THE DIFFERENCE BETWEEN BRACKT PRESCRIPTION OF MBT ,ROTH AND ANDREWS IS PRESENTED

1. Orthodontic bracket
prescription
Prof Dr Maher Fouda
Mansoura Egypt
1

2. Tooth movement normally
occurs in three
dimensions. The
dimensions were originally
incorporated in the
edgewise mechanotherapy
by specific adjustments to
the arch wires, since the
first generation of brackets
was known as standard
edgewise brackets with no
prescription.
Typical finshing archwire
incorporating individual tooth bends for an
edgewise appliance.
Edgewise slot.

3. The arch wire adjustments
are called first-, second-,
and third-order bends.
First-order bends are the
so-called in-out bends,
which are represented by
the distance of the bracket
slot to the tooth surface
and is a horizontal
adjustment. This
accommodates for the
differences in the buccal
tooth anatomy.
First-order bends (in-out)
in edgewise, left,
compared with straight-
wire, right.

4. Second-order bends refer to
the vertical adjustments, up
and down or tip bends, to
provide correct axial
inclination and tooth-root
alignment in a mesiodistal
dimension. The mesial to
distal tip of the bracket slot in
respect to the long axis of the
tooth represents this
adjustment of the bracket
prescription.
Second-order bends (tip)
in edgewise, left,
compared with straight-
wire, right.

5. Third-order or
torque
adjustments
refer to the
bucco-palatal or
bucco-lingual
position of the
roots in respect
to the crowns of
the teeth.
Third-order bends (torque)
in edgewise, left, compared
with straight-wire, right.

6. All three orders are
built into the bracket
by the manufacturer
and thus represent
the prescription of
contemporary
brackets and in turn
meet the
requirements of the
straight-wire or
preadjusted
appliance
Siamese edgewise brackets
showing twin design and
contoured base

7. In the edgewise
bracket system, to
achieve an ideal
alignment of teeth all
the bends—first order
(in and
out), second order
(mesiodistal) and third
order
(torquing) have to be
built into the archwire
by the
clinician. n

9. First order bends
and arch form.
(A) Maxillary, (B)
Mandibular

11. Third-order bends
(torque) in
edgewise, left,
compared with
straight-wire, right

13. After studying a large
sample of untreated
ideal occlusions,
Lawrence Andrews
published
his six keys of
occlusion ( Andrews,
1972 ) and introduced
an
edgewise bracket
system that has
revolutionized fixed
appliance orthodontics
( Andrews,
1979 ).

14. The preadjusted
edgewise or
straight-wire
appliance that
Andrews
described
is the most
popular fixed
appliance system
in use today .
Prescription in Andrews technique.

15. Unlike standard
edgewise brackets,
which are identical for
each tooth and require
bends within the
archwire to generate
individuality of tooth
position, each tooth in
the preadjusted
edgewise system
has a customized
bracket.
Fully Programmed SWA
Genuine Straight-Wire Appliance
brackets are fully programmed
so that each tooth’s bracket
slot lines up horizontally with
all others to eliminate the need
for time-consuming wire bends.

16. The pre-adjusted edgewise
brackets were
programmed to impart
specific prescriptions
of tip (second order),
torque (third order), in-out
and rotational (first
order) control on each
tooth and reduced the
need for wire bending to
control tooth
position.

17. The name
STRAIGHT WIRE
suggests, in the
pre-adjusted
edgewise
appliance (PEA)
all these are built
into the
brackets or the
appliance
Siamese edgewise brackets showing twin
design and contoured base

18. Bracket prescriptions
Pre-adjusted
edgewise fixed
appliances have
first-order (in-out),
second-order (tip)
and third-order
(torque) adjustments
built into the
individual brackets.

19. This built-in prescription was
based around
Andrews ’ measurements from
the untreated sample of ideal
occlusions he studied and
included a number of features :
● Pre-angulated slots for correct
mesiodistal tooth angulation or
tip;
● Bracket bases inclined for
correct inclination or torque; and
● Variable distance from base of
slot to base of bracket for correct
in/out position.

