Self ligatingbrackets /certified fixed orthodontic courses by Indian dental academy

Seminars in
Orthodontics:
Self-Ligating Brackets
INDIAN DENTAL ACADEMY

Leader in continuing dental education
www.indiandentalacademy.com

History of Self-ligating brackets






Self-ligating brackets do not require an elastic or wire
ligature to secure the archwire
Rather they have an internal mechanism that allows
opening and closure with either an instrument or
fingertip
In 1935 Stolzenberg introduce the first self-ligating
bracket - Russell Lock edgewise attachment
Since then there have been a variety of SLB’s
available, with a recent surge in popularity over the
last 8 years or so

Self Ligating Bracket Types























Russell Lock - 1935
Ormco Edgelok - 1972
Forestadent Mobil-Lock - 1980
Forestadent Begg - 1980
Strite Industries SPEED - 1980
“A” Company Activa - 1986
Adenta Time - 1996
“A” Company Damon SL - 1996
Ormco TwinLock - 1998
Ormco/ “A” Co. Damon 2 - 2000
GAC In-Ovation - 2000
Gestenco Oyster - 2001
GAC In-Ovation R - 2002
Adenta Evolution LT - 2002
Ultradent OPAL - 2004
Ormco Damon 3 2004
3M Unitek Smart Clip - 2004
Ormco Damon 3 MX - 2005
Ultradent OPAL metal - 2006
Forestadent Quick - 2004
Lancer Praxis Glide - 2004
Class I/Ortho Organisers Carriere LX - 2004

Properties of an ideal ligation
system








Be secure and robust
Ensure full bracket engagement
Exhibit low friction between bracket and archwire
Be quick and easy to use
Permit easy attachment of elastic chains
Assist good oral hygiene
Be comfortable for the patient


Secure Ligation




Should be no loss of ligation between
appointments
Wire ligatures are reliable while elastomeric
ligatures are less


Full Bracket Engagement





Want archwire to be fully engaged in bracket
Wire ligatures allow this and can be maintained over the
lifetime of an appointment
Elastomerics can exert insufficient force to fully engage
and also degrade as the elastomer stretches over time


Low Friction






Frictional forces arising from ligation add additional
resistance that must be overcome by higher forces
This results in a net effective force that is difficult to
assess and a binding force that is higher between
bracket and wire
Wire ligatures produce lower friction then elastomeric
ligatures
However, wire ligatures can also result in high and
variable levels of friction relative to the force levels
optimal for tooth movement

Static versus Dynamic Friction








Static friction - the force between two objects having no motion;
being at rest
Dynamic (sliding or rolling) friction - to move over a surface
while maintaining continuous contact
Friction is affected by bracket material, bracket design, archwire
material and shape, ligation method, bracket-archwire angulation
and dynamic forces
Although several of these variables are out of our control, the
use of SLBs can greatly reduce friction between the archwire and
bracket


Quick and Easy to use


Significant disadvantage of wire ligation


Easy Attachment of Elastic Chain




Tie wings on conventional brackets make
attachment of elastic chain very convenient
Some SLBs have no tie wings


Maintenance of Optimal Oral
Hygiene




Most people feel that elastomerics result in more
plaque accumulation then wire ligatures
There are some studies that support this




Forsberg et al. Ligature wires and elastomeric rings: two methods of
ligation, and their association with microbial colonization of
Streptococcus mutans and lactobacilli. 1991. Eur J Orthod. 13:416-420.

There are other studies that found no difference


Sukotapatipark et al. A scanning electron microscopy study. 2001. Eur J
Orthod. 23:475-484. 2001.


