The document discusses various types of ligation methods in orthodontics, focusing on elastomeric ligatures and their mechanical properties. It highlights the advantages and disadvantages of different ligation techniques, including the frictional resistance they produce and their impact on treatment efficiency and comfort. The findings also address microbial plaque retention due to ligatures and suggest considerations for clinicians when choosing ligation materials.

2. Methods of Ligation
Prof. Dr

3. Elastomeric Ligatures
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9. Ligatures are used to tie the archwire to the bracket. The archwire
fits into the slot in the bracket and the ligature goes around the
wings of the bracket to hold the archwire in place
Elastomeric ligatures

10. Elastomeric ligatures

11. Elastomeric ligatures

12. Elastomeric ligatures

13. O-Tie elastics act like bungee cords- they
cause friction and pressure, by holding the
wires tight into the bracket. This makes
treatment slower and less comfortable. The
rubber ties also absorb plaque and bacteria.
Elastomeric ligatures

14. Effect of Ligation Technique on Friction : • The normal force
exerted by the ligature has a significant influence in determining
the frictional resistance developed within an orthodontic system.
This force has been estimated to be between 50-300g, and upto
375g in one study. • Various methods of ligation are available: -
stainless steel ligatures, elastomeric modules, polymeric coated
modules and finally the self ligating brackets, which may be
having a spring clip (Hanson SPEED and Adenta Time) which
pushes the wire into place, or it may have a passive clip which
does not press on the wire (Activa and Damon II brackets.)

16. There is a large body of literature to demonstrate the much higher
friction between bracket and archwire with elastomeric ligation
compared with wire ligatures
Elastomeric Ligatures

17. Elastomeric ligatures are adversely affected by the oral environment,
and demonstrate stress relaxation with time and great individual
variation in properties. • Stainless steel ligatures can be tied too tight
or too loose depending on the clinicians technique. • Self ligating
brackets with a passive clip have been shown to generate negligible
friction

18. Edwards et al (BJO 1995) compared the frictional forces produced
when elastomeric modules were applied conventionally or in a
“figure of –8” configuration, stainless steel ties or Teflon coated
ligatures were used for archwire ligation. The “figure of 8” modules
appeared to create the highest friction. There was no significant
difference in mean frictional force between the conventional module
and the SS ligature, but the Teflon coated ligature had the lowest
mean frictional force. •.

19. Dowling et al (BJO 1998) investigated the frictional forces
of differently colored modules & found the clear modules
to exhibit significantly lower friction than other modules.
This study however was carried out in absence of saliva

20. Khambay et al (EJO 2004) compared the effect of elastomeric type and
stainless steel ligation on frictional resistance and these were further
compared with self ligating Damon II brackets. There was no consistent pattern
in the mean frictional forces across the various combinations of wire size,
type, and ligation method. The polymeric coated module did not produce the
lowest mean frictional force. The introduction of a 45 bend into the module
(Alastik Easy-to-use) reduced mean frictional force to that of a SS ligature
when using 19 x 25” SS wire. The use of metal ligatures with 7 turns produced
the lowest friction confirming the findings of Bazakidon et al (AJO-DO 97).
They concluded that the use of passive self ligating brackets is the only way of
almost eliminating friction

21. Leone
Slide Low
Friction
ligatures

23. Lam et al., reported substantial variation in the range and
tensile strength of elastomerics from different
manufacturers and for different colors of elastomeric from
the same manufacturer
Elastomeric Ligatures

25. Zachrisson and Zachrisson stated the etiology and
pathogenesis of periodontal diseases are multifactorial, but
dental plaque certainly is an essential precursor. The
presence of elastomeric modules and stainless steel ligatures
are taken into account for microbial dental plaque retention
which causes enamel demineralization due to decrease in pH
level caused by increase in number of acid-producing
bacteria, mainly Streptococcus mutans and lactobacilli, which
ultimately results in appearance of white spots and caries in
approximately 50% of patients undergoing fixed orthodontic
treatment.

27. Mosquito forceps are used for placing elastic ligatures and
tightening the ligature wire around brackets. It is available
in straight and curved (45 ˚)end pattern. Beaks are serrated
for better grasp.
For elastic ligation
and usage.
Mosquito forceps
For elastic ligation.
The tips are made so
small to pick up the
elastic at ease and
usage.