20. In this
preadjusted
system, the work
in accurately
positioning the
teeth is done by
the bracket
prescription,
significantly
reducing the
amount of wire
bending
required.

21. A further advantage is
that it also allows
groups of teeth to be
moved and spaces
closed by sliding them
in unison along a rigid
archwire; because once
tooth alignment
has been achieved, the
archwire sits passively
in each bracket slot.

22. The original
Andrews bracket
prescription is
still available,
although there
have been
adaptations made
as the appliance
system has been
developed
clinically .

23. Lawrence Andrews
described the original
bracket prescriptions
for his
preadjusted appliance
based upon data he
obtained measuring
tooth positions
from untreated ideal
occlusions ( Andrews,
1972 ).

24. As experience was
obtained
with this appliance
during clinical use,
Andrews went on to
describe several
different bracket series
for extraction and non-
extraction cases, in
addition to
series for use with
different amounts of
crowding.

25. The extraction series
brackets included
adjustments for tip and
rotation to counter the
effects of
space closure (
Andrews, 1976 ), but
overall these different
series significantly
complicated stock
management for the
orthodontist.
Andrews’s prescription for maxillary arch
For mandinbular arch

26. In particular, it was
found that some of
the torque
prescriptions in the
original Andrews
appliance were not
being fully expressed,
most notably in the
upper incisors due to
the ‘ slop ’ or free
space that inevitably
exists between the
wire and bracket slot.
Andrews’s prescription for maxillary arch
For mandinbular arch

27. Therefore,
many later
prescriptions
have
increased
torque values
in the upper
labial segment
to compensate
for this.

28. Andrews soon recognised that
his prescriptions were not
universal and soon
developed an array of
prescriptions based on extraction
usage and malocclusion
type. Soon, however, the
inventory became complicated
and was rationed down
to a single prescription. Since
then, a range of prescriptions
have been developed
with various increments of torque
and angulation values (Roth
1987).
Andrews/Roth/MBT tip values;

29. Roth prescription and
MBT have become
particularly popular in
the USA
and UK, respectively.
Both incorporate more
torque in the upper
anterior region,
likely related to the
inefficiency of the fixed
system in respect of
torque delivery.
Andrews/Roth/MBT tip values

30. The amount of
‘torque’ in the
incisor brackets
controls their
inclination and
therefore
contributes to the
delivery of
decompensation
during pre-surgical
orthodontics.

31. In contrast,
Ronald Roth
recommended
a single series
based on the
Andrews
extraction
prescription.

32. Roth also incorporated
more mesial crown tip in
the maxillary canines in
order
to promote mesial
crown positioning and
canine guidance; this
led to a commensurate
increase in anchorage
requirements in Class II
cases, however.
Andrews/Roth/MBT tip values;

33. Ronald Roth This
prescription had
extra torque in the
upper labial
segment because
the edgewise slot
does not express
the full torque value
of
the bracket,
particularly as the
upper labial
segment is retracted
during space
closure.

34. Roth also
placed a
greater
emphasis on
functional
occlusion
and gave
the canines
greater tip to
facilitate
cuspal
guidance.
Prescription in Andrews technique

35. There was also
greater
torque in the
maxillary molar
region to
prevent
dropping of the
palatal cusps
and eliminate
non-working
side
interferences (
Roth, 1976).
Andrews’s prescription for maxillary arch
For mandinbular arch

36. More recently, Richard
McLaughlin, John
Bennett and Hugo
Trevisi have
developed the MBT
prescription, which has
increased torque in the
upper labial
segment and lingual
crown torque in the
lower labial segment.

