1. Archwire materials 2. Bracket and attachment materials 3. Auxiliary force delivery systems 4. Impression materials 5. Luting materials 6. Sealants and Adhesion promoters 7. Etching/conditioning and crystal growth systems 8. Bonding materials Textbook of Orthodontics. Gurkeerat Singh. 2007.
Archwires are the base wires, which are engaged in brackets of the various appliance systems. These are used to provide a proper arch form and / or provide a stable base to which the auxiliaries can be attached to generate the tooth moving forces. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Characteristics of orthodontic wires, which are considered desirable for optimal performance during treatment include : 1. Large springback 2. Low stiffness 3. High formability 4. High stored energy 5. Low surface friction 6. Biocompatibility and environmental stability 7. Capability to be welded or soldered to auxiliaries and attachments. Textbook of Orthodontics. Gurkeerat Singh. 2007.
1. Classification of arch wire materials based on material constituent a. Gold b. Stainless steel c. Chrome-cobalt d. Nickel-titanium • Martensitic, and austenitic • Superelastic, and thermodynamic/ temperature transforming e. Beta titanium f. Alpha titanium g. Titanium niobium alloy h. Multi-stranded arch wires I. Composite/coated wires j. Optiflex archwires Textbook of Orthodontics. Gurkeerat Singh. 2007.
2. Classification of archwires according to cross section : a. Round b. Square c. Rectangular d. Miscellaneous 3. Classification of archwires based on the diameter of the arch wire. Textbook of Orthodontics. Gurkeerat Singh. 2007.
GOLD Gold alloys were used prior to the 1930s. They were inert, biocompatible and environ mentally stable. Composition Gold-15-65% Copper-11-1S% Silver-10- 25% Palladium-5-1O% Textbook of Orthodontics. Gurkeerat Singh. 2007.
Advantageous properties 1. Extremely formable 2. Strength can be increased by heat treatment as well as cold working 3. Low modulus of elasticity 4. Good environmental stability 5. Good joinability 6. Excellent biocompatibility. Disadvantageous properties 1. Low yield strength 2. Low springback 3. High cost. Textbook of Orthodontics. Gurkeerat Singh. 2007.
STAINLESS STEEL. Introduced in 1929by Wilkinson. Composition Iron-71 % Chromium-1 8 % Nickel- 0,8 % Carbon less than- 0.2 % Textbook of Orthodontics. Gurkeerat Singh. 2007.
Advantageous properties 1. High stiffness 2. High yield strength. 3. High resilience 5. Good environmental stability 6. Good joinability 7. Adequate springback 8. Biocompatible 9. Corrosion resistant, except at weld sites 10. Economical. Disadvantageous properties 1. Soldering is demanding 2. Lower springback than Nickel-titanium alloys. 3. High modulus of elasticity. 4. More frequent activations are required to maintain the same force levels. 5. Heating to temperatures of 400-900 degrees causes the release of nickel and chromium, thereby decreasing the corrosion resistance of the alloy. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Also known as Elgiloy. These wires have properties similar to those of stainless steel but can be supplied in the softer and more formable state and then could be hardened by heat treatment. C omposition CobaIt - 40 % Chromium- 20 % Nickel- 15 % Iron- 15.4 % Molybdenum— 7 % Manganese— 2 % Beryllium- 0.4 % Others- 0.05 % Textbook of Orthodontics. Gurkeerat Singh. 2007.
Advantageous properties 1. Excellent tarnish and corrosion resistance. 2. Greater resistance to fatigue than stainless steel. 3. Greater resistance to distortion. 4. Good formability. 5. Functionally remains active for longer duration if used as a resilient spring Disadvantageous properties 1. Has to be heat treated. 2. Soldering is demanding. A low fusing solder has to be used. These wires should be soldered with a silver solder in the presence of a fluoride flux or can be joined by spot welding. 3. The modulus of elasticity is high causing higher forces to be delivered for similar activations as stainless steel wires. Textbook of Orthodontics. Gurkeerat Singh. 2007.
This alloy was developed in 1971 Composition Nickel-54-55% Titanium-43-44% Cobalt-1.6-3% Textbook of Orthodontics. Gurkeerat Singh. 2007.
Advantageous properties 1. High spring back 2. High stored energy 3. High elasticity. Disadvantageous properties 1. High friction as compared to stainless steel. 2. Low stiffness cannot be used at the completion stages of orthodontic treatment. 3. Fractures easily if bent over a sharp edge. 4. Very limited bending is possible. 5. Cannot be welded or soldered. 6. Expensive as compared to stainless steel wires. Textbook of Orthodontics. Gurkeerat Singh. 2007.
