Class III Malocclusion and Maxillary Retrusion

• Causes: Class III malocclusions can arise from mandibular protrusion, maxillary retrusion, or both.
• Studies on Maxillary Retrusion: Various studies report the contribution of maxillary retrusion to Class III malocclusions in individuals with normal mandibles, with percentages ranging between 19.5% and 37%.
• Treatment Focus: This recognition has led to introducing treatments like the orthopedic facemask for maxillary protraction.

Alternate Rapid Maxillary Expansion and Constriction (Alt-RAMEC)

• Protocol: Expands and contracts the maxilla alternately (1 mm/day for a week each, repeated for 7–9 weeks) using a two-hinged rapid maxillary expander.
• Rationale: Mimics the rocking mechanism in tooth extraction, disarticulating circum-maxillary sutures without over-expansion.

Alt-RAMEC Protocol Details

1. Activation Phase:
   • The expansion screw was turned twice daily at a rate of 0.20 mm per turn.
   • This phase lasted for 1 week, ensuring the maxilla was progressively expanded.
2. Deactivation Phase:
   • The screw was then turned twice daily in reverse at a rate of 0.20 mm per turn.
   • This phase also lasted for 1 week, gradually constricting the maxilla back.
3. Repetition:
   • The activation and deactivation sequence was repeated for a second cycle.
   • After each week-long activation or deactivation phase, the patients were examined to monitor proper opening or closing of the screw, ensuring precision in the procedure.
4. Post-Protocol Guidance:
   • Following the completion of the Alt-RAMEC cycles, patients were instructed to wear the Reverse Headgear (RH). This is a common adjunct in orthopedic facemask therapy designed to enhance maxillary protraction after the suture disarticulation achieved by Alt-RAMEC.

Results of Alt-RAMEC

• Comparison with RPE:
  • Alt-RAMEC: Achieved an average anterior movement of point A by 5.8 mm in cleft patients over 9 weeks.
  • RPE: Achieved only 2.6 mm movement after 1 week.
  • Suture Opening: Experimental studies confirmed that Alt-RAMEC opens circum-maxillary sutures more extensively than 1 week of RPE.

Clinical Implications

Parameter	A/D-RPE Group	RPE Group	Comparison with Previous Studies
Maxillary Advancement (Point A)	4.13 mm (T3)	2.33 mm (T3)	Greater movement in A/D-RPE group, similar to Liou and Tsai (2005) findings.
Anterior Movement of Point A	Significant difference (greater in A/D-RPE)	Observed, but lesser than A/D-RPE	Liou and Tsai (2005), Merwin et al. (1997), Kapust et al. (1998), Sung & Baik (1998) showed comparable results to RPE group.
Mandibular Rotation	Posterior rotation observed	Posterior rotation observed	Consistent with previous studies (Merwin et al., 1997; Kapust et al., 1998).
Anterior Face Height Increase	Observed	Observed	Findings align with previous studies.
Maxillary Plane Angle	Decrease of 1.53 degrees (T3)	Decrease observed	A/D-RPE showed significant decrease, consistent with previous studies.
SNA Angle Increase	Significant difference (greater in A/D-RPE)	Observed	A/D-RPE resulted in more significant SNA angle increase compared to RPE group.
ANB Angle Increase	Significant difference (greater in A/D-RPE)	Observed	A/D-RPE showed more significant increase in ANB angle.
Overjet Correction	Greater correction in A/D-RPE	92.5% skeletal, 7.5% incisor tipping	A/D-RPE showed a higher skeletal contribution (93%) vs. RPE (92.5%).
Skeletal vs. Dental Contribution to Overjet	93% skeletal, 7% dental	92.5% skeletal, 7.5% dental	A/D-RPE showed a higher skeletal contribution (57.9% maxillary, 35.1% mandibular).
Soft Tissue Profile Changes	More pronounced in A/D-RPE (upper lip anterior, lower lip posterior)	Observed (less pronounced)	Profile improvement observed in both groups; A/D-RPE showed more pronounced soft tissue changes.
RH Usage During Treatment	16-18 hours/day (initial 6 months), 12 hours/day (2nd 6 months), 6 hours/day (passive phase)	Varied by study, typically used for 14 hours/day	Similar to recommendations of Saadia and Torres (2000) and others (Macdonald et al., 1999).
Relapse	No significant relapse observed	No significant relapse observed	Consistent with previous studies (Macdonald et al., 1999; Vaughn et al., 2005).