The Inman Aligner:
An effective tool for minimally
invasive cosmetic dentistry - Part 1
By Dr Tif Qureshi
Traditionally, cosmetic dentistry has always
been faced with the challenge of treating
poorly aligned teeth. Treatment options available
for mildly and moderately crowded teeth
include orthodontics and restorative dentistry.
Many patients have chosen the restorative
approach, for example porcelain veneers, over
orthodontic techniques because of longer treatment
times combined with either unsightly labial wires
and brackets or the expense of ‘invisible’ braces.
In cases in which patients choose to have
crowded upper and lower anterior teeth treated with
veneers, it is extremely challenging to prepare teeth
conservatively, owing to their anatomy and the
minimum thickness of porcelain required. A difficult
balance has to be found between overpreparing
the teeth and placing over-contoured restorations.
However, owing to the excitement and emotion created
by the effect of popular large smile makeovers,
aggressive tooth preparations, in which teeth are
prepared to stumps, seem to have been accepted as
normal practice, simply because there has been no
alternative that could achieve the patient’s objectives
in a sufficiently short period.
InmanAligners are now offering aminimally invasive
alternative to patients inAustralia.With only one
appliance, most Aligner cases can be completed in
six to 16 weeks. In anterior crowding cases, Inman
Aligners have proven to be much more time- and
cost-effective than invisible braces or conventional
fixed and short-term orthodontics. To date, I have
treated about 1,000 cases and have found that case
acceptance has been close to 100%, simply because
many patients much prefer a removable solution that
fits their lifestyle more easily. Treatment can also
easily be combined with simultaneous bleaching and
final edge-bonding for dramatic, quick and non-invasive
results. From this, a new procedure has arisen in
cosmetic dentistry - alignment, bleaching, bonding -
which will be covered in the second part of this
series. The cases presented in this article will outline
some case types that can be treated.
The Inman Aligner
For over 30 years, spring aligners were used to correct
minor tooth movements. Early designs were
developed for minor tooth movements and to treat
slight rotations. Previous spring aligners were useful, but several problems always limited the amount of tooth
movement achievable. Their active components were made from
stainless-steel wire, which is relatively inflexible and lacks any
innate springiness. As a result, traditional removable appliances
required periodic reactivation, leading to short-lived force application
that limited the speed of tooth movement, owing to the
need to allow the bone around the roots of the teeth being moved
to ‘rest’ between successive activations. In addition, the direction
of force application with traditional springs was less easy to control,
leading to a mousetrap-like force that tended to unseat the
appliance. These factors limited the degree of correction that
could be accomplished. For larger movements, single appliances
were insufficient to complete the movement.
In developing the Inman Aligner, Donal Inman, CDT created a
patented design that takes advantage of the gentle, steady and consistent
forces generated by NiTi. The design relies on piston-like
components driven by NiTi coil springs. Inman designed lingual
and labial components to function or move in parallel to the
occlusal plane, eliminating the mousetrap-like unseating forces
and allowing actual physiological movement of teeth. Inman
Aligners are ideally worn for 16 to 20 hours a day. Studies have
demonstrated that the removal of orthodontic forces for four hours
a day massively reduces the risk of root resorption1 and that risk of
root resorption is lower in removable versus fixed appliances.2
A standard Inman Aligner as described in the following cases
consists of both lingual and labial components. The forces have
the effect of squeezing the teeth into alignment. The components
can be used in isolation to retract teeth with a more steady force,
requiring less adjustment than a standard labial bow retractor. In
Case III, a unique approach that incorporates an expander on the
Inman Aligner is described.
Patient selection
Case selection for the Inman Aligner is critical. The following criteria
should be met before treatment proceeds:
1. Cases should require movement of incisor and/or canine
teeth only.
2. Root formation of the teeth to be moved must be complete.
3. Crowding or spacing should be less than or equal to 3mm. Arch
evaluation must be performed to determine the amount of space
required. Cases with over 3mm of crowding require additional
space creation techniques which should only be attempted with
training. It is quite possible to treat cases with 5.5mm crowding
easily and predictably in less than 16 weeks.
4. Cases should have fully erupted posterior teeth to facilitate
retentive clasps, with a reasonably well-aligned arch form to
facilitate the path of insertion of the appliance.
5. Cases should be stable and preferably periodontal disease free.
6. Patients must agree to wear the Aligner for about 20 hours a
day and be responsible for good appliance and oral hygiene.
Should the patient wear the Aligner for 14 hours a day only,
treatment will still be successful.
Model evaluation/arch analysis with Spacewize
Arch analysis should be performed before any Aligner case is
attempted in order to ensure that the case is suitable and, if not,
what additional space creation techniques will be needed to allow
the Inman Aligner to work. The extent of crowding present is calculated3
bymeasuring the sumof themesial-distalwidths of the teeth
to bemoved.This distance is called the required space. If canines and
incisors are to be moved, this distance will be measured from the
distal surface of one canine to the distal surface of the other canine.
