Recent advances in orthodontic materials 8th ios-pgsc /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


Technological and material advancements in
Orthodontics has made possible a constant
improvement in the quality of orthodontic
treatment ultimately, benefiting the patient.

An analysis of the various dimensions of
orthodontic advancement reveal two
important truths.

Firstly, the biologic problems have remained
singularly unchanged.
New solutions to the old problems have resulted
principally from advancements in orthodontic
materials (Biomaterials) and their cascading end
effect on appliance design and treatment strategies
(Biomechanics).

The Problem, Treatment & The Result

Biomechanics

Biomaterials


Virtually every facet of orthodontic
treatment has been changed for the
better thanks to the advancement in
the orthodontic material &
biomechanics arena.
Technique dogma will soon slip
into orthodontic history !!

However there is still an inadequate
understanding of this area by todays
Orthodontists.
This area has been shunned by the clinical
orthodontist and by default has been the
preserve of the manufacturers, the
“engineer-orthodontist” and perhaps a few
academicians.

Orthodontic material science is an
emerging sub discipline of Orthodontics.

The earlier we recognise and initiate
efforts to foster it , the better it would be
for Orthodontics.

The canvas is too broad to address all of
the related issues, in this brief paper.

This is a humble attempt in this direction
within the constraints of the time allotted.


Have been in the market now for 3 years.
How good are they ?
What do we know more about them ?

SELF ETCHING (ACIDIC) PRIMER (SEP’s)
ADHESIVE SYSTEMS
An acidic primer
combines the etchant with the primer in one application
eg; Clearfil Liner Bond 2.( J.C.Moritta Kuraway, Japan)
ie; contains both the acid
(Phenyl-P) and the primer (HEMA and dimethacrylate)

NEWER ETCHING / BONDING SYSTEMS
Self Etching Primers (systems) – (SEP’s)
(
•

Clearfil Liner bond V (Kuraray)

•

Megabond (Kuraray)

•

Prompt –L-Pop (Unitek-3M)

•

First Step (Reliance)

•

Transbond Plus SEP (Unitek -3M)

•

Ideal1 (GAC)

•

One up Bond F (Tokuyama)

Moisture Insensitive Primers –
•

Assure (Reliance)

•

MIP (Unitek-3M)

Self – etching Adhesive Primer


Self Etching Primers
(Anirudh Agarwal & Jyothindra Kumar )

 To determine the mean shear bond strength of

orthodontic brackets bonded with an Acidic Primer
System (Clearfil Liner Bond 2V) using both the light
cured and the dual cure mode.

 To compare the mean shear bond strength of both

these materials with “Rely-a Bond”.

Table showing shear bond strength (MPa)
Mean

Minimum

Maximum

Std. Dev.

Std. Err.

1.043

0.301

Rely-a-Bond™

12.907

11.389

14.612

VLC Clearfil
Liner Bond
2V

13.465

12.271

14.612

0.802

0.232

Dual Cure
Clearfil Liner
Bond 2V

13.610

11.977

14.906

0.803

0.232


Bond strength of Acidic Primer System - adequate and acceptable for
clinical use. No statistical difference with conventional composite resin
adhesive system .Varies from 8 - 20 MPa.(In vitro-unground enamel)
and 12-25.Mpa on ground human enamel.

Can be used on Porcelain substrates – produces bond strengths of over 10
MPa when etched with Phosphoric acid and bonded with SEP. (Ajlouni
et al 2003)

A delay in bonding after SEP application further increases the bond
strength ( 20 MPa at 1 minute vs 25 MPa at 10 mins – Errera et al ’03)

SEP: Self-etching Primer vs. Two-stage Etch and Prime
system for Orthodontic Bonding: A RCT (Aljoubouri et al ’03)
• Mean bonding time of brackets bonded with SEP was
significantly shorter than that for the two-stage
bonding system (mean difference 24.9 sec)
• Bond failure rate was similar for each bonding system
(SEP was 0.8% and for the two-stage etch and prime
system was 1.1%. )
• Application of a self-etching primer provides no
resistance to enamel demineralization as compared
to a conventional sealant. (Kao et al ’03)

Bonding Durability of Orthodontic
Brackets using SEP’s
•

No significant difference in shear bond strength was observed
between phosphoric acid etching and self-etching primer before
thermal cycling.