Patient Comfort



Elastomerics are easy for the patient to handle
Wire ligatures require careful tucking of the ends
to avoid emergency visits


Limitations of Conventional
Ligation








Inability to provide and maintain full archwire
engagement
Increased friction
Elastomeric force decay resulting in non-optimal
tooth control
Ligatures can become displaced
Wire ligation is time consuming

Core Advantages of SLBs





Full archwire engagement
Low friction between bracket and archwire
Less chairtime assistance needed
Faster archwire removal and ligation


Low Friction and Secure Full AW
Engagement



Study by Srinivas (postgraduate thesis in India)
Split Mouth study of canine retraction - Damon SL on
once side and conventional bracket on the other side


Damon side resulted in





More rapid retraction (.24mm per month)
Shorter duration for 3mm retraction (12 wks v. 16wks)
Less rotation (8 degrees v. 12 degrees)
Less anchorage loss (.3mm)


Alignment of Severely malaligned teeth






Combination of low friction and secure archwire
engagement is useful for aligning very irregular
teeth
With low friction the wire is able to slide
through the brackets of the rotated teeth
resulting in rapid uncrowding
Full engagement results in full control while
sliding teeth along the archwire


Lack of Adoption of SLBs


Widespread use of these brackets has been hindered,
until recently, due to several problems with bracket
design - some examples include





SPEED: early brackets had clips that were easily displaced or
broken
Mobil-Lock: narrowness of the resulting labial face of the slot
resulting in poor rotational control
Activa Brackets: absence of wings, abnormal base shape
Damon SL: inadvertent opening of the slide, prone to
breakage


SPEED


The Speed appliance was developed in the 1970s by Dr. Herbert Hanson
(from Canada)



Has been commercially available since 1980.
It is a miniaturized self-ligating bracket with an active super elastic NiTi
spring clip to entrap the archwire
Archwire engagement can result in elastic deflection of the spring clip
The deflection of the spring clip represents energy stored in the spring clip,
and as the bracket and its accompanied tooth are reoriented relative to the
archwire, energy is released






Advantages of Design
•Highly flexible NiTi clip
•Minimal Friction during sliding mechanics
•Extended range of activation due to energy
stored in clip
•Large interbracket span
•Spring clip will not deform or fatigue
•Horizontal auxiliary slot


Treatment Philosophy - As outlined by Dr. Hanson










Try to treat without extractions in any case that has the necessary
potential
If extractions necessary, extract 2nd bicuspids to minimize any
reduction in prominence of dentition
Preliminary functional appliances as necessary to favorably alter jaw
growth if possible
Use intraoral distalization instead of headgear
Expand arches that have failed to develop to their full potential
In patients that exhibit lots of gingival tissue, intrude upper anterior
teeth
Correct tooth rotations to ideal alignment without overcorrection - rely
on IPR and circumferential supra-crestal fiberotomies to enhance
retention
Overcorrect Class II/III where strong tendency for relapse occurs

SPEED pictures
Supercable consists of seven strands of superelastic
nickel titanium wire in a coaxial form. It is impossible
to permanently deform Supercable regardless of the
malalignment of the dentition. (B) The combined
effect of the initial light multistrand Supercable
archwire, the wide interbracket span between the
narrow SPEED brackets, and the energy storing
capability of the spring clip greatly increases the range
of appliance activation.

The SPEED finishing archwire has a
quarter round shape, which
facilitates archwire insertion, spring
closure, and is highly effective in
torque control.


DAMON





Damon Philosophy - use just enough force to initiate tooth movement
Want this force to be low enough to prevent occluding blood vessels in the PDL
and allow cells the ability to transport messengers necessary to produce bone
resorption and apposition
Is a passive-self ligation system - it is suggested that this type of system results in
 Less anchorage requirements
 Less intraoral expansion - because the force of the AW is not transformed or
absorbed by the ligatures
 Less need for extractions
 Low levels of static and dynamic friction
 Rigid ligation
The Damon Evolution
 Control of tooth position

->

->

->

?

Effects of Passive Ligation on
Friction




Many authors (Thomas et al. 1998 Eur J Orthod, Pizzoni et al. 1998 Eur J
Orthod, Khambay et al. 2004 Eur J Orthod) have found that static friction
measured in vitro is much less with a passive self ligating appliance that any
other type of fixed appliance
When angulation or inclination is applied to the bracket friction is generated,
however it is less for SLB’s than for conventional ligation
Figure showing static friction for
passive, active, TipEdge, and
conventionally ligated brackets.
The value for the passive selfligating Damon SL bracket was
zero except for with the 0.019″ ×
0.025″ stainless steel archwire.
The wires were drawn through the
brackets and the frictional
resistance was measured using an
Instron 1193 testing machine.

