Esthetic orthodontic applainces /certified fixed orthodontic courses by Indian dental academy


Published on

The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Esthetic orthodontic applainces /certified fixed orthodontic courses by Indian dental academy

  2. 2. CONTENTS          Introduction Evaluation of esthetics Evolution of orthodontic materials Tooth colored brackets Esthetic arch wires Elastomeric Ligatures Tooth colored Ligatures Tooth colored appliances Lingual Orthodontics
  3. 3. Introduction:   Aristotle said "Beauty is a greater recommendation than any letter of introduction". The term “Esthetic” refers to an understanding of beauty.
  4. 4.   Esthetics which is derived from greek word for “aisthetikos”, deals with beauty and the beautiful. Lombardi defined “Dental Esthetics” by the way things were perceived visually.
  5. 5. Visual perception Proportion Composition
  6. 6.  Harmony between the dominant features of a face contributes to creating a beautiful face.  The "Facial Dominant Features" are 1. Smile with its components. Teeth, gingiva and lips. Eyes and facial frame. 2. 3.
  7. 7. Golden Proportion Beautiful Proportion   Greeks who tried to formulate beauty as an exact mathematical concept. "Golden Proportion” – Leonardo da vinci The Golden Proportion, phi, has been observed to evoke emotion or aesthetic feelings within us. The ancient Egyptians used it in the construction of the great pyramids and in the design of hieroglyphs found on tomb walls. At another time, thousands of miles away, the ancients of Mexico embraced phi while building the Sun Pyramid at Teotihuacan.
  8. 8.    The Greeks studied phi closely through their mathematics and used it in their architecture Renowned artists such as Michelangelo, Raphael, and Leonardo da Vinci made use of it for they knew of its appealing qualities. Evidence suggests that classical music composed by Mozart, Beethoven, and Bach embraces phi. "Beautiful Proportion” – Plato "The good, of course, is always beautiful, and the beautiful never lacks proportion”- Plato
  9. 9. Evaluating esthetics in Dentist’s chair Lombardi remarked that detailed esthetic judgments can only be made by viewing patients from front, in conversation, using facial expressions, and smiling.
  10. 10.
  11. 11. Evaluation of facial & Dental appearance  Face in three planes of space (Macro esthetics).  Smile frame work ( Mini esthetics).  The Teeth (Micro esthetics).
  12. 12. MACRO ESTHETICS  Asymmetry  Excessive or deficient face height  Imbalance in the facial profile.
  13. 13. MINI ESTHETICS  Gingival display on smile  Anterior tooth display  Gingival heights  Buccal corridors
  14. 14. MICRO ESTHETICS  Crown lengths of upper and lower incisors  Incisal edge contours  Midlines
  15. 15. Evolution of orthodontic materials  Like metallurgy, dentistry has a long history of artistic creativity.  Over 4500 years ago when the metal worker was sweating copper from malachite for weapons, making primitive tools from „„bia‟ n pet‟‟ (meteoric iron), and separating gold from crushed quartz stone literally using what became known as the Golden Fleece, the „„Toother‟‟ was likely splinting the teeth of the Egyptian court.
  16. 16.   Time passed from the Bronze Age to the Iron Age and the Industrial Revolution until, in the latter half of the 19th century Henry Clifton Sorby (1863–1887) and Edward Hartley Angle(1886–1930) professionally ascended to become the pioneers of modern metallography and modern orthodontics, respectively
  17. 17. THE BEGINNINGS     Teeth were regarded by the ancients as very precious to the extent that „„. . . special penalties [were exacted] for knocking out the teeth of an individual, either freeman or slave.‟‟ As early as 400 BC, Hippocrates referenced in his writings the correction of tooth irregularities And while Greece was in its Golden Age, the Etruscans (the precursors of the Romans) were burying their dead with appliances that were used to maintain space and prevent collapse of the dentition during life. Then in a Roman tomb inEgypt, Breccia finds a number of teeth bound a gold wire
  18. 18.  And at the time of Christ, Aurelius Cornelius Celsus first records the treatment of teeth by finger pressure EARLY CONTRIBUTORS     The French and English dominated the earliest contributions to the field of orthodontics, which as yet had not been formally named In 1819 Delabarre introduces the wire crib, and this marks the birth of contemporary orthodontics In the second half of the 19th century(ca 1865), Kingsley advocates plates as retaining devices In the early part of the 20th century, Angle would tout this device as one of the best tooth maintainers
  19. 19. Products made from alloys that orthodontics adopted. (A) 1936 Ford sedan made from stainless steel; (B) mainspring of a watch fabricated from cobalt-chromium alloy; (C) hydraulic shape-memory coupling manufactured from nickel-titanium intermetallic composition; and (D) SR-71 Blackbird constructed from titanium-molybdenum alloy
  20. 20. Orthodontic cases from yesteryear to today. (A) A fully banded patient with extensive stainless steel (SS) loop mechanics,ca 1965; (B) a patient fitted with maxillary polycarbonate brackets and a TeflonYcoated SS archwire and mandibular SS conventional brackets, ca 1980; And (C) a patient with conventional straight-wire CP-titanium brackets, ca 1995 (F. Sernetz, personal communication).
  21. 21.
  23. 23.
  24. 24.
  25. 25.
  26. 26. A)Plastic brackets 1) Polycarbonate brackets 2) Polyurethane-composite brackets 3) Thermoplastic-polyurethane brackets B) Ceramic brackets 1) Monocrystalline alumina (Sapphire) 2) Polycrystalline alumina 3) Polycrystalline Zirconia (YPSZ)
  28. 28.  The percentage of orthodontic patients increased dramatically in mid 80s to 25 % total orthodontic patients  Early commercially available aesthetic products included both plastic brackets and ceramic brackets  The first transparent bracket material-1960(Newman)  The first plastic brackets were manufactured from unfilled poly carbonate (early1970s)
  29. 29. • Initially an aesthetic alternative to metal brackets But short lived,because • Staining and odour • Lack of strength and stiffness • Tie wing fractures • Permanent deformation(creep) over constant load • Poly carbonate bracet slots distorted with time uder aconstant physiologic stress(2000 gm-mm)
  30. 30.  Sadat-Konsari et al study on torque deformation characteristics of seven commercially available plastic brackets (metal slot reinforced bracket,poly urethane,pure poly carbonate and fiber glass reinforced in plastic brackets) that,  plastic brackets are only suited for clinical application if they have a metal slots
  31. 31.  Plastic brackets are not as hard as ceramics, a fact which may be an advantage rather than a disadvantage.  Since it is generally thought that the harder a material is, the more it will wear an opposing material softer than Itself (Monasky.1971).  Plastic brackets will not wear or chip enamel. if occluded upon.