28. Steps of ligation

29. Steps of ligation

30. Steps of ligation

31. Elastomeric ligatures became available in the late 1960s and
rapidly became the most common means of ligation, almost
entirely because of the greatly reduced time required to place
and remove them when compared with steel wire ligatures
Steel ligature

32. It was also easier to learn the skills required to place these
ligatures, so new clinicians and staff greatly preferred
elastomerics .
Elastomeric
Ligatures

33. Initially these elastic bands were made from natural rubber,
but production of elastomeric chains and ligatures followed
the ability to produce synthetic elastics from polyester or
polyether urethanes.
Elastomeric
Ligatures

34. Steps of ligation

35. The ease of use and speed of placement of elastomerics
ligatures did, however, lead to other definite
disadvantages being generally overlooked, although
readily apparent. Elastomerics frequently fail to fully
engage an arch wire when full engagement is intended.
Elastomeric Ligatures

36. Twin brackets with the ability to “figure-of-eight” the
elastomerics are a significant help in this respect but at
the cost of greatly increased friction
Elastomeric Ligatures
B: elastomeric ties (Sani-ties GAC) (O-ring);
c: GAC figure-of-eight elastomeric ties;
c

37. Khambay et al. quantified
the potential seating forces
with wire and elastic
ligatures and clearly
showed the much higher
archwire seating forces
available with tight wire
ligatures.
Elastomeric Ligatures

38. A well-documented drawback with elastomerics
is the substantial degradation of their
mechanical properties in the oral environment.
Elastomeric Ligatures

39. Typically elastomeric chains and ligatures undergo
greater than 50% degradation in force in the first 24
hours when tested under in vitro experimental
environments.
Elastomeric Ligatures

40. Elastomeric o ties cause loss of rotational control of
canines during space closure. Twin brackets with the
ability to “figure-of-eight” the elastomerics are
indicted in this situation
Loss of arch wire control
with elastomeric ligation.
Elastomeric Ligatures

41. Interestingly, friction proposed as a factor of clinical significance
more than 30 years ago but was largely disregarded until more
recently. The great popularity of elastomeric ligation in the last 40
years was achieved despite these substantial deficiencies in relation
to wire ligatures.
Elastomeric Ligatures

47. Elastic Ties
• Once the arch wire has been positioned it must be ligated
into place, the elastic ties stretch around the bracket to
hold the arch wire in place. They come in different colors
• Use the Hemostat to place the elastic ties and the
orthodontic scaler to remove them

48. Speed and ease of use were the overriding assets of elastomerics,
and it is no surprise that the strongest motivation behind the early
efforts to produce a satisfactory self-ligating bracket was a desire to
have all the benefits of wire ligation but in addition to have a
system that was quick and easy to use.
Elastomeric Ligatures

49. With wider bracket the elasomeric
ligature was stretched more than with a
narrow bracket, producing almost twice
as much friction, due to greater normal
force exerted on the wire
Elastomeric Ligatures

50. B: elastomeric ties (Sani-ties GAC)
(O-ring); c: GAC figure-of-eight
elastomeric ties;

51. Figure 8 elastic tie
•Works in horizontal and vertical orientation. Use
vertical 8’s to allow easier M-D movement –less
friction- and horizontal 8’s when M-D achieved
to help lock in that spacing –greater friction.
Elastomeric
Ligatures

52. Figure 8 quick start
• Figure 8’s come in 3 sizes, small, medium and large. Choose
appropriate size for ligation based on the bracket size central,
lower anterior, etc. as well as how much force is required on
that specific bracket. Make sure the figure 8 is secured
beneath tie-wing . Since brackets come in many shapes and
sizes it is up to the practitioner to judge the fit is correct to
remain in place until the next office visit.

54. The placing of ‘figure-of-eight’ elastomeric ties increased
friction by a factor of 70-220 per cent compared to the
O” elastomeric ties
Elastomeric Ligatures

55. Alternatively, the clinician may choose to use the elastic figure-8
technique, in which the O-ring criss-crosses over the bracket (B).
Twist - ing the O-ring in this manner increases its elastic tension,
which helps seat the archwire, but because the force levels of the
O-ring are symmetrical, they may still be inadequate to fully seat
the wire
Elastomeric Ligatures

56. Asymmetrical O-Ring Ligation
Traditional elastic O-ring ligation with twin brackets often fails to
correct severe malrotations because of the inability to fully seat the
archwire into the bracket slot (A). The clinician is faced with the
decision whether to step down to a lighter nickel titanium wire or
conventionally ligate the wire to the tooth, which is time-consuming
and technique-sensitive and may result in de - bonding
Elastomeric
Ligatures

57. A method of asymmetrical O-ring ligation that is a slight
modification of the elastic figure-8 is used (C): 1. On the
side opposite the rotation, pull the Oring over the two
vertical tie wings. 2. Pull the O-ring under the incisal tie
wing on the rotation side. The O-ring should now seat over
the two vertical tie wings on the side away from the
rotation.
Elastomeric Ligatures

58. 3. Pull the O-ring under one vertical tie wing on the rotation
side (this step distinguishes the asymmetrical tie from the
figure-8 tie). 4. Wrap the O-ring over the other vertical tie
wing on the rotation side. By stretching the Oring behind the
tie wing, rather than crossing over the bracket slot, an
asymmetrical force load is created to help fully seat the
archwire into the bracket slot.
Elastomeric Ligatures

59. Alternatively, the clinician may choose to use the elastic figure-8
technique, in which the O-ring criss-crosses over the bracket (B).
Twist - ing the O-ring in this manner increases its elastic tension,
which helps seat the archwire, but because the force levels of the
O-ring are symmetrical, they may still be inadequate to fully seat
the wire
Elastomeric Ligatures

60. AlastiK ™ Easy-To-Tie Ligatures
AlastiK™ Easy-To-Tie Ligatures are designed with a 45˚ bend which
makes tie-wing hook-up easier and more efficient than ever before.
The unique angled shape reduces the range of movement needed
for bracket ligation, improving the entire process for you and the
patient. With less contact of the placement tool with the patient’s
lips, patient comfort is enhanced.

