The Journal
Massler and Malone found that even without
orthodontic treatment, incidence of root
resorption increases with age. Factors such as
periodontal ligament characteristics and
muscular adaptation to occlusal changes may
be more favorable in young patients. Many
resorbed lacunae and fewer repair zones were
reported in an adult population. These were
attributed to increased susceptibility to root
resorption and longer aplastic gaps between
resorption and apposition.5,6
Dental Age
Root development can be affected by tooth
movement, dilacertion, decreased expected
root length, and root resorption. Dilaceration
and stunting may be the final result of deflection
of the Hertwig epithelial sheath in developing
root during tooth movement. Partially formed
roots appear to develop normally during the
course of orthodontic treatment that coincides
with fast growth periods. Some teeth may be
stunted if treated vigorously during later
childhood.
Rosenberg reported that teeth with
incompletely formed roots showed less root
resorption than those with completely formed
roots. Teeth with incompletely formed roots did,
however, reach their normal root length.
Treatment increased the dilaceration incidence
from 25% before treatment to 33%. This
incidence is higher in canines than in
premolars.7 Linge and Linge found an average
loss of 0.5 mm root length in developed teeth
that were orthodontically treated.8
Tooth Structure
Deviating root form is more susceptible to post-
orthodontic root resorption. Convergent apical
root canal is considered to be an indicative of
high root resorption potential. The degree of
root resorption in teeth with blunt- or pipette-
shaped roots was significantly higher than in
42
teeth with normal root form. The pipette-shaped
root was shown to be the most susceptible root
form to root resorption.8
Previously traumatized teeth
Traumatized teeth can exhibit external root
resorption without orthodontic treatment.
Orthodontically moved traumatized teeth with
previous root resorption are more sensitive to
further loss of root material.
The average root loss for trauma patients after
orthodontic therapy was 1.07 mm compared
with 0.64 mm for untraumatized teeth.
Traumatized teeth without signs of resorption
are not resorbed more than nontraumatized
teeth.8,9
The presence of root resorption before
orthodontic treatment
There is a high correlation between the amount
and the severity of root resorption present
before treatment to the root resorption
discovered when the orthodontic appliance is
removed. One study reports that the incidence
of root resorption increased from 4% before
orthodontic treatment to 77% after treatment.10
Endodontically treated teeth
A higher frequency and severity of root
resorption of endodontically treated teeth
during orthodontic treatment was reported.
However, it has been suggested that
endodontically treated teeth are more resistant
to root resorption because of an increased
dentin hardness and density.10,11
Alveolar Bone Density
More dense alveolar bone, More root
resorption. Becks and Tager related increased
root resorption to bone architecture resulting
from hormonal and nutritional imbalance
Vol. 14 No. 1
Jan-Apr 2018