  32. 32. Bond strength  A wide variation exists in the results of different studies on bond strength with regard to the types of brackets, so that direct comparison of results is not feasible. The factors that may contribute to these differences include  the choice of composite,  the type of testing equipment used,
  33. 33.  -the orientation of the applied force,  -the storage medium of the extracted teeth,  -the bracket material, and  -whether the bracket base has a mechanical or chemical union to the composite resin (Crow. 1995).
  34. 34. • These materials are not cross-linked and the brackets may also undergo drifting when subjected to temperatures slightly higher than those In the mouth • Diacrylate cements used with plastic brackets were found not to bond well to them without plastic bracket primers • A bonding system, based on a unique thermosetting combination of mono- and dia-crylates and a high molecular weight polymeric filler, was developed to Improve the bond strength of polycarbonate brackets
  35. 35.  At present the new generations of plastic brackets are suitable for almost all adhesive systems.  No-mix adhesives or light-cure bonding materials with a supplementary primer are recommended by the orthodontic companies.  The adhesives with their own plastic primer demonstrated higher bond strength values than those without plastic primer  Satisfactory bond strength values were observed for polycarbonate brackets with no-mix orthodontic bonding resins and highly filled, self cured diacrylate cements (Blalock and Powers, 1995 Nkenke e1 al.. 1997)
  36. 36.  Among the factors that may cause these differences are geometry of the wings, presence of metallic reinforcement, sharp edges and geometry of the base.  Large and thick bases, rounded contours and provision for mechanical retention were factor associated with improved bond strength with the plastic brackets  The new ranges of plastic brackets offer a mechanical locking base, providing more bonding surface for mechanical retention with the adhesive.
  37. 37. Torque properties       Harzer et al reported significantly higher torquing losses and lower torquing moments with polycarbonate brackets So that additional torque should give To compensate strength problems , High grade medical poly urethane brackets , poly carbonate brackets reinforced with ceramic or fiber glass fillers and /or metal slots Although torqueproblems exists.(15% torque loss over 24hrs has been observed both ceramic reinfforced and metal lined poly carbonate brackets
  38. 38. Disadvantage polycarbonate brackets • • • Polycarbonate brackets undergo creep deformation when transferring torque loads generated by arch wires to the teeth Discoloration of first generation unfilled polycarbonate brackets during clinical aging. They absorb water to a slight extent and tend to weaken in the course of about one year (Newman 1973).
  39. 39. • Most efforts are directed toward improving the strength of polymeric brackets by reinforcing the plastic matrix. • Various reinforced polycarbonate brackets were, 1) Polymer fiber reinforced polycarbonate brackets 2) Fiberglass reinforced polycarbonate brackets 3) Ceramic reinforced polycarbonate brackets 4) Metal slot reinforced polycarbonate brackets 5) Metal slot and ceramic reinforced polycarbonate brackets
  40. 40. Commercially available plastic brackets Poly carbonate –glass fibers 1) Aesthetic Line 2) Image Poly carbonate-composite DBfibre Elan Poly urethane composite Envision Thermoplastic poly urethane Value line
  41. 41. Poly carbonate brackets Elation TM (GAC)
  42. 42. Fiber-Reinforced Polycarbonate brackets Spirit®MB (ORMCO) Classic (American Orthodontics) Fiber-Glass reinforce composite polymer OysterTM Bracket (GAC) VogueTM (GAC)
  43. 43. Commercially available plastic brackets
  44. 44. Commercially available plastic brackets
  45. 45. Commercially available plastic brackets
  46. 46. Commercially available plastic brackets
  47. 47. Ceramic brackets
  48. 48. Ceramic Brackets  Ceramics used for the manufacturing of ceramic brackets were Alumina and Zirconia. Both can be found as tridimensional inorganic macromolecules. Types of ceramic brackets  Monocrystalline (Sapphire)  Polycrystalline Alumina  Polycrystalline Zirconia-Yttrium oxide Partially Stabilised Zirconia (YPSZ)
  49. 49.  b2" Al3+ Al3+ b1 O2O2- O2- 2 Al3+ b" O 2- Al3+ 3 Al3+ b' 1 Al3+ O2- O2- Aluminium oxide crystal structure consists of a nearly Hexagonal close pack (HCP) arrangement of the larger oxygen anions (O2-), with smaller aluminium cations (Al3+), located in two- thirds of the octahedral interstitial sites in the HCP structure.These octahedral sites have six-fold coordination, i.e.,each aluminium ion is surrounded by six oxygen ions
  50. 50. Manufacturing process Mono crystalline brackets: Heating aluminum oxide to temperatures in excess of 2100 c Then, cooled slowly, and the bracket is machined (sintering process) - From the resulting crystal cut them in different shapes and dimensions of various brackets, using ultrasonic cutting techniques, diamond cutting, or combination of two
  51. 51. Poly crystalline brackets: -manufactured by blending aluminum oxide particles with a binder -temperatures above 1800 c are used to burnout the binder and fuse together and fused together the particles of the molded mixture Then , it is heat treated to remove surface imperfections and relieve stresses created by the cutting operation 
  52. 52. Advantage of the process:A relatively inexpensive process that yields large quantities Disadvantage this process - Presence of structural imperfections at grain boundaries or of trace amounts of impurities Impurities in quantities as minute as 0.001 percent or slight imperfections can serves as foci for crack propagation under stress
  53. 53.   Alternative method of making polycrystalline brackets is injecting molding Advantage is eliminates structural imperfections created by cutting process
  54. 54. Disadvantage of poly crystalline brackets   The larger the ceramic grains ,the greater the translucency. But, as the grain size increases the material tends to be weaker. it is up to 30 microns Poly crystalline brackets begins as aluminum particles of about 0.3 microns reached 20-30 microns.
  55. 55. Zirconium brackets    Zirconium is a mineral extracted from beach sands of AUSTRALIA The PSZ (partially stabilized zirconium) developed by the common wealth scientific and industrial research organization(CSIRO)as a reliable highly stress –resistant material Greatest toughness among all the ceramics
  56. 56. Properties of zirconium brackets     Greatest toughness Cheaper Good sliding properties for stainless steel and nickel titanium arch wires Reduced plaque adhesion
  57. 57. Base Characteristic of Ceramic Brackets  two types of ceramic bracket bases are available Bonding mechanisms that have been identified for ceramic brackets may be classified into three major categories: a) Mechanical retention employing large recesses. b) Chemical adhesion facilitated by the use of a silane layer. c) Micromechanical retention through the utilization of a number of configurations, including protruding crystals, grooves, a porous surface, and spherical glass particles. 
