Pacific Coast Society of Orthodontists Bulletin Summer 2017 - 26

Let's Talk About That

Figure 1. View of a maxillary
occlusion with sectional lingual
arch wire welded to the molar
band. The cantilever is activated
for occlusal and buccal movement
of the palatally impacted canine.
To extrude the impacted canine,
a NiTi closed-coil spring with an
eyelet engaged to the lingual
button of the impacted canine
was connected to the cantilever.

several peer-reviewed dental and orthodontic
journals, including the Journal of Dental Research,
the Journal of the American Dental Association,
and the AJO-DO. I was recently invited to be a
Guest Editor of Seminars in Orthodontics. I have
also been an invited guest speaker at the AAO
Annual Session for six consecutive years and have
spoken at the Angle Society Meetings, as I regularly lecture both nationally and internationally.

JP: In the maxilla, transposition usually occurs
between maxillary canines and first premolars.
In complete transposition, crowns and entire root
structures are in the transposed position. When
treating complete transposition, keep the transposed teeth in their transposed positions rather
than moving them into their normal positions.

KF: OK, getting down to the subject at hand: how
do you define what an impacted maxillary canine
actually is?

JP: CBCT can accurately identify and locate the
position of impacted canines. Using CBCT, we
can assess any damage to the roots of adjacent
teeth and determine the amount of bone surrounding each tooth. CBCT provides accurate
information about the IMC to surgeons and
orthodontists so they can properly manage
impacted canines surgically and orthodontically.

JP: An impacted maxillary canine can be defined
as the complete or partial un-eruption of a maxillary canine due to its position against adjacent
teeth, bone, or soft tissue.
KF: What other conditions or circumstances are
associated with IMCs?
JP: Baccetti reported that palatally impacted
maxillary canines are genetically associated with
anomalies such as enamel hypoplasia, infraocclusion of primary molars, aplasia of second
premolars, and small maxillary lateral incisors.1
Peck et al. stressed the high probability of additional dental abnormalities, such as congenital
tooth absence and delayed eruption, occurring in
combination with a palatally displaced canine.2
Becker reported an increase of 2.4 times in the
incidence of palatally impacted canines adjacent
to the sites of missing lateral incisors compared
with palatally impacted canines in the general
population. It remains uncertain, however,
whether an anomalous lateral incisor is a local
causal factor for palatally displaced canines or if
the displaced canines are the result of an associated genetic developmental influence.3
KF: Do you always bring IMCs into their intended
spaces?

KF: How has CBCT technology helped with IMC?

KF: As a student of the various techniques for
treating IMCs, do you support one technique as
being more effective than others? If so, please
share it with us.
JP: Many techniques have been used to move
impacted teeth into occlusion. Orthodontists prefer to create adequate space in the dental arch to
accommodate the impacted canine, and then
surgically expose the tooth, providing access to it
so that they can apply mechanical force to erupt
the tooth. Although various methods work, an
efficient way to erupt impacted canines is with
NiTi closed-coil springs with eyelets. Compared to
conventional elastic thread, NiTi coil springs do a
superior job of maintaining continuous force
between patient visits (Figure 1).4
KF: What is the earliest age at which one can
diagnose an IMC?
JP: Under normal circumstances, maxillary
canines usually erupt around 11 years of age;
however, impacted canines can be detected

PCSO Bulletin  Summer 2017

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Summer 2017