Self-ligating brackets: an update.
- [Show abstract] [Hide abstract]
ABSTRACT: To explore whether the use of self-ligating brackets is associated with better values for periodontal indices because of the lack of elastomeric modules and concomitantly, reduced availability of retentive sites for microbial colonization and plaque accumulation. Private practice of the first author. Patients were selected using the following inclusion criteria: age range 12-17 years, fixed appliances on both arches, aligned mandibular arch, and absence of oral habits and anterior crossbites. Prospective cohort investigation. Participants were grouped for bracket type, thus 50 patients formed the conventional bracket cohort and 50 patients the self-ligating bracket cohort. Both cohorts were followed with the purpose to examine periodontal status. Average length of follow-up was 18 months. This time period was considered adequate for a proportion of study participants to experience the outcome of interest. Outcome variables were plaque index, gingival index, calculus index, and probing depth for the two bracket cohorts. No difference was found in the indices recorded between the two bracket cohorts studied. Under the conditions as applied in this study, the self-ligating brackets do not have an advantage over conventional brackets with respect to the periodontal status of the mandibular anterior teeth.Orthodontics and Craniofacial Research 12/2008; 11(4):211-5. · 1.29 Impact Factor
- Journal of clinical orthodontics: JCO 12/2008; 42(11):641-51.
- [Show abstract] [Hide abstract]
ABSTRACT: In this prospective clinical study, we assessed the relative speed of archwire changes, comparing self-ligating brackets with conventional elastomeric ligation methods, and further assessed this in relation to the stage of orthodontic treatment represented by different wire sizes and types. The time taken to remove and ligate archwires for 131 consecutive patients treated with either self-ligating or conventional brackets was prospectively assessed. The study was carried out in the orthodontic department of a district general hospital in the United Kingdom. The main outcome measure was the time to remove or place elastomeric ligatures or open/close self-ligating brackets for 2 matched groups of fixed appliance patients: Damon2 self-ligating bracket (SDS Ormco, Orange, Calif) and a conventional mini-twin bracket (Orthos, SDS Ormco). The relative effects of various wire sizes and materials on ligation times were investigated. The study was carried out by 1 operator experienced in the use of self-ligating and conventional brackets. The Damon2 self-ligating system had a significantly shorter mean archwire ligation time for both placing (P <.001) and removing (P <.01) wires compared with the conventional elastomeric system. Ligation of an archwire was approximately twice as quick with the self-ligating system. Opening a Damon slide was on average 1 second quicker per bracket than removing an elastic from the mini-twin brackets, and closing a slide was 2 seconds faster per bracket. This difference in ligation time between the Damon2 and the conventional mini-twin brackets became more marked for larger wire sizes used in later treatment stages. The type of bracket and the size of wire used are statistically significant predictors for speed of ligation and chairside time. The self-ligating system offered quicker and arguably more efficient wire removal and placement for most orthodontic treatment stages.American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 03/2007; 131(3):395-9. · 1.33 Impact Factor
(Editor’s Note: In this quarterly column, JCO
provides an overview of a clinical topic of inter
est to orthodontists. Contributions and suggestions
for future subjects are welcome.)
eliminating the need for wire or elastomeric liga
tures. Although SLBs were first developed in the
1930s (Table 1), they have experienced a dra
matic revival since the 1990s, with a number of
new appliances being developed and others being
refined and modified to suit the requirements of
clinicians and patients (Fig. 1).
The conventional edgewise twin bracket
requires four tie wings for archwire ligation and
thus has a broader shape, which improves rota
tional control and reduces the tendency toward
mesiodistal tipping, but makes the archwire less
flexible because of the shorter interbracket spans.1
The relative speed with which selfligating appli
ances can purportedly correct severe crowding has
made them extremely popular among today’s
orthodontists.2,3 This article reviews the pros and
elfligating brackets (SLBs) use mechanically
locking or sliding devices to close the slots,
cons of selfligation based on the most recent
The major advantage claimed for SLBs over
preadjusted edgewise appliances involves reduced
frictional resistance between the bracket slot and
archwire.47 ReadWard and colleagues, evaluating
the static frictional resistance of three different
SLBs and one conventional bracket, found that
increasing either archwire size or bracket/archwire
angulation resulted in greater static frictional
resistance for all bracket types, while the presence
of saliva had an inconsistent effect.8 The authors
concluded that SLBs exhibited less frictional resis
tance than wireligated brackets only under certain
More recent clinical studies support the view
that resistance to bodily tooth movement by sliding
has little to do with friction, but rather is largely a
“binding and release” phenomenon that occurs in
the same way with both conventional and self
SLBs have been associated with a reduction
in overall treatment time.10,11 It is possible, however,
that this retrospective research may have been con
founded by a number of variables, including oper
ator enthusiasm, different appointment intervals
and archwire sequences, and multiple operators.
