Introduction Historical Perspectives Creation of tip-edge Tip –edge concepts Bonding and setting up Treatment stages Stage I Stage II Torque in tip-edge Stage III Advantages Disadvantages Case reports Articles Conclusion References

1. TIP EDGE TECHNIQUE
DR. MILIYA PARVEEN

2. CONTENTS:
• Introduction
• Historical Perspectives
• Creation of tip-edge
• Tip –edge concepts
• Bonding and setting up
• Treatment stages
• Stage I
• Stage II
• Torque in tip-edge
• Stage III
• Advantages
• Disadvantages
• Case reports
• Articles
• Conclusion
• References

3. INTRODUCTION:
• The Tip-Edge bracket was invented by Dr.Peter Kesling
to introduce differential tooth movement within an
edgewise based bracket system.
• Tip-Edge technique was first introduced at the Kesling-
Rocke Orthodontic Center, Westville, Indiana, USA, in
1986.
• As its name suggests, Tip-Edge combines an initial
degree of tooth tipping, which greatly facilitates tooth
movement, prior to 'edgewise' precision finishing.

4. HISTORICAL PERSPECTIVES:
• Dr. Edward Angle, the father of fixed appliance orthodontics
created the ‘Edgewise’ Bracket in 1925.
• It provides the neatest way of achieving three-dimensional root
control in its day.
• Angle himself appreciated that tooth movement was facilitated
by allowing a tooth to tip.
¤ Unfortunately, he had no means of subsequent root uprighting.
• His well known non-extraction treatment doctrine was best
suited for his edgewise bracket.

5. • Dr. Raymond Begg evolved a different bracket system that
was a modification of Angle’s earlier ‘ribbon arch’ bracket.
• It was designed to overcome one of the prime disadvantages
inherent in all edgewise systems.
• This is - every tooth is subject to mesio-distal bodily control
from the moment of archwire engagement, thus increasing
resistance to retraction.
• Begg introduced a new sequence of tooth movement -
tipping the crowns into their corrected positions before
uprighting the roots as a later procedure.
¤ Root recovery, sometimes from extreme angles, could be less
than reliable
¤ Molar control and buccal segment torque were denied by the
inability to use rectangular archwires.

6. • The ‘straight-wire’ bracket system, pioneered by
Dr. Lawrence Andrews in the late 1970s.
• By incorporating in–out adjustments and finishing
angulations of tip and torque into the bracket itself,
individualized finishing prescriptions for each tooth became
available.
• Such new technology set higher standards for case finishing,
as defined by Andrews’ six keys to normal occlusion.
• Subsequent alternative prescriptions appeared, notably the
Roth ‘modified edgewise’.

7. • Dr. Peter Kesling, a student of Dr. Raymond Begg,
evolved the design of tip edge bracket system.
• Because of its initial tipping followed by edgewise
finishing functions, he nicknamed the slot as “tip edge”.
• It is officially and more formally known as the “differential
straight arch technique”.
• Initial crown tipping followed by controlled root
uprighting with straight arch wires (differential tooth
movement with straight arch wires).
• It converges the divergent philosophies of Begg and PEA
into one bracket system with no additional use of extra-
oral anchorage.

8. CREATION OF THE TIP-EDGE:
• Kesling modified a single straight-wire bracket to create the Tip-
Edge - the Rx-1 bracket.
• Removed two diagonally opposite corners from the rectangular
archwire slot which allowed the bracket to tip up to 25° either
mesially or distally.
• Each bracket requires an auxiliary in the final stage in order to
deliver root correction and coming of the latest Ni-Ti wires – TE
Plus brackets
• These had a horizontal ‘deep tunnel’ in the bracket base allows
torquing and tipping powered by a light Ni-Ti auxiliary archwire

9. 1. BRACKET FACE -
• Conventional tie-wings for elastomeric ligature.
• Bracket identification - small circular markers on
disto-gingival tie wing for maxillary anteriors &
triangular for mandibular.
• The ‘cut out surfaces’ of the archwire slot form the
‘tip limiting surfaces’ - restrict the degree of
tipping permitted during tooth translation.
• The intact surfaces - the ‘finishing surfaces’, containing the individualized finishing
prescription for each tooth.
• The point at which the tip-limiting and finishing surfaces meet constitutes the central
ridge; the opposing central ridges provide vertical control until final finishing.
• The laterally extended surface lingual to the main archwire preserves rotational control
throughout the range of tip permitted by the bracket.

