Tooth coloured biomaterials used in orthodontics /certified fixed orthodontic courses by Indian dental academy


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Tooth coloured biomaterials used in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INTRODUCTION Orthodontics needs a variety of devices, made from a large array of materials, which should be harmless. According to paracelsus in 16th century a physician “All substances are poisons. There is none, which is not a poison. The right dose differentiates the poison from remedy”. Newer materials such as composites present new challenges because of the potential for interaction. Although so some extent the problems raised by orthodontic materials are the same as those raised by dental materials in general, the former deserve a more specific and differentiated approach. Specialization has created a gap between the materials used by orthodontics and those used by dentists. Few branches of medicine match orthodontics in its dependence on materials and concomitant rapid assimilation of new products.
  3. 3. GENERAL REQUIREMENT FOR BIO MATERIALS It should be :  Non-toxicity  Strength  Hydrolytic stability  High purity  Reproducible quality  Sterilizability
  4. 4. EVOLUTION OF ORTHODONTIC BIO MATERIALS Material Scarcity(1750 - 1930) At the 19th century E.H. Angle launched a list of few materials appropriate for orthodontic work, basic design for most of the orthodontic appliance stemmed from that period, these include strips or wires of precious metal, wood, rubber, vulcanite, piano wire and silk thread. Half a century later, it was focused on molar band versus screw band, German silver arches versus gold arches and different types of band materials and ligatures. (1930 - 1975) Major developments in metallurgy and analytic and organic chemistry as well as improvement in metal treatment and emergence of new plastic, gave rise to first mass production orthodontic device in the 1960s.
  5. 5. 1975 to the present Over the past 25 years the number of orthodontic manufacturers has grown both in quantity and variety of the products. Manual and analog machines have been replaced by digitally controlled molds, increasing both production and quality. Computer Aided Design (CAD) and Computer Numerically Controlled (CNC). Machines now allow large production, to the traditional materials (i.e. metals, plastics) manufactures have added ceramic and composite device.
  6. 6. In fixed orthodontic appliance system, consist of active and passive component like bands, brackets, arch wires tubes and other accessories like ligature, springs, elastomeric chains. One of the requirement from the patient view is esthetics or invisible orthodontics. Hence, various brackets and arch wire have been introduced into the market.
  7. 7. TOOTH COLOURED BIO MATERIALS USED IN ORTHODONTICS ARE : I. Brackets • Plastics - reinforced type (glass, ceramic, metal) • Composite Ceramic - Polymer Metal - Polymer Ceramic filler, plastic body, metal liner. Ceramic II. Arch wires • Composite arch wires (optiflex) • Teflon coated arch wires • Plastic coated arch wires
  8. 8. III. Ligature wire • Composite coated • Teflon coated IV. Retainers Essix Appliance V. Invisalign System
  9. 9. POLYMERS Organic polymers are natural allies of medicine because they enter the composition of living tissues. IDEAL REQUIREMENT FOR ORGANIC POLYMERS  Non-degradable  Stable  Compatible with biological materials.  Must not have mutagenic or carcinogenic properties The first organic polymers used in orthodontics were rubber and its sulfur cross-linked derivative, vulcanite (good year 1840), polymethyl methacrylate (plexi-glass) was synthesized by O. Rohm in 1936 and polyurethanes were synthesized by O. Bayer in 1937. Along with these, other more recently discovered polymers such as polycarbonates and polysulfones have made it possible the manufacture esthetic attachments.
  10. 10. STRUCTURE AND COMPOSITION Polymers can be linear, branched or 3 dimensional. First 2 types form carbon chain packed in lamellae, which are folded in different ways without being inter-connected. Depending on their structure and molecular weight, their properties can vary significantly. Some coils maintain active chemical functions, which allow them to bond with other molecules through bridges or cross-links, thus restricting their movement. If these bonds are few, the stretched material returns to its previous form after mechanical activation.
  11. 11. ELASTICS Slightly cross-linked polymers exhibit some flexibility and elasticity as well as greater toughness and on increased resistance to stress and abrasion. As the number of bridges between the coils increases, the material becomes considerably harder and more difficult to stretch. STRONG ELASTICS The highly cross-linked polymers form a tridimensional network. These bridges render the material hard, insoluble and impossible to reshape by heating. A pre polymer obtained from an aromatic diisocyanate, which are semi-crystalline, hard and are dispersed in an amorphous matrix, soft, low molecular weight diol. Because of the hard segment of the polymer, the stretching energy is partly dissipated. The initiation of cracks is delayed and deflected, and the stress concentrations are relieved. These features exist in the plastic bracket.
  12. 12. PLASTIC BRACKET These brackets were described and tested by Newman in 1969. They had limited popularity because of the following clinical problems :  Staining and discoloration.  Poor dimensional stabilities, so that is not possible to provide precise bracket slots or built in all the straight wire features.  Friction between the plastics bracket and metal arch wires that makes it difficult to slide teeth to a new position.
  13. 13. Most efforts are directed towards improving the polymeric brackets by reinforcing that plastic matrix, apart from strength and esthetics. Other benefits are, the roughness brought by the addition of fillers - conditions of the plastics base. Polyurethane and polyesters alike have been reinforced with powder or fibres - steaming both stiffness and strength.
