Long-term follow-up of late maxillary orthopedic advancement with the Liou-Alternate rapid maxillary expansion-constriction technique in patients with skeletal Class III malocclusion

Introduction The objective of this study was to evaluate short and long-term results of the application of the alternate rapid maxillary expansion/constriction (Alt-RAMEC) technique in patients with skeletal Class III malocclusion. Methods Forty-two white patients were consecutively treated with the Alt-RAMEC technique. The average age of the patients was 12.7 ± 1.6 years (range, 9.4-15.9 years) before protraction. The average age at long-term follow-up was 19.4 ± 2.8 years (range, 17.2-26.9 years). A sample of nontreated patients with Class III malocclusion from the archives of orthognatic surgery in our hospital was used as a control group. The initial records were matched for sex, the severity of Class III malocclusion, and age (mean, 12.1 ± 1.4 years; range, 9.7-14.1 years) with the old records available in the archive. The control sample had records presurgery (mean, 19.8 ± 2.2 years; range, 16.6-21.6 years). Results The sagittal advancement of A-point, after the application of the technique, was 5.43 ± 2.71 mm. Some mandibular dentoalveolar adaptation was noted. The position of the maxilla was stable in the long term. In contrast, the control group showed limited growth at the maxillary level during the long-term follow-up period. Conclusions Our results showed that the Alt-RAMEC technique, performed at the correct time, with a double-hinged expander, followed by Class III spring or elastic traction, 24 h/d, allows for satisfactory maxillary protraction, with stable long-term results. The comparison with a sample of matched nontreated patients with Class III malocclusion allowed to suggest the positive effect of the treatment on the maxillary position vs the natural evolution of the Class III skeletal discrepancy.