Dr. William Roth Introduction The Roth Rx Reasons For Modification Treatment Philosophy Treatment Goals Roth Rationale Selection Of Treatment Mechanics Roth Set-up Sequencing Of Treatment Objectives Treatment Mechanics Anchorage Considerations Detailing Of Tooth Position Advantages Comparisons Conclusions

1. ROTH Philosophy
Miliya Parveen

2.  Dr. William Roth
 Introduction
 The Roth Rx
 Reasons For Modification
 Treatment Philosophy
 Treatment Goals
 Roth Rationale
 Selection Of Treatment Mechanics
CONTENTS
* Roth Set-up
* Sequencing Of Treatment Objectives
* Treatment Mechanics
* Anchorage Considerations
* Detailing Of Tooth Position
* Advantages
* Comparisons
* Conclusions

3.  Ronald H. Roth (1933 – January 24, 2005) was an American
orthodontist.
 He believed that if the condyles and mandible were positioned
correctly in centric relation, Andrew's six keys to occlusion was
compatible for orthodontic treatment.
 He also believed that some degree of over-correction must be
introduced into the brackets - introduced “Roth Prescription" in
1975.
 Roth along with Dr. Williams started the Roth Williams
International Society of Orthodontists.
DR. WILLIAM ROTH

4.  Dr. Roth received his orthodontic training from Dr. Jarabak in Chicago and used
Andrew’s SWA for his cases but was bothered by the post-treatment facial
declines.
 He noted that following changes occur after appliance removal:
• Teeth will move after appliance removal, no matter where they are placed.
• Curve of spee will return or deepen after appliance removal.
• As the teeth in buccal segments settle they will tip mesially.
• Teeth adjacent to an extraction site will tend to rolate & tip towards extraction
site
• As band spaces close, there is a corresponding loss of torque of the anterior
teeth.
INTRODUCTION

5.  Logically planned for these changes to happen during treatment & set up a goal that
will overcome these factors – by overcorrection
 These changes, incorporated into the appliance, wouldn’t need offset bends in the arch
wires or various prescriptions.
 Also reduces the need for a large inventory of bands and brackets and was compatible
with achieving functional occlusion goals.
 The Roth Rx was available in 1975 and part of its success is the coupling with Roth
Treatment Mechanics.

6. THE ROTH Rx
 Roth introduced a bracket setup containing modifications of the tip, torque,
rotations and in out movement of the Andrews standard setup brackets.
 The major difference between the Andrews philosophy and the Roth approach to the
use of the straight wire appliance has to do with the manner in which the teeth are
moved and not necessarily the desired end result or the result attained.

7.  ANDREWS attempts to translate teeth throughout treatment without ever
tipping teeth. This leads to the necessity of utilizing sliding mechanics and
number of different series of brackets to solve the problem of translating
teeth depending on how far the teeth must be moved.
 In the ROTH approach, tipping of teeth is allowed, by using round wires in
the initial phase of the treatment, but the attempt is to keep the tipping to a
minimum wherein it is not necessary to resort to complex mechanics to do
the uprighting

8.  Andrews' occlusion study was based purely upon anatomical measurements of
tooth positions on untreated normals.
 According to him teeth should be positioned from an “ANATOMICAL
STANDPOINT’”
 Roth’s occlusion study was based purely upon pantographically recorded and
mounted a large number of post-treatment orthodontic cases on the Stuart
articulator
 According to him natural teeth should be positioned from a
“GNATHOLOGICAL STANDPOINT”

9. REASONS FOR MODIFICATION OF SWA
 Inventory problem - To treat different cases clinicians were to buy band
kits for all Andrews sets and series. They are very extensive inventory on the
self. Also, changing anything about the appliances would be prohibitively
expensive.
 Anchorage loss - When mesially angulated brackets are placed on the
posterior teeth, the teeth tend to tip mesially and migrate forward that
resulted in anchorage loss.
 Problem in finishing - To achieve desired tooth positions with the
standard SWA, it was necessary to finish the mechanotherapy phase of
treatment by placing compensating and reverse curve in the upper and lower
archwire.

