Oct. 9 (Tue.), 2001

3. Problems with early treatment

Case 1
Chief complaint: Anterior crossbite
Age and sex: 10y1m, female
Diagnosis: Angle Class III
Treatment: Phase I (mandibular retraction with a chin cup) followed by Phase II (edgewise, full-appliance treatment)
Case 2
Chief complaint: Anterior crossbite
Age and sex: 9y6m, male
Diagnosis: Angle Class III
Treatment: Phase I (mandibular retraction with a chin cup) followed by Phase II (edgewise, full-appliance treatment)


Although the ANB and APDI values indicated that Case 2 had a severe skeletal Class III problem, I could not elect to observe the patient until he was ready for orthognathic surgery.


Case 1 underwent early treatment (Phase I) with a chin cup and lingual arches, followed by edgewise treatment (Phase II). The case remains stable after retention.

In contrast, Case 2 had an excessive pubertal growth of the mandible, which had to be corrected with orthognathic surgery. The figure shows cephalometric superimposition on the SN plane at N. Compared with the change in 'S' point, Ar did not move back enough to compensate for the horizontal component of the excessive mandibular growth, resulting in mandibular prognathism.


I was not able to predict that there would be such a difference in outcome between the two cases simply by looking at their initial data. In those days, I was not using a rapid maxillary expander in combination with a facial mask. Instead, I was using a chin cup.
If this had been predictable, I would have managed the case differently. For cases like Case 2, there are two possible options. One is early treatment with an active use of a rapid maxillary expander and a facial mask. The other is to observe the patient without early treatment until the patient is ready for orthognathic surgery. What is the rationale for each option?

Before answering this question, I want to summarize the principles and objectives of 'early treatment' based on the conclusions reached at the Sendai Class III Symposium.
In this context, early treatment refers to Phase I treatment initiated in the early mixed dentition rather than treatment starting in the primary dentition.