Self-activated leaf expander versus William's expander in expansion of collapsed mandibular arch

The current randomized clinical study will be directed to compare the selfactivated leaf expander to William's expander for the expansion of collapsed mandibular arch.

Inclusion Criteria:

• An age from 12-16 years.

  • Low to average facial vertical pattern.
  • A mild to moderate crowding in mandibular arch with reduced transverse dimension which require non extraction orthodontic approach.
  • Similar amount of crowding on each side of the mandibular arch.
  • No previous orthodontic treatment.
  • Good oral and general health.

Exclusion Criteria:

• Severe crowding.

  • Steep mandibular plane.
  • Asymmetric crowding on both sides of the arch.
  • Shifting of mandibular dental midline.
  • Impacted lower 2nd premolar.

An age from 12-16 years.

• Low to average facial vertical pattern.
• A mild to moderate crowding in mandibular arch with reduced transverse dimension which require non extraction orthodontic approach.
• Similar amount of crowding on each side of the mandibular arch.
• No previous orthodontic treatment.
• Good oral and general health.