10.  The FACE philosophy is an orthodontic diagnosis and treatment system
established by Dr. Roth.
 It allows for objective evaluation and diagnosis of jaw position and functional
occlusion (an overlooked area) and execution of treatment based on the
diagnostic information.
 It enables the orthodontist to improve diagnostic accuracy and predictability
of treatment.
ROTH TREATMENT PHILOSOPHY

11.  Facial Esthetics
 This goal helps the orthodontist realize which tooth
movements will harm the esthetics of the patient.
 It allows us to determine the position of the maxilla,
mandible and chin, as well as the position and
angulation of maxillary and mandibular teeth, and
the orthodontic procedures to achieve the desired
results.
 For example, in many cases it is important to
prevent the mandible from rotating clockwise and
instead, rotate it counterclockwise. This would move
the chin forward and shorten the lower face height
thus improving facial esthetics.

12.  Dental Esthetics
* Dental esthetics and facial esthetics are mutually
complementary.
* The teeth should be perfectly aligned, free of rotations,
spacing or crowding thus providing the patient with a
healthy, esthetic smile.
* In particular, the mesial buccal cusp of the upper first
molar should look most prominent in the arch -
incorporated into the Roth arch form, which consists of
five curves, making the first molars more prominent.
* Other considerations include the leveling of the curve of Spee and the cant of
the occlusal plane both sagittaly and transversely.
* These criteria for dental esthetics bring to our attention the close relationship
between esthetics and function.

13.  Functional Occlusion
 Roth’s criteria for a functional occlusion are as follows:
1. Teeth in maximum intercuspation with the mandible in centric relation.
2. On closure into occlusion, the stress on the posterior teeth should be directed
down the long axis of the posterior teeth so that the resultant stresses will be
transmitted as tension to the periodontal ligament and lamina dura.
3. Posterior teeth should contact evenly and equally on closure into occlusion with
light anterior contact when the joints are seated so as to protect the anterior teeth
from lateral stress.
4. Adequate overbite and overjet to immediately disengage the posterior teeth in any
excursive movement to protect the posterior teeth form lateral stresses.
5. Cusp height, fossa depth, ridge and groove direction, and cusp placement should
be in harmony with the mandibular movements in all directions (border
movements) to provide minimal interference of the teeth with the movement
pattern of the mandible dictated by the TMJ.

14.  Signs of mandible being not in centric relation:–
• Occlusal wear
• Excessive tooth mobility
• TMJ sounds
• Limitation of mouth opening
• Myofacial pain
• Tightness of mandibular musculature

15.  Tempromandibular joint health
 Every effort is made to ensure that the
temporomandibular joints or jaw joints are healthy,
free of pain and other symptoms, and seated in their
most orthopedically stable position.
 It is the job of the orthodontist to ensure these
conditions exist before, during, and most importantly,
after orthodontic treatment.
 Healthy and properly positioned jaw joints are critical
to the long term stability of a completed orthodontic
case.

16.  Periodontal Health
 It is a general goal in all aspects of dentistry to help the patient obtain and maintain
healthy teeth and gums (the periodontium).
 This is mostly accomplished through patient education, i.e., teaching the patient
how to care for their mouth.
 Another aspect of periodontal health involves the proper positioning of the teeth
within the bone that supports them. This is the job of the orthodontist.

17. ROTH’S ORTHODONTIC TREATMENT GOALS
FOR AN IDEAL FUNCTIONAL OCCLUSION
1. Centric occlusion or maximum intercuspation
of the teeth should occur with the mandible in
centric relation, in which the condyles are centered
transversly and seated against the articulator disks
at the posterosuperior slopes of the eminence.
 This centric relation occlusion should have three
point contact of the opposing centric cusps in their
respective fossae.

18. 2. Mutually protective occlusion
 Occlusal force during closure should be of equal magnitude for all posterior teeth
and the stress should be directed along the long axes of the teeth.
 The lower incisors should not be in contact with the lingual surface of upper
incisors and should have a clearance of 0.005 inch.
 Anterior guidance / incisal guidance and Canine Guidance

19.  Anterior guidance / incisal guidance -
• In straight protrusion the anterior teeth should
serve as a gentle glide path to disocclude the
posterior teeth very gently.
• To have such anterior guidance, there should be
minimal but sufficient anterior overbite.
• In the absence of anterior guidance,excessive
lateral stress on the cuspids may cause lingual
movement of the lower cuspids and resultant
lower anterior crowding, and/or labial movement
of the maxillary cuspids and affects post treatment
stability.