In a recent prospective clinical trial, Pandis
and colleagues found no overall difference in the
time required to correct mandibular crowding with
selfligating Damon 2 and conventional edgewise
brackets.12 When the results were broken down by
© 2012 JCO, Inc.
Self-Ligating Brackets: An Update
NAZEER AHMED MEERAN, BDS, MDS
VOLUME XLVI NUMBER 4 235
Dr. Nazeer is an Assistant Professor,
Department of Orthodontics and Dento-
facial Orthopedics, Priyadarshini Dental
College and Hospital, Thiruvallur Taluk,
Pandur 631203, Tamilnadu, India;
©2012 JCO, Inc. May not be distributed without permission. www.jco-online.com
TIMELINE OF SELF-LIGATING BRACKETS*
Manufacturer** Bracket Year
*Listing is not intended to be allinclusive.
QuicKlear 2nd Generation
3rd Generation Active SLB
3rd Generation Passive SLB
Agility Passive Self Ligation System
severity of crowding, the selfligating appliance
was 2.7 times faster among patients with moderate
crowding (Irregularity Index < 5), but the differ
ence was much less marked among subjects with
higher Irregularity Index scores. More severe
crowding prolonged treatment by an additional
20% for each Irregularity Index unit in the Damon
group. Increases in intercanine and intermolar
widths associated with correction of crowding
were noted across the board, although the self
ligating group showed a statistically greater inter
molarwidth increase than in the conventional
group. An alignmentinduced increase in the pro
clination of mandibular incisors was observed in
both segments, with no significant difference
between the bracket types.
SLBs have been reported to produce faster
initial alignment and relief of crowding compared
to conventional brackets.4 Alleviation of dental
irregularity is impossible to measure precisely,
since most trials fail to control for individual
metabolic variation, and results may be uninten
tionally biased by inaccurate bracket placement.
Recent prospective studies suggest, however, that
any treatment time saved by the use of SLBs does
not occur in the initial alignment phase.13,14 Ham
ilton and colleagues found that active SLBs appear
to offer no measurable advantages in ortho dontic
treatment time, number of treatment visits, or time
spent in initial alignment over conventional pread
justed edgewise brackets, with both bracket sys
tems averaging 15.7 months of treatment.15
Fleming and colleagues similarly reported that
bracket type did not influence the duration of treat
ment or the number of visits required.16
VOLUME XLVI NUMBER 4237
Fig. 1 A. Ormco’s Damon 3 (upper) and Damon
MX (lower) brackets. B. GAC’s In-Ovation C ceramic
brackets. C. Patient before and after initial align-
ment using recently introduced TenBrook self-
ligating bracket from Ortho Classic.
**Adenta GmbH, Gilching, Germany, www.adenta.com; American
Orthodontics, Sheboygan, WI, www.americanortho.com; Den
taurum GmbH & Co., Ispringen, Germany, www.dentaurum.de;
Forestadent, Pforzheim, Germany, www.forestadent.de; GAC Inter
national, Bohemia, NY, www.gacintl.com; Gestenco International
AB, Gothenburg, Sweden, www.gestenco.com; Lancer Orthodontics,
Vista, CA, www.lancerortho.com; Ormco Corporation, Orange,
CA, www.ormco.com; Orthodontic Design and Production, Inc.,
Vista, CA, www.odpinc.com; Ortho Classic, McMinnville, OR,
www.orthoclassic.com; Ortho Organizers, Carlsbad, CA, www.
orthoorganizers.com; Ortho Technology, Inc., Tampa, FL, www.
orthotechnology.com; Strite Industries, Cambridge, Ontario, www.
speedsystem.com; 3M Unitek, Monrovia, CA, www.3munitek
.com; Ultradent/Opal Orthodontics, South Jordan, UT, www.