  58. 58. 1. bracket base is formed with undercuts or grooves that provide a mechanical interlock to the adhesive.  The mechanical retention of such brackets is less as compared to other bracket base that are having both micromechanical retention and chemical adhesion. 2.Bracket base has a smooth surface and relies on a chemical coating to enhance bond strength.  A silane coupling agent is used as a chemical mediator between the adhesive resin and the bracket base.  It has been claimed that chemical adhesion provided higher bondstrength when compared with mechanical
  59. 59. Silane coating of bracket bases    The coupling agent -methacryl oxypropyl trimethoxy silane ( -MPTS) has been used for promoting chemical adhesion between surfaces. The -MPTS is hydrolysed to the corresponding silanol. A limited number of silanol groups per silanol molecule are hydrogen-bonded to the water layer adsorbed on the base surface. Side chain silanols are condensed, establishing a siloxane network that stabilizes the structure.
  60. 60.  Owing to the silanol orientation toward the bracket base, methacrylate groups are placed in a configuration that favours cross-linking with the methacrlate-based adhesive. Bonding arises from two mechanisms:  Silanol groups of the hydrolysed silane adhere to the hydration layer of the inorganic surfaces  Methacrylate groups of the silane copolymerize with the methacrylate resin matrix, forming covalent bonds
  61. 61. Recently another two developments………  polycrystalline alumina with a rough base comprised of either randomly oriented sharp crystals or spherical glass particles.  These brackets provide only micromechanical inter locking with the orthodontic adhesive
  62. 62.  In an attempt to overcome the potential damage of enamel during debonding, a ceramic bracket with a thin polycarbonate laminate coating on the base has been manufactured (CeramaFlex, TP Orthodontics)
  63. 63. Ceramic brackets with different base types Viazis (1990) compared the shear bond strength for two types of ceramic brackets and concluded that, The shear bond strength of silane chemical bonded ceramic brackets is significantly higher than the grooved mechanical bonded ceramic brackets.
  64. 64. Physical Properties of Ceramic Brackets  Hardness,  Tensile strength and  Fracture toughness or brittleness
  65. 65. Hardness of ceramic and enamel wear    Extremely high hardness due to aluminum oxide Ceramic brackets are 9 times harder than stainless steel or enamel(Swartz1988) Douglass (1989) gave a clinical report of enamel damage found on the lingual surfaces of maxillary central incisors that were in contact with poly-crystalline sapphire ceramic brackets placed on the facial surfaces of lower incisors. This is because, when natural tooth surfaces have opposing contact with ceramic brackets in occlusion, due to the hardness of ceramics enamel damage may occur.
  66. 66. Tensile strength    Tensile strength is much higher in mono crystalline alumina than in poly crystalline alumina Tensile strength characteristics of ceramics depend on the condition of the surface of the ceramic Metal brackets deforms 20% under stress before fracturing whereas ,ceramic brackets deforms less than 1% before failing.
  67. 67. Fracture Toughness or Brittleness  Ceramics used in orthodontic brackets have highly localized, directional atomic bonds. This oxidized atomic lattice does not permit shifting of bonds and redistribution of stress.  When stresses reach critical levels, the interatomic bonds break and material failure occurs. This is called “brittle failure”.
  68. 68.  Fracture toughness is a measure of the strain energyabsorbing ability prior to fracture for a brittle material. The higher the fracture toughness, the more difficult it is to propagate a crack in the material.  Vickers hardness testing machine is used to test the fracture toughness of ceramic brackets. Microscopic indentations are placed on the surface of bracket and the associated cracks at the tip of the indentation are evaluated.
  69. 69.  Fracture behaviour is controlled by the influence of surface cracks and other microscopic defects or internal pores. These are called “Griffith flaws”.  Fracture toughness of ceramics is 20 to 40 times less than that of stainless steel (Scott 1988)
  70. 70. • • 1. 2. The brittle nature of ceramic brackets has resulted in a higher incidence of bracket failure (fracture) during debonding Ceramic compounds, unlike metals, are also susceptible to crack propagation The combination of very hard and brittle properties and high bond strength leads to reports of two significant problems. Bracket fracture specifically during debonding Enamel fracture which may occur during function but mostly during debonding.
  71. 71. Optical properties • Single crystal brackets are clearer than polycrystalline brackets. The sintering process produces a polycrystalline alumina microstructure with grain boundaries, resulting in some translucency. • There is loss of light transmission through the ceramic . • Optical properties and strength are inversely related for the polycrystalline alumina ceramics .
  72. 72. Photograph showing difference in optical clarity between plastic bracket and ceramic bracket assigned to decreased light transmittance of polymeric appliance
  73. 73. Why Enamel and Bracket Get Fracture?  Enamel fractures is due to the high bond strength of ceramic brackets.  However, most of the adhesives available in the market have adequate bond strength to resist orthodontic forces.
  74. 74. SEM (25x) image showing enamel surface SEM (25x) image showing enamel after fracture after debonding Inspire bracket. ARI score 5. shear bond test, Inspire bracket.
  75. 75. SEM (25x) image showing bracket fracture on tooth surface, Inspire bracket
  76. 76. Frictional Resistance • • • • • Polycrystalline brackets have a higher co-efficient of friction than monocrystalline ceramic and stainless steel This is due to their rougher and more porous surface. Ceramic brackets manufactured by machining - significantly greater rough surface. Omana, Moore and Bagby reported that ceramic brackets manufactured by injection-molding technique had less friction than other ceramic brackets. They also found that wider brackets had less friction than narrower brackets
  77. 77. Tie-wing strength • Photoelastic studies and finite-element analyses have shown that tie-wings are generally the locations of concentrated stresses when forces are applied to the ceramic brackets.  Tie-wing fractures have been much more common for the single-crystal alumina brackets because of their lower resistance to crack propagation.
  78. 78.  Sonneveld et al (1994) compared the breaking force in compression for alumina and zirconia brackets and found that zirconia brackets did not experience any tie wing fractures, but instead underwent visually perceptible deformation prior to bulk fracture.
  79. 79.  Research using finite element analysis has indicated that brackets possessing an isthmus connecting the tie-wings demonstrated better stress tolerance than those without this feature.