20.  Canine guidance or canine rise
• In lateral excursions the maxillary
cuspids should act as guiding inclines
to disocclude the teeth on the
balancing or non-functioning side and
to disocclude the teeth on the working
or functioning side after approximately
0.5mm of group contact.

21. 3. Tooth-to-two-teeth or cusp-embrasure occlusion
 During maximum intercuspation, there should be Tooth-to-two-teeth or
cusp-embrasure occlusion between the upper and lower teeth,
 Because this makes the lateral and protrusive movements with proper cuspid
and incisor contact.
4. Tooth structure
 Tooth position and occlusal form should correlate perfectly with mandibular
border movements, including the Bennett movement and immediate side
shift.

22. ROTH RATIONALE
 The purpose of the Roth setup was to provide over corrected tooth
positions prior to appliance removal that would allow the teeth in most
instances to settle to what was found in non-orthodontic cases studied by
Andrews.
 With the appliance in place, it is virtually impossible, because of bracket
interference, to position the teeth precisely into the occlusion shown by the
non orthodontic normal sample
 After appliance removal no matter how well treated the patient may be, the
teeth will shift slightly from the positions they occupied at the time the
appliance were removed

23. Complete levelling to the flat curve of spee
Slight uprighting of the mandibular teeth in buccal segments with a hint of distal rotation of
the mandibular first premolars.
Overcorrected torque of the maxillary anteriors
Slight overcorrecting of lingual crown torque of the maxillary molars.
Overcorrecting of the antero-posterior relationship of the upper to lower teeth towards class III
relationship of the buccal segments and edge to edge relationship of the anteriors.
* Specific areas that required overcorrecting were:

24. ROTH CONCEPT OF SELECTION OF
TREATMENT MECHANICS
Thorough diagnosis
Establishing treatment goals
Dynamic treatment planning

25. DIAGNOSIS
 The traditional method of selecting treatment mechanics, based on the
Angle’s classification of malocclusion, is inadequate.
 Treatment mechanics should be selected by the set of conditions that exist
along with the parameters that are placed on the situation.
 The treatment mechanics must be tailored to the individual situation and the
individual facial type.

26. TREATMENT GOALS
 In diagnosis and treatment planning, it is necessary to diagnosis the case
from a mandibular position of centric relation.
 One must utilize a specific set of criteria for a functional occlusion goal
throughout diagnosis, treatment planning, and retention.
 One must have records. (Standard orthodontic models and cephalometric
centric relation head films) taken in centric relation as well as if any
significant centric discrepancy exists in a particular case.

27. * Treatment goals include -
1. Pleasing facial esthetics, evaluated by soft tissue and skeletal
measurements cephalometrically.
2. Molar relation and tooth alignment, evaluated by Angle's description
of anatomical occlusion.
3. Functional occlusion, evaluated gnathologically on an articulator.
4. Stability of postreatment tooth positions and alignment.
5. Comfort, efficiency, and longevity of the dentition, supporting structures,
and the temporomandibular joints.

28.  So a REPOSITIONING SPLINT should be fabricated -
• To get the patient’s mandible into centric occlusion
• To make the true discrepancy apparent.
 Once the discrepancies are apparent, one should make a treatment plan to deal with
all of the discrepancies present and not just the ones seen intraorally.
* In case of Centric occlusion - Centric
relation discrepancy, neuromuscular
positioning of the mandible will
accommodate to existing occlusal
discrepancies and hide the true nature
of malocclusion.

29. * The mandibular postural changes during splint therapy are of three different types:
1. Changes due to relaxation of the musculature that postures the mandible
incorrectly due to muscle contracture or spasms.
2. Changes due to elimination of intracapsular inflammatory fluid.
3. Changes due to remodeling or recontouring of the bony parts of the joints (e.g.
condyles or fossae).

30. ROTH CONCEPT OF
TREATMENT PLANNING
 Factors to be considered includes -
• The facial type of an individuals.
• Reactions of various facial types to the proposed treatment.
• How much growth remains and in which direction the mandible can be expected
to grow and what means must be taken to alter the direction of this growth -
favourably with treatment mechanics.
• Effect of treatment mechanics on the patient's soft tissue profile.

31.  To plan and to select appropriate treatment mechanics, Roth utilized:
1. An adjusted head film tracing from centric (habitual)occlusion to
centric relation.
2. Ricketts VTO
3. The five position superimposition
4. Jarabak analysis.

