The document discusses advances in lingual orthodontics, specifically focusing on the development of specialized brackets and techniques for better positioning and measurement. It highlights the aesthetic and functional advantages of using lingual braces over traditional labial braces, while also addressing the challenges such as speech interference and adaptation difficulties. Notable innovations include the introduction of the Torque Angulation Device (TAD) and Bracket Placement Device (BPD) to improve accuracy in bracket placement and treatment outcomes.

1. orthodontic | TECHNIQUES
Lab procedures for
lingual orthodontics - Part 1
By Terry Whitty
ost of us are surely familiar with Ortho-
M dontic braces. They’ve been around for a
long time, in fact since the late 1800’s.
We’ve either had the experience as a patient or
know someone who has. Simply put, they are com-
prised of brackets and/or bands bonded to the teeth
with an archwire interconnecting these brackets to
move the teeth in three dimensions. They are very
efficient but in today’s fashion conscious world, for
“These some, they are just plain ugly, especially for adults.
There are alternatives to standard metal labial
days, there Figure 1. Standard labial-bonded brackets (braces).
bonded braces and these include clear ceramic or
are many plastic brackets or a series of invisible aligners such
different types as Tru-Line™, but these articles will focus on the
of lingual development of and some of the laboratory proce-
brackets on dures of lingual orthodontics.
Lingual orthodontics is exactly as the name sug-
the market
gests - orthodontic brackets placed on the lingual
but the surfaces of the teeth and connected by special arch-
positioning of wires. The advantages aesthetically are immediately
these brackets evident, but other advantages include the labial
in relation enamel is not etched, bonded or scarred during
debonding. Braces do not have to be removed early
to the teeth Figure 2. Ceramic brackets (braces).
for social events and people with highly visible social
is really jobs can still continue without embarrassment.
the critical The disadvantages of lingual Orthodontics
factor common include speech interference and patient adaptation
to all...” is not always predictable. Tongue irritation is
common and patients with narrow arches or tongue
thrust may not adapt well. The technique is clini-
cally more time consuming and patients tend to be
more demanding. Some traditional labial
mechanics cannot be used due to the smaller inter-
bracket distances and smaller arch radius. Delving
into the details of most of this is beyond the scope
of the article but suffice to say there are differences
between the two modalities.
The lingual bracket had to be specifically
designed for the lingual surface of the teeth and a Figure 3. Lingual braces.
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2. orthodontic | TECHNIQUES
Figure 4. The original TARG Figure 5. TARG with Dial Figure 6. Various bracket placement-measuring devices.
with wooden base. Test Indicator.
Figure 7. The lingual bracket jig.
method of positioning these brackets had Over the years, various improvements to
to be invented as direct bonding of lingual the TARG device were made. Adding thick-
brackets is virtually impossible, hence an ness compensation and height determination
indirect method had to be developed. in a digital measuring environment were
These days, there are many different some of the advances.
types of lingual brackets on the market but In 1997, a new TARG Professional by Dr
the positioning of these brackets in rela- Weichmann from Germany - the Transfer Figure 8. Later from Korea came the Mini
tion to the teeth is really the critical factor Optimised Positioning System (TOPS) was TARG which was almost impossible to
common to all. So the real trick to get lin- released, but still used the Torque blades of use, lacking in precision and ease of use.
gual orthodontics to work in the real world the TARG. He also invented the first
was to devise a method so the brackets CAD/CAM Incognito system, which uses The laboratory uses it in the opposite
could be placed onto the tooth with the customized gold brackets. Various other way by pre-setting the angulation and
correct torque and angulation in relation inventions were introduced over the years torque then orientating the survey base to
to the tooth already determined. This is but none with significant merit. the best fit, thus giving a reference to
much easier to do with labial braces but a In 2004, a real breakthrough in lingual transfer the work over and allow correct
real challenge for lingual braces. orthodontics arrived. The Torque Angula- bracket placement. The invention of the
Lingual braces were invented in the tion Device (TAD) prototype was first TAD finally provided the orthodontist
1970’s when a Playboy model wanted to introduced. This device was unique as it had with the tools to accurately measure
know if she could have some type of the ability to survey and measure the torque existing torque and angulation on models
“invisible” orthodontic treament so she and angulation of individual teeth in a dif- of mal-occluded teeth. After the
could keep working. The first attempts ferent way than previous devices and with prototype TAD was finished, intensive
were crude but lead to more interest in lin- great accuracy. With the prepared study lab work was carried out testing and
gual orthodontics. In 1984, the Ormco model in position, the surveyor base is set to cross-referencing with the old TARG to
company devised the TARG (Torque horizontal and then the TAD is adjusted to find the differences in Angulation and
Angulation Reference Guide) device for give the best fit for angulation and torque. Torque given. The Torque differences
more precise bracket positioning, espe- The operator thereby receives precise dig- were significant, leading the researchers
cially for the lingual technique. The first ital measurement data for the mal-occluded to believe the old TARG had an
of these machines had a wooden base teeth in the mouth so that you can make a inaccuracy of + or - 3 degrees! Again the
which proved to impede precision. suitable prescription for treatment. inventors concentrated one ease-of-use
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3. orthodontic | TECHNIQUES
Figure 9. The prototype TAD. Figure 10. Measuring torque and angulation. Figure 11. TAD Device with key elements
explained.
Figure 12. Production TAD. Figure 13. Bracket Placement Device (BPD). Figure 14. Bracket Placement Device key
- elements explained.
maintenance. Increased accuracy in con-
trolled bracket placement allows the
operator to work faster and smarter. After
the model is measured with the TAD,
these measurements are transferred to the
BPD and the brackets are placed onto the
model before a custom tray is fabricated.
This process will be fully detailed in part 2
of this article.
Acknowledgement
The author wishes to thank Peter Sheffield
from Hexa Ceram Dental Laboratory for
his assistance with tis article.
About the author
Terry Whitty is the technical editor of
eLABORATE and also runs a successful
Figure 15. Brackets are accurately placed on the model using the TAD and BPD. orthodontic laboratory in Sydney’s
eastern suburbs where he produces inno-
and speed for the technician. The accu- To make bracket placement easy, the vative appliances using the latest
racy was already there. In 2006, the first Bracket Placement Device BPD was techniques and technologies including
production TAD is finished and the world devised and is used in conjunction with laser welding. He has also lectured
had the first digital TARG accurate the TAD. It is reliable, strong, compact throughout Australia and New Zealand on
to 0.1 degrees! and easy to use, as well as being very low a variety of subjects.
26 eLABORATE November/December 2007