•

However, after 2000 and 5000 thermal cycles the bond strength
obtained using self-etching primer was significantly higher than that
with phosphoric acid etching (P<0.05).

•

There were no significant decrease in shear bond strengths using
self-etching primer treatment after thermal cyclings (P>0.05).

•

Conclusion: Self-etching primer treatment produced more durable
bonding of orthodontic brackets to human enamel than phosphoric
acid etching.

SEP’s resistant to saliva
contamination
(S.

SIRIRUNGROJYING et al ’03)

• With self-etching primer treatment, saliva
contamination did not cause any decrease of bond
strength
• Phosphoric acid etching produced more enamel
fracture than self-etching primer treatment after
debonding orthodontic brackets.
• Field-emission scanning microscopy revealed that
self-etching primer produced less dissolution of
enamel surface www.indiandentalacademy.com
compared with phosphoric acid.

Hydrophilic Primers

Works in both dry and wet environments

Moisture Insensitive Primers (MIP)
• Generally available as a primer formulation
• An aqueous solution of methacrylate functionalised
polyalkenoic acid copolymer and hydroxyethylmethacrylate. (Used earlier in hydrophilic dentin
bonding systems).
• Moisture active adhesives require the presence of
water for initiating the setting reaction and will
therefore fail in the dry environment.
• Cyanoacrylates (Smart bond) is an example.Early
reports indicate that they work adequately.

Zn treatment of enamel enhances bond
strength & reduces decalcification
(Olivier et al –’02)

• Incorporation of Zn into hydroxyapatite is known
to reduce plaque growth. It may be effective in
resisting decalcification surrounding orthodontic
brackets which is a common clinical problem
• The shear strength (MPa) of the Zn-treated and
control specimens were 11.31 ± 3.46 and 9.10 ±
3.94, respectively –No statistically signficant
difference.

Zn treatment of enamel
• SEM, the Zn-treated surface was found to be rough
and porous, characteristics conducive to mechanical
bonding. EDXA revealed the incorporation of a
significant amount of Zn in treated enamel.
• Zn treatment of enamel, with its shear bond strength
comparable to that of traditional phosphoric acid
etched enamel, has the potential to be used in
orthodontic bonding with possible protection against
decalcification.

EDTA Etching
( Cehreli et al, 2000)

• Evaluated the effects of 17%
ethylenediaminetetraacetic acid (EDTA) and nonrinse
conditioner (NRC) on enamel surface morphology
and compared with traditional 37% phosphoric acid.
• EDTA treatment had the least effect of all etchants
tested. The SEM photographs revealed a smooth,
wavelike, and reactive etched surface,while the
integrity of enamel prisms was maintained

EDTA Etching
• Irrespective of treatment time, NRC produced
an aprismatic etch pattern, which suggested
a potentially retentive morphological
character.
• Shorter etching time with phosphoric acid
resulted in a relatively smooth enamel
surface compared with longer treatments.

Classification of Light curing Sources

• Halogen Light curing Units (80’s)
• High energy Laser curing systems (90’s >)
• Plasma Arc Curing Units (2001 & >)
• LED Curing Units (2002 & > )

Halogen LC: Drawbacks
Halogen bulbs have a limited effective lifetime of
approximately 40-100 hours.
High temperatures cause a gradual degradation of the
halogen bulb, reflector, and filter, reducing the
intensity of the light output and thus the unit’s
effectiveness in curing composite resins.
The clinical implication is that with an aging light-curing
unit, adhesives will be less well cured, with poorer
physical properties and an increased risk of bond
failure.

Halogen LC: Drawbacks
Dental halogen light-curing
units do not reach the
minimum power output
specified by the
manufacturers.
This can be a result of improper
maintenance, including
failure to make a critical
check of the light irradiance
and to replace the filter and
the halogen bulb on a
regular basis

History Of LED in Dentistry
• First suggested by:
Mills, R.W.: Blue light emitting diodes—another
method of light curing? Br. Dent. J. 178:169, 1995.

