Download Intrusion of Overerupted Molars using Miniscrews

Case Report
Intrusion of Overerupted Molars using Miniscrews
and TMA Spring: A Case Report
Praveen Prakash1, Kuttapa Nishanth2, Nikul Jasani1, Aneesh Katyal1, US Krishna Nayak3
Post Graduate Student, Department of Orthodontics & Dentofacial Orthopaedics, A.B. Shetty Memorial Institute of Dental Sciences, Mangalore,
Karnataka, India, 2Professor, Department of Orthodontics & Dentofacial Orthopaedics, A.B. Shetty Memorial Institute of Dental Sciences, Mangalore,
Karnataka, India, 3Dean Academics, Head of Department, Department of Orthodontics & Dentofacial Orthopaedics, A.B. Shetty Memorial Institute of
Dental Sciences, Mangalore, Karnataka, India
1
Over eruption of posterior tooth due to the loss of antagonist teeth causes occlusal and functional disturbances. To restore proper occlusion,
intrusion of the overerupted tooth becomes essential before multidisciplinary reconstructive dental approaches can be initiated. Conventional
orthodontic techniques do not intrude posterior teeth effectively, and almost all methods result in anterior extrusion rather than posterior
intrusion. New absolute anchorages (miniscrews and miniplates) are said to make posterior tooth intrusion possible. This case report describes
the treatment of a patient with supra-erupted maxillary right and left first molars intruded with titanium molybdenum alloy spring and
miniscrew anchorage. The results showed that the biological responses of the teeth and the surrounding bony structures to the intrusion
appeared normal and acceptable. Periodontal health and vitality of the teeth were maintained throughout the treatment.
Keywords: Miniscrews, Molar intrusion, Titanium molybdenum alloy spring
INTRODUCTION
An early loss of any molar, is bound to cause supra-eruption
of opposing molar into that space. Overeruption of
such molar can lead to occlusal interference, functional
disturbances and cause great difficulty during prosthetic
reconstruction.1 To reconstruct the proper occlusion for
the posterior dentition and to maintain periodontal health,
an interdisciplinary and comprehensive dental treatment
is necessary. Correction of the overerupted molar is a first
and essential step before other procedures can be started.2
Procedures such as orthodontic intrusion, prosthodontic
reduction, and surgical impaction are required to deal with
this kind of problem.1
Prosthodontic reduction requires endodontic intervention
and crown restoration at the expense of tooth vitality,
whereas surgical impaction involves an aggressive
segmental operation.2 Restorative options for removing such
interference include coronal reduction of molar crown with
or without root canal therapy followed by crown placement.1
Hence, a plausible procedure is orthodontic intrusion, which
demands calibrated anchorage support from intraoral
multi-unit teeth and from extraoral headgear wear.2
Conventional orthodontic techniques for intrusion require
anchorage reinforcement by incorporating multiple
teeth which depend heavily on patient cooperation and
usually result in extrusion of other teeth rather than molar
intrusion. To overcome these problems, new methods
like skeletal anchorage system has become popular now.
Skeletal anchorage, including surgical miniplates and
miniscrews, is now growing because of its ability to
provide absolute anchorage. However, miniplates have
certain disadvantages like higher cost, limited area for
insertion, and the need for two separate insertion and
removal surgeries.1
The development of mini-implants in the last few years
has enabled efficient anchorage, requiring no tooth
support, with no aesthetic compromise and minimal
patient compliance. These devices have been used in the
orthodontic office with increasing frequency in cases where
an inadequate number of dental units stand in the way of
an effective anchorage, or even only to simplify orthodontic
mechanics and make it more predictable. Hence, absolute
anchorages with miniscrews was used to make molar
intrusion possible.3
Until date, the available literature for molar intrusion with
skeletal anchorage devices, especially miniscrews, shows
that teeth can be successfully intruded in variable rates
ranging from 1.2 mm in Carillo et al.’s study4 to 5 mm in
Umemori et al.’s study.5 Intrusion forces also ranged from
50 g in the former to 500 g in the la er. In some of these
studies, elastomeric materials were used for delivering
Corresponding Author:
Dr. US Krishna Nayak, Dean Academics, Head of Department, Department of Orthodontics & Dentofacial Orthopaedics, A.B. Shetty Memorial Institute
of Dental Sciences, Mangalore, Karnataka, India. E-mail: [email protected]
4
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Prakash, et al.: Miniscrew Assisted Molar Intrusion
intrusion forces, which may have several shortcomings like
rapid force degradation, hygienic problems, and need for
patient cooperation.1,3,5,6 Also, besides elastomeric materials,
NiTi coil springs4,7,8 used in some other studies lack the
ability to change force vector, which is sometimes needed
for controlling molar crown torque during intrusion, and
operators were obliged to use lingual or transpalatal arches
or brackets on multiple teeth for correcting crown torque.8-10
This case illustrates the solution of a complex dental and
functional problem with an interdisciplinary approach
through the use of orthodontic, periodontontal, restorative
and prosthodontic therapy. An adequate space is prepared
for the missing lower molars by intruding the overerupted
upper molar using titanium molybdenum alloy (TMA)
spring and mini-implants for skeletal anchorage.