10. 2. BRACKET SLOT -
• Slot size: 0.022”X0.028” is called the propeller slot.
• It is a ‘dynamic’ slot because:
i. Unique feature that the slot increases its vertical archwire
space from 0.022 to 0.028 inches as the tooth tips
ii. When the vertical slot is closed down by the auxiliary
against a rectangular archwire, it produces a three-
dimensional precision finish.
iii. It reduces friction during the first stage of treatment.
• Vertical slot is 0.020 inches square, lingual to main.
• Has a rounded ‘funnel shaped’ entry to facilitate insertion
of auxillaries.

11. 3. THE FIRST MOLAR TUBES -
• Tip-Edge employs double buccal tubes –
i. a normally sited preadjusted straight-wire rectangular tube of
.022 × .028”
ii. a gingivally placed round tube of .036” diameter.
• The first comes with a convertible rectangular buccal tube and
tie-wings so that the tube can become a bracket when the
buccal welded insert is peeled away - facilitates alignment of
second molars.
• Non-convertible molar tube has been introduced - carries no
tie-wings, helps patient comfort and reduces the chance of
occlusal interferences.
• All rectangular tubes are of Easy-Out® design, with the
posterior inner lumen slightly flared towards the occlusal -
facilitate archwire removal when a cinch back has been used

12. 4. AUXILIARIES -
A. The Side-Winder
• Used to be the everyday ‘workhorse’ among auxiliaries.
• Primarily in Plus, it generates mesio-distal root movement.
• For the Rx-1 bracket - produces torque correction as well, when used with rectangular
archwires.
• Made in .014 inch high tensile stainless steel wire.
• So called because it carries its coils along the archwire, over the bracket face.
• Side-Winders - only be used with SS arches, others are insufficiently stiff to resist the
vertical deflections arising from the active arms of the springs.

13. B. Invisible side-winder springs
• Wire of spring lies on archwire & brackets.
• Advantages
i. Aesthetic
ii. Retained in position by the elastomeric
module, in addition to its own spring pressure
- reduces the risk of detachment
iii. Enables modules to be changed if necessary during the root uprighting process
without removing springs.
iv. Because the bulbous hook has been reduced, the spring arm has a wider range of
activation
• Steel ligature ties avoided – insufficiently elastic to allow the bracket to rotate relative to
the archwire, as is necessary for the correction of tip (and torque) - therefore restricts the
action of the spring.

14. • Side-Winder springs should always be inserted from the
occlusal and never gingivally.
• The action of the spring will be the same either way but the
forces of mastication coming from the occlusal will be
deflected harmlessly off and if gingivally inserted, it will be
distorted.
• The direction of action of each spring can easily be ‘read’ in
the mouth by the clinician, according to the direction of the
spring arm. Since each spring is inserted occlusally, the
spring arm points in the direction towards which the
occlusal tip will rotate.
• Out of the mouth, hold the spring in a plier, hook facing the
operator - starting from its free end, if the hook curves away
in a clockwise direction, it is a clockwise spring, and vice-
versa

15. C. Power Pin
• This is a traction hook that can be fitted in the vertical slot
• Made of soft stainless steel, inserted from the gingival, and is
retained in the slot by bending the occlusally projecting tail 90
degrees.
• Strictly, this bend should be made in the opposite direction to the
elastic pull, since this avoids the possibility of a slackly turned pin
doing a ‘U-turn’ and being pulled out of the slot by the elastic.
• Most commonly used as hooks for seating elastics in the final
treatment visits.
• Also useful when an individual tooth requires retraction. Using an
elastomeric to a Power Pin, instead of directly to the bracket,
reduces the risk of distal rotation, since the bracket is secured by its
own elastomeric module (instead of by the end link of elastomeric
chain, which will inevitably be stretched open by the traction)

16. D. Rotating Spring
• Seldom required for correcting initial rotations – because
rotations of anterior teeth are dealt with by full bracket
engagement with light Ni-Ti wires.
• Very useful for recapturing a rotation that has recurred in
treatment, particularly if the patient is in a heavy archwire.
• E.g if a ligature or a bracket has detached from a previously
rotated tooth - convenient to be able to realign the
rotation with the flexibility of an auxiliary spring, than
stepping down to a lighter archwire.
• Comes in clockwise and counter-clockwise versions
• Made in .014 inch high tensile stainless steel.