• First report by:
Fujibayashi, K.; Ishimaru, K.; Takahashi, N.; and
Kohno, A.:Newly developed curing unit using blue
light-emitting diodes,Dent. Jap. 34:49-53, 1998.

GC – E light

3M Unitek
Ortholux


LED CURING UNITS
• LEDs are semiconducting materials that
transform current into light of a specific
wavelength.
• They are much smaller and lighter than
conventional bulbs. They offer high shock
resistance, as there is no filament to be
damaged, and their relatively low power
consumption makes them suitable for
portable use in cordless devices.

• LEDs have lifetimes of more than10,000 hours and
experience little degradation of light output over this time
—a distinct advantage over halogen bulbs
• LEDs require no filters to produce blue light. The spectral
outputof these LEDs falls mainly within the absorption
spectrum of the camphoroquinone photoinitiator (400500nm) of most dental composites.
• LED sources have been found to produce a depth of
cure significantly greater than that achieved with a
conventional halogen light.

• LED sources have been found to produce a
depth of cure significantly greater than that
achieved with a conventional halogen light.

• No significant differences in compressive
strength, flexural strength, or modulus10 were
found between composites polymerized with
halogen units and those cured with LED units.

• Is the claim of adequate bond
strength when using LED units borne
out by in vitro / vivo evidence?


• Reynolds & Lalani have recommended a value
of 6-8.MPa as adequate for clinically successful
bonding.
• Reviewing the published reports( 8 ),all studies
have reported bond strengths of 6 – 16 MPa
and as high as 19.9 ± 5.7 MPa (Cacciafesta –’02)
• This is adequate for clinically successfull
bonding.
• Bond strength increases with exposure time and
is a critical factor. There is a minimum exposure
time. For current units it is about 10 secs or >

• Halogen lights still produce the highest bond
strength approx – 30-40% more.
• Etch – Prime –Bond (EPB) technique still
produces the highest bond strength compared to
One step techniques.
• In terms of the initial cost the benefit is clinically
not very significant.
• Nevethless it is yet another way of delivering
curing energy for bonding adhesives

• Does curing time length produce an
intra pulpal temperature rise ?


• Halogen lights were found to produce a greater
pulpal temperature rise – with longer curing
cycles increasing iatrogenic pulpal damage risk.
• LED’s tended to produce significantly lesser
pulpal wall heating and had shorter cooling
times.
• May be related to their narrow energy spectrum.

PLASMA ARC CURE BONDING UNITS

Apollo 95E Plasma Curing Unit


PLASMA ARC CURE BONDING
Advantages
 Overall time reduction – 2 mins for whole arch
 Immediate bond strength appears to be very high
 No enamel damage on debonding
 Re - bonding of brackets is easy

Disadvantages
 Light emitted from plasma arc device is so powerful that both the

operator and assistant should wear protective glasses
 Additional cost of curing light


Exposure Time for PAC Systems
• Two curing cycles of 3 seconds each can be
recommended for bonding stainless steel
brackets with xenon plasma arc curing lights.
• Reducing curing time from 6 to 2 seconds
resulted in a significant decrease in mean
bond strength of premolar brackets.
• Time saved is the significant advantage of
plasma curing lights.

LASER DEBONDING
1. The time spent to debond ceramic brackets is less when
using lasers. Debonding forces are significantly reduced
with lasers.
2. The risk of enamel damage and bracket fracture is
significantly reduced with lasers.
3. The CO2 super-pulse laser is superior to normal pulse
CO2 and YAG lasers. MMA resins are recommended
over Bis-GMA resins.
4. The use of monocrystalline brackets is suggested over
polycrystalline brackets.

LASER DEBONDING
5.Ceramic brackets should be irradiated and debonded
one by one immediately after laser exposure.
6. The risk of pulpal damage is significantly reduced if
the following are used:
a. Super-pulse CO2 laser at 2 W for less than
4 seconds.
b. CO2 laser (10.6 m) for 3 seconds at 3 W.
c. CO2 laser (normal pulse) at 18 W for 2 seconds.

•

Recently, the implant has been recognized as one of the useful
methods for orthodontic anchorage. In cases where nonabsorbable implants are placed, it is necessary to remove them
after orthodontic treatment.