length and 1.3 mm in diameter) with bracket-type head were
inserted: One in the mesiobuccal aspect and another in the
mesiopalatal aspect of the selected tooth. The procedure was
performed under local anaesthesia. The miniscrews were
placed in the a ached gingiva between the maxillary second
premolar and maxillary first permanent molar. The angle of
placement was between 30° and 45° to the occlusal plane.
The position ofthe miniscrews were documented with an
intraoral periapical. Post-operative antibiotics and analgesics
were given to the patient.
After a 2-week interval for soft tissue healing, band was
cemented on the tooth and the TMA (017” × 025”) springs
CASE REPORT
A 21-year-old female patient came to the Department of
Orthodontics with the chief complaint of forwardly placed
upper front teeth. She was mesocephalic and mesoprosopic
with a convex facial profile (Figure 1).
Diagnosis and etiology
This patient had a class II apical base relation with a vertical
growth pa ern. Intraoral examination revealed missing
lower first and second molars on both sides. She had a class II
canine relation on both sides with an overjet of 4 mm and an
overbite of 1 mm. The maxillary right and left first molars
were supra-erupted 3 mm occlusally, encroaching upon the
antagonistic missing dental space and leading to the occlusal
interference upon mastication. The maxillary right second
premolar and left first and second premolar were root canal
treated with a decayed crown (Figures 2 and 3).
Figure 1: Pre-treatment extraoral photographs
Treatment objectives
1. Intrude maxillary right and left first molars.
2. Reduce the upper and lower anterior proclination.
3. A ain an ideal overjet and overbite.
4. Achieve optimal facial balance and esthetics.
Treatment plan
• Extraction of 15 and 25.
• Intrusion of upper right and left first molars with
miniscrews and TMA spring.
• Leveling and alignment followed by space closure.
• Finishing and detailing.
• Prosthetic replacement of missing lower molars on both
sides.
Treatment progress
The patient was treated using pre-adjusted edgewise appliance
with 0.022 slot MBT prescription. Two miniscrews (8 mm in
IJSS Case Reports & Reviews | May-June 2014 | Vol 1 | Issue 1
Figure 2: Pre-treatment intraoral photographs
Figure 3: Pre-treatment orthopantamograph
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Prakash, et al.: Miniscrew Assisted Molar Intrusion
were fi ed into the slot on the miniscrew’s head and ligated
with molar tube. Other end of the spring was ligated to
the lingual sheath that was welded on the band. Glass
ionomer cement was placed on the head of palatal implant
to prevent irritation to the tongue. Patient was recalled every
4 weeks for spring adjustments and observation of treatment
progress (Figure 4).
RESULTS
The intrusion of the two molars were achieved by using a
combination of a mini-implant and TMA spring. The results
showed that the biological responses of the teeth and the
surrounding bony structures to the intrusion appeared
normal and acceptable. Periodontal health and vitality of
the teeth were maintained throughout the treatment. The
upper extraction spaces were closed and class I canine
relationship with a normal overjet and overbite was
a ained. After debonding, the patient was referred for
prosthetic replacement (Figures 5 and 6).
