The document discusses methods for closing spaces during orthodontic treatment. It describes two main methods: sliding mechanics and loop mechanics. Sliding mechanics involve sliding brackets along the archwire using elastics or coils, while loop mechanics use loops of wire between brackets to close spaces without bracket movement. The document outlines considerations for each method and discusses techniques for closing extraction spaces and retracting canines specifically. It also notes potential problems and solutions during space closure.

1. SPACE CLOSURE
Prepared By:
Dr.Maeen Saleh Al-Bahloly
2nd year orthodontic resident
Supervised By:
Dr.Ahmad Altarawenah
Dr.Raed Alrbta

2. Outlines
1) Introduction.
2) Methods of space closure:
 Sliding mechanics.
 Loop mechanics.
3) Closure of extraction spaces:
 Moderate anchorage treatment with 18 & 22-slot
edgewise.
 Maximum anchorage treatment with 18 & 22-slot
edgewise.
 Minimum anchorage treatment.
4) Retraction methods.
5) References.

3. Introduction
 Space closure is an important step on
orthodontic mechanotherapy ,solely dictated
by clinical treatment objectives and
irrespective of method employed.
 Space closure should be individually tailored
based on the diagnosis and treatment plan.
 Selection of any method should be based on
desired tooth movement.

4. Goals for any space closure method
• Differential space closure capability.
• Axial inclination control.
• Control of rotation and arch width.
• Optimum biological response.
• Minimum patient cooperation.
• Operator convenience.

5. closureDeterminants of space
• Amount of crowding.
• Anchorage .
• Axial inclination of canine and incisors.
• Midline discrepancy and R/L symmetry.
• Vertical dimensions.

6. When you start space closure??
After alignment and leveling when you reach the
working arch wire.
18-slot 16x22 SS.
22-slot 19x25 SS.

7. Methods of space closure
Sliding mechanics (frictional system):
The bracket slides along the arch wire by using
elastics, Niti coil spring or others.
Loop mechanics (frictionless system):
The teeth are moved without the bracket sliding
along the arch wire by a numerous design of
springs and loops.

8. Sliding mechanics
• Teeth slide along the arch wire by energy stored in elastic
or wire coil spring.
• Usual use 19x25 SS arch wire and place coil spring from a
hook on the arch wire to the hook on molar band.
• Pre-adjusted appliances facilitate sliding mechanics
because the level-slot line-up means that torque can stay
passive during sliding.

9. Sliding mechanics
Advantages:
• Minimal wire bending time.
• Initial wire placement is less time consuming.
• Enhances patient comfort.
• More efficient sliding of arch wire through posterior bracket slots.
Disadvantages:
• Confusion concerning the ideal force levels.
• Tendency to over activate the elastic and spring forced which cause
initial tipping and need time for tooth uprightening.
• Variable forces.
• Degradation of force.
• Slower than loop mechanics due to friction.
• Staining of E-chain.

10. Types of sliding mechanics:
1) Movement of brackets along an arch wire.
2) Movement of arch wire through brackets.
Methods of canine retraction in sliding mechanics:
Elastic module with ligature.
Elastomeric chains.
Coil springs.

11. Elastic modules with ligature
• A single elastic module used to secure arch wire
to brackets is attached to canine by ligature wires
extending from the molar.
• These tiebacks are activated 2-3 mm or twice
their original size to produce 100-150 gm of force.
Elastomeric Chain
• Introduced to orthodontic at 1960.
• Used for canine retraction,diastema closure,
rotation correction, arch constriction.

12. Advantages:
• Inexpensive.
• Relatively hygienic.
• Easily applied.
• No need for patient cooperation.
Disadvantages:
• Decreased and loss of effectiveness.
• Chance of breakage.
• Staining.
• Difficult to clean.

13. Clinical consideration when using elastic
• To optimize tooth movement, sufficient time should
be allowed for distal root movement to occur.
• A common mistake is to change the elastic chain or
module too often that lead to high force level and
M/F which cause distal crown tipping only.
• Also cause excessive mesial out rotation of canines.
• Excessive force can inhibit direct resorption around
the canine, bone resorption in posterior segment
with loss of anchorage.
• Elastic modules or chain should be changed every4-6
weeks.

