How do Haas and Hyrax expanders affect the periodontal tissues in patients with Unilateral Cleft Lip and Palate? A Randomized Clinical Trial

Abstract

Aim and Background: This randomized clinical trial was to evaluate periodontal effects of Haas and Hyrax maxillary expanders in patients having unilateral cleft lip and palate.

   Methods: Twenty-four patients having posterior crossbite were randomly divided into; Haas group (9.5±1.24) years and Hyrax group (9.7±1.26) years. Pre-treatment radiographs were taken, activation regimen was to open the screw two times in the morning and two times in the evening till overcorrection of the crossbite. Retention phase was 6 months then post-retention radiographs were taken. Eligibility criteria included patients having erupted upper first molars, periodontally sound teeth and didn’t undergo any previous orthodontic intervention. The outcome was to assess periodontal effects of Haas and Hyrax appliances. Random sequence table was done with 1:1 allocation ratio. Blinding was possible for the statistician and the outcome assessor.

    Results: Non-significant thinning of the buccal plate of bone of the anchoring teeth occurred with Haas appliance. Hyrax appliance caused significant decrease in the thickness of mesio-buccal plate of bone of the upper first molar on the non-cleft side by (-0.52± 0.55) (P=0.01), with confidence interval (-0.92, -0.13). There were no significant changes in neither palatal bone plate thickness of the anchoring teeth nor alveolar bone crest level in both appliances. There wasn’t any serious harm with either appliances.

    Conclusions: Both appliances were considered safe on the periodontal tissues. The periodontal side effects were not clinically significant in the Hyrax appliance.