  14. 14. PARTICLE OF FIBRE REINFORCED CURRENTLY AVAILABLE  Polymer fiber reinforcement - Goldberg  Glass reinforcement - Adam et al,  Mineral filler reinforcement - Masuhara BRACKETS
  15. 15.  Ceramic liner - Sernate  Metal liner - Wall Sherin  Metal reinforcement - Andrew
  16. 16. PHYSICAL PROPERTIES  Polycarbonates have high strength and modulus.  Show little elastic deformation under load.  Solvents attach them.  Ductile in nature.  They show low co-efficient of friction against stainless steel but under excessive rapid force result in high coefficient of function.  It reacts with the acrylic adhesive enhancing adhesion of the adhesive attachment interface.  It has relatively low water absorption but over a period of time it becomes soft.
  17. 17. BOND STRENGTH In vitro, bond tests reveal that mean bond values of about 5.10 Mpa, when used with a plastic conditioner as recommended by a manufacture. When used without such conditioner, the value is 4.36 Mpa, which may not be clinically adequate. Miura had stated that 5.1 Mpa is the desirable value for satisfactory clinical performance. These brackets do not show any tendency for brittle fracture like ceramic bracket and do not posses and hazard in de-bonding. They may be de-bonded like metal brackets. No enamel damage unlike ceramic brackets is consequent in debonding. They cannot be recycled satisfactorily.
  18. 18. COMPOSITE BRACKETS A composite is a multiphase material brought about by combining materials that differ in composition or form in order to obtain specific characteristics and properties. The constitutes retain their identities and properties such that they exhibit an interface between one another and act in concert to achieve improved synergistic properties not obtainable by any of the component acting alone.
  19. 19. In orthodontics, the 1st composite resin were launched in 1950s and the first attachments in the mid 1990s. In composites, the particles are dispersed in the polymer matrix. As a result, the whole material composed of several phase. Each of these components phase can possibly be made of other phases. E.g. metal slot is inserted into a ceramic powder - reinforced plastic.
  20. 20. STRUCTURE AND COMPOSITION Basic types of composite are the dispersion of the fillers (a discontinuous phase made up of round or irregularly shaped particles, fibers and whiskers), in a binder or matrix (continuous phase made up of metal, ceramic or resin). The physical mixtures with properties that lie some where between the values of their constituent material are known as blends. In composite, matrices are weak link, under load, these are the first to crack and craze. This can be reduced by adding fibers (filler) to the matrix. By keeping the reinforced fibers together in the right orientation and position and by transferring and distributing the load, matrices protect fibers against chemical attack and during handling, this renders composite remarkable for their strength and endurance.
  21. 21. The most efficient filler are the stiff fibers, these fibers reduces the slip between the plans of atoms. The preferred orientation achieved by adding oriented fibers changes the shape of the macromolecules. Because of high strength and stiffness, material usually fail, as a result of flawed propagation, fibers limits the destruction phenomenon to the length of their size. A flaw in a fiber cannot lead to failure of the entirely assemblage. Adding whiskers to the matrix results in increase in the strength of the material. They measure about 0.5 MM in diameter and 40 to 50 MM in length. Whiskers can be handled in a manner similar to powder.
  22. 22. COUPLING AGENT Filler matrix interface within composite plays a major role. Its defects or weakness can severely limit performances. Void of affinity, the components do not behave as a whole easily disassembled. For this reason, coupling agents are used. In orthodontics, the best-coupling agent is the silanes, which are extensively used both for treating fillers entering the composite adhesive and for adhesion of ceramics. A variety of materials such as metals, plastics and ceramics can be used both as matrices and reinforcements. The most common combination used in orthodontics is the reinforcement of polymer with ceramic, metals and other polymers of ceramic with metals and of metals of ceramic.
  23. 23. SYNTHESIS Method of making composite are based on the controlled additional pretreated solid fillers to the liquid / Melton matrix of the synthetic resin. For composite brackets, the preferred manufacturing method is injection molding. The process is based on forcing into a mold, a dispersion of filer in polymer at controlled temperatures. To avoid contamination and discolouration, clean, non-metal apparatus must be used throughout. The future may bring so called molecular mixing in which rigid backbone molecules are uniformly dispersed in a matrix of flexible polymers. Such composites are expected to have superior impact resistance and compressive strength, retaining their optical properties.
  24. 24. COMMERCIALLY AVAILABLE COMPOSITE BRACKETS ARE :  Plastic reinforced with ceramic - Lee Fisher (Lee Pharm)  Plastic (GAC) with glass - Image
  25. 25. Plastic reinforced with ceramic - Value line (Uree)  Plastic reinforced with ceramic - Silkon (Am Ortho)  Plastic with insert - Spirit (Ormco)
  26. 26. Plastic with metal insert - Spirit MB (Ormco)  Plastic with metal insert - New plastic (Tomes)  Ceramic with metal insert - Clarity R (Unitek)
  27. 27.  Plastic reinforced with ceramic and metal insert - New spirit (Ormco)  Metal with plastic base - Ceramic moflex (TP Ortho)  Plastic with glass - Self locking - Oyster (GAC)
  28. 28. CERAMICS Esthetics constitutes an important consideration in orthodontics. Demand for esthetics in treatment has been reason for change in bracket morphology and material. Ceramic bracket was first introduced in 1987 and today it has found wide acceptance and still holds more promise.