238 JCO/APRIL 2012
Only one study has considered the relative
rate of orthodontic space closure, following each
patient at fiveweek intervals until complete space
closure was achieved.17 This splitmouth sample
was inadequate, with four of 18 subjects failing to
complete the trial, and since posted archwires were
used on both sides, tooth movement on one side
may not have been independent of the other.
Active vs. Passive Self-Ligation
The relative benefits of active and passive
SLBs (Fig. 2) have been a source of confusion
among clinicians, with various manufacturers
claiming the superiority of one system over the
other. Active appliances were supposed to achieve
better torque expression, whereas passive appli
ances were said to relieve initial crowding more
quickly and en hance sliding mechanics by reduc
ing friction. Recent findings by Badawi and col
leagues support the contention that active SLBs
are more effective than passive brackets in express
ing torque.18 On the other hand, Pandis and col
leagues suggest that the choice of passive or active
SLBs does not seem to make any difference in the
time required to alleviate initial crowding.19
Extractions and Arch Development
SLB systems are reputedly more capable
than preadjusted edgewise appliances of relieving
severe crowding without extractions, mainly due
to their ability to increase arch dimensions—par
ticularly intermolar width. This effect is aug
mented when expansion archwires are used in the
Damon system.20 A number of case reports have
documented arch development with the Damon
appliance,2123 some describing increases in inter
molar width of more than 10mm that facilitated
nonextraction treatment. Of course, the longterm
stability of such significant changes is highly reli
ant on permanent retention.
Fig. 2 Interaction of self-ligating brackets with .016" round archwire (A-C) and .019" × .025" rectangular arch-
wire (D-F). Active appliance (In-Ovation R) is shown in A and D, passive appliances (SmartClip 2 and Damon
3MX) in B, C, E, and F. Both passive and active brackets are interactive, with contact between wire and por-
tion of bracket slot. (Reprinted by permission.5)
In a 2010 study, Ong and colleagues found
that SLBs were no more efficient than convention
ally ligated brackets in terms of anterior alignment
or passive extractionspace closure during the first
20 weeks of treatment.24 The authors reported that
similar changes in arch dimensions occurred irre
spective of bracket type, attributing the efficiency
of treatment to other factors such as archwire form.
Bracket design, wire/slot play (engagement
angle), mode of ligation, bracket deformation, wire
stiffness, magnitude of wire torsion and dimen
sion, and wire edge beveling have all been cited as
influences on torque expression. Clinical factors
such as initial tooth inclination, tooth anatomy, and
bracket positioning are also involved. Manu
facturers have sought to address these issues by
preangulating their bracket slots relative to the
bracket bases; some companies offer a variety of
Pandis and colleagues found that SLBs were
as efficient as conventional brackets in delivering
torque to the maxillary incisors in both extraction
and nonextraction cases.25 Morina and colleagues,
comparing the torquing capacity of active and
passive SLBs with that of metallic, ceramic, and
polycarbonate edgewise brackets, found that
Fascination 2*** ceramic brackets registered the
highest torquing moments.26 When torquing the
.022" brackets with .019" × .025" stainless steel
archwires, the authors observed the least torque
loss with the ceramic and Ultratrimm*** stainless
steel brackets. Selfligating, polycarbonate, and
certain metallic brackets demonstrated almost
seven times less torquing moments after insertion
of .019" × .022" stainless steel wires into .022"
slots, as well as 100% more torque loss compared
to the ceramic bracket.
Clinical studies evaluating the speed and
efficiency of archwire removal and replacement in
the orthodontic office have generally favored
SLBs, reporting a modest but consistent reduction
in chairtime compared to conventional applianc
es.2730 Users have long held that selfligating sys
tems can produce a dramatic improvement in
clinical efficiency, resulting in the ability to sched
ule more patients. The time saved in opening and
closing SLBs compared to elastomeric ligation of
conventional brackets has ranged from a modest
25 seconds to seven minutes for both arches.27,29
Com pared with wire ligatures, however, the dif
ference is a more substantial 12 minutes.28,31
Two studies examining failure rates of bond
ed attachments over 20 weeks14 and 12 months32
of treatment reported no significant differences
between conventional and selfligating brackets.
