Good time for discussion of early treatment

Abstract

The AAO has scheduled an Early Treatment Conference, Feb 8–10, 2002, in Phoenix, Ariz. From my perspective, the timing for a discussion of this somewhat controversial issue could not be better. Orthodontists face decisions concerning the timing of treatment every day, and their patients must live with the long-term implications of those decisions. An interesting dilemma exists because, on one hand, the public seems more aware than ever of the need for interceptive care, while at the same time, we clinicians know that some problems cannot be fully corrected until all teeth have erupted, and in the case of Class III treatment, all growth is complete. Unanimity of opinion on the issue of when to start treatment is nonexistent even among the participants of one of our most highly touted orthodontic meetings. This past summer I participated in the annual meeting of CDABO (College of Diplomates of the American Board of Orthodontics), where I asked the audience who would correct a severe posterior x-bite with functional shift in a 6-year-old in the full deciduous dentition stage of development. I was surprised to see only a few hands go up, with most choosing to wait at least until the mixed dentition stage with all permanent incisors fully erupted. The entire meeting was dedicated to a study of Class III malocclusion, with emphasis on the long-term outcome of various treatment approaches. Scientific presentations by David Sarver, Patrick Turley, Peter Ngan, Hideo Mitani, Martin Chin, and John Casko provided a wealth of experience on the subject. As the meeting progressed, I became more and more convinced that the timing of treatment and the mechanics used are less important than a real under-standing of the individual patient's growth. In summa-rizing his studies of Class III growth over the past 30 years, Professor Mitani noted:1.The basic pattern of mandibular prognathism is established before puberty and does not change fundamentally.2.Prognathic mandibles show a wider variation of growth direction than normal mandibles.3.The total growth increment of the prognathic mandible is about the same as that of the normal mandible, and it does not show any peculiar growth acceleration before, during, or after puberty.4.The progressive timing of growth and development are essentially the same between Class I and Class III subjects.5.However, the total increase in posterior cranial base in a prognathic sample is less than that in a normal group. There is also a significant difference in the total change of the Wits appraisal between prognathic and normal groups.6.The morphology of the prognathic face differs from normal, not only in the size of the mandible, but also in the basic craniofacial and dentoalveolar structure. As I witnessed the presentation of long-term cases treated by Mitani and the other speakers, I began to better understand why the timing of treatment is so controversial. When the focus of correction was on maxillary development as a component of Class III treatment, I was reminded of the ever-present need for a better understanding of rapid maxillary expansion. In this issue of the AJO/DO, Braun et al, in a study of “The biomechanics of rapid maxillary sutural expansion” call for a redesign of the Hyrax expansion device to improve its effectiveness. With their engineering backgrounds, the authors recommend that manufacturers increase the diameter of the activation screw as well as that of the 2 adjacent wire guides to reduce tipping of the maxillary halves. Analyses of the maxillary expansion force system are concomitant with holographic findings that strongly suggest the stainless steel wires joining the teeth to any expansion device be of the largest diameter possible. Please take time to read this article on page 257, and continue to have an interest in early treatment when appropriate. You might even want to visit Phoenix in February 2002.