High versus Low Torque
Brackets




High Torque Upper Incisors
 Extraction cases
 Class II Div I where
mechanics might
excessively retrocline
teeth
 Class II Div II
High Torque Upper canines
 First PM extraction cases
 When crowns of upper
cuspids are palatally
tipped





Low Torque Upper incisors
 Excessively Proclined upper
incisors
 Isolated upper incisors with
palatally displaced roots
 Malocclusions where Tx
mechanics may result in excessive
upper incisor proclination
 Moderate and severe upper arch
crowding
 Anterior open bite cases
Low Torque Lower Incisors
 Cases where control is needed to
avoid proclination of lower
incisors (extreme lower labial
segment crowding, Class II
elastics, fixed class II correctors


Stages of Treatment






Phase 1 - Light Round High Technology Wires (.013, .014 or .016 CuNiTi)

Level the arches, excluding 2nd molars

Correct all anterior rotations and partial correction of posterior rotations

Initiate arch development with use of light forces to allow soft tissue to influence arch shape
Phase 2 - High Technology Rectangular Wires (14x25 CuNiTi --> 18x25 CuNiTi or 16x25
CuNiti)

Fully correct all rotations

Consolidate any anterior space

Initiate torque control

Initiate bite opening

Continue arch development

Use of .025 in first order dimension is critical to obtain tooth alignment by almost completely
filing the .027 slot depth
Phase 3 - Major Mechanics (19x25 pre-posted stainless steel archwires)







Maintain archform
Finish torque control
Consolidate posterior space
Completely correct AP, buccolingual and vertical relationships

Phase 4 - Finishing and Detailing


Can continue use of SS AW’s or can use 19x25 TMA for individual adjustments

Damon Case Presentation

14 years old


12 Months into Tx

1 yr post-retention (26 month Tx)


•Lower Cast Measurements
•Intercanine: 19.2  29.4
•Inter 1st Premolar 29.6  38.1
•Inter 2nd Premolar: 38.2  43.8
•Inter 1st Molar: 49.9  50.7
•IMPA – 87.4  97.8
•L1-Apo: 0.2  3.4


In-Ovation


In-Ovation









Innovation R – the standard In-ovation bracket we
use in clinic
Innovation C - esthetic innovation brackets
Innovation L MTM - indirect bonding of anterior
teeth (3-3) with these lingual braces, no wire changes
Innovation L - lingual innovation braces
Innovation brackets open from the gingival margin -


In-Ovation R


Bracket design has a closing clip that can apply pressure
or no pressure to the archwire as the situation requires



This bracket was designed to be a passive or active SLB
The clip secures the AW into place but also allows the
clip to flex buccally if the wire is not fully seated
At max flex the clip can apply 250 g of force





In-Ovation R


Our In-Ovation bracket has an .022 slot



To completely fill the slot without impinging on the clip
you would want to place an .022 x .018 wire



Fully seating this .022 x .018 results in full in-out, tip
and torque control without clip friction

Smart Clip





NiTi clip mechanism that retains the wire by two Cshaped spring slips on either side of the bracket slot
The wire contains no moving door or latch and thus
are the only true self-ligating brackets
MBT prescription
The force required for the removal and insertion of
heavy stainless steel wires is often uncomfortable for
patients

Active Clip or Passive Slide?








Active Clips - SPEED, In-Ovation, Quick Brackets, Time2 (American
ortho)
Passive - Damon, Smart clip, Praxis Glide, and Carriere LX
Intended benefit of storing some force in the clip - “a given wire will
have its range of labiolingual action extended and produce more
alignment than would a passive slide with the same dimension wire”
However, with increased clearance between a given wire and a passive
slide, lower forces will be generated along with less binding to possibly
allow teeth to push each other as they slide along the wire
Not many studies have been done to assess the effectiveness of active
versus self ligation at this point


Current Literature…


Evaluation of frictional forces during dental alignment: an
experimental model with 3 nonleveled brackets









Aim of study was to evaluate frictional forces generated by various
combinations of brackets and orthodontic wires
Used passive self-ligating brackets (Damon SL2) and conventional twin SS
brackets
Tests 3 NiTi wires (.014, .016, .016x.022), 2 SS multistranded wires, and 1
TMA
Used elastic ligatures and SST’s for the twin brackets
Each 10-bracket AW combo was tested 10 times
The ability of the wire to slide through the bracket was influenced by wirecross section dimension, wire material, number of wire strands, and type of
ligation
Overall conclusions were that frictional forces can be greatly reduced through
the use of SLBs, smaller diameter wires and less stiff wires