17. • By using elastic ligatures in the normal way, there is a risk that
ligature failure or stretch may allow the spring arm to displace
the crown lingually.
• The difference between wire or elastic ligatures is that a wire
tie will limit the action to a perfect alignment, while an elastic
ligature will allow some degree of over-rotation.
• The ligature should be placed first, before inserting the spring.
• A wire tie should only secure the archwire on the side of the
bracket which is contacting the archwire and the ligature
should run around the backplate, rather than across it.
• To avoid occlusal interference, Rotating Springs should always
be inserted gingivally

18. E. Tip edge rings
• Elastomeric rings designed to function with tip-
edge brackets.
• Provide both arch wire attachment and mesial or
distal tip control in Stage III by filling the
chamfered wedge area.
• It parallels the archwire with the gingival and
occlusal edges of the tie wing tips. This is called
“hammock effect”.
• These rings are normally used only in the final
stage of treatment to maintain the crown
uprighting achieved with springs.

19. F. Straight Shooter
• A ligature gun, invented by Dr. Peter Kesling, is
ideally suited to Tip-Edge.
• Made from autoclavable plastic.
• Secure in position and press the trigger - the ring
is released.
• Advantages,
i. Less time consuming
ii. Places less pressure on the tooth ,more
comfortable for the patient
iii. Needs less concentration from the operator
iv. Safer

20. G. E-links
• Space closure is carried out using elastomeric
E-Links.
• Preferred to elastomeric chain, the force of
which can only be crudely adjusted
according to the number of links chosen.
• E-Links come in graded lengths with a
working life of up to 3 months in the mouth.
• Runs from the buccal hook on the first molar
to the cuspid circle.
• A long strand of elastomeric running parallel
to the archwire can be routed beneath the
retaining module on the premolar.

21. H. Outrigger appliance –
• Automatically reminds non-compliant
patients to replace the elastics by flicking out
sideways whenever the elastics are not
attached.
• Consists of a pair of hooks, coiled on the end
of an interconnecting span made in .016 inch.
• Seated in the occlusal tie-wings of the upper
central and laterals using ‘bilevel pins’.

22. TIP EDGE CONCEPTS:
Variable
anchorage
Root
uprighting
Light
forces
Differential
tooth
movement

23. DIFFERENTIAL TOOTH MOVEMENT -
• The very design of the edgewise derived brackets exerts
mesiodistal second order root forces from the time of first
engagement with an archwire.
• Yet it is recognized that positioning a root apex toward the
direction of pull will generate resistance to tooth movement
in response to that force.
• Dr. Charles Tweed developed the concept of ‘anchorage
preparation’, moving his apices mesially in the mandibular
buccal segments so as to increase anchorage resistance to
Class II elastic traction. (Tent- peg analogy)

24. • A bracket designed for differential tooth movement will not
impart root-angulating forces when an archwire is engaged.
• Instead, the crown will be able to tip in the direction of
desired tooth movement, essentially leaving the root apex to
trail behind.
• Such simple free tipping requires far less force and
anchorage than moving the same tooth bodily, although this
would in itself amount to incomplete treatment - makes
initial decrowding and reduction of big overjets dramatically
easy and rapid.
• This lends stability to the subsequent root uprighting
process - by establishing a strong interdigitation and
bringing the labial segments within the safety of normal lip
control.

25. VARIABLE ANCHORAGE -
• With differential tooth movement,
root control of the bracketed teeth
can be prescribed by the operator,
rather than occurring automatically
from first archwire engagement.
• This can be simply done by the
addition of an auxiliary (Side-Winder)
spring or springs, as was the case with
the Rx-1 bracket.
• The orthodontist now has the choice of which roots to control and when, perpetuates
the concept of variable anchorage control.
• This was not possible with conventional brackets, without resorting to more
complicated add-ons such as lingual arches, headgears or other anchorage
reinforcement.

26. LIGHT FORCES -
• It is fundamental to differential tooth movement that all forces should be light.
• A mere 50gms of intermaxillary elastic force bilaterally is quite sufficient for the
reduction of even large overjets.
• Heavier forces - unnecessary and harmful - posterior anchorage will be strained and
periodontal ligament put at risk.
• Differential tooth movement naturally implies a differential periodontal response -
tipping a tooth will induce most root movement at the gingival, diminishing towards
the apex - forces are therefore less evenly dissipated along the root.
• With light forces, this will not present any hazard.

