Jarvie Journal - College of Dental Medicine - Columbia University

Volume 56, Spring 2013
Alveolar Bone Changes to Orthodontics in an Osteopenic Patient with
Possible Hajdu-Cheney Syndrome
Jeremy Zuniga 1 , Zachary Hirsch 2 , Ying Wan 2 , Sunil Wadhwa 3 *
1
Postgraduate Orthodontics Program, College of Dental Medicine, Columbia University, NY, NY
2 Columbia University, College of Dental Medicine NY, NY; 3 Division of Orthodontics, College of Dental Medicine,
Columbia University, NY, NY *Faculty Mentor
Introduction: Hajdu-Cheney Syndrome (HCS) is a very rare autosomal dominant disorder of
bone metabolism characterized by progressive focal bone destruction, including acro-osteolysis
of the distal phalanges and progressive osteoporosis. Only approximately 50 cases have been
reported to date. The disorder is associated with a Notch2 mutation that is thought to be
important in the development and maintenance of the skeleton by modulating RANKL-induced
osteoclastogenesis. A 13-year old osteopenic male with skeletal Class III malocclusion and
possible HCS presented for orthodontic treatment. The maxillary arch was severely crowded
and the incisor angulation was extremely flared. In order to determine the extraction pattern of
the patient in the maxillary arch for pre-surgical orthodontics, we needed to determine how the
patient would handle orthodontic tooth movement.
Objective: To evaluate the alveolar bone effects of orthodontic tooth movement on an
osteopenic patient with possible Hajdu-Cheney Syndrome using a cone-beam computed
tomography (CBCT) and compare that to published norms of alveolar bone density and bone
levels during orthodontic tooth movement.
Materials and Methods: The first premolars were preferentially prescribed to expand 2.0 mm
using clear plastic aligners, Invisalign (Align Technology). Cone-beam computed tomography
(CBCT) images were taken prior to expansion (T 0 ) and 3 months following (T 1 ) the completion
of expansion. Linear alveolar buccal bone levels were made by measuring for buccal bone
thickness (BBT) and buccal marginal bone level (BMBL) at the right and left first premolar. In
addition, bone density changes around the buccal aspects of the right and left first premolars at
three portions of the root (cervical, intermediate, and apical) were calculated.
Results: Actual expansion achieved immediately following expansion was 0.9 mm. Expansion
remaining post-retention was measured at -0.01 mm. Linear CBCT measurements of the BBT
from T 1 to T 2 revealed and a gain of 0.25 mm for the right premolar and a loss of 0.20 mm for
the left premolar. The BMBL measurements revealed a gain of 0.66 mm and a loss of 0.07 mm
for the right and left first premolars respectively. The bone density measurements increased
during the study at 6% and 23% for the right and left first premolars respectively.
Discussion: Out data indicates that, while 0.9mm of expansion was achieved initially, the
patient was non-compliant in the retention phase of treatment. When the T 2 CBCT was taken,
there was a slight constriction of the first premolars of 0.10 mm. In addition, the bone density
around each premolar actually increased from T 1 to T 2 , which is the complete opposite of what
happened in normal orthodontic tooth movement. Both BBT and BMBL were negligible in
comparison to that of someone with normal bone physiology. Using a banded hyrax device
would have eliminated the need for compliance during the retention phase of treatment.
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