•

An absorbable implant (FIXSORB-MX) Takiron company, Japan, poly
lactic acid, with molecular weight 200,000, mini-screw-type
2.0x8.0mm has been tried as an orthodontic implant .


Preliminary findings
• The loading of orthodontic force resulted in
no mobility and deciduation in the implant

• The results showed that the absorbable
implant had a clinically acceptable strength
when the orthodontic anchorage was applied.

Ethyl – Cyanoacrylate material was tested as
orthodontic bracket adhesive and found to have
significantly higher strength than conventional
composite (1991)

Significant advantage
– Ability to polymerize as a thin film at room

temperature, without a catalyst, when pressure is
applied in moist environment

Resistance to thermocycling
(Bishara et al ’03)
• In dry environment it gives comparable bond
strength values to single step bond resins
and can be misleading. (Wiltshire ’03)
• Smartbond cyanoacrylate adhesive has
adequate bond strength 24 hours after initial
bonding, but its strength decreases by 80%
after thermocycling between 5°C and 55°C
After 24 hours
After thermocycling

- 7.1 + 3.3 Range1.4-13.2 MPa
-1.5 +1.4 Range 0.1- 6.5 MPa


Glass Polyphosphonate Cement
(Diamond® Kemdent®, Associated Dental Products Limited, Swindon, UK)

• Glass Polyphosphonate cements have recently been
introduced for use in restorative dentistry.
• The claimed advantages of glass polyphosphonates
over conventional glass polyalkenoate cements are:
– A rapid set, a high compressive strength,and a low
solubility.
– The latter is said to result in a less unpleasant taste, a
common complaint by patients when cementing bands with
glass polyalkenoate cement.

-Saliva resistant snap-set
-Chemical set
-Adhesive to Dentine and Enamel
-Fluoride release
-Radiopaque
-7 aesthetic shades
-Class leading mechanical properties give Diamond up to
50% higher compressive strength than conventional glass
ionomer cements

Evaluation of glass polyphosphonate
cement in orthodontic banding
(J. R. Clark, A. J. Ireland and M. Sherriff - EJO ’03)

• After 6 months of active treatment the overall failure rate
for bands cemented with Diamond® in this study was 4.8
per cent, same as that with a conventional GIC.
• 50% of the patients showed better acceptance of the
polyphosphonate cement
• It would seem that glass polyphosphonate cements
maybe used for orthodontic banding.

Contemporary Metal lined
Ceramic Brackets
How Good are They ?

(especially when we pay 600% more than SS
Brackets and 25% more than Ceramic
brackets for them!!)

………..the aesthetics of
ceramics, and the strength
& surface properties of
metal all in one bracket !!

Clarity - SS Inserted Ceramic bracket

Gold reinforced ceramic brackets
Luxi ™ contains an 18-karat (75%) gold
insert,which is similar in composition to high-quality
gold crown and bridge alloys.


Aspire & Inspire
ASPIRE GOLD - KERAMIK BRACKET
-mit Gold-Sliding-Guide
F O R E S TA D E N T ®

Illusion + Orthorganisers

Inspire - Ormco

Mystique-Ceramic-glazed slot
(GAC)


 G .I -

Clarity (Ceramic -SS insert)- Unitek 3M

 G .II –

Luxi (Ceramic - gold insert) - RMO

 G.III –

Aspire (Ceramic- gold insert)- Forestadent

 G.IV –

Illusion + (Ceramic-Silver) – Ortho Organiser

 G.V -

Classic – Polycarbonate-Gold insert – American Ortho

 G.VI-

Elation (Polycarbonate –SS insert)- GAC

 G. VII -

Spirit MB – Polycarbonate – SS insert – Ormco

 G.VIII-

Inspire (Monocrystalline – Ceramic)- Ormco

 G. IX-

Mystique – Glazed Slot – Ceramic - GAC

 G. X-

Gemini – SS brackets ( gold standard) – Unitek 3M

Parameters


Frictional characteristics using
stainless steel arch wire - .016 x .022
dimension

 Shear bond strength (bonding with
Rely – a – Bond)

Results - Kinetic Friction
Brackets

Mean ± SD of
µK

50 grams
Clarity (SS)