27. ROOT UPRIGHTING -
• Edgewise & straight wire brackets offer very poor recovery from tipped angulations.
• Correction of mesio-distal crown tip by engaging the brackets with an active archwire
provokes major vertical consequences with extrusion of adjacent teeth.
• Use of power arms may facilitate the uprighting process but the vertical archwire
deflections remain.
• In tip edge recovery is by the light and progressive action of auxiliary springs.
• The vertical arch stability is maintained by relatively heavy but passive archwire

28. BONDING AND SETTING UP :
• The Tip-Edge appliance should be set up just like any other straight-wire
appliance.
• Some noted features will be explained under –
i. Bracket placement
ii. Premolar brackets
iii. Molar banding

29. 1. BRACKET PLACEMENT -
• Each bracket should be aligned with its vertical axis parallel with the long axis of
the tooth, and at the mid-point of the crown mesio-distally.
• The height of the bracket should be at the vertical mid-point of the fully erupted
clinical crown.
• Being a smaller bracket has aesthetic advantages, but also makes the accurate
placement more difficult - supplied with the option of plastic jigs.
• These provide ready ‘sight lines’ for the correct angulation and make the brackets
much easier to handle with conventional bonding tweezers.

30. • The jigs were produced only in ‘L-shaped’
form, which prescribes a fixed bonding
height for each bracket from the incisal
edge or tip, as denoted by the colour
coding.
• Jigs can be modified by cutting off the
horizontal section leaving only straight
vertical markers
• Universal jigs are more recent and can
easily be aligned up the long axis of the
tooth, while the mid-crown height can be
gauged by eye.

31. 2. PREMOLAR BRACKETS -
• Anterior tip-Edge brackets are designed to allow distal
crown tipping but premolars may require to tip either
mesially or distally, according to the extraction pattern.
• E.g: In a first molar extraction case, a second premolar
will require to tip distally.
If first premolars have been extracted, the same second
premolar will need to tip mesially into the extraction
space.
• Simplified bracket selection by using identical torque
and tip values in upper 1st and 2nd premolars – only
need to check whether the bracket is an upper or lower,
and if it is required to tip clockwise or counter-
clockwise.

32. • Upper premolar brackets are identified by circular
markings on the tie wings, lowers by triangular markings.
• These are offset towards the direction of tip.
• On the occlusal tie wings, an arrow is an additional
indicator of the direction of rotation.
• In various possible extraction patterns, the arrows usually
point towards the extraction site and in a non-extraction
case, towards the distal.
• As a rule of thumb, all the arrows point distally, except
second premolars in first premolar extraction cases

33. 3. MOLAR BANDS -
• Use of bonded first molar tubes is contraindicated - the withdrawal of the rectangular
archwires at the end of Stage III is likely to cause bond failure.
• The rectangular buccal tubes should be aligned to the brackets, at mid-crown height,
just as with a straight-wire appliance.
• The round tube will sit towards the gingival margin.
• In the mandibular arch, the tubes should be parallel to the occlusal cusps; in the
maxillary arch, seating the band fractionally higher toward the distal may be helpful in
obtaining final seating of the disto-buccal cusp.

34. TREATMENT STAGES :
STAGE 1
Anterior alignment
and incisor space
closure
STAGE 2
Closure of extraction
spaces
STAGE 3
Root uprighting

35. STAGE I :
• Objectives:
1. Initial alignment of upper/lower anterior segments
2. Closure of anterior spaces
3. Correction of increased overjet or reverse overjet
4. Correction of increased overbite or AOB
5. Work towards arch coordination

36. • Mechanics:
1. Place upper and lower 0.016 SS base archwires with cuspid circles just mesial to
the canine brackets and gently engage all possible teeth into round molar tube.
2. Severely displaced teeth can be engaged with elastic thread passed through the
vertical slot.
- Round nickel–titanium underarch, usually of .014 inch diameter can be used to
align instanding anterior teeth,
3. Leave out the premolars.

37. 4. Place gentle anchor bends in front of the molars, placing the base archwire in the
gingival slot. These bends reciprocally intrude incisors by the idea of ‘’dig in heels’ of
lower molars to resist the light mesial pull of the elastics.