14. Closed coil springs
• Introduced to orthodontic world at 1931.
Types :
1. S.S coil spring:
• Efficient for canine retraction.
• It has a higher load deflection rate compared to
Niti springs.
2. Niti coil spring.
3. Elgiloy coil spring.

15. • Samuels et al (1993), compared the space closing
effectiveness of elastic modules and “150gm” Niti
coil spring on 19x25 arch wire and found:
1. Niti springs produce more rapid and consistent
movement.
2. Elastic modules produce approx. 33% less
movement per unit time.
• 150gm coil spring is recommended.
(Samuels et al 1998)

16. • Niti coil spring (9mm) coils, (3mm of actual coil
spring) should not stretched by more than 9mm.
(Seidenbusch et al 1996)
• Force degradation in Niti spring ranged from
8 -17% over 28 days. (Angolkar et al 1992)
• Force degradation in elastomeric chain ranged
from 50-70% in the 1st day and 30-40% for the
remaining 3weeks. (Baty 1994)

17. Causes of failure of spaces to close with
sliding mechanics
1. Excessive friction: (1st suspected cause)
Situations in which friction excessive:
• Active forces between bracket & wire
(especially torque force)
• The ends of arch wire inside the molar tube.
• Bracket or tube may be distorted with distal-end cutter.
• Ceramic bracket produce more friction. (Kusy et al 1990)
• Excessive space closing force plus severe curve of spee cause
bowing of the wire.
• Multiple bracket distal to the space to be closed.
• Conventional ligation with elastomeric modules as figure of 8.

18. 2. Occlusal interference:
• Lower canine brackets can impede upper canine tip
when correcting Cl II relationship.
• Ricketts type utility & T-loop arches.
• Higher occlusal forces in adult & Cl II /2 cases.
3. Intra alveolar causes: (rare)
• Retained deciduous teeth fragments.
• Apices of extracted permanent teeth.
• Root too close:
Especially in the upper arch where canine
angulation is greater.
• Waisting of the bone:
Atrophy of the alveolus due to old tooth loss.
4. Idiopathic.

19. Sequence for dealing with a failure of
space closure with sliding mechanics
• Check for causes as listed previously.
• If no cause can be found and wire hard to swivel,
so the friction is too high.
• Steps to lower friction:
o Use thinner wire.
o Remove curve of spee with overbite situations.
o “ O ” configuration in one tie-wing only.

20. • Propping the bite with GIC on lower molars.
• Increase the force for one visit.
• Leaving the 2nd molar out of space closure for
1 or 2 visits.
• If the space still not closed, increase in force is
not advisable. Check again for friction &
occlusal interference, and consider switching
to closing loop mechanics.

21. Other methods for reduction of friction
• Wonder wire:
It is a dual diameter wire has a rectangular
anterior segment to maintain torque control &
round in cross section in posterior segment.

22. • Self - ligating brackets:
Use the elastic chain under the arch wire.
• Sectional mechanics:
Using TMA cantilever spring in the buccal
sulcus.

23. Problems during sliding mechanic of
canine retraction
Occlusal interference -solution: bite plane.
Poor canine control-solution: using a heavier
arch wire.
Rotation of canine mesiobuccally and molars
mesiopalatally-solution:palatal traction using
lingual cleats or buttons.

24. Loop mechanics
Advantages:
• No friction except for the bracket between the loop
and the space.
Disadvantages:
• fabrication; loop must not impinge on mucosa and
placed accurately between bracket.
• Need good oral hygiene.
• Increase flexibility at a stage when rigid wire is
needed.
• Small single loops give a short range of action.
• Difficult activation.

25. Closing loops
Design considerations:
• Fabricated from rectangular wire to prevent
rolling of wire in the bracket slot.
• The performance of the loop is determined by:
1.Spring properties:
Determined by wire material (SS, beta -Ti), size of
wire, distance between points of attachment.

26. 2.Moment:
It generates to bring the root apices together.
o Placing some of the wire of the loop in a horizontal
direction improves it is ability to deliver the
moments needed to prevent tipping.
o Additional moments must be generated by Gabel
bends.