  29. 29. They are classified on the basis upon:1. The crystal structure polycrystalline brackets. 2. It into - into mono crystalline or may be classified depending on its retentive mechanism Mechanical Chemical Combination – mechano chemical 3a. Based on the material constituents into - Pure ceramic - Laminated ceramic 3b. Based on the material constituents - Alumina based - Zirconia based materials.
  30. 30. PROPERTIES A very important physical property of ceramic bracket is the extremely high hardness of aluminium Zirconium. oxide and Both mono crystalline and polycrystalline, alumina has a significant advantage over stainless steel. Because ceramic brackets are at times harder than stainless steel brackets or enamel. Tensile strength is much stronger in mono crystalline alumina than in polycrystalline alumina that is in turn significantly stronger than stainless steel.
  31. 31. Tensile strength characteristics of ceramics depend on the condition of the surface of the ceramic. A shallow scratch on the surface of a ceramic bracket will drastically reduce the load required for fracture. Fracture toughness in ceramics is 20 to 40 times less than in stainless steel making it much easier to fracture a ceramic bracket than a metallic one. Among ceramic materials, poly crystalline alumina presents higher fracture toughness than single crystal alumina.
  32. 32. BOND STRENGTH Ceramic material does not bond chemically with adhesives, ceramic brackets derive their strength from the use of silane-coupling agent on the base of the bracket, through groove for mechanical retention or both. Laboratory testing of mechanical retention indicates that adhesive to bracket bond strength of ceramic is lower those equivalent size foil/mesh metallic brackets.
  33. 33. Ceramic bracket base have considerably fewer mechanical undercuts than these found in mesh base design therefore ceramic brackets might be expected to have greater bond failures rates if they are used without a silane coupling agent. According to the system of chemical bonding, glass is added to the aluminum oxide base and is treated with a silane-coupling agent. Silane bonds with glass and leaves a free ends of its molecules that react with any of the acrylic bonding materials.
  34. 34. The presence of different behavior between mechanical and chemical bonding is due to the way stress concentration is distributed over the bonding surfaces. Ceramic brackets that offer a mechanical bond with the adhesive have retentive grooves in which edges are 90°. There are also cross cuts to prevent the brackets from sliding along the undercut grooves that have sharp edge and resulting in brittle failure of the adhesive.
  35. 35. One application of shear bonding force part of the adhesive is left on the tooth and part on the grooved brackets. On the other hand, the shiny surface of ceramic brackets bonded chemically allow a much greater distribution of stress over the whole adhesive interface without the presence of any localized stress bond is needed to cause de – bonding and pure design, but also by various other factors including type of bonding resin, etching time, condition, and preparation of teeth.
  36. 36. FRICTIONAL RESISTANCE Stainless steel brackets generate lower frictional than ceramic bracket. The injection-molded ceramic bracket creates less friction than other ceramic bracket and then wide metallic or ceramic bracket creates less friction then narrower brackets of the same materials. Comparison of frictional forces produced in ceramic and stainless steel materials, the different wires are used, suggested that for most size, the wire in ceramic brackets produced significant greater friction. Also beta- titanium and nickel-titanium wires were associated with higher frictional force than stainless steel cobalt-chromium wires. To reduce frictional resistance, development of ceramic brackets with smoother slot surfaces and consisting have metallic (clarity brackets) or ceramic/plastic slot surfaces was considered and it has been accomplished.
  37. 37. BASE SURFACE CHARACTERISTICS Currently there are 3 types of ceramic bracket base, available:Type 1 : Bracket base is formed with undercuts or grooves that provide a mechanical interlock to the adhesive. These brackets may have a flat base, covered with silane layer with recesses for mechanical anchoring. This structure minimizes the parameters of mechanical retention, compared with other base. Type 2 : Bracket base has a smooth surface and relies on a chemical coating to enhance bond strength. A silane – coupling agent is used as chemical mediation between the adhesive resin and the bracket base because of the insert composition of the aluminum oxide ceramic brackets. The manufacturers of the such brackets have reported that they achieve higher bond strength when compared with mechanical retention.
  38. 38. Types of ceramic brackets base Bracket base designs of brackets tested: A, Allure IV x 35, B, Ceramaflex x 19, C, Intrigue x 23, D, Transcend 2000 x 18, and E, DynaBond II x 18.
  39. 39. Type 3 : Bracket has a thin poly carbonate laminate on the base, (plastic breaking attachment) to which premier is treated before chemical bonding the plastic will bend and allow for a separation between the brittle ceramic and the enamel, fracture site were at the adhesive bracket base interface and 90% of the sample, the plastic water remained on the tooth with the adhesive.
  40. 40. BRACKET FRACTURE The breakage of ceramic bracket is a problem related to the low fracture toughness of the aluminum oxide, and the ability to resist it depends on the type and shape and bulk of the material present. Bracket breakage might occur either in function or in the de-bonding process. Investigation on torsional , shear and peel de-bonding of ceramic brackets reported differences on the incidence of bracket fractures and on the fractured parts between different types of brackets. As primary causes of fracture, the internal defects and machining interface.
