Newsletter - December 2021

Temporary anchorage devices:
a paradigm shift
SARA HOSNI
Sara is an associate specialist orthodontist at Northenden House Orthodontics and a consultant at Salford
Royal NHS Foundation Trust and Glan Clwyd Hospital. She qualified at the University of Newcastle and
following a variety of hospital posts, Sara undertook her orthodontic specialist training at the University of
Liverpool. In 2015, Sara gained her doctorate of dental sciences degree at Liverpool University.
Although temporary anchorage devices (TADs) have
been available for clinical use for at least a couple of
decades now, it’s fair to say that they are not yet
being utilised to their full potential. We are well
versed in the theoretical workings of TADs or, more
specifically, miniscrews, but how often are we using
them as realistic alternatives in otherwise complex
cases?
Every now and then, a case comes along
that challenges our well-rehearsed rhythm of the
usual treatment mechanics and acts as a paradigm
shift in how we practise clinical orthodontics. So,
what exactly are TADs, and why are more and more
people raving about them?
Temporary Anchorage Devices
TADs are used for skeletal anchorage and are
inserted into the bone to enhance orthodontic
anchorage (Chen et al, 2006), either by supporting
the anchor teeth (indirect anchorage) or by acting
as anchor units in their own right (direct anchorage),
eliminating the need for supporting teeth (Mizrahi
and Mizrahi, 2007). They are removed once their
function has been completed. They have many
advantages, which have been summarised in Table
1. The risks associated with TADs are well documented
(Table 2); however, with appropriate training
and diligence in case planning, most of these can be
avoided.
There are several indications and
contraindications for the use of TADs, which are
summarised in Table 3, as good case selection is
key to achieving the intended outcome in a
predictable manner. Impressive success rates for
TADs, ranging from 76% to 96%, have been reported
in the literature (Bearn and Alharbi, 2015; Son
et al, 2014). It has been shown that success rates
are directly correlated with various factors, including
age, site of placement and miniscrew diameter (Lee
et al, 2010).
Case Study
Figures 1 to 11 demonstrate a case where Infinitas
TADs were used to provide both direct and indirect
anchorage for the treatment of an anterior open bite
and class 2 malocclusion.
The alternative treatment option was a
combination of orthodontics and orthognathic
surgery, which the patient was not keen on. The
plan was for the TADs to be placed palatally and
‘locked’ to the transpalatal arch in order to provide
indirect anchorage for correction of the buccal
segment relationship after extraction of the upper
first premolars. They would then be used for direct
anchorage for the intrusion of the upper buccal
segments, thereby correcting the anterior open bite.
The patient was compliant, the TADs
survived the treatment duration, and in the end, we
had one delighted patient who didn’t need
orthognathic surgery. So, should we be offering this
to all anterior open bite patients? Case selection is
fundamental to achieving a successful outcome, so
undoubtedly, there will always be cases that will still
require a surgical approach. However, for a
number of patients, the use of TADs can mean
avoiding orthognathic surgery and the risks that
come with it.
Being critical of the finish, despite
undertaking lower arch extractions,the patient still
had some gingival recession of the lower left central
incisor. A gingival graft was discussed to address
the recession of the lower left central incisor.
Summary
In summary, TADs provide an alternative to
conventional mechanics for anchorage control, and
there is increasing interest in their use. Outcomes
that would otherwise require orthognathic surgery or
would not be possible may be achieved using TADs
in combination with orthodontics.
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