ORTHO

1. MATERIAL USED
IN
ORTHODONTICS

2. INTRODUCTION
 Evolution of fixed orthodontic appliance systems and their components are
closely linked to the development of the science of metals, technology, milling
instruments and lately advances in computer technology.
 A biomaterial/material is any substance that has been engineered to interact with
biological systems for a medical purpose - either a therapeutic or a diagnostic
one.
 Because wide array of metallic, ceramic and polymeric materials in the profession,
and new materials are continuously being introduced.
 It is essential that the scientific basis for selection and proper use of materials for
clinical practice be thoroughly understood .

3. CLASSIFICATION OF ORTHODONTIC MATERIALS
ARCHWIRE MATERIALS
1. Gold
2. Stainless Steel
3. Chrome- Cobalt.
4. Nickel – Titanium
(i) Super elastic
(ii) Thermodynamic or
temperature transforming
5. Beta Titanium
(i) untreated
(ii) Surface treated
6. Alpha Titanium
7. Composite / coated arch wires
8. Titanium niobium arch wire
9.Newer NiTi wires
10.Nickel free stainless steel and other
modifications

4. ETCHING AND CRYSTAL GROWTH SYSTEMS
• Etching system
I. Phosphoric acid based
2. Polyacrylic acid based
3. Miscellaneous acid
(I) citric (ii) maleic
4. Self etching systems
5. Moisture insensitive primers
• Crystal growth systems
(i) polyacrylic based
(ii) lithium based
• ADHESION PROMOTERS
(i) to metal
(ii) to plastic
(iii) to porcelain
(iv) to gold

5. BONDING MATERIALS
• Composite system
1 Acrylic based – PMMA
(polymethylmethacrylate)
2 Diacrylate based –
bis-GMA (Bisphenyl A- glycidal methacrylate)
TEGDMA (triethyline glycol dimethacrylate)
UDMA (urethane dimethacrylate)
• Glass Ionomer systems
– conventional GIC
– metal reinforced GIC
– resin modified GIC (hybrid GIC)
• Combination of composite and glass ionomer system
Compomer (derived from composite and ionomer).

6. BRACKET & ATTACHMENT MATERIALS
1. Stainless Steel.
2. Polycarbonate. .
3. Fibre Glass reinforced plastic brackets.
4. Ceramic - Alumina based
(i ) Monocrystalline
(ii) Polycrystalline
(iii) Laminated brackets
(IV) Zirconia based brackets
5. Nickel free bracket materials - Titanium
- Duplex steel
6. Composite brackets
7. Self ligating brackets
8. Adhesive precoated brackets

7. LUTING AGENTS ( for band cementation)
Zinc Phosphate cement
Polycarboxylate cement.
Glass ionomer cement
(i) Chemical cured
(ii) light cured
(iii) dual cured
AUXILLARY / ADJUNCT FORCE DELIVERY SYSTEMS
• Elastomers
Latex based
Polyurethane based
Silicon based – Positioner materials
• Magnets
• Stainless steel springs
• NiTi springs Etc.

8. ARCHWIRE MATERIALS
 The material which is actively involved in orthodontics since the
beginning of this specialty and has advanced a lot over a period of century.
• Orthodontic wires, are central to the practice of our profession.
• They generate the biomechanical forces communicated through brackets for
tooth movement .
Gold was the first material to be used as archwire by Dr. E.H. Angel.

9. DESIRABLE PROPERTIES OF AN ARCHWIRE
• High springback capacity
• Large working range
• Low stiffness
• High formability
• Low surface friction
• Biocompatibility and environmental stability
• Capable of being welded or soldered
• Cost effective/affordable

10. Currently, orthodontists principally use wires of four major
base metal alloy types:
• Stainless Steel,
• Cobalt-Chromium-Nickel,
• Nickel-Titanium
• Beta-Titanium.

11. • Advancement of arch wire material has directly influenced force delivery
system beginning with “variable cross-section orthodontics” through
“variable modulus orthodontics” to latest one, “variable transforming
temperature orthodontics”.
• This advancement can be divided into five phases.
(Evans and Durning BJO 1996)

12. PHASE I Gold and Stainless Steel Alloys
• Until the early 1940's, wrought gold (type IV) was the main source of
material for construction of orthodontic archwires.
• In the 1940's, austenitic stainless steel was introduced with a greater yield
strength than gold ,higher elastic modulus, good resistance to corrosion and
moderate costs.