  41. 41. Bracket – wing fracture is frequently problems, encountered by clinician. during orthodontic When ceramic bracket break treatment, the patient is subjected to increased chair time. There is also potential health risk due to the possibility of swallowing or aspirating bracket fragments, which would be difficult to locate because of the radiolucent nature of alumina.
  42. 42. Second order wire activation’s do not usually cause ceramic bracket failure, unless the bracket during treatment. Third order wire activation may be more likely to cause ceramic bracket failure but it seems that in most real situation the fracture resistance of the ceramic brackets during arch wire torsion appears to be adequate for clinical use. Orthodontics should be aware of the brittle nature of ceramic brackets. Extra care should be undertake during treatment to avoid scratching of the bracket surface with the instruments. Careful ligation is necessary, coated ligature are recommended to prevent tie wings fractures.
  43. 43. RECYCLING CERAMIC BRACKETS Recycling of ceramic brackets are done by heating, comparison of de-bonded ceramic bracket base with those of recycled brackets after heating and application of the silane coupling agents suggested that “recycling” method is effective in providing clean surface. Bond strength of recycled brackets appeared to be clinically adequate, although it was significantly lower than of new brackets. The weaker bond strength after “recycling” of ceramic brackets minimizes the likelihood of unwanted enamel removal during de-bonding.
  44. 44. CERAMIC BRACKETS Manufactures introduced ceramic brackets to eliminate the problem of the unesthetics appearance of stainless steel bracket without the disadvantage of plastic bracket. The current ceramic bracket composed of either mono crystalline or polycrystalline. Mono crystalline brackets are manufactured by heating aluminum oxide to temperature in excess of 2100C. The molten mass is cooled slowly, and the bracket is machined. The bracket is then that treated to remove surface imperfection and relieve stress created by the cutting operation.
  45. 45. Blending aluminum oxide particles with a binder and molding the mixture into a shape from which a bracket is machined or by injecting mould manufacture polycrystalline brackets. Temperatures in excess of 1800°C are used to burn out the binder and fuse the particles together. The most apparent difference between polycrystalline and single bracket is in their optical clarity. Single crystal brackets are noticeable clearer than polycrystalline brackets, which tend to be translucent. Both single crystal and polycrystalline brackets resist stains and discoloration.
  46. 46. ZIRCONIA BRACKETS Zirconia is tri-dimensional inorganic macromolecules. Their ionic, crystalline structure accents for its hardness and compressive strength , which exceeds that of metals. At room temperature, pure zirconia exists in the monoclinic phase. When heated to 1000°C pure zirconia transforms to the tetragonal phase, which is accompanied by a substantial volume change that is structurally catastrophic. Crack formation can be inhibited by addition of 4-6% of a stabilizing oxide like calcia, yttria or magnesia. This partially stabilized zirconia (PSZ) results from the retention of some tetragonal particles at temperature between the normal transformation temperature ranges. Increase in the volume known “transformation toughening” protects the ceramic by arresting the propagation of cracks.
  47. 47.  When compared with aluminum PSZ are make up of smaller grain sizes and has higher fracture strength.  Fracture toughness of partially stabilized zirconia is about 3 times that of aluminum.  Low frictional co-efficient achieved with PSZ.  Zirconia brackets do have problems related to color and opacity, which detracts from the esthetics can inhibit composite photo polymerization.
  48. 48. New collapsible ceramic bracket A new collapsible ceramic bracket designed with a metal lined arch wire slot, a vertical slot designed to help create a consistent failure made during de-bonding. The new bracket is tough combine the aesthetic advantage of ceramics and the functional advantages of debonding metal brackets.
  49. 49.  The advantage of having stainless steel slot to minimize the increased friction that occurs as a result of arch can function ceramic furthermore. The metal slot helps to strengthen the bracket order to withstand torque forces.  The new bracket also incorporates a vertical slot (0.019 inches and 0.018 inches) in width and depth designed to help create a consistent bracket failure made during de-bonding. The vertical slot can also be used to insert auxiliaries such as uprighting spring.
  50. 50. DEBONDING BRACKET WITH PLIER The collapsible ceramic brackets were de-bonded according to the manufactures directions with a weingart AEZ plier. The tip of the weingart plier was placed over the mesial and distal ends of the metal lined arch wire slot. The tie wings are the squeezed gently until the bracket collapses. It is critical that the tips of the plier be placed over the ends of the metal slot and not over the bracket base.
  51. 51. PROBLEMS ENCOUNTERED IN CERAMIC BRACKETS I. Enamel fracture and flaking or fracture lines in during de-bonding . Solution :  Avoid sudden impact loading or stress concentration within the enamel by using proper de-bonding techniques.  Do not bond ceramic brackets on structurally damaged teeth. - Reduce bond strength. - Mechanical retention - Laminates - Reduce chemical adhesive (silane to reinforced mechanical retention). - Adding metal mesh of the base of the bracket. - Use of weaker resin. - Modify the thickness of the adhesive use.  De – bonding with ultrasonic, electro thermal and laser devices.