63. Elastomeric Ligature with Guard
• Not Made With Natural
Rubber Latex • .124 in. (3.1
mm) outer diameter •
Reduces tooth contact with
ceramic brackets on
mandibular teeth • Injection
molded memory material

64. A comparative study of the physical and elastic properties of new generation
elastomeric ligatures with conventional elastomeric ligatures
Journal of Dr. NTR University of Health Sciences 2015;4(2) 91-96
Four groups of clear elastomeric modules (inside diameter 1.3 mm, outside diameter 3.1
mm, thickness 0.9 mm) were evaluated and compared in this study [Figure 1]. The first
group (CO) comprised of the conventional polyurethane-based elastomeric modules
obtained from Millenium Orthodontics, New Delhi, India. The second group (LF) constituted
the latex free elastomeric modules obtained from Desires Orthodontics, Davangere, India.
The third group (AL) comprised of Alastik™ Easy-to-tie modules (with 45° bend) obtained
from 3M Unitek, Monrovia, CA, USA. The fourth group (SL) constituted the super ligatures
which were silver and silicone impregnated obtained from D-tech, Pune, India
CONCLUSION The decrease in tensile properties of elastomeric ligatures shows that they
may have to be replaced at each appointment to reduce the risk of rupture.
There are signifi cant differences in tensile properties of different brands of ligatures, which should be considered
during the selection of these products. Considering the number of variables evaluated in this study, it is difficult
to conclude about the best elastomeric ligature from the point of physical and elastic properties. It is also
suggested that manufacturers offer the relevant data to their customers in order to facilitate the selection of
appropriate elastomeric ligatures as per their clinical demands.

65. Space closure by elastomeric module with ligature wire is better than the E-chain.
During space closure procedure two different retracting components were applied in
right and left sides of each case. On right side elastic chain (E-chain) applied in both
upper and lower arches and on left side elastomeric module with steel ligature (0.010″)
stretched double its diameter fixed in both arches
bimaxillary dentoalveolar protrusion; elastic chain; elastomeric module with ligature
Retraction with elastomeric chain. Retraction with elastic module.
A comparative evaluation of rate of space closure after extraction using E-chain and stretched modules
in bimaxillary dentoalveolar protrusion cases

66. Retraction with elastomeric chain. Retraction with elastic module.
To facilitate tying of retracting component anteriorly, a small piece of 0.019″ ×
0.025″ wire was shaped as “S” and welded to the base arch wire in all four
quadrants immediately
distal to canines. This “S”-shaped wire was ligated by the force
delivery system in all the four quadrants with molar hooks.
Slide* ligatures

67. Leone offers elastics manufactured with the best quality of latex available. The
innovative low friction Slide* ligatures are manufactured in a special medical grade
polyurethane mix providing all the advantage of low friction biomechanical properties
with shorter therapeutic times and without the need of extractions. These ligatures are
especially indicated for use with Logic Line brackets. Leone modules for ligatures are
stamped from elastomer offering the best elasticity and resistance to oral liquid
absorption. Leone wires for metal ligatures are manufactured out from a high vacuum
annealed alloy for the best fit and higher mechanical load.
Slide* ligatures

68. Slide* ligatures

69. A new low force ligation system – jco 2005-
• This article describes an alternative
to self ligating system a ligature that
markedly reduced the friction b/w the
Arche wire and bracket.
• The slide ligature wire is made of
special polyurethane, is applied in the
same way as conventional as a
elastomeric ligature .
• Like a passive self ligating it forms a
fourth wall and allow archewires to
slide freely in the slot while
transmitting its full force to the teeth.
Elastomeric Ligatures

70. This ligature also forms the buffer b/w the bracket and soft
tissues considerably improving patient comfort.
A new low force ligation system – jco 2005-

71. If high friction is demanding, conventional brackets tied
with elastomeric ligatures may be used. If low friction is
required, it is possible to use low friction ligatures, such as
Slide ligatures (Leone, Florence, Italy)
Elastomeric Ligatures

72. The new Slide low friction ligatures AQUA are not subject to corrosion
by oral liquids and are now even more resistant to discoloration (a
recurring issue with transparent elastomers). Changing ligatures
frequently is no longer necessary and perfect aesthetics is guaranteed.
This ligature is indicated for use with logic line aesthetic brackets which
are featuring a housing to keep Slide ligature in place for the
integration in the bracket’s profile. Clear color.
Slide AQUA low
friction ligatures

73. Ligatures: Conventional elastomeric ligature (CEL) (Leone)
Slide ligation also showed lower friction with
different archwires combinations.
Frictional force released during sliding mechanics in nonconventional
elastomerics and self-ligation: An in vitro comparative study