38. 5. Once anterior alignment has been achieved, each canine bracket should be
ligatured to its respective cuspid circle with an elastomeric.
- Purposes:
i. the canines are prevented from unwanted further distal migration, so that the
anterior segment will not become spaced
ii. the archwire is stabilized laterally, and cannot swing from side to side.
6. Use Class II elastics (60g only) from circles on the upper archwire to the lower 6’s.

39. 7. Power tipping: If unwanted proclination of lower incisors during overbite
reduction, utilize ‘reverse Side-Winder springs’ – induce distal crown torque to
the lower canines, and hence distal retraction, which in turn uprights the lower
anterior segment lingually

40. 8. The Protraction Arch: In non-extraction cases with mildly crowded lower incisors, a
small amount of proclination of the incisors is deemed permissible.
- Fabricated from the same wire, .016 inch high tensile stainless, cuspid circles are
placed at least 3 mm distal to the canine bracket
- Protraction is activated by means of an elastomeric module stretched between each
canine bracket and the circle behind it
- As the elastomeric contracts, the archwire will be drawn forwards through the molar
tubes, making more wire available at the front, allowing the incisors to align onto a
bigger curvature.

41. STAGE II:
• Objectives:
1. Closure of residual spacing - by retraction of labial segments or by protraction of
buccal segments.
2. Correction of centrelines.
3. Derotation of first molars.
4. Levelling of first molars.
5. Continuing crossbite correction.
6. Maintenance of Stage I corrections.

42. • Mechanics:
1. Premolars should be included prior to the start of Stage II and use the same archwires
after removing the anchorage bends and replacing them with vertical bite
sweeps,(reverse curve of spee) to retain the overbite reduction. The wire is inserted into
the rectangular molar tubes.
2. Correction of premolar displacements and rotations can be corrected with elastomeric
E-Links, elastic threads or an .014 inch nickel–titanium underarch.

43. 3. The archwire size is then increased to 0.020” round SS.
4. When closing buccal segment spacing, by class one elastic by using E-links
between the circles on the archwire to the hooks on the 6’s, it is possible to choose
between retraction of the labial segment or protraction of the posterior segment
by adding adding Side-Winder ‘brakes’.

44. 5. In view of a centreline discrepancy, consider using unilateral sidewinders.
- The centreline is to the patient’s right,
where the extraction space closed.
Closure of remaining space will
automatically correct the centreline
without the need for a brake.
- With a correct centreline, a defensive
brake is now required to the left canine,
so that space is closed by protraction.

45. - The centreline needs correcting into the patient’s left quadrant space, by retraction,
whereas the space remaining in the right quadrant must be closed by protraction. The
lower right canine is therefore braked and an additional side-winder is placed on the
right central incisor, for distal root movement.

46. 6. A limited amount of first molar rotation can be expected as a result of space
closure with free-sliding mechanics.
- Requires a simple adjustment to the archwire, placing a 1 mm buccal offset and
10 degrees of lingual toe-in opposite the interspace between the fi rst molar
and premolar
- To prevent space recurring, the distal archwire ends should be annealed and
turned gingivally.

47. 7. Leveling of molar should done to allow the placement of rectangular archwires
- Anti-tip bend of 10° opposite to premolar-molar contact point.
- Ensures seating of the distal cusp of tipped molars
8. Maintain Class II elastics as required to keep the upper and lower incisors in
gentle contact.

48. TORQUE IN TIP-EDGE :
• A conventional edgewise or straight-wire bracket has flaws,
i. Rectangular wire required to provide active torquing and offering three-
dimensional stability to the remainder – physical impossibility
ii. active torque imparted to a single unit, or quadrant - unwanted secondary
torque reactions in adjacent units
iii. flexibility of a nickel–titanium archwire preferable for torquing with light forces
but stainless steel preferable for maintaining stability.
iv. nearly 10 degrees of ‘torque slop’ between .019 × .025 inch archwire and .022 ×
.028 inch bracket slot

49. • A Tip-Edge bracket cannot be torqued by an
active archwire in the conventional manner as
intact upper and
• lower finishing surfaces in each bracket are
offset from one another, and are therefore never
directly opposed.
• Insertion of an actively torqued rectangular
archwire will elevate one finishing surface and
depress the other - torquing effort in the
archwire dispersed by increasing the vertical
dimension within the Tip-Edge slot.
• The net result - relapse of root uprighting in the
mesiodistal direction - ‘torque escape’.