  80. 80. Commercially available ceramic brackets Monocrystalline alumina 1) Inspire 2) Starfire TMB Polycrystalline alumina 1) Allure 7) Mxi 2) Clarity 8) Signature 3) Fascination 9) Virage 4) Intrigue 10) CeramaFlex (with polycarbonate base) 5) 20/20 11) InVu 6) Lumina Polycrystalline zirconia 1) Hi-Brace
  81. 81. Facial (A), lingual (B), and profile (C) views of the MXi ceramic bracket
  82. 82. Facial (A), lingual (B), and profile (C) views of the Clarity ceramic bracket. 88
  83. 83. GAC International introduces the InOvation® C, seif ligated LeoneAmerica introduces AQUA™ ceramic brackets.slot is crystal gloss
  84. 84.
  85. 85. Experimental brackets: left, UDMA bracket without filler; center, UDMA bracket with 40% by volume silicon dioxide filler; right, UDMA bracket with 70% by volume silicon dioxide filler.
  86. 86. Nd: YAG laser for debonding ceramic orthodontic brackets Kotaro Hayakawa Lasing positions, polycrystalline bracket
  87. 87. Experimental setup and laser delivery.
  88. 88. This study on the effects of Nd:YAG laser irradiation on ceramic brackets on bovine teeth produced the following findings. 1. The application of a high-peak power Nd:YAG laser at 2.0 or 3.0 J notably weakened or eliminated the bond strength. • 2. At the 2.0-J level, polycrystalline ceramic brackets exhibited a significant decrease in bond strength compared with singlecrystal ceramic brackets
  89. 89. 3. No significant differences were found among different types of adhesive resins. 4. The rise in intrapulpal temperature as a result of lasing was extremely low, and the maximum temperature increase was 5.1 C.
  90. 90. Bond strength and debonding characteristics of a new ceramic bracket Jia-Kuang SEM (25x) images of 3 types of brackets with mechanical base. A, Inspire; B, Clarity; C,metal
  91. 91. Stereoscope images showing 2 debonded ceramic brackets from occlusal surface. A, Clarity; B,Inspire
  92. 92. Scanning electron micrographs of base surface of brackets, before bonding; A, Begg ceramic bracket (SEM x 24); B, Begg metal bracket (SEM x
  93. 93. Facial (A), lingual (B), and profile (C) views of the Clarity ceramic bracket. 88
  94. 94. Facial (A), lingual (B), and profile (C) views of the MXi ceramic bracket
  95. 95. Bracket Jacketz offers interchangeable clips for brackets, which allow children to customize their smile with alphabetical letters
  96. 96. American Orthodontics offers Radiance brackets, which are made from singlecrystal,pure grown sapphire
  97. 97. Comfort Solutions offers soft caps designed from mouthguard materialThe soft caps also provide comfort to patients who play musical instruments and provide protection to incisal edges that occlude against ceramic brackets.
  98. 98. Ortho-byte introduces Integra™ ceramic brackets
  99. 99.
  100. 100.
  101. 101.
  102. 102.
  103. 103.
  104. 104. Ceramic bracket debonding techniques 1.Debonding lift of pliers 2.Hows or weingart pliers and ligature cutters 3.Special debonding pliers 4.Electrothermal debonding 5.Ultrasonic debonding 6.Laser debonding
  105. 105. 1. Conventional method (Swartz 1988) 2. Electrothermal debonding (Sheridan 1986) 4. Ultrasonic debonding (Bishara and Trulove 1990) 5. Grinding method (Vukovich 1991) 6. Lift-off debracketing method (Reed and Shivapuja 1991) 7.Peppermint oil application (Winchester 1992) 8.Laser aided debonding using Nd: YAG laser (Strobl et al 1992), - XeCl excimer laser (Tocchio, Williams and Mayer 1993), - Carbon-di-oxide laser (Rickabough and Marganoni 1996).
  106. 106. Debonding lift-off pliers Method:gentle squeezing pressure at the bracket/adhessive interface Advantages: 1.Quick and simple 2.Standard orthodontic instrument 3.Safest and most effective technique for ceramic bracket removal Disadvantages: Increased debonding force Risk of enamel damage Risk of bracket fracture and aspiration of fragments
  107. 107. Plastic plier for debonding Inspire brackets, designed by Ormco Weingart plier used to debond Clarity ceramic bracket. A mesiodistal force is applied to tiewings of brackets at level of metal slot.
  108. 108. ETM plier used to debond MXi ceramic brackets. Blades are applied between bracket base and enamel surface.
  109. 109. Elecctro thermal debonding  Method : Softening of the resin adhesive via a rechargeable heating gun inserted into the bracket slot whilst applying a tensile force to the bracket Advantages: Reduced debonding force Reduced risk of enamel damage Reduced incidence bracket fracture Reduced patient discomfort
  110. 110. Disadvantages      Risk of pulpal damage Risk of soft tissue burns Expense of unit Increased clinical time Bracket failure may not occur at first attempt
  111. 111. Ultrasonic debonding Method: Ultrasonic instruments used to create a purchase point within the adhesive between the bracket base and the enamel surface Advantages: Reduced debonding force Decreased chance of enamel damage Reduced incidence bracket fracture Removal of residual resin with same instrument
  112. 112. Disadvantages:  Time consuming  Excessive wear of ultrasonic tips  Water spry coolant required to minimise detrimental heating effect on the pulp
  113. 113. Laser debonding Method:  Irradiation of the buccal surface with laser light Debonding occurs through thermal softening of the adhesive Advantages : Reduced debonding force Decreased chance of enamel damage Reduced incidence bracket fracture Potentially less traumatic and painful
  114. 114. Disadvantages: Potential pulpal damage due to heat production Expensive units laser hazards
  115. 115. Esthetic arch wires
  116. 116. Composite arch wire  Composed of S2- glass fibers & acrylic resin. Manufacturing process: Pultrusion is a continuous process of manufacturing of composite materials with constant cross-section whereby reinforced fibers are pulled through a resin, possibly followed by a separate preforming system, and into a heated die, where the resin undergoes polymerization.  Many resin types may be used in pultrusion including polyester, polyurethane, vinylester and epoxy.
  117. 117. Composite - properties  Esthetically pleasing because of their translucent quality tends to transmit the color of host teeth.  Prototype have been constructed with stiffness ranging from that of niti to beta titanium without change in the cross sectional dimension.  When the fiber &resin content are equal ,spring back is greater than 95% and the total water sorption is only 1.5% by wt so that dimensional stability is good.