Torque Expression of Self
Ligating Brackets










Purpose of the study was to measure the difference in 3rd order
moments that can be delivered by engaging a 19x25 SS AW to various
brackets
2 Active SLBs were used - In-Ovation and SPEED
2 Passive SLBs were used - Damon2 and Smart Clip
A bracket/wire assembly torsion device was used - is able to apply
torsion to a wire while maintaining perfect vertical and horizontal
alignment between the wire and the bracket
The torque was then measured by a multi-axis force/torque transducer
Results showed that torque started to be expressed at lower degrees of
torsion (7.5) for the active SLBs versus the passive SLBs (15)
Concluded that active SLBs are more effective in torque expression


External apical root resorption in patients with
conventional and self-ligating brackets






Aim was to investigate the amount of external apical
root resorption between conventional and passive SLBs
(Damon2)
96 patients selected
Pts received Tx with either SLBs or conventional
brackets with .022 slot
No difference was found in the amount of EARR, but
a positive association existed between EARR and
duration of TX


Alignment efficiency of Damon3 self-ligating and
conventional orthodontic bracket system: A randomized
clinical trial








Aim of this study was to compare the efficiency of mandibular
tooth alignment and the clinical effectiveness of a self-ligating
(Damon 3) and a conventional preadjusted orthodontic bracket
(Ormco bracket).
62 pts from 2 orthodontic clinics (32 male, 30 female) with
mandibular incisor irregularities (Little’s Irregularity Index) of 5
to 12mm and prescribed extraction pattern including the
mandibular first premolars
Wire sequence: .014 NiTi  14x25 Niti  18x25 NiTi 
19x25SS
No difference in the initial or the overall rate of mandibular
incisor alignment between the two bracket types
Only significant influence of initial rate of alignment was the
amount of initial irregularity

References













Sadowsky, PL. Self-Ligating Orthodontic Brackets. 2008. Seminars in Orthodontics. 14(1).
Scott P, DiBiase A, Sherriff M, Cobourne M. Alignment efficiency of Damon3 self-ligating and
conventional orthodontic bracket systems: A randomized clinical trial. 2008. Am J Orthod
Dentofacial Orthop. 134:470.e1-470.e8.
Pandis N, Nasika M, Polychronopoulou A, Eliades T. External apical root resorption in patients
treated with conventional and self-ligating brackets. 2008. Am J Ortho Dentofacial Orthop.
134:646-51.
Matarese G, Nucera R, Militi A, Mazza M, Portelli M, Festa F, Cordasco G. Evaluation of
frictional forces during dental alignment: An experimental model with 3 nonleveled brackets.
2008. Am J Ortho Dentofacial Orthop. 133:708-15.
Badawi H, Toogood R, Carey J, Heo G, Major P. Torque expression of self-ligating brackets.
2008. Am J Orthod Dentofacial Orthop. 133-721-8
Rinchuse D, Miles P. Self-ligating Brackets: Present and Future. 2007. Am J Orthod Dentofacial
Orthop. 132:216-22
Thomas S, Birnie DJ, Sherriff M. A comparative in vitro study of the fricitonal characterisitics of
two types of self-ligating brackets and two types of preadjusted brackets tied with elastomeric
ligatures. 1998. Eur J Orthod 20:589-596.
Srinivas S. Comparison of canine retraction with self-ligated and conventional ligated brackets—a
clinical study. 2003. Thesis in fulfillment of postgraduate degree, Tamilnadu Medical University,
Chennai, India


Thank you
For more details please visit


Self ligatingbrackets /certified fixed orthodontic courses by Indian dental academy

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

Similaire à Self ligatingbrackets /certified fixed orthodontic courses by Indian dental academy

Similaire à Self ligatingbrackets /certified fixed orthodontic courses by Indian dental academy (20)

Plus de Indian dental academy

Plus de Indian dental academy (20)

Dernier

Dernier (20)

Self ligatingbrackets /certified fixed orthodontic courses by Indian dental academy