Received by the Editorial Office: 07.05.2026
Accepted for publication: 24.05.2026
Published online: 30.06.2026
UDC: 617.52‑089‑053.2(075.8)
DOI: 10.70113/1815-9443.2026.24.15.003
CLINICAL EFFECTIVENESS OF THE MODIFIED HYRAX APPLIANCE IN CHILDREN WITH RESIDUAL HARD PALATE DEFECTS AFTER URANOSTAPHYLOPLASTY
Adilbek K.A.¹, Yermukhanova G.T.², Tulepbergenova A.P.¹
¹Al-Farabi Kazakh National University, Department of Dentistry, Almaty, Kazakhstan
²Asfendiyarov Kazakh National Medical University, Department of Pediatric Dentistry, Almaty, Kazakhstan
Introduction. Congenital cleft lip and palate is a major medical and social problem in pediatric dentistry and maxillofacial surgery. Residual hard palate defects after primary uranostaphyloplasty may be associated with malocclusion, impaired nasal breathing and nasal regurgitation of food, requiring staged orthodontic preparation and subsequent surgical correction.
Objective. To evaluate the clinical applicability and preliminary effectiveness of a modified fixed Hyrax appliance in children with residual hard palate defects after uranostaphyloplasty.
Materials and methods. A prospective descriptive case-series observation was conducted. The study included 23 children aged 6-11 years with residual hard palate defects after uranostaphyloplasty and mixed dentition malocclusion. All patients received a modified fixed Hyrax appliance with Ortocryl EQ acrylic added to the area of the residual defect. Complaints, oral and palatal status, occlusal characteristics, adaptation to the appliance, changes in breathing and feeding functions, and readiness for further surgery were assessed. No control group was included; data analysis was descriptive.
Results. Of the 23 patients, 15 had unilateral and 8 had bilateral cleft lip, alveolar process, hard and soft palate. Crossbite was diagnosed in 9 patients and mesial occlusion in 14 patients. Clinical follow-up showed reduced nasal regurgitation of food, subjective improvement in nasal breathing and generally satisfactory adaptation to the appliance. Some patients experienced temporary difficulties with oral hygiene and feeding during the initial adaptation period.
Conclusion. The modified Hyrax appliance may be considered a promising orthodontic preparation method in children with residual hard palate defects after uranostaphyloplasty. Controlled studies with objective measurements and long-term follow-up are required to confirm its effectiveness.
Keywords: cleft lip and palate; residual hard palate defect; Hyrax appliance; orthodontic rehabilitation; mixed dentition; uranostaphyloplasty.
