Periodontal Changes Associated with Hyrax vs Damon Expansion

  • Author / Creator
    Kobewka, Marissa N
  • Background: Orthodontic expansion is used to treat maxillary transverse deficiency (MTD). Purpose: Determine alveolar and soft tissue changes in adolescents undergoing expansion using Hyrax expanders followed by non self-ligating brackets or only the Damon® system. Research Design: MTD patients were randomly allocated to the Hyrax or Damon® group. Records (CBCT, photos) were taken at different stages of treatment. CBCTs from 45 patients were used to measure buccal alveolar bone widths (BBW) at 2 root points for 4 tooth groups before treatment, at debond and 2 years post treatment using a technique described by diGregorio et al (2019). Recession (GR) and its risk factors were ascertained using the same patients’ digital photos via techniques described by Le Roch et al (2019). Results: At debond, the maxillary molars demonstrated a significant reduction in buccal alveolar width in response to orthodontic expansion (p=.016) and the Hyrax group demonstrated more BBW loss than the Damon® group (p=.014). There was no difference between the groups at follow up (p=.085). Absence of BBW measured via CBCT is not related to the presence of GR at debond (p=0.74) or at two year follow up (p=0.99). Keratinized tissue width (<2mm) had higher odds of exhibiting gingival recession than KT width ≥ 2mm [OR≥12, p<.0005]. Conclusions: BBW decreased with expansion. There was more BBW loss with Hyrax than Damon® at debond, though groups were similar at follow up. Absence of BBW measured via CBCT was not related to the presence of gingival recession; however keratinized tissue width <2mm was.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.