  118. 118. Esthetic retainer  Organic polymer retainer wires made up of poly ethylene terephthalate 1.6 mm diameter.  To contour the material plier is used to bent and heated for few secs of temp less than 230 C  In prefabricated wire –anterior portion (st) & posterior portion (wave).  Shrinkage takes place during heating which compensated by posterior segment.  No significant discoloration & does not absorb water.
  119. 119.
  120. 120. Esthetic retainer- newer version  The anterior plastics part is a flat organic polymer wire with 100 labial torque is attached to .032‟ ss posterior arm each 11cm long.  The plastics comes in 3 inter canine with or without activating omega loop in posterior arm.  It requires no special tool or instrument only on ordinary hair hair dryer.
  121. 121.
  122. 122.
  123. 123. Fiber- Reinforced composite       FRC materials are superior to polymer because they offer a structural rigidity & strength as well as reduction in stress relaxation. Modules of elasticity is 70% greater than that of the highly filled dental composite. Yield strength is 6 times greater than dental composite. 24 times resilience than dental composite. FRC can be bonded to another FRC and attachment(brackets,hooks) can be added directly. They are available in 3-different configurationround,strip & woven pattern.
  124. 124.
  125. 125. FRC MANUFACTURING PROCESS: The fibers are correctly oriented and excellent coupling is achieved ,followed by an initial polymerization makes the matrix flexible and adaptable, so it can be easily contained to the teeth. The result is a user friendly polymer that is as easily manipulated as any plastics, but as structurally strong as metal.
  126. 126. Clinical application-FRC Open bite cases.  Space closure.  Up righting molar.  Maxillary anterior intrusion.  Fixed lingual retainer. Limitation: They are weakest in shear & torsion. 
  127. 127.
  128. 128.
  129. 129.
  130. 130. OPTI-FLEX ARCH WIRE    Designed by Dr.Taloss & manufactured by Ormco. It is made up of :1) Silicon-di-oxide. 2) Silicon resin. 3) Nylon. Available in 10‟‟ to 6‟‟ st lengths of 0.17‟‟ & 0.021‟‟.
  131. 131. Advantages of opti-flex      Most esthetic arch wire. Stain resistant. Light continuous force exerted( showed low load deflection rates reaching the proportional limit much earlier when compared to other wires More flexible. It can be used in bracket system.
  132. 132. Disadvantages of opti-flex      Sharp bends are avoided. Metal ligatures tie are avoided. Special instruments are used to cut. Rough diet are restricted. This arch wire is not recommend for cuspid retraction.
  133. 133. Teflon coated SS arch wire Teflon is a commercial synthetic resin ( polytetrafluoroethylene). ADVANTAGE:  Used to prevent wetting of the metal surface. DIS ADVANTAGE:  Does not discolor.  Grayish hue of these wire makes them esthetically inferior.  Teflon coating wear off 2-3 weeks exposing the metal surface. 
  134. 134. Marsenol arch wire  Tooth colored niti wire manufactured by glenroe technologies.  It is a E.T.E coated niti (Elastomeric poly tetra florethylene emulsion)
  135. 135. Lee white wire     Manufactured by lee pharmaceutical. To the niti or stainless steel tooth colored Epoxy coating is bonded. It is completely opaque and does not chip, peel, stain or discolor. Suitable for ceramic & plastics brackets.
  136. 136. ELASTOMERICS
  137. 137. ELASTOMERICS  Elastomer is a general term which encompasses materials that after substantial deformation rapidly returns to their original dimensions.  Strictly speaking, elastic is an elastomeric material whose threads are interwoven with strands of rubber.
  138. 138. HISTORY OF DEVELOPMENT Natural Elastomers - Natural rubber probably used by the ancient Indian and Malay civilizations, was the first known elastomer.  It had limited use because of its unfavorable temperature behavior and water adsorption properties.  With the advent of vulcanization by Charles Goodyear in 1839, uses for natural rubber greatly increased.
  139. 139.  Early advocates of natural latex rubber elastics in Orthodontics include Baker, Case and Angle Recent Advancements  Recently, polynorbornen, a shape memory plastic developed in Japan in 1983 has been tried experimentally for intra-oral usage.  This plastic has a glass transitional point of 350 C. Once the environmental temperature exceeds the critical point, this plastic will begin to display an elastic property, then return to its original shape, if deformed
  140. 140. Fluoride releasing elastomerics :  Advances in the field of elastomerics are the introduction of fluoride releasing elastomerics. Long term fluoride releases in the area adjacent to bracket – adhesive margins is of significance.  There is a steep decline in rate of fluoride ion elution after 3 weeks.  Fluoride – releasing elastomerics are unable to deliver force within the optimal range for tooth moment.
  141. 141. Elastomeric Ligatures Preferred over S. S ligatures  Ease of application.  Patient friendly nature.  Aesthetic appearance.  Potential of fluoride release.  Decreased force delivery.
  142. 142. •They are available in a range of diameters and thickness and are often colored to encourage patient motivation. •They are also available in various colors
  143. 143.  The staining of clear elastomeric modules used to ligate ceramic and tooth coloured brackets is a problem.  The study by Kenneth K.K found that elastomeric modules get stained by many food products, coffee and tea being the main culprits.
  144. 144. Elastomeric E Link Modules  Elastomeric E link modules with connecting filaments are excellent for rotating individual tooth or closing intra arch space.  Stamped from highly resilient opaque white or gray material (T.P. Lab Inc.,) they provide gentle, continuous force over long periods of time without breakage
  145. 145. Elastomeric chains :  Elastomeric chains of polyurethane nature is commonly used to generate light continuous forces for canine retraction, diastema closure, rotational corrections and arch constriction  They can also be used for bringing a displaced tooth into the line of the arch.  Available in a range of sizes which have different lengths between the rings that fit over the brackets
  146. 146.
  147. 147.  This allows them to be used in a variety of clinical situations such as moving lower incisors, where the inter bracket distance is smaller than that used with upper incisors and in situations where different forces are needed in various parts of an arch  Chain elastics are thus most useful for closing small space. Disadvantages  When extended and exposed to oral environment, they absorb water and saliva, permanently stain and suffer a breakdown of internal bonds that leads to permanent deformation.
  148. 148.  They are also difficult to clean and tend to accumulate food debris.  If breakage occurs, there is the possibility of unwanted tooth movement taking place, for example, space opening at the site of failure.  They generally lose 50-70% of their initial force during the first day of load application and at 3 weeks, retain only 30-40% of the original force.
