Download Accelerated Orthodontic Tooth Movement Clear-Aligner

feature \\ case presentation
Accelerated Orthodontic
Tooth Movement
with
Clear-Aligner Therapy
Introduction
Edmund Khoo, BDSc (hons), ABO, FICD
Contributing Authors:
Anderson T. Huang • Joana Forsea
Darren Huang • Tommy Ng
Alejandro J. Lopez • Jung S. Moon
Ki Y. Kil • Sami Affes
Tatiya Ungphakorn • Daniel Rozen
Rebecca Poling
Tom S. Lien
The trend of adults seeking orthodontic treatment has been on the rise. Indeed, adults
have become a significant population of the total orthodontic patient pool.1
The use of conventional metal braces is trialed and tested to be efficient and effective
in orthodontic treatment. However, social concerns have led to the development of more
esthetic options for orthodontic tooth movement. The use of clear-aligner therapy in
particular has become increasingly popular with the adult orthodontic patient population.
As with most modalities of treatment, clear-aligner therapy when combined with sound
case selection, diagnosis and treatment planning has been shown to be an effective
alternative to conventional braces.2
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case presentation // feature
Fig 1a (top): MOPs being performed on Patient A
Fig 2a (center and bottom): Patient A – Initial intraoral photographs
Regardless of which modality of orthodontic treatment is
selected, the movement of teeth is a biological process and has
been shown to be limited by biological mechanisms. There is a
biological saturation point at which the rate of tooth movement
will hit a plateau, and applying additional force will have no
additional effect on moving teeth faster.3 Researchers from the
Consortium for Translational Orthodontic Research (CTOR) at
New York University College of Dentistry have applied the same
biological principles activated during fracture healing and have
developed a technique to increase the rate of tooth movement by
up to 2.3-fold, with the possibility of treatment durations by up to
62 percent.3-5, 9, 10 Utilizing these advantages inherent to the bonerepair mechanism, this technique to accelerate tooth movement is
called micro-osteoperforations (MOPs).
When MOPs are performed, small holes are created in the
alveolar bone adjacent to the teeth that need to be moved, under
local anesthesia, without the need for raising a tissue flap. This
technique has shown to be a reliable and minimally invasive
method of increasing the rate of orthodontic tooth movement.9,10
The advantages of combining clear-aligner therapy and MOPs are
self-evident; they give us the double advantage of both esthetics
and reduced treatment duration times.
Clinical procedure
Fig 2b: Patient A – Initial panoramic radiograph
Fig 3: Patient A after MOPs during her subsequent aligner visit
Fig 4b: Patient A – Final panoramic radiograph
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In the case series of three patients discussed here, we utilized MOPs to enhance the rate of tooth movement. The MOP
device used was a version of Propel (osteoperforation instrument
developed by AlveoLogic in collaboration with NYU). The clearaligner system used was Invisalign by Align Technology.
The clinical procedure is as follows:
1. Obtain an up-to-date panoramic radiograph or periapical
radiograph of the region of interest.
2. Apply infiltrative local anesthesia.
3. Verify the regions of tooth movement with the tooth movement prediction software (Clincheck by Align Technology).
4. Manually perform the MOPs (Fig. 1. Clinical photographs
of MOPs being performed on Patient A).
5. Place about two to three MOPs proximal to the teeth/tooth
to be moved.
6. Prescribe a non-anti-inflammatory analgesic such as
acetaminophen or paracetamol (Tylenol).
7. Evaluate the patient every four to six weeks and repeat the
procedure, if necessary.
Fig 4a: Patient A – Final intraoral photographs
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Case series of three patients
Patient A
A 25-year-old female patient presented with a Class I crowding
malocclusion. Her diagnosis revealed 5mm and 8mm of crowding
on the maxillary and mandibular arches, respectively. Multiple
teeth also had rotations of more than 30 degrees (Fig. 2a) and the
initial panoramic radiograph (Fig. 2b) showed that some of the
roots required improved parallelism. Her treatment plan consisted
of using clear-aligner therapy (full Invisalign) with a total of 18
aligners for completion, the crowding was alleviated primarily by
IPR and secondarily by expansion and proclination.
On a traditional protocol, the aligners would be changed
every two to 2.5 weeks, resulting in total treatment duration of
36-45 weeks. We performed MOPs during her initial aligner visit
and subsequently every six to eight weeks until completion (Fig.
3). The accelerated protocol prescribed was to change the aligners
every 10 days, resulting in total treatment duration of approximately 26 weeks, a reduction of treatment duration of up to 42
percent. The patient was satisfied with the final outcome (Fig. 4a),
and the final panoramic radiograph (Fig. 4b) exhibited improved
root parallelism. No bone loss was evident, either.