  52. 52. II. Attrition of teeth against ceramic bracket. Solution:  Select the teeth to be bonded.  Adding composite over the interference point III. Increased friction with ceramic bracket Solution:  Develop of bracket with smoother slot  Avoid less of anchorage by building up the anchorage.
  53. 53. IV. Increased pain or discomfort while de-bonding ceramic brackets Solution :  Have a bite with pressure on cotton roll and or gauze during de-bonding. V. Limited rotation of teeth with ceramic bracket.  This problem mainly affects bracket designed because they are necessarily the smallest and bulkier than metal brackets as this required for sufficient resistance to fracture.
  54. 54. DE-BONDING TECHNIQUES FOR CERAMIC BRACKET  Heat removal of ceramic bracket. Heat the tip of the utility plier for about 10 seconds with micro torch with light rotation force bracket is removed.  Removal of excess adhesive from mesial, distal and incisal portion of the bracket base with No. 7901 tapered finishing bur. Bracket is removed using unitek de-bonding instrument No. 800-804 using quick circular motion. If the bracket fractures, remove the rement with ‘A’ company debonding plier No. 079-960. In case small bracket remant can be moved with diamond but in high-speed hand piece.
  55. 55. CONVENTIONAL REMOVAL TECHNIQUES This recommended OF BRACKET by the manufacture were effective, required little expenditure of time and did not result in significant enamel damage under the condition employed. Disadvantages :  Enamel fracture  Aspiration of bracket fragments by point  Patients discomfort
  56. 56. ULTRASONIC BRACKET REMOVAL Ultrasonic de-bonding approach includes a decreases chance of enamel damage and decreased bracket failure. Removal of the adhesive after de-bonding can be accomplished with same ultrasonic tip. Disadvantages :  Increased de-bonding time.  Excessive wears of expensive ultrasonic tip.  Need to apply moderate force level (sensitive).  The Potential for soft tissue injury by a careless operator.  The need for a water spray to reduce the heat build up and minimize any possible pulp damage.
  57. 57. ELECTRO THERMAL DE-BONDING ETP method reduces the incidence of bracket failure, small amount of force required to break the bond minimal for enamel damage. Disadvantages :  Potential for pulpal damage  Increase in the temperature of the hand piece, which has the potential to cause patient discomfort on mucosal irritation.  Bulky hand piece design, which makes its intraoral use difficult in the premolar region.  Instruments is designed to fit specific bracket design.
  58. 58. LASER DE-BONDING CO2 and ND are used. It is “Cold” universal de-bracketing instrument. Advantages:  Significantly reduction de-bonding force.  Potential to be a traumatic  Less risk of enamel damage. Contra indication of ceramic bracket  Deep bite case.  Patient with bruxing teeth with cracks on large restoration.  A need of significant incisor torque.  Children – due to brittleness of the ceramic bracket.
  59. 59. PROBLEMS WITH CERAMIC BRACKET  Incisal wears (Elastometric cover on the lingual incisor helps in preventing attritional damage).  Frequent fracturing of tie wings.  Difficulty of torquing and tipping  Increase arch wire friction.  Longer treatment time.  Under finishing  Discomfort of bracket removal  Enamel damage during de-bonding  Ceramic bracket using mechanical appears to cause enamel damage less often than using chemical retention.
  60. 60. InVu CERAMIC BRACKET InVu has been introduced with significant improvements in product design, low friction, bonding and also reliable and safe characteristics. Design Rationale The InVu ceramic bracket has been designed to optimize various key design parameters, such as :  Profile height (offers the lowest).  Low friction (comparable to metal brackets).  Ease of debonding (debonds just like metal brackets).  Good bond strength (only ceramic bracket offering a mesh base).  Smooth radii on all edges to prevent archwire binding and cutting of elastomerics.
  61. 61. True Twin Bracket Design InVu incorporates a true twin brackets design. It has four individual tie wings to allow for various modes of ligation. The tie wings provide substantial overhang for reliable ligation. The mesiodistal aspect (arch wire slot length) is wide enough to permit excellent tip translation and rotational control. The inter-tie wing space is large enough to allow for bracket position alignment using a flat bladed adjuster.
  62. 62. Profile Height InVu brackets have the lowest profile height of anyt ceramic bracket currently available.
  63. 63. Frictional Resistance - Archwire in Slot Ceramic brackets traditionally show higher frictional resistance as compared to metal brackets. The InVu ceramic brackets are made by an injection molding process, which produces an extremely smooth surface as compared to brackets that have machined surfaces. InVu - TP Signature III - RMO
  64. 64. Virage American Mystique GAC InVu Clarity Unitex Inspire Ormco surface yields a lower friction force as compared to rough machined surfaces. InVu brackets have smooth rounded edges at the mesial and distal edges of the archwire slot to reduce static friction.
  65. 65. InVu - Advanced Bonding Mesh Base InVu ceramic brackets have an advanced bonding base that replicates the mesh architecture of the mesh in metal brackets. This high strength, polymer mesh base provides for excellent mechanical and chemical bonding to most orthodontic adhesives.