32.  It is utilised to quantify -
1. The amount of growth needed to correct
the jaw relationship.
2. The amount of orthopedic changes or jaw
relationship changes necessary to correct
the dental arch relationship.
3. The extent of tooth movement allowable
or desirable both antero-posteriorly and
vertically of the anterior and posterior
teeth in each arch.
The Five Position Superimposition

33. Jaraback analysis
 For qualitative assessment of the facial type and its probable response to the
various kinds of treatment mechanics and growth.
 The most important measurements are-
• The anterior to posterior face height ratio
• The tendency of the individual facial type
to rotate clockwise or counter clockwise
during growth
• Response to certain treatment mechanics

34. ROTH SETUP
 Roth setup is available in both 0.018 and 0.022 slot .
 Roth preferred 0.022 slot brackets because it offered more advantages.
1. In terms of wire size selection
2. In terms of stabilizing arches as anchor units and for orthognathic
surgery
3. For control of torque in the buccal segments, which is very important
from the stand point of functional occlusion.

35. Brackets
 The original standard SWA was introduced with single-wing brackets,
and shortly thereafter Siamese brackets were introduced.
 The molar tubes were bulky and were "capped" to form tubes.
 Later the brackets were made smaller, and power arms were cast as integral
parts of the brackets designed by Andrews to place the force at the centroids
of the teeth and effect translatory movement
 The Roth setup incorporated into it a member of hooks for various types of
elastic configuration and also double triple and lip bumper tube for the use of
auxillary wires and attachments.

36.  Configurations currently available are Twin, Single, Attract, Steiner, and
Lang— bondable, on bandable
 1984 the "Attract" brackets were introduced These were single-width brackets
that had rounded contours and micro-molar tubes. These brackets were also made
with short ball hooks in the Roth Prescription
 Currently metal and ceramic self-ligating brackets with Roth prescription are also
available.

37. Roth prescription
7-Mar-22
37
MAXILL
A
1 2 3 4 5 6 7
TIP 5 5 13 0 0 0 0
TORQUE +12 +8 -2 -7 -7 -14 -14
MANDI
BLE
1 2 3 4 5 6 7
TIP 2 2 7 1 1 1 1
TORQUE -1 -1 -11 -17 -22 -30 -30

38. Features of Roth prescription
 5º more torque in upper incisors
 Less torque in upper canines
 2º more tip in the canine
 2ºanti rotation in canine & pre molars
 Upright posterior segments
 Overcorrection of molar off-set and torque
 Lower posteriors –
• 3o distal tip
• Distal rotation

39. Ramifications &
Additional changes in Roth Set up
 Increased upper incisor torque – increased over jet
 Lingual crown torque of Upper cuspids and labial root torque –Reduce cuspid
torque to 20 - more vertical inclination
 00 torque brackets in lower cuspids - more vertical inclination
 Invert lower incisor brackets to get + 20 torque – reduces the over jet and also
produces better anchorage control
 5 degree torque increased in upper incisors –
• Improved aesthetics
• Increased space for lower anteriors - aids in class I intercuspation
• Enhance function and reduce facio-lingual stress

40.  Also available –
• Molar tubes with no upper molar offset
• “Super torque” anterior brackets
• Canines with 0o tip

41. Bracket Placement
 Bracket placement (as advocated by Andrews except) –
• Upper anteriors and lower incisors bonded more incisally
• Lower canines bonded slightly more gingivally
 The positioning gauge was shifted from 2 ½ inch gauge to 4 ½ inch gauge:
• For better vertical control on the instrument and precession in bracket positioning.
• Better visualization of the instrument angulation to the buccal surface of the teeth.

42. Arch form – Tru Arch
 Roth Tru-Arch form was derived from his extensive clinical
testing and recording of jaw-movement patterns in treated
patients who were out of retention and had remained stable.
 The Roth Tru-Arch form actually overcorrects the arch width
slightly.
 In the front part of the arch, the widest part is at the bicuspids, not
at the cuspids.
 The widest point in the entire arch is at the first molars
region,(mesiobuccal cusp of I molar) There are actually five arcs in
the Arch
 Has a gentle curve at post. legs.