  149. 149. Draw backs     Though elastic ligatures are used during initial aligning and leveling, their rapid force loss and permanent deformation may preclude use for rotational and torque corrections Elastomeric chains are not inert in the oral environment. The deleterious synergistic effect of loading and water immersion is attributed to susceptibility to hydrolysis of the ester or ether backbone linkages in polyurethanes. This result in reduction of required to maintain fixed extension. Elastomeric ligatures may be ineffective for treatment applications involving large rotational moments.
  150. 150.   The pH and temperature variations in the oral environment, along with accumulation of plaque and formation of microbial colonies on surface can affect the properties of elastomerics. Elastomeric modules experience a steep decline in force of 40 – 50% during first 24 hrs, which continues at a lower rate for 2 to 3 weeks. Force degradation arises form 2 processes in elastomerics: Rapid mechanism i.e. responsible for the large initial force loss.  Relatively slow rate of force loss at longer periods of time.
  151. 151. Tooth colored – ligature wires
  152. 152. Teflon coated Ligature     No discoloration. The coating wears off after 2-3 weeks and the metal is exposed. Produces less friction when compared with elastomeric ligatures & stainless steel ligatures. It generates lighter forces of engagement of the arch wire into bracket slot.
  153. 153. Composite ligature   Fabricated from the acrylic monomer n- butyl methacrylate and drawn poly ethylene fibers. Due to stress relaxation properties within an hour it loss 98% of ligation forces( not used in sliding mechanism).
  155. 155. TOOTH COLORED ALIGNING APPLIANCES- INVISALIGN  The Invisalign system was introduced at an orthodontic meeting in 1999 and first described in a peer-reviewed publication in 2000.  Controversy remains over whether the system is appropriate for moderate-to-difficult malocclusions.  Early longitudinal clinical trials demonstrated successful use of Invisalign for tipping movements, incisor rotations, and closure of naturally occurring spaces.
  156. 156. Intra oral picture of Invisalign appliance
  157. 157.   The system is less effective in more difficult procedures such as extraction space closure Invisalign system (Align Technology,Santa Clara, Calif) has become a popular treatment choice for clinicians because of the esthetics and comfort of the removable clear aligners compared with traditional appliances.  With the advent of 3-dimensional graphic imaging and computer-aided design/computer-aided modeling techniques  Align can accurately fabricate numerous aligners to move many teeth with relative precision to provide comprehensive orthodontic treatment.
  158. 158. Indications for invisalign:  Include mild to moderate crowding (1-6 mm), mild to moderate spacing (1-6 mm), nonskeletal constricted arches, and relapse after fixed appliance therapy In 2003, Align Technology formed a Clinical   Advisory Board (CAB) consisting of 13 orthodontists who had used Invisalign treatment extensively in their practices This group decided to adopt a new protocol already being used by several of its members
  159. 159. The principles of this new protocol are as follows:    1. Simultaneous movement of all involved teeth(Similar to the use of light archwires and low-friction brackets for leveling and alignment) this creates the space needed for tooth movement and slows down the movement of all teeth except the one requiring the greatest number of stages to be corrected at a given velocity (the “determining tooth”) 2.Use of beveled 1mm (buccolingual dimension)horizontal rectangular premolar attachments for retention of aligners during intrusive movements 3.Use of 1mm vertical rectangular attachments for rotation of round teeth or canines, as well as translation of teeth adjacent to an extraction site
  160. 160.     4.Slowing down certain types of tooth movement,including rotation, extrusion, torquing, and bodily movement, below the previous standard velocity of .25mm per stage 5.Maintaining visible space (approximately .1mm)between teeth during movement of one tooth past another. 6.Using expansion instead of interproximal reduction as a primary method of increasing the space available for correction of crowding. 7. Delaying any interproximal reduction that may be needed to correct Bolton discrepancies and other toothsize issues until the teeth are aligned,to avoid removing enamel at an angle.
  161. 161. A case treated with Invisalign Pre-treatment views
  162. 162.
  163. 163. Pre Treatment OPG
  164. 164. Post-treatment views
  165. 165.
  166. 166. Post Treatment OPG
  167. 167.
  169. 169.  Adult patients present with unique challenge, of wanting to look good even during orthodontic treatment.  Some orthodontists thought of placing braces on the lingual side, leaving the labial surface untouched.  Thus was born the methodology of lingual orthodontics.
  170. 170. History 1889 by John Farrar. "lingual removable arch" 1918, Dr. John Mershon "The Removable Lingual Arch as an Appliance for the Treatment of Malocclusion of the Teeth". 1922 Mershon's presentation on labial and lingual arches with finger springs
  171. 171. History  March 1942 , Dr. Oren Oliver gave a clinic on a labiolingual appliance  Mid-'50s, Dr. William Wilson demonstrated a labio-loop-lingual appliance
  172. 172. History  The orthodontic company Ormco in conjunction with Dr. Wildman, had attempted to develop a system to align the dentition using the lingual approach.  Consisted of a Pedicle positioner.
  173. 173. History In early 1970s Dr. Craven Kurz, an assistant professor at UCLA school of dentistry, developed Lingual system. A particular patient , because of her public position refused metal or plastic labial appliance.
  174. 174. History  After much advice (Dr. Jim Mulick), Dr. Kurz developed first True lingual appliance. The turning point in the development of the appliance was the addition of an anterior inclined plane as an integral part of the maxillary incisor brackets .
  175. 175. History  This inclined plane converted the shearing forces produced by the mandibular incisors to compressive forces applied in an intrusive and labial direction.  It was this design that, Dr.Kurz applied on a patent for the Kurz Lingual Appliance on November 15, 1976.
  176. 176.  The lingual task force pioneers Dr. Kurz, Gorman and Smith were the first to conduct courses on the Edgewise lingual appliance.
  177. 177. History  Dr. Vince Kelly of Oklahoma and Dr. Steve Paige of Florida were the first to start giving courses using Begg appliance lingually.  Dr. Dilier Fillon of France is the only orthodontist to have restricted his practice to lingual orthodontics exclusively.  Dr. Lorenzo Favero, Italy, was first to treat children and adolescents with LO.
  178. 178. Lingual Brackets Generations
  179. 179. First generation (1976) Flat maxillary occlusal bite plane from C-C Lower incisor and premolar bracket had low profile and half round. No hooks on any bracket
  180. 180. Second generation (1980)  Hooks were added to canine brackets
  181. 181. Third generation (1981) Hooks are added to all Anteriors and Premolar brackets The first molar had a bracket with internal hook 2nd molar had a terminal sheath with out a hook.
