Related Experiment Video
Updated: Feb 11, 2026

Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
Short- and Long-Term Effects of Late Maxillary Advancement With the Liou-Alt-RAMEC Protocol in Unilateral Cleft Lip
Maria Costanza Meazzini1, Laura B Zappia1, Chiara Tortora1
11 Department of Maxillo-Facial Surgery, Smile House, Regional Center for CLP, San Paolo Hospital, University of Milan, Milan, Italy.
Objective:
The objective of this retrospective longitudinal study was to evaluate short- and long-term results of the application of the Liou Alt-RAMEC (alternate rapid maxillary expansion and constriction) technique, a late orthopedic maxillary protraction technique, with intraoral anchorage, in patients with cleft.
Materials And Methods:
Twenty-six patients with unilateral cleft lip and palate (UCLP) were consecutively treated with the Alt-RAMEC technique. The average age of the patients was 11.7 years (10.3-13.2 years) before protraction and 18.3 years (17.4-21.1 years) at long-term follow-up. A sample of nontreated patients with UCLP was used as a control group. It was matched for sex, skeletal class III, and age (11.3 years). The control sample had records at the end of growth (18.7 years).
Results:
The sagittal advancement of A-point, after the application of the technique, was 5.7 (2.17) mm. Some mandibular dentoalveolar and positional adaptation was noted. The position of the maxilla was stable in the long term. On the other hand, the UCLP control group showed hardly any growth at the maxillary level during the long-term follow-up period.
Conclusion:
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 hours per day, allows for satisfactory maxillary protraction, with, at this stage, apparently stable long-term results. Nevertheless, as only 50% of the patients had long-term follow-up data, we are still unable to predict the percentage of patients which will not eventually need orthognathic surgery.
Related Concept Videos
Long-term Depression
Long-term Depression
Calcium Ion Concentration Mechanism
If over...
Framing Effects
Biological Effects of Radiation
Overview of Advanced Functional Groups
Functional groups are groups of atoms with specific chemical properties that occur within organic molecules and are sometimes denoted as “R”. Functional groups can “functionalize” a compound by enabling it to adopt different physical and chemical properties.
Types of Advanced Functional Groups
The table below summarizes some of the major functional groups in organic chemistry.
Extraction: Advanced Methods

