In the year 1997, an internationally known clinician and author published a discussion of his opinion on the correction of deep bites, in an American journal.

As is well known, deep bite malocclusions are usually associated with low angle morphology. Also well known is the fact that deep bites are very difficult to correct and very difficult to maintain the overbite correction. How much overbite is considered a "deep bite?"

For our purpose here we are speaking of overbites from say 8 mm to 11 mm. Eleven millimeters of overbite usually will mean that the lower incisors are impinging on the gingival tissue of the upper arch. It is my opinion that if these cases are to be successfully treated, the overbite must be reduced to one millimeter without intruding the lower incisors.

Whether or not the upper incisors are intruded will depend on the relationship of the upper lip to the level of the incisal edges of the upper incisors. We should not hesitate to intrude upper incisors to improve the smile. They do not have a strong tendency to move downward post treatment, if the torque has been properly corrected.

1. If the overbite is reduced to one millimeter,
2. The upper incisors are about 24° to line NA,
3. The interincisal angle is about 130°,
4. The lower incisors have not been intruded,
5. The sagittal jaw relation is firmly established,
6. The case has been properly retained and growth has ceased,

then overbite is corrected for life. The author is aware that some patients continue to grow long after treatment, but I do not believe that latent growth will cause the overbite to relapse. It is realized that these thoughts run counter to conventional thought, but we hope that they will be confirmed in this essay. If the ANS-Menton distance is increased as much or more than the depth of the overbite and growth has ceased at the end of treatment, then overbite correction is permanent.

Recently I was visiting with an orthodontist who was associated with me for a three year period of time. He "unsolicitedly" stated, "You always treated deep bite to an end to end relationship." He could have also said, "You seldom intruded lower incisors." To take an 11 mm overbite and reduce it to 1 mm without intruding lower incisors is not easy, but it can be done consistently. See "Schudy Chronicles," Article 16.

The reason for avoiding intrusion of lower incisors is that they nearly always erupt post treatment, if they have been intruded, and cause a relapse of overbite and crowding of the incisors.

Getting back to the author mentioned above: He stated that in the case of a deep bite, the incisors are over erupted; and that it is the responsibility of the orthodontist to determine whether it is the upper incisors or lower incisors or both. Just how you go about determining this, he did not say. I would not know how to make this determination.

Since he did not mention any other cause of deep bites, it can be assumed that he thought there are no other causes. The entire discussion seemed to be full of generalities and "double talk." So long as we depend on a lot of words, talk around the subject, and use generalities, we will never solve the problem of retention. The solution is to be found in the quality of the treatment.

Then the clinician under discussion recommended that we should intrude the incisors to correct the overbite. There was no mention of any other method of correcting the overbite; and the implication was that there is no other way. He later states that, "In many cases the deep overbite returns as the maxillary and mandibular incisors 'over erupt' following appliance removal." He infers that there is no difference in the tendency to "over erupt" between the upper and lower incisors. It is my studied opinion that when these teeth have been intruded that there is a much greater tendency for the lower incisor to erupt post treatment. It is also implied that deep bites cannot be successfully treated. Again see "Schudy Chronicles," Article 16.

There is another cause of the deep bite which was not mentioned. In most instances the real cause of deep bite is the underdevelopment of the vertical dimension-the underdevelopment of the vertical growth of the molar teeth. When we can take a patient with an eleven mm overbite and reduce the overbite to one mm without intruding the lower incisors, it would seem self evident that molars are under developed

Frankly, it is regrettable that an international clinician and author, who speaks all over the world and who is in great demand as a speaker, would not know that lack of vertical growth of molars (lower and upper) plays a dominant role in causing deep bite malocclusion.

In 1997 it is surprising that it is not commonly known that underdevelopment of molars is largely responsible for the deep bite. All orthodontists world wide should be acutely aware of this obvious fact.

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