13. • In order to overcome the problem of high elastic modulus, incorporation of
arch wire loops or the use of multistranded stainless steel was recommended .
or
“Variable cross Section Orthodontics” where Stainless steel archwire
dimension was changed in order to vary force delivery characteristics.

14. PHASE II ( Beta Titanium and Stabilized Nickel Titanium Alloys)
• In 1971, Andresen and Hilleman first proposed the use of 'stabilized' nickel
titanium in the field of orthodontics. The stabilized variant ‘nitinol' was formed
by cold working :- (55%nickel and 45% titanium)
• Nitinol was first introduced clinically in May 1972

15. • Goldberg and Burstone (1979) introduced Beta Titanium material.
• In 1981, Burstone introduced the concept of ‘Variable Modulus
Orthodontics’
This was achieved by using the same archwire dimensions of different materials
to produce required linear force/deflection characteristics.

16. PHASE III
Superelastic Nickel Titanium AIIoys ( Active Austenitic)
In 1985, Burstone et al reported new superelastic nickel titanium alloy with
unique properties of superelasticity.
• The super elastic nickel-titanium alloy are able to demonstrate the unique
hysteresis (Stress/strain) curves because their crystal structures are able to vary
under different environmental conditions.
• The material is capable of phase transformation (unlike the original stabilized
nickel Titanium alloy) under conditions of stress and temperature.

17. • For clinical purposes 'active' austenitic archwires are not intended to undergo
phase transformation at mouth temperature (as their TTR is very high ~ 45
deg. Celcius).
• so their super elasticity result from stress induction as during archwire ligation.

18. This group is also referred to as A-NiTi.
This group includes :
- Chinese NiTi.
- Japanese NiTi (Sentinol)
- 27C superelastic Cu-NiTi.
In Austenitic active alloy both Martensite and Austenitic phases play an
important role during its mechanical deformation

19. PHASE IV
Thermodynamic Nickel Titanium Alloy ('Active' Martensitic)
Using exact heat treatment procedures under inert atmospheric or vacuum
conditions, it’s possible to vary percentage of austenite present at particular
temperature; in other words now it’s possible to precisely control transitional
temp. (TTR)
This is a feature of sentalloy arch wires (GAC).

20. PHASE V
Graded Thermodynamic nickel Titanium
The level of force applied is graded throughout the arch length according to
tooth size (PDL surface area) by introducing variable TTR within the same
archwire,
• This is based on concept that the response of a tooth to force application and
the rate of tooth movement is dependent on the surface area of the
periodontium.
• These wires provide light forces of approximately 80g anteriorly and a
heavier force of 300g posteriorly.
( example: “Bioforce” from GAC)

21. VARIOUS RECENT ADVANCES OF ARCHWIRES
1. Titanium Niobium wire
2. Timolium titanium wire
3. Super cable
4. Combined archwire
5. Bio force archwire
6. Optiflex archwire
7. Fiber reinforced composite archwire etc.
• Clinical selection of orthodontic wires:
Clinically, it is evident that there is no ideal orthodontic wire alloy. Each of the
four popular base-metal wires has distinct advantages and disadvantages.

22. ORTHODONTIC BRACKETS
This term was introduced by Dr. Edward Hartley Angle in 1916 when he devised the
ribbon arch appliance.
• Orthodontic brackets bonded to enamel provide the means to transfer the
force applied by the activated arch wire to the tooth.
• Bracket material must be:
Hygienic , non- toxic
Resistant to corrosion
It must resist force applied to it by wire
Have minimal bracket wire friction
Not absorb water or discoloured by oral fluids
Esthetic

23. TYPES OF BRACKETS
A) METAL BRACKETS
• Stainless steel brackets
• Gold-coated brackets
• Platinum-coated brackets
• Titanium brackets
B) PLASTIC BRACKETS
• Polycarbonate brackets
• Polyurethane-composite brackets
• Thermoplastic-polyurethane brackets
C) CERAMIC BRACKETS
 Monocrystalline alumina (Sapphire)
 Polycrystalline alumina
 Polycrystalline Zirconia (YPSZ)

24. METAL BRACKET STAINLESS STEEL BRACKETS
 Most brackets currently used are made of austenitic stainless steel containing
18% chromium and 8% nickel
 SS brackets have most of the basic characteristics expected from a bracket
 It is resistant to all kinds of corrosion , hygienic and economical
 However it has two important disadvantages:
• Not esthetic
• May release nickel into the oral environment
 Therefore various alternatives materials have been introduced to overcome this
problem