  66. 66. TOOTH COLOURED ARCH WIRE Composite Composite prototype arch wires have been made from S-2 glass fibers and acrylic resin. Such composites are esthetically pleasing because their translucent quality tends to transmit the color of the host teeth.  They are quite strong and springy.  Processed by photo pultrusion and by Electro magnetic radiation.  Arch wire prototype have been constructed with stiffness from that of nickel titanium to beta titanium. This variability can be achieved without a change in other over all cross sectional dimensions.
  67. 67. When the fiber and resin content are equal, spring back is greater than 95% so that the energy applied at the wire insertion point may be retrieved months later without significantly loss.  The water absorption of fiber resin content is only 1.5% by weight so that dimensional stability is good of stain and odour is minimized.
  68. 68. COMPOSITE PROCESS ARCH WIRE MANUFACTURING In the photo-pultrusion process, fibers are drawn into a chamber when they are cured, uniformly spread and coated with monomer. The wetted surfaces are then reconstituted into profile of specific dimension via a die from which they then exit into a curing chamber. As the photons of the light polymerizes, the structure quickly into a composite. After final dimension of the desired profile, the cure is completed and the material is taken up in a form of a large spool. If further shaping or sizing of the profile is required, however, the composite is only partially cured. This staged material is further processed using a second die and staged into the final form.
  69. 69. ESTHETIC RETAINERS (QCM) organic polymer retainer wire made from 1.6mm diameter round polytheline terephthalate. This material can be bent wit a plier, but will return to its original shape if it is not heat–treated for a few seconds at temperature less than 230°C (melting point). In prefabricating, the QCM retainer wire, the anterior portion of the wire and the “wave” portion are heat–treated at about 150°C immediately after bending.
  70. 70.  These wires showed a module of electricity similar to that of flat bow retainer wire.  After heat-treated it displayed little deformation.  More shrinkage during heating was observed in the posterior segment of the arch wire, which was compensated by posterior segment.
  71. 71.  No significant discoloration of QCM was noted indicating that it does not esthetic quality.  New esthetics organic polymer.  They are made up of (poly ethylene terephthalate).  The new version, easy to fabricate and fit to the dental arch.  It requires no special tools or instruments only and ordinary hair dyer.
  72. 72. New Version of Esthetic Retainer
  73. 73. It consists : - Anterior plastic part - A flat organic polymer wire with 10° labial torque is attached to 0.032” stainless steel posterior arms, each 11cm long. Plastic portion comes in three intercanine widths, with or without activating omega loops in the posterior arms.
  74. 74. FIBER REINFORCED COMPOSITE  FRC materials have the potential to replace metals in clinical orthodontics. Unlike metals, a FRC has good bonding characteristics not only to the tooth, but also to appliance itself.  FRC can be bonded to another FRC and also attachments like brackets hooks etc can be added directly.  FRC materials are superior to polymers because they offer a structural material of improved rigidity and strength as well as reduction in stress relaxation. They are highly formable and can be fabricated in complex shapes.
  75. 75.  They are available in 3 configuration:- Rope type (round) used as fixed retainers - 2mm wide strip where the fibers are in unidirectional parallel configuration. - Woven pattern, they have best mechanical properties.  Application of FRC to the tooth involves straightforward technique, either direct or indirect. a
  76. 76. ACTIVE APPLICATION  Engagement inter-maxillary elastics without bonding or wires, eliminating wire racket play.  Full arch FRC used in vertical elastics to close open bite where incisor extrusion is indicated.  Extrusion incisor only segment of for maxillary open bite closure, using mandibular full bar as anchorage unit.
  77. 77.  Posterior anchorage unit and active anterior unit with bonded attachment used for esthetics space closure.  Uprighting second molar with full FRC from 1st molar to 1st molar. Absence of brackets allows greater, more efficient inter-bracket distance between bonded attachments.
  78. 78.  For maxillary anterior intrusion with 4 incisor joined to form active connection. Tube is placed on posterior connector of continuous TMA intrusion arch wire, which applies force of bonded button or hook attached to the anterior segment.  Fixed lingual retainer.
  79. 79. PASSIVE APPLICATION  For bonded tooth-to-tooth retainer  Maryland bridges, to replace missing lateral incisors LIMITATIONS They are weak in shear and torque force.
  80. 80. MANUFACTURING PROCESS The fibers correctly oriented and an excellent coupling is achieved, followed by an initial stage of polymerization of the matrix. This initial polymerization makes the matrix flexible and adaptable, so it can be easily contoured to the teeth. The result is a user-friendly polymer that is easily manipulated as any plastic, but as structurally stronger as metals. The modulus elasticity is 70% greater than that of a highly filled dental composite. Yield strength is 6 times greater than the dental composite and 24 times greater resilient than a dental composite.
  81. 81. AN ORGANIC POLYMER ORTHODONTIC APPLIANCE We have developed a new, esthetic orthodontic appliance (QCM) in which the brackets, wires and attachments are all made of polycarbonate, an organic polymer.