37. This was
designed to
minimize
proclination
of the lower
incisors
during
treatment.

38. The
MBT
prescription
also has
reduced tip,
most notably
in the upper
arch, to
reduce
anchorage
requirements.
Andrews/Roth/MBT tip values

39. MBT
also incorporates more
labial root torque (6°) in
the lower incisor
attachments
relative to Andrews or
Roth (1°) designed to
resist the use of Class II
traction in
Class II cases and
potentially facilitate
retraction of lower
anteriors in Class III
cases.
Andrews/Roth/MBT tip values

40. One of the most common
currently used
prescriptions, MBT™, has
negative torque in the
lower incisor brackets and
increased torque in the
upper incisor brackets,
which is aimed primarily
at conserving anchorage
in the orthodontic
camouflage treatment of
class II malocclusions.

41. Relative to Andrews’
original research, the
MBT System reduces
lingual crown torque in
the lower posterior area
for three reasons: • In
cases of cuspid and
bicuspid gingival
recession, the teeth may
benefit from having the
roots moved closer to
the center of the
alveolar process.

42. Relative to Andrews’
original research, the MBT
System reduces lingual
crown torque in the lower
posterior area for three
reasons: • In cases that
show narrowing of the
maxillary arch with lower
posterior segments that are
inclined lingually, buccal
uprighting for the posterior
area is a favorable step for
both arches.

43. Relative to Andrews’ original
research, the MBT System reduces
lingual crown torque in the lower
posterior area for three reasons: •
Lower 2nd molars tend to torque
lingually over the course of
treatment, especially when there is
a high degree of buccal root torque
in the buccal tube. Therefore,
reduced torque values can more
consistently assist the effort to keep
the posterior segment centered and
uprighted.

44. Biological and
anatomical
variation, as
well as
mechanical
deficiencies
associated with
the appliance,
mean that one
overall
prescription
does not
fit all cases.

45. Different
appliance
prescriptions
have different
torque values for
the upper and
lower incisors
and so may be
more or less
suitable as aids to
decompensation
Dental compensation in skeletal Class II malocclusion
Direction of incisor
decompensation in Class
II malocclusion: the
lingual inclination of the
lower incisors is
increased and in some
cases (Class II.1
malocclusion), the upper
incisors retroclined
Dental compensation seen in skeletal Class III malocclusion
Direction of incisor
decompensation in
Class III
malocclusion: the
labial inclination of
the lower incisors is
increased and the
upper incisors
reduced

46. MBT prescription
is advantageous
in the pre-
surgical
preparation of
class II cases,
where retraction
of lower incisors
and the
maintenance of a
large overjet are
required.
The MBT™ prescription.

47. However, in class
III cases MBT
PRESCRIPTION
will tend to be
disadvantageous,
limiting lower
incisor
proclination and
maintaining upper
incisor
proclination

51. A variety of
modifications in
bracket
prescription and
occasionally some
wire bending are
often required
during the normal
clinical use of a
preadjusted
appliance.

52. These may be needed
to overcome errors in
bracket positioning,
significant variations
in tooth structure or
position, and the
presence of marked
skeletal
discrepancies
( Creekmore & Kunik,
1993 ; Thickett et al,
2007 ).

53. The degree of buccal
root torque in the
upper buccal segment
has also
been increased,
progressive uprighting
torque added to the
lower molars and
increased torque
options provided for
the maxillary canines
(McLaughlin and
Bennett 2015).
Prescription in Andrews technique.
Prescription in Roth technique.
Prescription in MBT technique.