Using an orthodontic retaining or jeweller’s chain or a polishing
strip, the ideal arch form is then measured from the distal
of each canine in alignment with the ideal arch form following
orthodontic correction. Critically, the arch needs to pass through
the suggested position of the contact points and not the incisal
edges. This is described as the available space or the curve.
It is possible to perform this task more quickly and just as accurately
with software such as Spacewize. Just one simple occlusal
photograph is required, which can be taken chairside. One tooth
needs to be measured for calibration. A curve can be digitally
established and the extent of crowding is immediately calculated
using such software.
Laboratory requirements
Accurate upper and lower impressions are taken, preferably two of
the arch being treated. Simple alginate can be used if cast quickly.
A bite registration and prescription should be completed and sent to
a certified Inman Aligner Laboratory. The technician should be
informed of the amount of crowding calculated. The teeth to be
repositioned should be noted clearly. The prescription should provide
full details to the technician regarding the teeth to be moved,
the area they are to be moved to and the distance they are to be
moved.A Spacewize trace of the ideal curve can also be submitted.
Interproximal reduction
Interproximal reduction (IPR) is begun at the fitting appointment
using abrasive strips or discs. The model analysis will have
already calculated the extent of IPR required.
Many authors acknowledge that the reduction of half of the
interproximal enamel on the mesial and distal of each incisor
tooth is a safe technique.4-7 This equates to 0.5mm per contact
point, creating 2.5mm of space between the canines. In some
cases, the distal of the canine and mesial of the premolar can be
reproximated allowing for a total of 3.5 to 4.5mm. These cases
will require more experience in using the system but offer a
number of possibilities for clinicians once trained to use the
system correctly.
Meticulous records of the amount of stripping performed
should be kept. An in-surgery fluoride rinse or application of topical
fluoride is recommended after any enamel reduction
procedure. El-Mangoury et al8 and Radlanski9 have demonstrated
that there is no increased risk of caries after IPR, provided surfaces
are smoothed correctly. Heins et al10 and Tal11 have
demonstrated that there is no increased risk of periodontal disease,
despite the decreased interproximal space.
Critically, Inman Aligner treatment uses progressive, anatomically
respectful IPR. While the extent of IPR required is already
known, it is never carried out in one treatment. In order to ensure
minimal risk, IPR (0.13mm per visit per contact point) is carried
out only in small increments. The patient is sent away with the
Aligner. Owing to the Aligner forces, the gaps will be closed after
two weeks. Interproximal reduction is performed at each appointment
only as needed, using strips or discs, which ensures the
stripping is far more anatomically conservative than would be the
case using burs. This significantly reduces the risk of excess
space formation, gouging or poor contact anatomy.
Lingual/labial anchors
Composite resin placed just incisally either incisal or gingival to
where the bows contact will help them to function more efficiently.
This can also be used for the labial surface, especially in
cases in which teeth are being retracted. Strategic placement is
vital for success and can be very helpful in the treatment of
rotated teeth and the extrusion of teeth.
Appliance adjustment
The forces can be varied by adjusting the spring components or
replacing springs. Generally, adjustments are not necessary,
except in more complex cases, for which training is required to
understand the correct spring types and compression rates to use.
Case I
The 25-year-old female patient complained about the appearance
of her lower anterior teeth. She gave a history of orthodontics in
her teenage years, having a fixed appliance fitted for a period of two
years. She had been given a retainer at the time but was told to wear it
at night for 3 months only. She had noticed her lower four incisors
starting to become crowded again. Treatment options discussed were
invisible braces, conventional fixed brackets or an Inman Aligner.
The amount of space required for reduction was calculated as
3.5mm. Interproximal reduction was performed using diamond
strips (Brasseler). A reduction of 0.13mm at each contact point
was achieved at the fitting appointment. This was verified with a
thickness gauge. The patient was seen three weeks later and a further
0.13mm reduced at each contact point. The teeth were
aligned in just over nine weeks. The Aligner was left in for one
month to stabilise the tooth positions. Tooth whitening was undertaken
for two weeks during the last two weeks of treatment.
Simultaneous bleaching is a significant advantage in removable
systems and helps patient motivation. Finally, an orthodontic
retention wire was bonded in place on the lingual surfaces,
ensuring the patient could still use super floss for hygiene.
Case II
A female patient presented complaining mainly about her rotated
upper right central tooth. She was considering veneers to redistribute
the space over the four front teeth. This would have meant that she
would undergo three aggressive preparations and one invasive preparation
with endodontic treatment of the upper right central tooth.
