The Schudy Chronicles

Post Treatment Growth

While we have discussed post treatment growth, while discussing other subjects, we have never used post treatment growth as the subject of an article. Since post treatment growth is probably one of the most important segments of the growing process, and since it probably has the greatest effect on the final outcome of the treated case, it seems appropriate to dignify the subject by discussing it separately.

Most of the post treatment growth studies in the U.S.A. have been done by interns1-to-12 at universities and have not been published. This is unfortunate, for it may give the impression that this subject is of little importance. Except for our retaining devices we have no control over this segment of growth. Our retaining devices are designed to perpetuate only the status quo. They have little control over the dynamics of this period of growth. Just how much of total growth occurs post treatment is not known, but this growth is tremendously effective. The only way that we can control this growth is by superior treatment. "Superior treatment" means that we must carefully execute certain principles. Following is a partial list of principles and segments of treatment which must be executed:

1. Maxillary incisors must be torqued to about 24° to line NA, or possibly higher if there is a small root-crown angle.
2. The interincisal angle should be about 135° , in most cases.
3. The maxillary incisors should be intruded if needed (to about 2 mm below the lip line at rest).
4. Maxillary incisors should be slightly inclined mesially.
5. Mandibular lateral incisor apices should be about 17 mm apart.
6. Mandibular incisors must not be intruded in growing patients.
7. Mandibular arch must be completely leveled.
8. Mandibular molars and bicuspids must be uprighted (90° to occlusal plane).
9. Maxillary first molars must be well rotated.
10. Good cuspid relationship is essential. We should not hesitate to remove enamel from the appropriate teeth to accomplish this.
11. Overbite should be reduced to about 1 mm.
12. Overjet should be reduced to about 1 mm. To leave more than 1 mm of overjet will invite bite closure and crowding of lower incisors.
13. When the extraction of 4 bicuspids is considered advisable for a given individual and the extraction of four 2nd bicuspids seems feasible, a far better result can be produced when 2nd bicuspids are removed.
When these aspects of treatment have been accomplished then post treatment growth will complement our treatment. Condylar growth will usually translate the maxillary molars and bicuspids forward, tip the maxillary incisors and cuspids forward, reduce the overjet and improve the interdigitation. Most post treatment growth is condylar growth. The palatal plane seldom grows downward appreciably.

The "poor treatment scenario" is as follows: (1) The interincisal angle is too high, (2) the maxillary incisors have inadequate torque, (3) the overbite is still 3 to 5 mm, (4) the upper incisors have been moved downward when they should have been intruded, (5) the upper 1st molars are poorly rotated, (6) the cuspid interdigitation is poor and (7) there has been too much lower anterior dental height suggesting too much Class II elastics or cervical headgear.

These conditions invite complete disaster. As post treatment growth ensues the overbite increases, the lower incisors become crowded and crowding continues to increase with time.

To many colleagues this above list will seem quite lengthy. For forty years we tried to execute every one of these concepts on all patients. Recently, a colleague who was associated with me for three years said, "You always corrected deep bites to an end to end relationship." Please see Article No. 16 of the Schudy Chronicles.

This is but another effort to try to convince colleagues of the importance of these concepts in the treatment of malocclusion.



Bibliography
1. Boerman, I. E.: Vertical facial development from ages five to seventeen, unpublished master's thesis, Department of Orthodontics, University of Michigan, 1967.

2. Bradley, W. R.: The stability of the interincisal angle in thirty posttreatment cases treated with the Begg light wire technique, unpublished master's thesis, Department of Orthodontics, Fairleigh Dickinson University, 1967.

3. Cleven, D.: A longitudinal roentgenographic cephalometric investigation of mandibular growth in height, width and depth in males from early childhood to adulthood, unpublished master's thesis, Department of Orthodontics, Northwestern University, 1969.

4. Cruser, D. K.: A cephalometric study of posttreatment mandibular plane angle changes in orthodontically treated patients who exhibited an increase in their mandibular plane angle during treatment, unpublished master's thesis, Department of Orthodontics, Southern California University School of Dentistry, 1969.

5. Ferdinand, R. L.: Mandibular growth and its effect on posttreatment crowding of mandibular anterior teeth, unpublished master's thesis, Department of Orthodontics, Washington University School of Dentistry, 1968.

6. Leff, R. L.: Overbite correction and relapse as analyzed by some cephalometric and treatment-related variables, unpublished master's thesis, Department of Orthodontics, University of Minnesota, 1969.

7. Loos, J. F.: An evaluation of relapse following orthodontic therapy, unpublished master's thesis, Department of Orthodontics, Southern California University School of Dentistry, 1966.

8. Payne, G. W.: A cephalometric analysis of the effects of growth on certain anatomical facial planes after orthodontic treatment, unpublished master's thesis, Department of Orthodontics, University of Washington, 1964.

9. Urban, L. B.: A longitudinal study relating to some of the factors affecting the stability of the incisal overbite in Class II, Division 1 malocclusion, unpublished master's thesis, Department of Orthodontics, Northwestern University School of Dentistry, 1969.

10. Weneger, J. L.: A cephalometric appraisal of the significance of the interincisal angle and a method of retention in the maintenance of overbite correction, unpublished master's thesis, Department of Orthodontics, Case Western Reserve University School of Dentistry, 1969.

11. Zamarin, R. J.: A ten year statistical cephalometric survey of the changes occurring during the treatment of posttreatment periods in Class I (Angle) malocclusions treated with extraction, unpublished master's thesis, Department of Orthodontics, Southern California University School of Dentistry, 1966.

12. Schudy, G. F.: Posttreatment Craniofacial Growth: Its Implications in Orthodontic Treatment, AJODO, 1972.

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