative of second molar extractions, or better yet, as I almost always do, expand the palate to straighten all the teeth at once.