0.71 ± 0.02

Luxi

0.45 ± 0.03

(Cer-Gold)

Aspire (Cer-Gold)

0.399 + 0.14

Illusion + (Cer-silver)

0.196 + 0.015

Inspire (M.C.Cer)

0.497 + 0.069

Mystique (PC Glazed)

0.318 + 0.042

Gemini SS

0.69 ±0.04

Results – Kinetic Friction
Brackets

Mean ± SD of µK

100 grams
Clarity

0.50 ± 0.015

Luxi

0.26 ± 0.008

Aspire

0.246 + 0.069

Illusion Plus

0.11 + 0.011

Inspire

0.311 + 0.083

Mystique

0.233 + 0.035

Stainless Steel

0.44 ± 0.016


Slot Surface Topography - SEM
Normal
Luxi (with gold insert) – porous.
Clarity (Steel insert) – relatively smoother surface with
uniform distribution of cracks.

After frictional evaluation.
Luxi – severe wear of slot material.
Clarity – horizontal lines visible, smooth surface
maintained.

Unused Clarity
Bracket slot – x 1000

Unused Clarity
Bracket slot – x 5000

Mystique – Unused
Bracket slot- 25x

Mystique – Unused
Bracket slot – 1000x


Unused Aspire

Unused Aspire
Bracket slot-5000x

Inspire- Unused
Bracket slot -25x

Inspire-Unused


Clarity bracket – 5000 x magnification

Before Frictional Evaluation

After Frictional Evaluation


Luxi – 5000 x magnification

Before frictional evaluation

After frictional evaluation


Aspire - 5000x magnification



Inspire - 1000x magnification




Mystique - 1000x magnification




Look At the striations in the slot

Frictional Characteristics
Tidy’s protocol was followed
Coefficient of kinetic friction was
calculated
Values obtained were tabulated and
entered into SPSS Ver.10
Mean, SD were calculated
Student ‘t’ test performed


 Shear bond strength.
Instron universal testing
machine was utilized.
Occlusal gingival load
applied to the bracket –
produces shear force.
Values recorded in
Newtons – by the computer
attached to the machine.

Mean shear bond strength.
Group I
Clarity
Mean ± SD

13.09 ±
0.214

Group II
Luxi

Group III
Gemini

12.69 ± 0.51 12.68 ± 0.69

Minimum

12.84

12.09

11.36

Maximum

13.41

13.20

13.20

•Statistical Evaluation - Comparison of
Group

II and group III brackets – no statistical significance.

Group

I and Group III – significant at 0.01 level.

Group

I and Group II – significant at 0.01 level.

Mean shear bond strength.
Aspire

Inspire

Mystique

Mean ± SD

4.396 ±
1.18

7.023 ±
1.901

4.997± 2.023

Minimum

3.49

5.26

3.44

Maximum

5.31

8.78

6.55


Mean shear bond strength - MPa
Mean

Minimum

Maximum

13.09 ± 0.214

12.84

13.41

12.69 ± 0.51

12.09

Gemini

12.68 ± 0.69

11.36

13.20

Aspire

4.396 ± 1.18

3.49

5.31

Illusion +

12.423 + 2.12

8.48

13.87

5.26

8.78

Clarity
Luxi

Inspire
Mystique

7.023 ± 1.90
4.997± 2.02

3.44


13.20

6.55

Bases of Luxi & Clarity

Luxi Base x 25

Clarity Base x 25


Bracket base surface topography – SEM Evaluation

Clarity – bracket base – 500 x

Luxi – bracket base – 500x

Bases of Inspire and Mystique
Inspire bracket
base- 25 x

Mystique bracket
base – 25 x


Bracket base surface topography –
SEM Evaluation
Inspire bracket base
– 500x

Mystique bracket
base – 500x


Bases of Aspire

Aspire base -25 x

Aspire bracket base –
500x


Stereomicroscopic Evaluation (Proximal)
Mystique bracket

Inspire bracket

Aspire bracket

How Good are they ?
Frictional characteristics of metal inserted
ceramic brackets generally is
comparable to or better than stainless
steel brackets.