25. PLASTIC BRACKETS
 Initially made of polycarbonate and plastic moulding powder (Plexiglas)
 These brackets did not last long because of their:
 Discolouration
 Fragility
 Breakage under stress
 Most of the energy in the wire was expended in distorting the brackets because of the
poor integrity of the arch wire slot and therefore forces wre not transmitted to the
tooth.
They improved and reinforced plastic brackets by introducing.
• Precision-made stainless steel slot inserts(to minimize friction)
• Ceramic fillers (colour stability).

26. CERAMIC BRACKETS
• They are the esthetic alternative to plastic brackets.
• Made of monocrystalline and polycrystalline ceramic material
• Advantages:
– Excellent colour
– Stain resistance
– Biocompatible
– Hardness

27. • Disadvantages
– Fracture tendencies
– Cause abrasion of opposing teeth
– They damage the enamel during debonding procedure.
• Many modifications have already been implemented for the correction of
these shortcomings with newer/recent advances in ceramic bracket.

28. AUXILIARY FORCE DELIVERING MATERIALS
 Auxilliary are used as “aids” in orthodontic treatment with fixed
appliances, but which alone cannot be used to carry out a complete
orthodontic treatment.
 Auxilliary includes:
– Elastics and elastic modules
– Springs
– Magnets
– Buccal tube
– Lingual attachments
– Lock pins
– Power pins

29. ELASTICS
 They provide the cheapest and relatively
reliable force delivery.
 Elastics can be of
– latex or non-latex material.
 Non-latex elastics deteriorate less as
compared to the latex elastics, in the oral
environment.

30. • Elastics are available in various strengths, which
is dependent upon their diameter and thickness.
• They are chosen according to the purpose of
their use.
• They may be color code according to strength

31. ELASTIC MODULES OR ELASTOMERIC LINKS
• Elastic modules or elastomeric links They are made
of two elastic rings separated by a variable distance
• used to closed spaces or for derotation of teeth.
• 1- Closed or short elastic chain
• 2- Long elastic chain
• 3- Continuous elastic chain

32. SPRINGS
 Used as auxlliaries to generate tooth-moving forces.
 Made from either stainless steel or nickel-
titanium alloys.
 The force generated by any spring is inversely
proportional to its length
 Stainless steel springs will exert a greater force than
nickel-titanium springs

33. • OPEN COIL SPRINGS (TO OPEN OR
MAINTAIN OR REGAIN SPACE)
• CLOSED COIL SPRING (TO RETRACT OR CLOSE
ALREADY EXISTING).

34. MAGNETS
 Magnetic materials as a source of motive force for effecting orthodontic
tooth movement is a relatively recent development.
 Used for the generation of tooth moving forces in both repulsion
(regaining lost space) as well as attraction mode(space closure).
 Applications of magnets in orthodontics include:
• Diastema closure (magnets used in attraction mode)
• Arch expansion (magnets used in repulsion mode)
• Distal driving of molars (magnets used in repulsion mode)
• Removable appliance for treating impacted teeth (magnets used in
attraction mode)

35. BUCCAL TUBES
• They are horizontal hollow tubes, round, rectangular
or oval in shape
• Used on molars and help provide better three
dimensional control of these anchor teeth.

36. LINGUAL ATTACHMENTS
• Lingual buttons :
attachment of elastics.
• Lingual seating lugs :
help in seating of bands.
• Lingual eyelets :used to tie
elastic threads or ligature
wires.

37. LUTING MATERIALS IN ORTHODONTICS
• In orthodontics, application of cements is limited to luting of removal,fixed
appliances and molar bands.
• For acceptable performance the luting , agent should have a variety of
properties-
 Adequate working time and setting time.
 High tensile
 Compressive
 Shear strength
 Resistance to dissolution
 Clinically acceptable bond strength, low adhesive remnant index score on
debonding and anti cariogenic potential.