DISCUSSION
Figure 4: Intrusion of molars using miniscrews and titanium molybdenum alloy
spring
Figure 5: Post-intrusion
Loss of the mandibular first molar often results in overeruption
of the opposing teeth, resulting in occlusal interference,
functional disturbances, compromised periodontal health,
and increased complexity of restoring the edentulous space.6
Prior to the advent of orthodontic miniscrews, leveling of the
over erupted maxillary posterior teeth often entailed invasive
prosthodontic reduction with root canal treatment, surgical
impaction, or demanding orthodontic therapy requiring
extraoral headgear or full-arch braces.11-13
Intrusion by conventional methods usually is accompanied
by extrusion of the anchorage unit, based on the law of
action and reaction. Preventing this side effect is the key of
successful intrusion. In existing methods, many brackets
have to be bonded or an extraoral appliance designed in
order to reinforce the anchorage unit. However, despite
these efforts, efficient intrusion of molars is still difficult to
accomplish.1 To overcome these problems new methods
like skeletal anchorage system has become popular now.
Skeletal anchorage including, miniplates, and miniscrews,
is now gaining popularity because of its ability to provide
absolute anchorage.14-16 However, miniplates have certain
disadvantages like higher cost, limited area for insertion, and
the need for two separate insertion and removal surgeries.17,18
The development of mini-implants in the last few years has
enabled efficient anchorage, requiring no tooth support and
with no aesthetic compromise whatsoever, with minimal
patient compliance is required. These devices have been
used in the orthodontic office with increasing frequency in
cases where an inadequate number of dental units stand in
6
Figure 6: Post-treatment intraoral photographs
the way of an effective anchorage, or even only to simplify
orthodontic mechanics and make it more predictable.
Hence, absolute anchorage with miniscrews was used to
make molar intrusion possible.19-22
We used a new, simple approach for molar intrusion with a
0.017 × 0.025-in TMA spring and bracket-type miniscrews,
which had some advantages over other methods for
posterior intrusion using miniscrews including:
• Lighter and more continuous force in contrast to
elastomeric materials used for force delivery used in
some studies.3,5,6
• Excellent control of force vector by altering the horizontal
extension of the occlusal arm of the spring.1
• Perfect control of the labiolingual position of the
tooth during intrusion by altering the force in buccal
IJSS Case Reports & Reviews | May-June 2014 | Vol 1 | Issue 1
Prakash, et al.: Miniscrew Assisted Molar Intrusion
Figure 7: Post-treatment extraoral photographs
or palatal springs, in contrast to others that are
obliged to use extra devices like TPA, lingual arches,
or conventional fixed appliances to control tooth
buccolingual position.5,9,23 Active intrusion was carried
on for a period of 5 months.
• Even though lots of benefits of technique we found
some difficulty in ligating spring into the bracket head
implants, which caused religating of spring again.
REFERENCES
1.
2.
3.
To avoid root resorption, intrusive force levels should be
kept optimal. Although an optimal force has not yet been
suggested for intrusion with miniscrews, forces greater than
what is generally accepted for intrusion in conventional
treatments are reported to be applied with miniscrews
and miniplates.24 The amount of force used in other studies
were; Yao et al.6 used 150-200 g of force, Xun et al.10 used 150
g of force, Park et al.25 used 100 g of force. We have used
approximately 100 g force (50 g per miniscrew) to intrude
the molar on both sides.
4.
5.
6.
7.
In this report, we have demonstrated a simplified version of
combining mini-screws with a TMA spring to intrude the
maxillary first molars on both sides. Most importantly, the
molar responded well to the intrusive forces throughout
treatment, no root resorption was detected during follow-up
and the vitality of the teeth was sustained after 6 months
follow-up. The coordination of different specialties allowed
us to gain optimal results in a shorter treatment time
(Figure 7).
8.
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11.
CONCLUSION
The case presented in this article demonstrates the intrusion
of overerupted maxillary right and left first molars using
TMA spring and mini-screws for skeletal anchorage.
The favourable result obtained shows that the intrusion
procedure is an acceptable treatment option for extruded
molars that can be preferred instead of prosthodontic
reduction or the extractionof the extruded tooth.
IJSS Case Reports & Reviews | May-June 2014 | Vol 1 | Issue 1
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How to cite this article: Prakash P, Nishanth K, Jasani N, Katyal A,
Nayak USK. Intrusion of overerupted molars using miniscrews and TMA
spring: A case report. IJSS Case Reports & Reviews 2014;1(1):4-8.
Source of Support: Nil, Conflict of Interest: None declared.
IJSS Case Reports & Reviews | May-June 2014 | Vol 1 | Issue 1