Hamilton and colleagues did find a significantly
higher number of debonded brackets and other
emergency visits in patients treated with active
SLBs compared to conventional preadjusted edge
SLBs’ elimination of ligature wires obvi
ously makes them superior to conventional edge
wise brackets in terms of softtissue injuries.
In a 2009 study, Tecco and colleagues found
that orthodontic patients reported pain for a period
of nine days after initial archwire insertion.33
Those treated with SLBs reported the highest
levels of pain on the day following placement of
the first archwire, while those treated with con
ventional brackets experienced the greatest pain
intensity after placement of the first archwire and
after the second orthodontic appointment. Patients
treated with conventional brackets seemed to
experience greater and more intense pain for a
longer period, at a more constant level than the
transitory pain in chewing or biting reported by
patients treated with SLBs. There were no reports
of pain after seven to nine days of archwire inser
tion in either group.
Also in 2009, Fleming and colleagues found
VOLUME XLVI NUMBER 4239
***Registered trademark of Dentaurum GmbH & Co., Ispringen,
that the subjective pain experience at four hours,
24 hours, three days, and seven days following
fixed orthodontic appliance placement was inde
pendent of bracket type.34 Insertion and removal
of rectangular archwires with the SmartClip pas
sive SLB tended to increase pain levels, corrobo
rating a previous report on the Damon 2 system.14
Fixed orthodontic appliances not only restrict
the patient’s ability to practice good oral hygiene,
but create shelters for microbial colonization.
Studies have demonstrated increased amounts of
Streptococcus mutans and lactobacilli in saliva
and dental plaque during orthodontic treatment.35,36
In a randomized controlled study using a split
mouth design and adenosine triphosphatedriven
bioluminescence, Pellegrini and colleagues found
that selfligating appliances promoted less reten
tion of oral bacteria, including streptococci, com
pared to preadjusted edgewise appliances with
elastomeric ligation.37 On the other hand, Pandis
and colleagues concluded that the levels of
Streptococcus mutans in whole saliva of orthodon
tically treated patients were not significantly dif
ferent whether conventional or selfligating
brackets were in place.38
In another recent study, Pandis and col
leagues found that SLBs do not have an advantage
over conventional brackets with respect to the
periodontal status of the mandibular anterior
teeth.39 The question of whether selfligation
improves periodontal health because of a reduced
availability of retentive sites for microbial coloni
zation and plaque accumulation remains to be
resolved by further research.
Based on the currently available literature,
the following conclusions can be drawn:
• SLBs exhibit reduced frictional resistance in
comparison to stainless steel ligated brackets only
under certain conditions. Friction is largely a “bind
ing and release” phenomenon that is about the
same with conventional and selfligating brackets.
• SLBs are no more efficient than conventionally
ligated brackets in achieving anterior alignment.
• SLBs appear to offer no measurable advantages
in terms of orthodontic treatment time, number of
treatment visits, and time spent in initial alignment
over conventional preadjusted edgewise brackets.
• The choice of passive or active SLBs does not
seem to make any difference in the time required
to alleviate initial crowding.
• Self-ligating appliances, particularly the Damon
system, can increase arch width, but no longterm
followup studies have assessed the stability of
• Damon 2 and SPEED brackets exhibit reduced
torquing moments compared to one conventional
ceramic bracket and higher torque loss compared
to ceramic and stainless steel brackets.
• Clinical efficiency is improved by the use of
SLBs due to the ease of opening and closing the
clip or slide and the speed of archwire changes,
particularly when compared to individual wire
ligation of preadjusted edgewise appliances.
• Subjective pain experience following fixed ortho-
dontic appliance placement is independent of
bracket type, with no significant difference be
tween selfligating and conventional systems.
• There is some controversy regarding the effect
of SLBs on periodontal health, with one study
reporting that selfligating appliances promoted
less retention of oral bacteria compared to pread
justed edgewise appliances with elastomeric liga
tion, and other studies reporting no appreciable
difference in the levels of Streptococcus mutans
or in general periodontal status.