38. LUTINGS CEMENTS
• Zinc phosphate
• Zinc silicophosphate cement
• Zinc polycarboxylate
• Glass ionomer cement
• Resin cement

39. ZINC PHOSPHATE CEMENT
• Once zinc phosphate cements were widely used for cementation of orthodontic bands.
• These cements are available as hand mixed powder and liquid system although some
encapsulated products are marketed.
ZINC POLYCARBOXYLATE CEMENT
• These cement were introduced by smith in 1968 and these cements were the 1st
dental materials developed with an adhesive potential to enamel and dentin and it
has the desirable properties of zinc phosphate and zinc oxide eugenol
• Use for cementation of bands

40. GLASS IONOMER CEMENT
• First introduced by Wilson and kent in 1972
• It is referred to as polyalkenoate cement, also known as
ASPA(Alumino-silicate polyacrylate)
Glass ionomer cements and light cured glass ionomer cements
routinely used in orthodontics for cementation of bands and
appliances.

41. Glass ionomer cement was introduced to orthodontics in 1986
COMPOSITION
• GIC powder is a acid soluble calcium fluroalumino silicate glass
• Main constituents include : silicone dioxide, aluminium phosphate, aluminium
fluoride and sodium fluoride.
• The liquid for GIC is an aqueous solutions of polyacrylic acid in a
concentration of about 50%
PROPERTIES OF GIC
 The luting GIC working time -3 to 5 minutes and setting time -5 to 9 minutes.
 Compressive strength – 90 -140 Mpa
 Tensile strength – 6 - 8 Mpa
 Modulus of elasticity – 3.5 - 4 Gpa
 Flexural strength and fracture Toughness is highest for GIC
 Shows considerably lower Solubility than other cements
 Initially there will be elevated level of fluoride release and finally attains low constant
level

42. • With GIC having better properties in comparison with the other cements, it
is widely use in our practices even today.
• Resin modified glass ionomer cement (RMGIC) required significant higher
forces to deband in comparison with other cements . Hence not commonly
use in daily practices

43. BONDING AGENTS / MATERIALS
• The advent of direct bonding of resin to enamel surface by Buonocore in 1952
was a significant breakthrough in dentistry in general and orthodontics in
particular.
• He advocated the use of acid for alteration of enamel surface to render it more
amendable to adhesion.
• Since then, material scientists and clinicians have strived to develop better
handling and mechanical properties of these materials which involves in
bonding.

44. MATERIAL USE FOR ENAMEL ETCHING
 A concentration 30-40 % phosphoric acid was considered most suitable for effective
etching.
 Current practice guidelines recommend the application of 37 % orthophosphoric acid gel
for 30 secs.
 A properly etched enamel surface gives a frosty white appearance on drying.

45. Other examples of conditioners
• Air abrasion (Al2O3)
• Laser etching (neodymium-yttrium- garnet)
• Crystal growing solution
• Crystal bonding involves application to enamel of a poly
(acrylic acid) solution containing sulfate ions, which causes
growth of calcium sulfate dihydrate crystals on the enamel
surface. These crystals in turn retain the adhesive.
45
 10% Phosphoric acid
 10 % Maleic acid
 2.5 % Nitric acid
 EDTA
 Citric acid + 3% ferric chloride
Alternate methods of etching

46. GENERATIONS OF BONDING AGENTS

47.  Buonocore (1956)
 Resin containing glycerophosphoric acid dimethacrylate
 Bowen
 N- phenyl glycine &glycidyl methacrylate(NPG-GMA)
 Bonding- chelation of bonding agent to calcium of dentine
 DRAWBACK
 Poor dentine bonding
 Enamel bonding is good.
 Poor bond strength (1 to 3 MPa ).
 The first commercial system of this type – Cervident, SS White
FIRST GENERATION

48. SECOND GENERATION
• Late 1970’s
• Incorporate halophoshorus esters of unfilled resins
• Bis-GMA: bisphenol-Aglycidal methacrylate
• HEMA: hydroxyethyl methacrylate
• Bonding- through an ionic bond to calcium by chlorophosphite groups
• Weak bond strengths
• Example: Scotch Bond (3M dental)
• Clearfil (kuraray Co. Japan)
• First and second generation are no longer used.

