Maxillodental responses of banded hyrax expansion on unilateral dentoalveolar non-functional crossbite

Abstract EN

Banded Hyrax was used for treatment of 29 patients at age range from 8-11 years for the correction of left side, unilateral, dentoalveolar, non-functional posterior crossbite.

Active expansion begun with one complete turn then followed by twice 1 / 4 turn every day until 2-3 mm over correction within time 16-36 days.

This was followed by stabilization period for 3 months.

A posterioanterior radiographs were taken before and after treatment to examine the transverse changes due to Hyrax expansion on the molars inclination (both sides) to the cranial reference line and the distances from the midsagittal plane to the outermost point of the upper first permanent molar, base of maxilla and nasal cavity widths for left and right sides.

It was found that the faster the expansion, the more the orthopedic and the less orthodontic effects and the asymmetrical expansion of the banded Hyrax is a rule rather than exception.

Expansion magnitude was more on the cross-bite side (left) for dental, basal and nasal widths.

The increase in dental distances was about twice of basal part (orthopedic).

The increase in nasal cavity width was greater on crossbite side that was about twice the amount of right side.

The banded molar try to move with the alveolar bone bending rather than tipping within the bone itself.