27. 3. Location: there are 3 location
o Equal distance.
o Closure to anterior .
o Closure to posterior.
• If it is in the center of the span, it produce equal
force and equal couples on the adjacent teeth.
• If it is in one 1/3 of the distance between adjacent
brackets, the tooth closer to the loop extruded
with moment and the tooth far away intruded .

29. 4. Fail safe:
Tooth movement should stop if patient not come
for scheduled appointment.
5. Design:
Should be simple, and loop more effective when
closed rather than opened.

30. Biomechanics of closing loops
Bends are placed on the mesial & distal legs of
loop, called Alpha& Beta bends.
These bends produce Alpha and Beta moments
when wire is placed into bracket.
Moment is determined by loop design.
Force is produced by loop activation.
Neutral Activated

31. If Beta moment > Alpha moment
Anchorage enhanced by mesial root movement of
posterior teeth with posterior extrusion& anterior
intrusion.
If Alpha moment > Beta moment
Anchorage of anterior segment increased by distal root
movement.
Anterior extrusion & posterior intrusion.
If both equal no vertical force.

32. Activation of loop:
• Pulling the distal end of wire through molar tube
and cinching back.
• Soldering a tie back mesial to molar tube on
arch wire.

33. • Moment to force ratio (M/F) determined the
type of tooth movement.
• Moment to force ratio for various tooth
movement:
( M/F Ratio) ( Tooth movement)
5 : 1 Uncontrolled tipping.
8 : 1 Controlled tipping.
10 : 1 Translation.
> 10: 1 Root movement.

34. M/F could be increased by: (Brustone& Koenig)
• Increase vertical dimension of loop.
• Increase horizontal dimension in the apical part of
loop.
• Increase the apical length of the wire.
• Helix incorporation.
• Angulation of loop legs.
• Decrease interbracket distance.
• Position of loop close to tooth to be retracted
bodily.

35. • The most way to increase M/F ratio by placing
Preactivation bends or Gable bends
(20 degree in each side).

36. Vertical loops
• There are 2 types:
1. Open vertical loop.
loop legs should be separated.
2. Close vertical loop.
loop legs should be closed together and parallel.
• Modified vertical loop like Omega loop.

37. Omega loop

38. Disadvantages of vertical loop:
• Very high force.
• Force & M/F extremely sensitive to small changes
in activation.
• Discomfort to the patient.
• Loss of anchorage and root control.
• Dumping of teeth.
• Small activation leads to rapid force decay &
intermittent force delivery.

39. Horizontal loops
1) Opus closing loop:
• Designed by Siatkowaski.
• Fabricated from 16x22 or 18x25 SS
or 17x25 TMA .
• Close space under good control.
• Activated by tightening it distally behind the molar
tube to produce maximal, moderate or minimal
incisor retraction.

40. 2) T-loop:
• Segmented T-loop made from 17x25 TMA.
• Continuous arch wire with T-loop:
Made from 16x22 SS or 19x25 SS.

41. Space closure problems during using
continuous arch wire T-loop
Tipping of anterior &posterior segments to the
extraction site-solution: increase alpha &beta
moment.
Flaring of anterior teeth-solution: reduce alpha
moments or increase distal activation.
Excessive lingual tipping of anterior teeth-
solution: increase alpha moment.

42. 3)Composite retraction spring:
• Designed by Brustone.
• Used with segmented arch technique for en
masse retraction of incisors or canine retraction.
• Made of 18mil beta-Ti wire(the loop) welded to
17x25 beta-Ti.

43. Closure of extraction spaces
• To obtain the desired result of closing spaces
within the arch, it is essential to control the
amount of incisor retraction versus molar and
premolar protraction.
• It depends on the amount anchorage needed.

44. • Most patients fall into the moderate anchorage
category, it is desired to close the reminder of
premolar extraction space with 50:50 or 60:40
ratio of anterior retraction to posterior
protraction.
• The difference wire size in 18- and 22-slot
edgewise appliances require a different approach
to mechanotherapy.