  182. 182. Fourth generation (1982-84)  Addition of low profile anterior inclined plane  Hooks were optional
  183. 183. Fifth generation (1985-86) Anterior inclined plane became pronounced Increase in labial torque in maxillary anterior region
  184. 184. Fifth generation (1985-86)   Canine – bibeveled inclined plane Attachment for TPA provided
  185. 185. Sixth Generation (1987-90) The inclined plane on the maxillary anteriors become more square in shape. Hooks were elongated and were available for all the brackets.
  186. 186. Seventh generation 1990- 2002 The lower anterior brackets have larger inclined plane with short hooks Maxillary anterior inclined plane is now heart shaped with short hooks
  187. 187. Seventh generation 1990- 2002 The premolar brackets were widened mesiodistally and hooks were shortened the increased width of Premolar bracket allows better angulation and rotation control.
  188. 188. Insertion of wire
  189. 189. Generation–8. (2002) (STb) Giuseppe Scuzzo & Takemoto The STb lingual bracket was developed to obtain the maximum satisfaction for the patient. Reduced dimension together with its special rounded design, makes it unique from all other lingual brackets.
  190. 190. LIGHT LINGUAL PHILOSOPHY Based on 3 fundamental points: 1. Less Lab Procedures STb does not need a lab set-up in non extraction cases.
  191. 191. LIGHT LINGUAL PHILOSOPHY 2. Low Friction  A friction free system (using light wires)  Reduced treatment time.
  192. 192. LIGHT LINGUAL PHILOSOPHY 3. Low Forces The low force mechanics decrease stress of the dental movements and make this appliance reliable not only from a biomechanical but also from a biological point of view.
  194. 194. Advantages Of LO  Esthetic role.  Decreased plaque accumulation
  195. 195. Advantages:  No permanent and unsightly decalcification marks on lingual surface.  Easy access for routine oral hygiene procedures on the labial surfaces.  Clinical judgement of treatment progress can be enhanced.
  196. 196. Advantages:  Evaluation of individual tooth position.  Soft tissue responses of the lips and cheeks to treatment can be judged accurately.
  197. 197. Disadvantages:  Discomfort to the tongue  Difficulty in speech, which usually improves after 2-3 weeks of appliance placement
  198. 198. Disadvantages:  Extended chair side time needed for appliance placement and adjustments  Expensive
  199. 199. Mechanical characteristics: Four distinct situations exist where lingual appliances may be more effective than labial appliances. Intrusion of anterior teeth  Maxillary arch expansion  Combining mandibular repositioning therapy with orthodontic movements  Distallizationwww.indiandentalacademy.commolars. of maxillary 
  200. 200. Intrusion of anterior teeth: Lingual bracket positioning places the bracket closer to centre of resistance of the tooth than is found with labial bracket placement
  201. 201. Bite plane effect : Since the appliance is bonded, the bite plane is always present. The net effect appears to be light, continuous, intrusive force, a passive extrusion occurs in posterior segment.
  202. 202. Maxillary arch expansion :
  203. 203. Maxillary arch expansion : Reasons are : Centrifugal force type. Shorter interbracket distance may play a significant role in this effect. The thickness of the brackets.
  204. 204. MANDIBULAR REPOSITIONING THERAPY WITH ORTHODONTIC TOOTH MOVEMENTS  When patients have (TMD) it is often necessary to treat in two distinct phases.
  205. 205.  The initial phase of treatment addresses the TMD and associated pain symptoms.  The second clinical phase of treatment addresses changes in the occlusion as a result of new mandibular position.
  206. 206. DISTALLIZATION OF MAXILLARY MOLARS  Lingual brackets are placed closer to the centre of resistance of the tooth than labial brackets.  Molar distalization through lingual techniques produce more bodily movement of the tooth and less distal tipping.
  207. 207.
  208. 208. DIAGNOSIS AND TREATMENT PLANNING Diagnosis:  Case diagnosis is conducted in a manner similar to established procedures.  Non-growing adult patient - Additional diagnostic input may be required from the periodontist, restorative dentist, and orthognathic surgeon.
  209. 209. Treatment planning : 1. Periodontal Considerations 2. TMJ Considerations 3. Restorative Considerations
  210. 210. Periodontal Considerations  This is more important with lingual and adult patients.  Short lingual clinical crowns can present a contraindication to optimum lingual bracket positioning.
  211. 211.  Lingual brackets are bonded closer to the gingival crest than their labial bracket counterparts.  The natural cleansing action of the tongue seems to maintain the lingual appliance with less plaque relative to the labial appliance.
  212. 212. Restorative Considerations  More extensive restorative and prosthetic work is naturally increased in the adult patient.  The bonding materials will adhere only to etched enamel, other plastics, and some porcelains (using an intermediate silane primer).
  213. 213. Restorative Considerations  Any practicality of replacing porcelain-fused-tometal crowns or other metallic restorations with provisional plastic crowns ?  In case of loss of several teeth, extreme tipping, and multiple or complex bridgework, the lingual appliance may be contraindicated.
  214. 214. Restorative Considerations As a rule, if the clinician believes that the case poses multiple technical problems if treated with a labial approach, then these problems are magnified greatly when treated with a lingual mode.
  215. 215. Lingual crown height  Lingual clinical crown heights - 30% shorter than the available crown on the labial surfaces.  The most critical crown heights - the Mandibular Incisors and Mandibular bicuspids
  216. 216. TMJ CONSIDERATIONS  Relief of joint symptoms following lingual appliance placement.  In those cases where the health of the temporomandibular joint complex is in question, splint therapy and conservative treatment approaches are recommended.
  217. 217. This apparently occurs due to 1. Disarticulation of posterior interferences, 2. Creation of freedom of movement of the "locked“ mandible, 3. Changes in muscle position and length due to different posturing of the mandible.
  218. 218. IDEAL LINGUAL CASES Non Extraction: 1. Deep bite, mild class II. 2. Class II div 2 with retruded mandible. 3. Cases requiring expansion.
  219. 219. IDEAL LINGUAL CASES Extraction cases: 1. Class II, Maxillary 1st bicuspid & mandibular 2nd bicuspid 2. 3. Only Maxillary 1st bicuspids Mild bimaxillary protrusion with four 1st bicuspids where anchorage is not critical.
  220. 220. DIFFICULT LINGUAL CASES 1. 2. 3. 4. 5. Surgical cases Class II tendencies Class II four 1st bicuspids extraction Mesiofacial pattern &/or moderate mandibular plane angle. Cases with multiple restorative work.
