Dento-skeletal Effects of Quadhelix Versus Mini-hyrax Expanders in Patients With Cleft Lip and Palate at the Mixed Dentition Stage: A Randomized Clinical Trial

Maxillary expansion is usually performed before the secondary alveolar bone grafting procedure. Expansion improves the maxillary arch morphology and causes the segmental alignment creating appropriate conditions for bone grafting surgery as well as correcting the posterior crossbites. An important treatment objective in cleft cases is to achieve greater anterior than posterior maxillary expansion since there is a greater anterior than posterior maxillary constriction in most of those patients. Variable appliances have been used for maxillary arch expansion in cleft patients.

• Hyrax expanders exert parallel forces to the alveolar bones and the maxillary complex, generating similar amounts of anterior as well as posterior expansion and might be indicated for patients with overall maxillary transverse deficiency. While with patients of greater anterior constriction, Hyrax expander must be frequently interrupted before the full correction of the anterior transverse deficiency in order to avoid the occurrence of a posterior buccal crossbite.
• Fan-shape expanders and mini-hyrax (supported on the first premolars and associated to a transpalatal arch cemented to the first molars) enhanced expansion in the maxillary anterior region and restricted posterior expansion.
• Mini-hyrax (supported on the first permanent molars) can expand anteriorly as well as posteriorly and was found comparable to hyrax.

I this study we are comparing the dentoskeletal effects of quadhelix versus mini-hyrax utilizing CBCT and digital models performed before and after expansion.

Inclusion criteria

• Mixed dentition.
• Both males and females.
• Unilateral cleft lip and palate
• Presence of maxillary constriction that needs maxillary expansion prior to secondary alveolar bone grafting.
• Erupted first permanent maxillary molars.
• Good periodontal health.
• No previous orthodontic treatment

Exclusion criteria

• Syndromic cleft lip and palate patients.
• Previous secondary alveolar bone grafting.
• Taking medications that influence growth.
• Absence of teeth to support the expansion appliance