45. Moderate anchorage treatment with
18-slot edgewise
• Most commonly used wire 16x22 SS.
• Beta-Ti wire produce smaller force than SS.
• Either loop or sliding mechanics can be used.
• Single or narrow twin brackets on canine and
premolar is ideally for use of closing loops in
continuous arch wire.

46. • Closing loop in a horizontal direction rather
than vertical to prevent tipping.
• Greater retraction if 2nd molar is part of
anchorage &less if incisor torque is required.
• Delta-,L- or T- shaped loop is preferred.
• 17x 25 Beta-Ti wire used for finishing phase of
treatment.
Delta- loop T- loop

47. Moderate anchorage treatment with
22-slot edgewise
• Most commonly used wire 19x25 SS.
• 18x25 SS wire can be used.
• As a general rule,(60:40) it can be done in two
steps:
1st Retracting the canines usually with sliding
mechanics using Niti coil spring.
2nd Retracting the four incisors usually with
closing loop mechanics.
• En masse retraction as one step using opus or
T-loop.

48. Maximum anchorage treatment with
18-slot edgewise
• Most commonly used wire 16x22 SS.
• Friction from sliding mechanics should be
avoided and using closing loop mechanics is
better.
• To augment anchorage and reduce its strain by
doing the following:
1. Adding stabilizing lingual arch.

49. 2. Reinforce maxillary posterior anchorage with
extra oral force and if needed use Cl III elastics
from high pull headgear to supplement retraction
force in the lower arch.
3. Retraction of canines independently preferably
using a segmented closing loop and then retract
the incisors with a second closing loop arch wire.

50. 4. Use bone screws to stabilize the posterior
segment which used to avoid two steps space
closure.

51. Maximum anchorage treatment with
22-slot edgewise
• Most commonly used wire 19x25 SS.
• The same basic approaches are used with 18-
slot appliance.
• In sliding mechanics, a bone screw between
2nd molar and 1st molar is effective and easier
with a Niti coil spring.
• The recommended procedure in two-step
space closure, is en masse distal tipping of
anterior teeth followed by uprightening.

52. Minimum anchorage treatment
• Requires anchor control to reduce the incisal
retraction by the following:
1) Involving many teeth in the anterior anchor unit
as possible.
2) Extraction the most posterior teeth.
3) Reinforce the incisor anchorage by placing active
lingual root torque in the incisor section of arch
wire.
4) Break down the posterior anchorage by moving
the posterior teeth forward one tooth at a time.

53. 5)Use skeletal anchorage (bone screw) in either arch in
canine region to bring posterior teeth forward.

54. Retraction methods
A) Methods of canine retraction:
 Sliding mechanics:
• Closed coil spring ( SS, Niti, Co-Cr-Ni)
• Elastomeric chains.
• Elastic module activated with ligature wire.
 Loop mechanics:
• Gjessing retraction spring.
• Brustone T – loop.
• Delta loop.
• Omega loop.
• L – loop.
 Extra oral: headgear. Gjessing retraction spring

55. B) Methods of en masse retraction of four incisors:
 Sliding mechanics:
• Closed coil spring ( SS, Niti, Co-Cr-Ni)
• Elastomeric chains.
• Elastic module with ligature wire.
 Loop mechanics:
• Brustone T – loop.
• Retraction utility arch.
• Delta loop.
• Omega loop.
• L – loop.
• Closing loop arch wire.
 Extra oral: headgear.

56. C) Methods of en masse retraction of six incisors:
 Sliding mechanics:
• Closed coil spring ( SS, Niti, Co-Cr-Ni)
• Elastomeric chains.
• Elastic module activated with ligature wire.
 Loop mechanics:
• Closing loops.
• Brustone T – loop continuous arch wire.
• Opus loop (siatkowaski).

57. Niti closed coil spring
Closing space with power chain

58. References
• Contemporary Orthodontic 5th edition – William
R. Proffit.
• Excellence in orthodontic 2010 – David Birnie,
Nigel Harradine.
• Biomechanics in clinical orthodontic – Ravindra
Nanda.
• Modern Edgewise mechanics and the segmented
arch technique – Dr.Charles J. Brustone.

59. Thank you