49. THIRD GENERATION
 Late 1980’s, Principle- partially removed or modified smear layer
 The primer contains hydrophilic resin monomers which include
• 4- META: hydroxyethyl trimellitate anhydride OR
• BPDM: biphenyl dimethacrylate
 Hydrophilic group infiltrates smear layer
 Bonding : smear layer softening – resin cure which form hard surface.
Unfilled resin adhesive is applied, attaching cured primer to the composite
resin.
• Drawback- bonding to smear layer
Example :
• Mirage bond
• Scotch bond

50.  Total etch technique
 Complete removal of the
smear layer is achieved
 40% phosphoric acid for 15 to 20
seconds
 Bond Strength – 17-25 Mpa
• All bound -2 (BISCO)
• Scotch bond Multipurpose (3M)
• Optibond FL (Kerr)
FOURTH GENERATIONS

51. ONE –BOTTLE SYSTEM
•Primer and adhesives are combined into one solution
•Show high bond strength values both to the etched enamel and dentin
due to adhesive lateral branches and hybrid layer formation.
•Total etching was done with 35-37% phosphoric acid for 15 to 20 secs
•Bond strength – 20-25Mpa
•Example: SingleBond(3M), One step (BISCO), Prime and Bond (Dentsply)
FIFTH GENERATIONS

52. • These are ‘SEP’. This system eliminates wash and dry
step after etching.
• The advantages is that collagen collapse by airdrying is
avoided.
Drawbacks:
•Enamel bonding
•Hydrolytic degradation
•Frequent renewal is required
SIXTH GENERATION
Examples -

53. • Late 1990’s & early 2000’s
• These are the first , no- mix, self etch adhesives
combining etching,priming and adhesive in one
bottle.'All in ONE’
• This generation of adhesives has proven to have
the lowest initial and long term bond strength-
considered as a disadvantage
•Example - I - Bond
SEVENTH GENERATION

54. All in
one

55. • A self etching self adhering flowable composite technology eliminates
the need for separate bonding application step with composites for
direct restorative procedures.
• Stable nanofiller that will not settle out of dispersion.
• Highly functionalised SiO2
• Nano Particle - < 20nm
• Bond Strength – 30Mpa
• Curing time – 35 sec
• Vertise flow (Kerr), Single Bond, Optic Bond Solo Plus, Adper Single
Bond 2 adhesive, Futurabond DC, Voco, Germany 3M
EIGHT GENERATION

56. • Moisture – Resistant
An aqueous solution of methacrylate functionalised
polyalkenoic acid copolymer & hydroxyethyl –
methacrylate
• Excess interfacial water ionizes carboxylic groups forming
hydrogen bonded dimers, thus water is incorporated in
bonding mechanism
• Application of primer on wet enamel surface.
• Useful in difficult moisture condition.
eg. Impacted teeth, partialy erupted teeth.
• Transbond MIP
(3M)
MOISTURE INSENSITIVE PRIMER (MIP)

57. ORTHODONTIC BONDING ADHESIVES
 It involves the application of bonding composite on bracket base.
 Mainly Two types of bonding material based on their curing properties-
 Self cure
 Light cure
 The light cure composite are preferred owing to their better bond strength and
handling properties.
 Available in a syringe for ease of dispensing.

58. BOND/ADHESIVE PROMOTERS
 With adult orthodontics becoming more popular, there is an increasing
percentage of patients with prosthesis and restorations seeking treatment in
whom orthodontic bonding is needed.
 This involves bonding to other surfaces apart from natural teeth.
BONDING TO PORCELAIN:
• The etchant used is 9.6 % Hydrofluoric (HF) acid in gel form and etching time is 2-4
mins.
• HF acid dissolves the crystalline and glassy phases of porcelain thus enhancing the
surface area.
• Adhesion promoters is principally organo-silanes and bonding agent used is bis
GMA resin.

59. BONDING TO AMALGAM
can be enhanced by:
1 Sandblasting or diamond bur roughening of amalgam surface
2 Use of intermediate resins (metal primer, amalgambond plus)
3. adhesive resins that bond chemically to metals ( 4-META resins, 10-MDP bis GMA
resins
BONDING TO COMPOSITE RESTORATIONS
Bonding to old composite restoration can be enhanced by
• Roughening the restoration with sandblasting or
• Rotary instruments
followed by application of intermediate primer.

60. CONCLUSION
• Orthodontics is a fascinating part of the dental profession that employs current
biophysical principles and constantly seeks better and more effective biomaterials
resources
• As we know , Materials advancement is a constantly evolving science, and
advancement in materials / biomaterials is prerequisite for development of any
science and orthodontic is not exception to it.
• This has benefited both orthodontist and their patients.
• Much more achievements may come in near future and hence, one need to be
well aware of all these new advances to know about advantages and
disadvantages of newer materials.