54. In class III cases the amount of
lower incisor proclination that
will be achieved as a result of
crowding should be assessed.
As a general rule, each
millimetre of lower arch
crowding will produce
approximately 0.5mm of labial
movement of the incisal edges,
in the midline. Equally, in a
class II case, where retraction
of the lower incisors is
required, each millimetre of
space will allow 0.5mm of
lingual movement

55. Individual adaptations.
Whilst some clinicians
may opt for customised
prescriptions to ensure
that the brackets are
working in sympathy with
their treatment goals in all
cases, it is possible to
make certain adaptations
that can help to overcome
some of these problems.
In this class III case with an
absence of lower incisor
crowding, the lower MBT™
incisor brackets have been
inverted to convert 6° of
lingual crown torque to 6° of
labial crown torque to
encourage incisor proclination

56. Individual adaptations.
For example, the torque
values of the lower incisor
brackets can be changed
from − 6° to + 6° by inverting
them, which will help to
procline the lower incisors in
a class III case with minimal
crowding . In addition,
incisor inclinations can be
adjusted by introducing third
order bends into stainless
steel rectangular archwires
In this class III case with
an absence of lower
incisor crowding, the lower
MBT™ incisor brackets
have been inverted to
convert 6° of lingual crown
torque to 6° of labial crown
torque to encourage
incisor proclination

57. Does the prescription matter?
Moesi et al and Mittal et al
demonstrated that there was
no difference in subjective
aesthetic judgement or
anterior tooth angulation
between MBT and Roth
bracket prescriptions, and
small changes in the
prescription do not make
clinically detectable results
(Kattner & Schneider, 1993;
Mittal et al., 2015; Moesi et
al., 2013).
Angulation prescription (in degrees) with popular pre-
adjusted edgewise prescriptions.
Positive values indicate mesial crown tip
Inclination/torque prescription (in degrees) with popular
pre-adjusted edgewise
prescriptions.
Positive values indicate palatal root torque

58. Does the prescription matter?
The concept of torsional
(slot) play must be
addressed. The engagement
angle between the bracket
and wire is variable, so small
changes in brackets may not
fully express as the working
wire only engages the
bracket at few points and full
prescription expression may
never occur (Archambault et
al., 2010).
the concept of torsional play

59. Does the prescription matter?
Prescription
expression is
dependent on
the working
archwire and
the variation in
engagement.
The amount of play between the bracket and
archwire depends on the size of the archwire

60. Does the prescription matter?
Increasing the
thickness of
archwires in different
bracket slots
decreases torsional
play; a change in
archwire is a similar
difference to the
prescription
difference in degrees
between Roth and
MBT .

62. Does the prescription matter?
Increasing
the
thickness of
archwires in
different
bracket slots
decreases
torsional
play . change in wire size versus slop; from (Johnson, 2013)

63. Does the prescription
matter?
A change in
archwire is a
similar
difference to
the
prescription
difference in
degrees
between Roth
and MBT .

64. Does the prescription
matter?
Using a wire
sequence that
gradually
expresses the
prescription and
finishing cases
in the thickest
wire possible is
therefore
essential.

65. Does the prescription
matter?
Errors in
prescription can
also stem from
improper
machining .In an
attempt to express
more of the desired
values, high torque
prescriptions have
been advocated.

66. Clinicians must
understand prescriptions
to achieve ideal tooth
position. Even with
preadjusted appliances,
achieving all six keys of
occlusion is still difficult
(Davies, Gray, Sandler, &
O'Brien, 2001; Kattner &
Schneider, 1993).
Does the prescription matter? Angulation prescription (in degrees) with popular pre-
adjusted edgewise prescriptions.
Positive values indicate mesial crown tip
Inclination/torque prescription (in degrees) with
popular pre-adjusted edgewise
prescriptions.
Positive values indicate palatal root torque

67. There is a need
for a bracket
inventory to
include a variety
of prescriptions
and the
knowledge to
apply them in
different
scenarios for
individual patient
needs. .
Does the prescription matter?

68. Whilst the pre-adjusted
appliance is economical
and efficient, and has no
doubt revolutionised
orthodontic treatment, it
relies heavily on accuracy
of bracket placement,
and no single
prescription totally
eliminates wire bending.
Does the prescription matter?

69. The outcome of
orthodontic
treatment,
however, does
not rely on the
prescription
alone.
Does the prescription matter?