SLBs have a few clear advantages, particu
larly in terms of clinical efficiency, due to the ease
of opening and closing the clips and changing arch
wires. Stainless steel ligatures used in conventional
systems are capable of lacerating the soft tissues,
particularly if they are not tucked in properly.
Apart from these benefits, based on the cur
rent literature, SLBs do not seem to confer any
particular treatment advantages, and the potential
failure of the locking system is a disadvantage
compared to conventional systems. Continued
refinement of the selfligating systems may result
in further improvements, leading to more effi
ciency and flexibility in orthodontic mechanics.
VOLUME XLVI NUMBER 4 241
1. Rinchuse, D.J.; Rinchuse, D.J.; and KapurWadhwa, R.:
Orthodontic appliance design, Am. J. Orthod. 131:7682, 2007.
2. Harradine, N.W.: Selfligating brackets and treatment effi
ciency, Clin. Orthod. Res. 4:220227, 2001.
3. Miles, P.G.: SmartClip versus conventional twin brackets for
initial alignment: Is there a difference? Austral. Orthod. J.
4. Harradine, N.W.: Selfligating brackets: Where are we now? J.
Orthod. 30:262273, 2003.
5. Fleming, P.S.; DiBiase, A.T.; and Lee, R.T.: Selfligating
appliances: Evolution or revolution? J. Clin. Orthod. 42:641
6. Rinchuse, D.J. and Miles, P.G.: Selfligating brackets: Present
and future, Am. J. Orthod. 132:216222, 2007.
7. Miles, P.G.: Selfligating brackets in orthodontics: Do they
deliver what they claim? Austral. Dent. J. 54:911, 2009.
8. ReadWard, G.E.; Jones, S.P.; and Davies, E.H.: A comparison
of selfligating and conventional orthodontic bracket systems,
Br. J. Orthod. 24:309317, 1997.
9. Burrow, S.J.: Friction and resistance to sliding in orthodon
tics: A critical review, Am. J. Orthod. 135:442447, 2009.
10. Harradine, N.W.: Selfligating brackets and treatment effi
ciency, Clin. Orthod. Res. 4:220227, 2001.
11. Eberting, J.J.; Straja, S.R.; and Tuncay, O.C.: Treatment time,
outcome, and patient satisfaction comparisons of Damon and
conventional brackets, Clin. Orthod. Res. 4:228234, 2001.
12. Pandis, N.; Polychronopoulou, A.; and Eliades, T.: Self
ligating vs conventional brackets in the treatment of mandibu
lar crowding: A prospective clinical trial of treatment duration
and dental effects, Am. J. Orthod. 132:208215, 2007.
13. Miles, P.G.: SmartClip versus conventional twin brackets for
initial alignment: Is there a difference? Austral. Orthod. J.
14. Miles, P.G.; Weyant, R.J.; and Rustveld, L.: A clinical trial of
Damon 2 vs conventional twin brackets during initial align
ment, Angle Orthod. 76:480485, 2006.
15. Hamilton, R.; Goonewardene, M.S.; and Murray, K.: Com
parison of active selfligating brackets and conventional pre
adjusted brackets, Austral. Orthod. J. 24:102109, 2008.
16. Fleming, P.S.; DiBiase, A.T.; and Lee, R.T.: Randomized
clinical trial of orthodontic treatment efficiency with self
ligating and conventional fixed orthodontic appliances, Am. J.
Orthod. 137:738742, 2010.
17. Miles, P.G.: Selfligating vs conventional twin brackets during
enmasse space closure with sliding mechanics, Am. J.
Orthod. 132:223225, 2007.
18. Badawi, H.M.; Toogood, R.W.; Carey, J.P.; Heo, G.; and
Major, P.W.: Torque expression of selfligating brackets, Am.
J. Orthod. 133:721728, 2008.
19. Pandis, N.; Polychronopoulou, A.; and Eliades, T.: Active or
passive selfligating brackets? A randomized controlled trial
of comparative efficiency in resolving maxillary anterior
crowding in adolescents, Am. J. Orthod. 137:12.e16, 2010.
20. Mikulencak, D.: A comparison of maxillary arch width and
molar tipping changes between rapid maxillary expansion and
fixed appliance vs. the Damon system (abstr.), Am. J. Orthod.