Space calculation with model analysis indicated that treatment
would be possible with an Inman Aligner. Because of the relatively
low cost, the patient selected this option, understanding that
we would not be able to achieve Golden Proportion, owing to the
width and length of her lateral teeth. A midline screw was incorporated
to allow for a small amount of operator-controlled
expansion to provide a little more space. (Incorporated expanders
can be used to release extra space in cases with very constrained
space.) Up to 2mm of space can be created by expansion, which
has the effect of pushing the cuspid away from the lateral. After
alignment, this expansion will just relapse. It is a temporary technique
to create sufficient space to align the anterior teeth. After
alignment, the expander can even be unwound if required.
Treatment took 13 weeks with three sessions of IPR. A total of
3mm was stripped and 1mm was gained with the expander. The
teeth were retained using orthodontic gold chain bonded from
canine to canine. An upper Essix Retainer was also worn nightly
as back-up for retention.
Case III
The patient in this case originally presented for porcelain veneers
on her upper anterior teeth. The preparations would have required
root-canal treatment of two of her incisors in order to achieve
adequate emergence profiles.
After case options had been discussed in detail, the patient
decided upon an Inman Aligner to align the teeth with
veneers following this treatment. The patient was aware that after
alignment, retention would be mandatory. Spacewize arch
analysis calculated only 0.8mm crowding in deviation from the
ideal curve.
An upper Inman Aligner with combined expander was fabricated
and fitted. Minimal IPR was carried out with a 0.1mm
reproximation strip to separate the teeth. The patient turned the
screw every five days for six weeks, which created nearly 2mm of
space. This allowed space for the centrals to advance and derotate.
At this point, the expander was unwound to ensure that any
mild residual spacing had closed. The teeth were aligned within
nine weeks. An Essix Retainer was used to retain the teeth passively
for a further four weeks, after which a bonded wire retainer
was placed.
The patient was very pleased with the alignment and decided
that she would not need veneers. Veneers could always be used at
a later stage if necessary, after more enamel has eroded with age
and when veneers can be placed additively, for example.
The result was not a perfect smile with regard to the criteria
defined by Smile Design theory. Yet, that she no longer wanted
veneers arguably provides us with a far better and more ethical
outcome long term.
Retention
Retention for anterior alignment is essential.12-14 Recommended
retainer types are bonded canine-to-canine fixed retainers commonly
fabricated from .0195” or .0175” multi-strand
stainless-steel wire. An indirect method can be used to adapt the
wire to a working model. This can then be transferred to the teeth,
using a specially made jig and bonded with flowable composite
resin to the backs of the aligned teeth. The occlusion must be
clear when placing a retainer on the maxillary arch.
Advantages of this method are that the flexibility of the arch
wire allows for physiological tooth movement and prevents bond
fracture through occlusal forces. Periodontal ligament stability is
also achieved with this technique.15
Essix Retainer
This retainer is a thermo-formed, clear, thin appliance that is easily
made and very comfortable for patients.The recommended post-operative
regimen for Inman Aligner treatment is to wear the retainer
at night for 18 months and after that for 2 nights a week indefinitely.
Conclusion
With the Inman Aligner, patients previously put off by the treatment
time and fixed brackets of traditional orthodontic techniques
or the expense of more recent invisible braces, could, if their case
is suitable, achieve anterior tooth alignment far more quickly with
a simpler, single appliance. Inman Aligners are suitable for alignment
of incisors and canines with up to 3mm of crowding -
5.5mm once the treating clinician is trained in using the system -
and represent a very conservative and potentially revolutionary
alternative to radical tooth preparation for achieving tooth alignment
using porcelain restorations.
The InmanAligner allows for a rapid and aesthetic alignment at low
risk and cost to our patients. The patient is able to previewthe staged
changes of alignment, perhaps followed by bleaching and bonding.
As a result, the Inman Aligner is profoundly changing the
approach to cosmetic dentistry by those using it with the
advanced techniques of domino effect, combined expansion and
strategic anchor placement in the UK and Europe.
This new approach to cosmetic dentistry in the UK has been
confirmed by figures from the British Academy of Cosmetic Dentistry
(BACD). The 2008 study of data from 200 BACD members
demonstrated a massive 345% increase in ortho dontics used in
cosmetic cases but no increase in the use of veneers. Of this
increase, 230% was solely due the use of the Inman Aligner in
cases in which patients would not otherwise have had their teeth
treated, owing to the time cost of fixed braces and no desire to
have appliances adhered to their teeth. Many of these patients
were those who would have opted for aggressive preparation of
their teeth for veneers, before the Inman Aligner.
References
A full list of references related to this article is included in the
online version or can be supplied on request.
About the author
Dr Tif Qureshi is vice president of the British Academy of
Cosmetic Dentistry.
Australasian Dental Practice November/December 2010
clinical | EXCELLENCE