  221. 221. CASES CONTRAINDICATED FOR LINGUALTHERAPY 1. 2. 3. 4. 5. Acute TMJD Mutilated posterior occlusion High angle / Dolichofacial pattern Extensive anterior prosthesis Short clinical crown
  222. 222. CASES CONTRAINDICATED FOR LINGUALTHERAPY 6. 7. 8. 9. Critical anchorage cases. Severe class II discrepancies Poor oral hygiene or unresolved periodontal problems Unadaptable or demanding patients
  223. 223. KEYS TO SUCCESSFUL LO Key-1 A. Patient Selection  Lingual patients must be well educated in oral hygiene and motivated from the beginning.  Poor oral hygiene, particularly when coupled with short clinical crowns, should be excluded.
  224. 224. B. Speech Adaptation and Tongue Irritation  A common complaint of lingual patients is temporary speech alteration.  The "s", "sh", "t-d", and "th" sounds are slightly distorted less than 10 percent of the time with lingual appliances.  From one to nine months after appliance placement, there is a clinically insignificant residual distortion of sounds.
  225. 225. Key 2 Bracket Placement Accuracy  Accurate placement exceedingly difficult with a lingual appliance due to 1. 2. 3. 4. 5. Arch radius Interbracket distance Compound lingual geometry Highly variable tooth morphology and Limited access and visibility
  226. 226. Key 3 Indirect Bonding:  The Advanced techniques.
  227. 227. Key 4 Double Over Ties on Anterior Teeth:  Conventional ligation does not exert a proper parallel force vector with the amount of force required to seat or adequately hold the archwire in anterior lingual brackets.  Double-over ties are imperative to correct rotations, achieve and maintain torque, and retract teeth. The ties are removed with a Hu-Friedy U15-30 scaler.
  228. 228. Metal over-ties
  229. 229. Elastic over-ties
  230. 230. Key 5 Buccal and Lingual Molar Attachments Set the band as occlusally as possible on the lingual surface. Any lingual molar attachment should then be welded flush with the occlusal edge of the band.
  231. 231. Buccal and Lingual Molar Attachments  In extraction cases, the first molar attachment should be tipped mesiogingivally about 6° to help parallel the roots
  232. 232. Key 6 Correcting Rotations  With labial brackets, teeth usually rotate out to the labial to a greater arch radius, thus providing the necessary space to correct the rotations.  With lingual brackets, the reverse occurs and the teeth are brought into a more constricted arch radius.
  233. 233. Correcting Rotations  Failure to adequately seat the archwire in the base of the slot can cause rotation problems. These can be avoided by using the double-over ligation technique
  234. 234. Key 7 Arch Form and Archwire Sequence  Natural variations in facial-lingual tooth dimensions are common on the lingual aspect.
  235. 235. Wire sequencing :  First initial wires 0.016 NiTi.  Second initial wires 0.016 special plus (wilcock) heat treated stainless steel.  Intermediate wires 0.017 x 0.025 TMA.
  236. 236. Wire sequencing:  Finishing wires 0.017 x 0.025 or 0.016 x 0.022 SS.  Detailing wires : Wilcocks (Australian) 0.016 or 0.018 special plus. This sequence is followed for all cases class I, II, III.
  237. 237. Key 8: Archwire Stiffness and Torque Control  Retraction of teeth into extraction sites and correction of anteroposterior discrepancies require a significant amount of force.  Partial retraction of cuspids - .016"  En masse retraction of the anterior segment .016" .022" .016" SS
  238. 238. If retraction is attempted on lighter wires, significant adverse changes may occur, including: 1. Excessive tipping into extraction sites . 2. Loss of torque control 3. Molar rotation 4. Buccal crossbite 5. Lateral outward bowing at the extraction site .
  239. 239.  D-RECT wire has sufficient resiliency and torque control to reverse some unwanted changes.  .0175" .0175" TMA excellent for establishing early torque control.  .016" .022" SS archwire provides adequate torque control.
  240. 240. Key 9 : Enmasse retraction  Enmasse retraction not only requires fewer wire changes but it eliminates the disadvantages of two stage retraction.  1. 2. It can be achieved by Loop mechanics Sliding mechanics
  241. 241. Key 10 Light, Resilient Wire for Detailing  Detailing done with a light, round wire such as .016" TMA or stainless steel.  A tie-back or bend-back distal to the second molars will help prevent spaces from reopening. Vertical elastics and artistic bends are used to obtain a final occlusion.
  242. 242. Lingual bracket jig
  243. 243.
  244. 244. References          Orthodontic materials -William A Brantley Current principles & techniques-Graber ,Vanarsdall Plastic Brackets-Schwartz AJODO 1971 July Shear bond strength of Plastic brackets-Guoqiang Guan AJODO 2000 Stress analysis of plastic bracket configurations-Michael D Rains A history of Braces Bond strength and debonding characteristics of a new ceramic bracket-Jia Kuang Liu Comparative evaluation of ceramic bracket base designs-Joseph M Bordeaux Lingual Orthodontics – Rafi Romano, DMD,MSc
  245. 245. References       Clinical characteristics and properties of ceramic brackets: A comprehensive review- Andreas Karamouzos AJODO1998 Clinical management of ceramic brackets- Richard N Carter, AJODO1998Apr A comparsion of shear bond strengths of metal and ceramic brackets-A John Gwinnett Clinical characteristics and properties of ceramic brackets: A comprehensive review- Andreas Karamouzos AJODO1998 Clinical management of ceramic brackets- Richard N Carter, AJODO1998Apr A comparsion of shear bond strengths of metal and ceramic brackets-A John Gwinnett
  246. 246. References     Complex Orthodontic Treatment Using a New Protocol for the Invisalign Appliance ROBERT L. BOYD, DDS, MED-JCO VOLUME XLI NUMBER 9; 525 Orthodontic Biomaterials: From the Past to the Present Robert P. Kusy, PhD-Angle Orthodontist, Vol 72, No 6, 2002 Outcome assessment of Invisalign and traditional orthodontic treatment compared with the American Board of Orthodontics objective grading system-Garret Djeu, Clarence Shelton, and Anthony Maganzin-(Am J Orthod Dentofacial Orthop 2005;128:292-8) Esthetic Orthodontic Treatment Using the Invisalign Appliance for Moderate to Complex Malocclusions-Robert L. Boyd, D.D.S., M.Ed.-Journal of Dental Education ■ Volume 72, Number 8; 948
  247. 247. Thank you Leader in continuing dental education