Summary
Shear bond strength of metal inseted
ceramic brackets are very close to that of
stainless steel.
Polycarbonate slotted brackets show much
lower values
Mystique and Aspire also show very low
values

Metal inserted
POLY
CARBONATE
BRACKETS


Reinforced Polycarbonate Brackets

BLONDE™
Glass-reinforced composite
polymer bracket

IMAGE™

SOLO™
The Bio-Esthetic Single System

Spirit MB: Polymeric/ SS
(Ormco)

Elation: Polymeric/steel
(GAC)

Comparative Evaluation of Metal inserted
Plastics Brackets
(Sushil Kumar & Jyothindra Kumar – 2003)

Group I - Classic (Urethane with gold insert)
Group II – Elation (Polycarbonate/PET with SS
insert)

Group III – Spirit MB (Ceramic reinforced
Polycarbonate/ with SS insert)

Group IV - Gemini (SS brackets – used as gold
standard)

Elation (Polycarbonate/PET with SS
insert) produced significantly higher
frictional resistance than all three
brackets.
All three plastic brackets demonstrated
shear bond strength lower than
stainless steel brackets.

Kinetic Friction-Classic, Elation, Spirit MB
& Gemini (SS wire)
Brackets

Mean + S.D of µK
50 grams

Classic (Gold Inserted)

0.1965 + 0.0388

Elation (SS Inserted)

0.36578** + 0.1263

Spirit MB (SS Inserted)

0.1792 + 0.0747

Gemini (Conventional SS)

0.2259 + 0.0932
100 grams


0.1154 + 0.0260


0.2972** + 0.0841


0.1060 + 0.0415


0.1512 + 0.0279


**- Highly significant

Kinetic Friction-Classic, Elation, Spirit MB
& Gemini (NiTi wire)
Brackets

Mean + S.D of µK
50 grams


0.2930 + 0.0197


0.5287** + 0.0906


0.3282 + 0.0795


0.3829 + 0.0790

100 grams

0.1744 + 0.0197


0.3986** + 0.0530


0.1986 + 0.0629


0.2397 + 0.0404



Elation- Stereomicroscopic Evaluation

es Elation
Why do
significantly
show
r Friction?
highe


Stereomicroscopic Evaluation (Proximal)

Classic bracket

Spirit MB bracket


Bracket slot surface topography –
SEM Evaluation

Classic bracket - 25 x

www.indiandentalacademy.com bracket slot - 5000 x
Classic bracket slot - 1000 x
Classic

Classic - 5000x magnification



After frictional evaluation (SS)

After frictional evaluation (NiTi)

SEM Evaluation

Elation bracket - 25 x

Elation bracket slot
- 5000 x

Elation - 5000x magnification


After frictional evaluation (Niti)

SEM Evaluation

Spirit MB bracket - 25 x

Spirit MB bracket
slot - 5000 x

Spirit MB - 5000x magnification




After frictional evaluation (NiTi)

Mean shear bond strength (MPa).
Classic
Elation
(Gold
(SS
Inserted) Inserted)

Spirit MB
(SS
Inserted)

Gemini
(Conv.
SS)

Mean ± SD 3.105 ±
0.9326

3.2033 ±
1.5022

2.962 ±
0.4316

12.676**
± 0.5491

Minimum

2.033

1.26

2.372

11.36

Maximum 4.216

5.52

3.752

13.20



SEM Evaluation
Classic base – 25 x

Spirit MB base – 25x

Elation base25x

SEM Evaluation
Classic base – 500 x

Spirit MB base – 25x

Elation base25x

Low Friction Ligatures
Super Slick Ties – TP Labs
(Metafasix)
Sili Ties – GAC


Comparison of Kinetic FrictionSuper Slick ties & Dispense-A- Stix
( Leander & Jyothindra Kumar, ’01)

Super Slick ties showed a 11-15%
reduction in the overall friction when
used in sliding mechanics. This is
clinically signficant.


Comparison of Super Slick & Sili ties (Webb
et al ’04)
• TP SS ties showed
a lower force decay
rate compared to Sili
ties when stretched
for 6 hrs.
• There is a significant
difference in the
brand, and the
coating material.

Recent advances in orthodontic materials 8th ios-pgsc /certified fixed orthodontic courses by Indian dental academy

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