Different Methods of Correcting
Asymmetries of the Jaws
There seem to be two basic methods of correcting asymmetries of the jaws which have been reported in the literature. One involves orthopedically moving the condyle forward out of the fossa on the side toward which the mandible is deviated -- as well as moving the molars and bicuspids vertically, more on the affected side than the other side. The other method depends entirely on distalization of the upper molars and bicuspids on the affected side. Since these two methods are basically different it would seem to be important to explore their merits.
The "orthopedic method" has been used since 1948 and reported in comprehensive detail in 1968 in the Angle Orthodontist. The other was discussed at the 1998 annual meeting of the AAODO, and obviously has been used in various forms for several years. One method moves the condyle out of the fossa on one side, while the other distalizes the maxillary molars and bicuspids on one side. Please see the June issue 1996 of the J.C.O. One method tries to harmonize the molar teeth vertically as well as horizontally, while the other makes no specific effort to move molars vertically more on one side than the other.
In the initial examination, if the patient is asked to move the mandible forward and laterally to where the upper and lower midlines coincide, it will always be noted that the molars on the affected side need more vertical movement than the other side.
The original article, published in 1968, has been republished verbatim in Article 28 of the Schudy Chronicles on the Internet. This original article addresses the subject in detail, and all deviations of the mandible are corrected by moving the mandible forward and laterally. The Internet article shows several types of problems requiring different mechanics for correction. The reader is urged to thoughtfully study this entire article. The following quote is from the original article:
"What is the rationale for this method of correction of midline asymmetries? Elastics must be strong to overpower muscle pull and overcome a deeply ingrained neuromuscular functional pattern. Elastics do not affect mandibular position per se. They only affect tooth position, which in turn influences mandibular position. In other words, a mandible will only adjust to an altered tooth position, and not be directly affected by elastic pull, however strong this may be. In many instances the vertical dimension plays an important part in the etiology of asymmetries of the teeth. A differential in the vertical growth of the alveolar process can be quite important in producing a horizontal asymmetry. The correction of this by the vertical pull of the elastics is an integral part of the over-all correction. Thus, both the vertical and horizontal disharmony must be corrected....
"Elastics must be very strong (up to 16 oz.). It is best to use weaker elastics for about three days leading up to the strong ones. The patient and parents must be informed carefully about the purposes of the elastics. They must be told that in order to break a habit of many years standing we must use strong forces to shock, disturb and confound the existing neuromuscular balance. They must also be told, with emphasis, that the elastics are not to be removed from the mouth under any circumstances -- not even to brush the teeth. But, they can be promised that only three to six weeks will be required to correct the asymmetry. The reader must be reminded that such a system of elastics must not be applied unless both arches are completely leveled....
"Many men have expressed concern about the possible reaction of the temporomandibular joint to such drastic and forceful changes in the position of the mandible. They have wondered if such therapeutic measures would lead to malfunction and discomfort at the time of the treatment or in the future. The author can truthfully say that in twenty years of application exactly as described here he has never noted any discomfort at the time or later. Quite to the contrary, on numerous occasions discomfort and clicking have been eliminated by these procedures."
While I have never used the distalization method of correction, I have wondered whether, when finished, the maxillary midline of the teeth is in the midline of the maxilla. The orthodontist who reported this method spoke of intermittent discomfort of the temporomandibular joints in some patients, post treatment.
Since the two methods of correction are so basically different, I should think that members would have a keen interest in further exploring their merits. Surely one method is better than the other; and surely one is more favorably related to the health of the temporomandibular joint, than the other.
Recently a well known orthodontist, whose name will not be divulged, expressed his views on the correction of asymmetries. He stated, "In the permanent dentition, dental asymmetries are corrected through tooth movement." He further stated, "The limit of maxillary midline deviation found to be aesthetically acceptable to patients is approximately 2 mm on either side of the patient’s facial midline." Please see a case report in the June 1996 issue of the J.C.O. by Fred Schudy.
In visiting an Orthodontic department of a dental school some years ago I had the opportunity to observe the treatment of an asymmetry. A student was treating an asymmetry by moving teeth. The patient was age 18 years, had been under treatment for about one year, and was experiencing considerable pain from the temporomandibular joints. An upper right first bicuspid had been removed and the upper midline was considerably off center. They were obviously in big trouble and there was little hope that the problem could be satisfactorily resolved.
My son, Dr. George Schudy, for 25 years has corrected asymmetries by moving the mandible forward and laterally. On at least one occasion, the mandibular deviation was 4 mm. The treatment was successful and uneventful. When two orthodontists have spent a combined total of 65 years of successful practice moving the mandible forward and laterally, and depending on the adjustment of the fossae and the condyles to fill in the void created by moving the condyle out of the fossae on one side, while others move the maxillary teeth off center and still others distalize molars and bicuspids on the affected side, now we have a crisis It is hoped that the profession will be sufficiently alarmed to conduct some studies.
Bibliography
1. A. Athanasiou; M. Arvystas; R. Nanda; B. Melsen – AAODO 1998 Annual Meeting in Dallas, Texas, USA.
2. Schudy, Fred – Sound Biological Concepts in Orthodontics, AJODO, 1972.
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