Fig 5a: Patient B – Initial intraoral photographs
Fig 5b: Patient B – Initial panoramic radiograph
Patient B
A 29-year-old female patient presented with a Class I spacing
malocclusion. Her diagnosis revealed 3mm and 5mm of spacing
on the maxillary and mandibular arches, respectively (Fig. 5a). Her
initial panoramic radiograph exhibited satisfactory root parallelism
(Fig 5b). Her treatment plan consisted of using clear-aligner therapy (Invisalign Express) with a total of 10 aligners for completion.
Due to a limited number of aligners, the movements per
aligner were increased by 50 percent compared to the traditional
protocol. With this increase in movements the aligners would
typically be changed every three weeks, resulting in a treatment
duration of 30 weeks. We performed MOPs during her initial
aligner visit and subsequently every six to eight weeks until
completion. The accelerated protocol prescribed was to change
the aligners every eight days, resulting in a treatment duration
of 12 weeks and a reduction of treatment duration of 60 percent.
The patient was satisfied with the final outcome (Fig. 6a), and
the final panoramic radiograph (Fig. 6b) still exhibited good root
parallelism and bodily movement after space closure; no bone loss
was evident, either.
Fig 6a: Patient B – Final intraoral photographs
Fig 6b: Patient B – Final panoramic radiograph
Regardless of which modality of orthodontic treatment is selected, the movement of teeth is
a biological process and has been shown to be limited by biological mechanisms. There is a
biological saturation point at which the rate of tooth movement will hit a plateau, and applying
additional force will have no additional effect on moving teeth faster.
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case presentation // feature
Patient C
Fig 7a: Patient C – Initial intraoral photographs
Fig 7b: Patient C – Initial panoramic radiograph
A 62-year-old male patient presented with a Class I malocclusion.
His diagnosis revealed a midline diastema on the maxillary arch of
5mm at the gingival margin and 5mm of lower incisor crowding (Fig.
7a). His initial panoramic radiograph exhibited mild misalignments
in root parallelism (Fig. 7b). His treatment plan consisted of using
clear-aligner therapy (full Invisalign) with a total of 31 initial and 10
refinement aligners for completion, following traditional protocols
for aligner change of two to 2.5 weeks per aligner. This would result
in treatment duration of 82 to 102.5 weeks.
As the patient wanted the maxillary diastema closed, we
decided to extract the lower right central incisor and perform
enamel recontouring as needed. We performed MOPs during his
initial aligner visit and subsequently every six to eight weeks until
completion. The accelerated protocol prescribed was to change
the aligners every eight days, resulting in a treatment duration of
46 weeks—a reduction of treatment duration by up to 55 percent.
The patient was very satisfied with the final outcome (Fig. 8a), and
the final panoramic radiograph (Fig. 8b) exhibited improved root
parallelism. No additional bone loss was evident, either.
This technique has shown to be a reliable and minimally invasive method of increasing the rate
of orthodontic tooth movement. The advantages of combining clear-aligner therapy and MOPs
are self-evident; they give us the double advantage of both esthetics and reduced treatmentduration times.
Contraindications to using MOPs
These guidelines are definitely not prescriptive or exhaustive
and it is always prudent for the clinician to consult the patient’s
physician before performing any MOPs:
• Patients with bleeding or immune disorders
• Patients who require prophylactic antibiotics
• Patients who have had previous radiotherapy of the mandible
• Patients who are taking anti-inflammatory medications10
Fig 8a: Patient C – Final intraoral photographs
Fig 8b: Patient C – Final panoramic radiograph
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Discussion and conclusion
From the above case series of three patients, it clearly shows
that in conjunction with MOPs, clear-aligner therapy is able to
deliver clinically acceptable results with marked reductions in
total treatment-duration times. The patients above described
only mild discomfort and gingival inflammation the day after
the procedure, while bleeding on the day of the procedure was
minimal and hemostasis was easily achieved. The effectiveness
and efficacy of MOPs with clear-aligner therapy may be
considered a viable treatment modality for accelerated esthetic
orthodontic treatment. n
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References
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What is your experience with clear-aligner therapy? Comment on this article at Orthotown.com/magazine.aspx.
Author Bio
Dr. Edmund Khoo is an orthodontist certified with the American Board of Orthodontics. He teaches orthodontics and dentofacial orthopedics
full-time at his alma mater, New York University. Dr. Khoo has been published in several journals and has been invited to chair numerous scientific sessions. His awards and achievements include the American Association of Orthodontists Charley Schultz Scholar Award; Academy of
Distinguished Educators Faculty Award; and the Faculty Council Teaching Recognition Award. He is the current chair-elect for the American Dental Education Association (ADEA) Section on Orthodontics and is a founding member of the Consortium for Translational Orthodontic Research
(CTOR). He holds multiple positions at NYU and is heavily involved in the board-certification training program for his residents. His professional interests are
accelerated tooth movement, evidence-based orthodontics and biomechanics, and mechanotherapy.
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