  82. 82. Appliance Design Plastic wires with homogenous cross-section do not exert as much force as metallic wires of identical size. These dynamic can be explained by the principle that "bending stiffness is directly proportional to the geometrical moment of inertia, which is function of the shape of the cross section of the object, regardless of the nature of its material or the magnitude of force applied on it". According, we made the cross-section of the plastic wire a "T" shape to yield the geometrical moment of inertia that would generate sufficient forces for tooth movement.
  83. 83. To hold the wire and efficiently transmit the force to the tooth, the bracket was given a "C" cross-section. The plastic arch wire is normally inserted into the brackets by sliding it from the canines to the posterior teeth, then snapping it into the incisor brackets without ligation. Cutting it between brackets with a pin-and-ligature cutter, then sliding it out with a plier removes it. The molar brackets also serve as buccal tubes, unlike those conventional systems.
  84. 84. Bending test A bending test was carried out to compare the new wire with existing metallic wires. The wires are deflected 2 mm, at a speed of 90 microns/minute, in a load - unload cycle. The force deflection curve on the plastic wire rose uniformly up to 1mm, at which point the curve gradually leveled off.
  85. 85. On unloading, the deflection curve dimensionally rapidly until it reached 0.4mm of permanent deformation. Although this permanent deformation was greater than that of the metallic wires, the polymers exerted adequate force on the tooth. Although the polymer arch wire is able to exert enough force to move a tooth, the force diminishes more rapidly than it would with metal wires. To overcome this disadvantage, we replaced the wires at shorter intervals (every two or three weeks during the leveling stages).
  86. 86. OPTIFIEX ARCH WIRES New orthodontic arch wires designed by Dr. Taloss and manufactured by ORMCO. It has got unique mechanical properties with a highly elastic appearance. Made of optical fibers.
  87. 87. It comprises of 3 layers.  A silicon dioxide core that provides the forces for moving teeth.  A silicon resin middle layer protects the core from moisture and adds strengths.  A stain resistant nylon outer layer that prevents damage to the wire and further increases its strength.
  88. 88. Optiflex possess 5 advantages, which makes it a unique arch wire in terms of esthetics and mechanical alike:-  Optiflex is the most esthetic orthodontic arch wire.  Optiflex is completely stain resistant. The arch wire will not stain or loose its clean look even after several weeks in the mouth. The yellowish stain commonly seen in elastomeric ligatures and chains will be never being observed in optiflex.
  89. 89.  Beyond esthetics, optiflex is very effective in moving the teeth using light continuous force. The force applied with optiflex is approximately equal to half the force with a corresponding with other arch wire of similar size.  Optiflex is very flexible. It has an extremely wide range of action. When indicated it can be tied with elastomeric ligature malaligned teeth without the fear of fracturing the arch wire.  Due to its superior mechanical properties, optiflex can be used with any bracket system.
  90. 90. When using optiflex, certain precautions should be undertaken  Optiflex arch wires must be tied into the bracket with elastomeric ligatures. Metal ligatures should never be used since they fracture the glass core.  Sharp bend similar to those placed in metal arch wire should never be attempt with optiflex. These bends will immediately fracture the core.  Avoid using instrument with sharp edges like the scaler, tie and tuckers etc, to force the wire into the bracket slot. Instead apply gentle force with your finger to insert the arch wire into the slot.
  91. 91.  The cut end of the arch wire, distal to the molar it is recommended to use the (501) mini distal end cutter. (AEZ). This cutter is especially designed to cut all 3 layers of optiflex in the proper manner.  Inform your patient about the nature of optiflex and its structure . Make sure they understand that rough diet can harm the arch wire and delay treatment progress.  Do not “cinch back” optiflex. You really don’t need an cinch back since friction between elastomeric ligatures and the outer surface of the arch wire will eliminate unwanted sliding of the arch wire.
  92. 92. Optiflex has got the following clinical applications:  It is used in adult patient who wishes that their braces not be really invisible for reason related to personal concern or professional consideration.  It can be used as an initial wire in cases with moderate amounts of crowding in one or both arches.  It should be used in cases to be treated without bicuspid extraction. Optiflex is not the ideal arch wire for major cuspid retraction. Retracting cuspid in the extraction cases with optiflex has been disappointed due to its limited ability to control the distal tipping and labio lingual rotation of the retracted cuspids.
  93. 93.  Optiflex can be used in pre-surgical stage in cases, which require orthodontic intervention.  Optiflex arch wire combined with translucent brackets to create ultimate esthetics appliance. Optiflex is available in 10 to 6 inch, straight lengths of 0.017 inch and 0.021 inch.  Optiflex arch wire showed low load deflection rates reaching the proportional limit much earlier when compared to other wires (braided stainless steel, niti, cooper niti), 0.4698 grams for a defection of 4.46 mm.
  94. 94. MARSENOL Marsenol is a tooth colored nickel titanium wire manufactured by glenroe technologies. It is E.T.E. coated nickel titanium. (Elastomeric poly tetra flor ethylene emulsion). Marsenol exhibits all same working characteristics of an uncoated super elastic nickel titanium wire. The coating adhesive to the wire remains flexible. The wire delivers constant forces over long periods activation and is fracture resistant.
  95. 95. LEE WHITE WIRE Lee white wire, manufactured by Lee pharmaceuticals is resilient stainless steel or nickel titanium arch wire bonded to a tooth colored Epoxy coating, suitable for use with ceramic and plastic. The epoxy is completely opaque and does not chip, peel, stain or discolors.
