Zygomaticomaxillary modifications in the horizontal plane induced by micro-implant-supported skeletal expander, analyzed with CBCT images by Cantarella et al

Maxillary Skeletal Expander (MSE)

• Type: Micro-implant-supported expander (MARPE)
• Anchorage: 4 bicortical miniscrews (palatal + nasal cortex)
• Placement: Posterior palate
• Expansion rate:
  • 2 turns/day until diastema
  • Then 1 turn/day
• Retention: ≥ 3 months post-expansion

Parameter	Mean Increase
Anterior Inter-Maxillary Distance (AIMD)	+2.76 mm
Posterior Inter-Zygomatic Distance (PIZD)	+2.40 mm
Posterior Inter-Temporal Distance (PITD)	Negligible

Parameter	Mean Increase
Zygomatic Process Angle (ZPA)	Right: +1.7°  Left: +2.1°
Zygomaticotemporal Angle (ZTA)	Negligible

• Rotation Center:
  Near the proximal zygomatic process of temporal bone
  (more posterior/lateral than in tooth-borne expanders)
• Movement Pattern:
  Lateral + Forward movement of maxilla + zygomaticomaxillary complex
• Bone Bending:
  Occurs at zygomatic process of temporal bone (adaptive mechanism)

• Achieves parallel midpalatal suture opening
• Disarticulates pterygopalatine suture
• Minimal buccal tipping of molars
• Suitable for late adolescent to adult patients (13.9–26.2 yrs in study)

• Use CBCT before & after expansion to analyze changes
• Avoid brackets/appliances until post-expansion imaging complete
• Monitor miniscrew engagement in both cortices on initial scan

📍 Source: Cantarella et al., Progress in Orthodontics, 2018🧪 IRB Approved Study | UCLA Orthodontic Clinic

🔍 DOI: 10.1186/s40510-018-0240-2