21. Damon, D.H.: The Damon lowfriction bracket: A biologically
compatible straightwire system, J. Clin. Orthod. 32:670680,
22. Garino, F. and Favero, L.: Control of tooth movements with
the SPEED System, Prog. Orthod. 4:2330, 2003.
23. Damon, D.H.: The rationale, evolution and clinical application
of the selfligating bracket, Clin. Orthod. Res. 1:5261, 1998.
24. Ong, E.; McCallum, H.; Griffin, M.P.; and Ho, C.: Efficiency
of selfligating vs conventionally ligated brackets during ini
tial alignment, Am. J. Orthod. 138:138.e17, 2010.
25. Pandis, N.; Stigou, S.; and Eliades, T.: Maxillary incisor
torque with conventional and selfligating brackets: A prospec
tive clinical trial, Orthod. Craniofac. Res. 9:193198, 2006.
26. Morina, E.; Eliades, T.; Pandis, N.; Jäger, A.; and Bourauel,
C.: Torque expression of selfligating brackets compared with
conventional metallic, ceramic, and plastic brackets, Eur. J.
Orthod. 30:233238, 2008.
27. Maijer, R. and Smith, D.C.: Time savings with selfligating
brackets, J. Clin. Orthod. 24:2931, 1990.
28. Shivapuja, P.K. and Berger, J.: A comparative study of conven
tional ligation and selfligation bracket systems, Am. J.
Orthod. 106:472480, 1994.
29. Berger, J. and Byloff, F.K.: The clinical efficiency of self
ligated brackets, J. Clin. Orthod. 35:304308, 2001.
30. Turnbull, N.R. and Birnie, D.J.: Treatment efficiency of con
ventional vs selfligating brackets: Effects of archwire size
and material, Am. J. Orthod. 131:395399, 2007.
31. Paduano, S.; Cioffi, I.; Iodice, G.; Rapuano, A.; and Silva, R.:
Time efficiency of selfligating vs conventional brackets in
orthodontics: Effect of appliances and ligating systems, Prog.
Orthod. 9:7480, 2008.
32. Pandis, N.; Polychronopoulou, A.; and Eliades, T.: Failure rate
of selfligating and edgewise brackets bonded with conven
tional acid etching and a selfetching primer: A prospective in
vivo study, Angle Orthod. 76:119122, 2006.
33. Tecco, S.; D’Attilio, M.; Tetè, S.; and Festa, F.: Prevalence and
type of pain during conventional and selfligating orthodontic
treatment, Eur. J. Orthod. 31:380384, 2009.
34. Fleming, P.S.; DiBiase, A.T.; Sarri, G.; and Lee, R.T.: Pain
experience during initial alignment with a selfligating and a
conventional fixed orthodontic appliance system: A random
ized controlled clinical trial, Angle Orthod. 79:4650, 2009.
35. Forsberg, C.M.; Brattström, V.; Malmberg, E.; and Nord,
C.E.: Ligature wires and elastomeric rings: Two methods of
ligation and their association with microbial colonization of
streptococcus mutans and lactobacilli, Eur. J. Orthod. 13:416
36. Rosenbloom, R.G. and Tinanoff, N.: Salivary Streptococcus
mutans levels in patients before, during, and after orthodontic
treatment, Am. J. Orthod. 100:3537, 1991.
37. Pellegrini, P.; Sauerwein, R.; Finlayson, T.; McLeod, J.;
Covell, D.A. Jr.; Maier, T.; and Machida, C.A.: Plaque reten
tion by selfligating vs elastomeric orthodontic brackets:
Quantitative comparison of oral bacteria and detection with
adenosine triphosphatedriven bioluminescence, Am. J.
Orthod. 135:426.e19, 2009.
38. Pandis, N.; Papaioannou, W.; Kontou, E.; Nakou, M.; Makou,
M.; and Eliades, T.: Salivary Streptococcus mutans levels in
patients with conventional and selfligating brackets, Eur. J.
Orthod. 32:9499, 2010.
39. Pandis, N.; Vlachopoulos, K.; Polychronopoulou, A.;
Madianos, P.; and Eliades, T.: Periodontal condition of the
mandibular anterior dentition in patients with conventional
and selfligating brackets, Orthod. Craniofac. Res. 11:211