43.  The bracket placement vary slightly from the position
advocated by Andrews, thus a flat, unbent, rectangular,
full sized wire can be used as the finishing wire rather
than one with reverse and compensating curve.
 Reference point: Andrews FA point - The point on the
facial axis that separates the gingival half of the clinical
crown from the occlusal half.
 The key in determining the bracket height is the canine
and premolars (second premolars in an extraction case).
 Ideally the center of the bracket should be placed at the
maximum convexity of the crowns of the posterior teeth.
In a teeth with average height of gingival attachment, the
maximum convexity of the teeth will be at the center of
the clinical crown.

44. SEQUENCING OF
TREATMENT OBJECTIVES
 The sequence of the treatment should be based on the dictates of the individual
case. The sequence of treatment objectives are generally -
1. Eliminating cross bite
2. Correcting jaw relationship
3. Eliminating severe crowding creating space in the dental arches for severely
malposed, impacted or blocked teeth
4. Aligning the teeth in the individual arches
5. Beginning space consolidation

45. 6. Finishing the lower arch - It is important that the lower arch must be finished
in the correct position to act as a template to receive the upper teeth, so that
the upper teeth can be set to the lowers.
7. Achieving class I relationship of buccal segment.
8. Retracting and if necessary intruding maxillary anterior teeth.
9. Detailing and finalizing the tooth position and the occlusion.
In many instances a number of these steps will be combined and will be
occurring simultaneously.

46. TREATMENT MECHANICS
3 phases
–
Unlocking
phase
Working
phase
Finishing
phase

47. UNLOCKING PHASE
 Main objective –
• Gross corrections
• Aligment with flexible wires – so that heavier wires can be used later
 Major corrections –
• Cross bites
• Severely malposed teeth
 Use of RME, Quad helix, Bimetric arches, Utility arches
 Jarabak style loops in light wire
 Braided wires

48. • Helical loop archwires, Jarabak fashion made from 0.016”
Elgiloy green wire(crowding) or
0.015” braided archwire (routinely) or
Nitinol (severe rotation)
• 0.019” braided wire
• 0.018”Australian special plus (finalisation of any stubborn rotation)
•0.019” square blue Elgiloy utility arches are used in case of intrusion of
incisor teeth.

49. ANCHORAGE CONSIDERATIONS
 The leveling process should be started with a small flexible wire. The best for
this purpose is the braided arch wire.
 When it is time to retract and upright lower anteriors that have been in labial
or procumbent position, they should be retracted initially with an anterior
facebow.
 In most instances 6 to 8 weeks of headgear to the lower anterior segment is
all that is needed to upright the lower anterior teeth sufficiently that the
remainder of the space can be closed with reciprocal mechanics.

50.  Factors responsible for anchorage loss -
1. Pulling distally with posterior teeth against extremely procumbent or labially
inclined incisors.
2. Attempting to level the curve of Spee with a continuous wire without the use of
distal traction.
3. Attempting to do any of the first three tooth movements utilizing either a stiff or a
resilient wire.
4. Attempting to expand the mandibular arch with a labial archwire.
5. Heavy wires for leveling COS
6. Attempts to gain rapid alignment with heavy wires
7. Uprighting distally tipped canines
8. Lingual root torque of max. incisors

51.  Anchorage management:
1. Band the second molars at the outset of full dentition treatment and use
them for anchorage.
2. When leveling the curve of Spee, wherever possible a utility arch should be
used to intrude the incisors followed by canine by Bioprogressive technique
and then going to the flexible small wires to gain bracket engagement and
alignment of the entire arch and gradually level the remainder of the curve
of Spee.
3. Procumbent teeth offer a lot of anchorage
4. Once teeth are upright, they retract easily.
5. Space closure can be done on any wire, as long as it is done slowly.

52. WORKING PHASE
 Anterior teeth are generally retracted en masse as a group of 6 second molars are
routinely banded at the outset of treatment in the permanent dentition.
 Goals –
• Closure of extraction site
• Correct Anterio- posterior jaw relation and dental relation
• Intrusion, if required
• Space closure with double keyhole loop
 Use – 19x26 mil rounded edge rectangular wire

53.  Double keyhole loop –
• Space closure with 1 wire
• Medium between tipping and translation
• Permit either ant. retraction or post. protraction
• Control of canine rotation
• Used as elastic hooks.