  96. 96. TOOTH COLOURED LIGATURE WIRE Teflon Coated Ligature Wire  It does not discolor.  Grayish hue of these wires makes them esthetically interior.  Teflon coating wear off after 2-3 weeks exposing the metal surface of the wire.
  97. 97.  Teflon coated stainless steel ligature produces less friction than elastomeric ligature regardless of bracket type, arch wire type or bracket wire angulations.  Teflon coated ligature, as an alternative to the clear elastomeric ligature appears to partly reduce the high frictional resistance of ceramic bracket.  Teflon coated ligature generates lighter force of engagement of the arch wire into the bracket slot.
  98. 98. Composite ligature wire Fabricated from the acrylic monomer n-butyl methacrylate and drawn as polyethylene fibers by use of photo-putrusion manufacturing process. the stress relaxation characteristics of the composite matrix will transfer the strain to the stronger polymer fibers, 98% of the stress is lost within few hours. Such a loss of force is critical for optimal sliding mechanics .
  99. 99. RETAINERS Essix Appliance Sheridan and Colleagues have developed the Essix appliance as a passive retainer and as a device for active minor tooth movement. Uses 1. For correction of anterior cross-bite. 2. For correction of bilateral posterior cross-bite. 3. For correction of ectopic canines. 4. Used as a retainer for anchorage.
  100. 100. Two key steps are involved : 1. Improving the retention of the Essix appliance so that intra or interarch elastics can be attached without dislodging it. 2. Adopting the appliance for elastic attachment. Undercuts for improved retention Adding undercuts in the Essix embrasure areas makes the appliance more tenacious. Use the Hilliard Undercut Enhancing Thermoplier for this purpose. Alternatively, Sheridan prefers to create the undercuts in the dental cast before vacuum-forming to avoid stretching and weakening the Essix material with the plier.
  101. 101. If the thermoplier is used, the Milwaukee Heat Gun is a quick and inexpensive device that can be used to heat it. The heat gun is directed at the beaked end of the Hilliard plier for 12 – 15 seconds, and the plier is then immediately pressed into the interproximal areas of the Essix appliance as needed for added retention.
  102. 102. Attaching Elastics We have tried various means for attachment of elastics, including the Hilliard Elastic Hook-Forming Thermoplier and ball hooks vacuum-formed into the Essix material is one we call the “Rinchuse Slit”. Use a scissor to cut a slit into the type of Essix appliance, with the location and angle determined by the direction of the elastics. Any type of elastic traction can then be used from maxillary to mandibular Essix appliances from an Essix appliance to fixed orthodontic appliances, from an Essix appliance to a face mask.
  103. 103. INVISALIGN SYSTEM The frequency of malocclusion in adults is equal to or greater than that observed in children in adolescents. Crowding and spacing are among the most common problems in adults.
  104. 104. Despite their need for orthodontic treatment, however, adults are often averse to wearing traditional fixed appliances with wires, bands, and brackets. The Invisalign System how makes it possible for orthodontics to offer adult patients requiring full-mouth orthodontic treatment an esthetically agreeable solution, using a computer-assisted technology that produces a series of clear plastic overlays.
  105. 105. Clear plastic overlays appliances take a variety of forms,  Retainers  Night guards  TMJ splints  Bleaching trays Invisalign System, to take a single impression of a patient’s dentition, and use that to:  Create a final setup  Project stages of tooth movement from the initial state to the final state.  Create a series of clear, custom-made appliances, called “aligners”, that move the teeth according to the projected stages of movement.
  106. 106. Patient Selection and Records A candidate for orthodontic treatment with the Invisalign System,  Should have fully erupted permanent teeth.  Growth should be completed. There are is no age requirement but full time wear is mandatory. Usual orthodontic records are including  Study casts  Photographs  Radiographs
  107. 107. Polyvinyl siloxane impression material must be used because it yields highly accurate impressions that remain stable for as long as three weeks and allow multiple pours. Fabrication of Aligners To ensure a high degree of accuracy throughout the process, impressions are taken of your teeth by your doctor.
  108. 108. Your doctor sends Invisalign your impressions which are used to make plaster models of your teeth. Using advanced technology, imaging Invisalign transforms your plaster models into a highly digital image. accurate 3-D
  109. 109. A computerized movie - called ClinCheck- depicting the movement of your teeth from the beginning to the final position is created. Using the Internet, the doctor reviews your ClinCheck file - if necessary, adjustments to the depicted plan are made.
  110. 110. From your approved ClinCheck file, Invisalign uses laser scanning to build a set of actual models that reflect each stage of your treatment plan. Your customized set of aligners are made from these models, sent to your doctor, and given to you. You wear each aligner for about two weeks.
  111. 111. After wearing all of your aligners in the series, you get the beautiful smile you’ve always wanted.
  112. 112. CONCLUSION Advances regularly. in Orthodontic biomaterials is seen More so in tooth coloured materials due to increased esthetic concern of orthodontic patients. The day is not far off when all attachments will be made in tooth coloured materials.
  113. 113.