Download Twin Block: A Compliant Class

Volume 2 Issue 1
February 2011
Twin Block
Short communication
Twin Block: A Compliant Class- II Corrector
Dr.Dinesh M.R*, Dr.Dharma R.M**, Dr.Prashanth C.S**, Dr.Amarnath B.C**
*Vice-Principal and H.O.D,
**
Professor, Dept of Orthodontics, D.A.P.M.R.V.Dental
College, Bangalore, Karnataka.
Abstract
Twin block from its inception and evolution of the appliance itself has
been widely accepted as a more competent Class-II corrector compared to
earlier bulky monobloc appliances. This article gives a bird’s eye view of the
most widely used functional appliance with its most common modifications
along with the case reports.
Keywords: Twin Block, Class-II, Jackscrew, magnets
Journal of Dental Sciences & Research 2:1: Pages 88-92
compared to earlier bulky monobloc
Introduction
The
correction
of
skeletal
Class-II in non compliant, growing
patients has been a major hurdle in
appliances.
Mode of action of Twin Block
The Twin block works on the
the success of functional appliance
philosophy
therapy. The introduction of twin
planes and use of masticatory force
block appliance to
throughout
the orthodontic
of
occlusal
the
day.
inclined
If
the
armamentarium in the year 1977 by
mandibular inclined planes are in a
Dr.William
a
distal relation to that of maxilla then
in
the force acting on the mandibular
treatment of non compliant Class II-
teeth will have a distal force vector
patients.
leading
significant
Clark,
has
been
improvement
Twin block from its inception
to
a
Class
II
growth
tendency. The aim of the inclined
and evolution of the appliance itself
planes of
has been widely accepted as a more
block is to modify these inclined
competent
planes and cause more favorable
Class-II
corrector
growth
88 Journal of Dental sciences and Research
the bite blocks in
pattern.
Hence
twin
the
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February 2011
Twin Block
unfavorable cuspal contacts of the
Twin Blocks do not distort speech by
distal
by
restricting movement of the tongue,
favorable proprioceptive contacts on
lips or mandible. Adjustment and
the inclined planes to correct the
activation is simple. The appliances
malocclusion and free the mandible
are comfortable and not prone to
from its locked distal position.1
breakage. Chair side time is reduced
occlusion
Claimed
are
replaced
Advantages
Of
Twin
in
achieving
major
correction1
Block
Patients wear Twin Blocks 24
hours
per
day
and
can
eat
comfortably with the appliances in
place. Twin Blocks can be designed
with no visible anterior wires without
losing its efficiency in correction of
arch
relationships.
interference
with
There
is
less
normal function
because the mandible can move
freely
in
anterior
and
Fig 1 Pre treatment
Fig 2 Post twin block
extra oral photograph
therapy
lateral
excursion without being restricted by
a bulky one-piece appliance.
Twin Blocks may
be fixed to the teeth temporarily or
permanently to guarantee patient
Fig 3 Fixed twin block appliance
compliance. Removable Twin Blocks
One of the added advantages
can be fixed in the mouth for the
of twin block is its versatility in
first week or 10 days of treatment to
being
ensure that the patient adapts fully
discrepancy by incorporating midline
to wearing them 24 hours per day. .
jackscrew since a deficiency in the
Patients can learn to speak normally
transverse
with Twin Blocks. In comparison
encountered with a skeletal Class II.
with
other
functional
able
appliances,
89 Journal of Dental sciences and Research
to
correct
plane
transverse
is
often
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February 2011
Twin Block
Fig 4 Twin block with midline jack screw
Fixed Twin Block
In
addition
to
effectively
Fig 5 Fixed twin block appliance
proving to be an alternative to the
functional
appliances
of
yester
years, Twin block in its fixed form is
emerging as an appliance of choice
in
comparision
to
other
fixed
functional appliances when minimal
growth is left.2,3,4,5
Here are the results of a case of a
female patient who reported at the
age of
14 years with a skeletal
Class-II malocclusion.
The
patient
was
undertaking
endodontic treatment for 11 that
ruled
out
the
possibility
of
orthodontic tooth movement for 612 weeks. The time required for
alignment
and
levelling
to
be
achieved as a prerequisite for fixed
functional
appliances
which
are
given on a stiff rectangular archwire,
was instead utilized for correction of
skeletal Class-II by a fixed twin
block.
Fig 6 pre treatment
Fig 7 Post Fixed Twin
extra oral photograph
block therapy
The immediate improvement
in facial profile plays an important
role in acceptance of the appliance
by teen patients belonging to the
age group of 13-14 years.
Magnetic Twin Block
Twin
instituted
block
when
last
is
usually
phases
of
growth are left and the effects of
magnets
in
response
documented
improved
have
in
been
cellular
well
orthodontic
literature6-10.We have also used this
90 Journal of Dental sciences and Research
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February 2011
Twin Block
combination
of
twin
block
with
Protraction
Appliance-IV
in
the
magnets to maximise the effeciency
Correction of Class II Malocclusion
in
Angle
correction
of
Class-II
malocclusion1
Orthodontist
2010;80(3)
;485-91
3. RT Lee, CS Kyi, GJ Mack A
controlled clinical trial of the effects
of the Twin Block and Dynamax
appliances on the hard and soft
tissues
Eur J Ortho
2007;29(3);
272-282
4. Qi J, Tan ZR, He H, Pan D,
Yeweng SJ A preliminary report of a
new design of cast metal fixed twinFig 8 Magnetic Twin block appliance
block appliance J Orthod Dec 2007
;34 (4);213-9
Conclusion
5.Read
The Twin Block appliance due
to
its
acceptability,
adaptability
versatility, efficiency, and ease of
incremental
mandibular
advancement without changing the
appliance has become one of the
most
widely
used
functional
appliance in the correction of ClassII malocclusion.
and
integration
fixed
of
appliance
treatment J Orthod March 2001 28
(1);13-18
6. PJ Sandler, S Meghji, AM Murray,
SD Springate, JR Sandy, V Crow and
RT Reed Magnets and orthodontics.
British
J
of
Orthodontics
1989
16;243-249
Orthodontics: An overview British J
1.Clark WJ. Twin-block functional
Ed
functional
The
7.Joseph Noar Rare Earth Magnets in
References
therapy.
MJ
1.
Mosby
Wolfe,
London; 1995.
2. AK Jena, R Duggal Treatment
Effects of Twin-Block and Mandibular
of Orthodontics March 1999 26 (1)
29-37.
8.M A Darendeliler A Darendeliler M
Mandurino
magnets
91 Journal of Dental sciences and Research
Clinical
in
application
orthodontics
of
and
Volume 2 Issue 1
February 2011
Twin Block
biological implications: a review Eur
10.Flavio
J Orthod 1997;19 (4);431-442.
Intramaxillary
9.Dauro
Bruno
absolute anchorage with endosseus
Franco de Oliveira Helio Henrique de
implant and rare earth magnets July
Araújo
2009 136;124-33
Douglas
Brito
Oliveira
Selective
alveolar
corticotomy to intrude overerupted
molars
Am J Orthod Dentofacial
Orthop 2008;133:902-8.
92 Journal of Dental sciences and Research
Uribe
Ravindra
and
Nanda
Intermaxillary