54.  Anterior teeth are retracted enmassse by using face bow which can be hooked
to neck strap to retract the lower anteriors.
 For upper anteriors high pull head cap is used.

55.  At the end of space closure - 0.018x0.025” blue elgiloy incorporating exaggerated
curve with special torque adjustments (to offset the undesirable effect produced by
curves) to provide -
• Rapid root paralleling
• Leveling of Curve of spee &
• Maxillary incisors lingual root torque
 During extraction space closure, faster the space is closed (regardless of wire size), the
more tipping there will be into the extraction space.
 So it is the force & rate at which the extraction space is closed determines the type of
tooth movement(tipping or bodily) and not the dimension of the wire used.

56. A. High angle cases –
 Avoid heavy wires – max use of Nitinol and TMA and braided wires
 Space closure on 0.016” SS wire
 Uprighting with 19x25 TMA/Nitinol/braided wire
B. Bimax cases –
 Initial space closure with 0.018” or 0.020” wire with double keyhole loops
 Once teeth are upright – intrude with Utility arch
 Continue space closure with 19x26 double keyhole loops and Asher face
bow

57. C. Maximum retraction and torque control –
 0.021 x 0.025 SS or Elgiloy double keyhole loops
 Maximum torque control
 Reduce posterior ends

58. FINISHING PHASE
 The final finishing phase of treatment requires filling of the bracket slot
(0.022 x 0.025) to get full bracket expression.
 Short class II or III elastics are used to create anteroposterior denture
adjustments

59. DETAILING OF TOOTH POSITION
 THE MANDIBULAR ARCH:
Lower incisors –
• The sequence of tooth positioning begins with placing the lower
incisors teeth at or slightly lingual to the cephalometric goal.
(-1 to A-Pog)

60. • The four incisors teeth should have the roots
divergent and roots appears to be in the same
plane of space when viewed from the superior
aspect.
• Lower cuspid crowns should have 5 degrees
angulation with the incisal tip 1mm higher than
the incisal edge of, the lateral incisors And it
should have should have a slightly exaggerated
mesial rotation on extraction cases.
• There should be overcorrection of root
parallelism in the extraction site, if extractions
were done.

61. • Bicuspids and molars should be upright and should
have slight distal rotation.
• There should be no spaces, and the arch form should
be symmetrical.
• The widest point of the mandibular arch should be
the mesiobuccal cusps of the mand. I molars and the I
bicuspid.
• The curve of Spee should be leveled.(because it
return to a 1- 1.5mm curve, at its deepest point, after
appliance removal and settling of the occlusion

62.  THE MAXILLARY ARCH:
• In the upper arch, the first tooth to be placed properly in relation to the lower
arch should be the maxillary first molar.
• The upper first molars should have sufficient distal rotation, mesioaxial
inclination, and buccal root torque, so as to fit with the lower first molars, as
described by Andrews
The maxillary second molar
The upper bicuspids
The upper anteriors

63.  The incisal edges of upper centrals and
laterals should be almost at the same level
with no more than 0.5mm height differential
approximately
 The widest point of the maxillary arch should
be the mesiobuccal cusps of the maxillary 1st
molars
 Cusp tip of the canine should be app 1-1.5mm
incisally than the of the occlusal plane.

64. ADVANTAGES
 Decrease in treatment time
 Better tooth positioning
 The performed arch wires allows full bracket engagement / expression
efficiently and gently as in case of 0.0215" x 0.028“ sentinol wire
 Heavy steel wires placed without using pliers because by the time the teeth are
well enough aligned to place such a large wire, the bracket slots are aligned in
both height and torque with automatic in/out – ‘LEVEL SLOT LINEUP’ –
allows the use of heavy wires without having to resort to heavy forces
 In 30 Years - MBT introduced in 1972

68. CONCLUSION
 A significant retroclination of upper and lower incisors occurred with MBT
prescription after first phase of orthodontic mechanotherapy while there could be
a proclination of labial segments with Roth prescription.
 Mesial migration of the upper molars was evident in patient treated with Roth
prescription hence reinforcement of molar anchorage is deemed to the necessary
in the maxillary arch right from the onset of the orthodontic treatment.
 ROTH prescription was characterized by significant forward inclination of the
canines, while canine distalized into extraction spaces with no influence on
incisal proclination in the MBT prescription