50. • Originally torqueing required a Side-Winder for each individual bracket but in
the Plus bracket all torquing and tipping can be carried out with a Ni-Ti
auxiliary archwire, threaded through the deep tunnels.
• In Stage III, a stainless .0215 × .028 inch archwire can be fitted without difficulty
due to the excess vertical dimension of slot.
• No torque will therefore be imparted at this point except in first molars.

51. • The vertical deflections of the auxiliary archwire (.014”) in the deep tunnels will
generate tip correction.
• After some initial correction of tip, a point is soon reached when further closing
down of the bracket becomes obstructed by the opposite corners of the
rectangular archwire.
• A two-point contact is thus established within the bracket.

52. • When the bracket becomes fully closed down to
the vertical dimension of the archwire, the upper
and lower flat surfaces of the bracket slot will be
in contact with the flat upper and lower surfaces
of the archwire.
• The rectangular archwire cross section remains
undeflected throughout the entire torquing
process, thereby the wire can torque teeth
individually, without unwanted torque reactions
to neighbouring teeth.
• In short, instead of increasing archwire thickness
to fill the bracket, a Tip-Edge bracket shrinks its
vertical dimension (under pressure from an
auxiliary) to fit a full sized archwire, conforming
to it precisely in all three dimensions.

53. STAGE III:
• Objectives:
1. Maintain Stage I/II changes
2. Correct torque and Tip
3. Detailing & finishing

54. • Mechanics:
1. Archwire: 0.0215” x 0.028” stainless steel base wire- flat or pre-torqued and place
crimpable hooks between canine and lateral incisor.
2. Using Side Winder springs or piggy back 014 or 016 NiTi in TE plus
- Thread the auxiliary wire first using midline or distal aproach.

55. 3. Maintain the space closure using ligatures from crimpable hooks to the hook on
the molars.
4. Use Class II elastics to maintain light contact between the upper and lower
incisors.
5. Final finishing to be done along with second molar alignment and occlusal
seating.
This should be followed by a long-term retention protocol.

56. ADVANTAGES:
1. Increased inter-bracket span because of the reduced bracket size MD
2. Little need for HG
3. Less anchorage demand because,
i. Differential force theory and light force
ii. Less expression of the tip during the first stage of treatment
iii. Round wire with reduced friction during the first stage of treatment
4. Precision in finishing
5. TE bracket can be used with SW in case of proclined or retroclined canines

57. DISADVANTAGES:
1. Expensive
2. Extraction philosophy and possible profile dishing
3. Reliant on elastic wear
4. Poor rotational control
5. High risk of root resorption and risk of PD damages
7. Complex in stage III specially the old TE system because each bracket requires
an auxiliary spring to deliver its final prescription.
8. Increased friction in later stages

58. CASE REPORTS :
Case report 1: A severe Class II division 1 malocclusion with increased overbite on a
very low mandibular angle Class II base treated with the Plus bracket

62. Case Report 2: A severe Class II division 1 malocclusion with a marked unilateral overjet
treated with the Plus bracket

67. ARTICLES :

70. CONCLUSION:
• The tip edge bracket provides varying degrees of tooth control not previously
available in an edgewise type bracket.
• It also offers advantages over ribbon-arch (Begg) brackets through ease of
manipulation provided by the horizontally facing slot plus predetermined
limitation of initial crown tipping and control of final root uprighting.
• But further studies need to be conducted to determine the true efficiency of this
bracket system over the currently accepted treatment protocols.

71. REFERNCES :
Tip-Edge Orthodontics and the Plus Bracket - 2nd Edition, Richard Parkhouse
Parkhouse, R. C. (2007). Current products and practice: Tip-Edge Plus. Journal of
Orthodontics, 34(1), 59–68. doi:10.1179/146531207225021933
Kesling PC. Dynamics of the Tip-Edge bracket. American Journal of Orthodontics
and Dentofacial Orthopedics. 1989 Jul 1;96(1):16-25
Kesling PC, Rocke RT, Kesling CK. Treatment with Tip-Edge brackets and
differential tooth movement. American Journal of Orthodontics and
Dentofacial Orthopedics. 1991 May 1;99(5):387-401.