This alloy was developed in 1994. The addition of copper decreases the difference between loading and unloading forces ca using delivery of more constant forces for small activations. Composition Titanium- 42.99% Nickel- 49.87% Chrornium - 0.50% Copper- 5.64% Advantages of copper Ni- Ti alloys 1. More resistant to permanent deformation 2. Better springback as compared to other Ni-Ti alloys 3. More constant forces are exerted over small activations. Textbook of Orthodontics. Gurkeerat Singh. 2007.
This alloy is made up of closely packed hexagonal crystals. This structure increases the number of slip planes between the crystals, making the alloy more ductile. Alpha titanium alloy wires are more stiff as compared to nickel titanium wires. Composition Titanium-90% Aluminium-6 % Vanadium-4% These wires are ideal as finishing wires as they can be bent more easily and still are able to maintain the low force levels required. Textbook of Orthodontics. Gurkeerat Singh. 2007.
These wires are made of a combination of materials coated one on top of another. The coating fibers include fiberglass and aramid. The candidate resins include polycarbonate and polyethylene terephthalate glycol. For each fiber/resin system, there is a heating or working range where the material can be formed or shaped without any degradation in its properties. Textbook of Orthodontics. Gurkeerat Singh. 2007.
These are composed of a silicon dioxide core which provides the force or resiliency to the wire. The silicon resin forms the middle layer. These wires are available in the round as well as rectangular cross-sections and are tooth colored, i.e. are more esthetic than other metaI alloy wires. These wires provide light continuous forces and are used during the initial aligning phase of orthodontic treatment. Textbook of Orthodontics. Gurkeerat Singh. 2007.
A bracket is defined as a device that projects horizontally to support auxiliaries and is open on one side usually in the vertical or horizontal. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Material used in Manufacture Morphology of the Bracket Technique for Which it is Used Slot Size of the Bracket Textbook of Orthodontics. Gurkeerat Singh. 2007.
Metal Plastic Polycarbonate Fibre glass reinforced plastic Polyurethane Ceramic a. Alumina based: - Monocrys talline - Polycrystalline - Laminated brackets. b. Zirconia based brackets Titanium Textbook of Orthodontics. Gurkeerat Singh. 2007.
Siamese Mini-twin Morphology of the Bracket Siamese Mini-twin Textbook of Orthodontics. Gurkeerat Singh. 2007.
Begg light wire appliance Edge-wise appliance Straight wire appliance Tip-edge appliance Lingual pre-adjusted edge-wise appliance, etc. Textbook of Orthodontics. Gurkeerat Singh. 2007.
0.018 " x 0.025" 0.022 " x 0.028", etc. Textbook of Orthodontics. Gurkeerat Singh. 2007.
The most commonly used metal in the manufacture of brackets is austenitic stainless steel or AISI 304 steel, AISI standing for-American Iron and Steellnstitute. The composition of AISI, has nickel 8 percent and chromium 18 percent hence, is also called from the metal. AISI 316 steel is used for the manufacture of brackets using the casting technique. These brackets are one piece brackets, with no separate mesh base; AISI 316 is too hard to be milled. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Polycarbonate brackets were described and tested by Newman in 1969. These brackets got stained easily, rendering them unanesthetic. They distorted easily and were..prone to fracture, particularly from torsional forces or 'creep" under such forces. The surface finish was poor and this led to an increased friction in the appliance system. Polycarbonate brackets with steel inserts were also introduced but have not been clinically popular. Textbook of Orthodontics. Gurkeerat Singh. 2007.
These brackets are basically polycarbonate, i.e. approximately 60 percent, reinforced with fiber glass. These fibers are about 2-3 mm in length and approximately 0.8 mm in diameter. The plastic conditioner is methylmethacrylate monomer to dissolve the polycarbonate base to enhance adhesion with the adhesive. Clinically acceptable bonding strengths are achieved when these are used as per the instructions of the manufacturer, i.e. along with the primer. Fibre glass reinforced brackets' do not show any tendency for fracture like ceramic bracket and do not pose any hazard in debonding. They can be debonded like metal brackets. No enamel damage unIike ceramic brackets has been encountered during their debonding. The only two disadvantages seen with these brackets are-they tend to get worn off if in contact with opposing teeth and they cannot be recycled satisfactorily. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Advances in material sciences and the demand for more esthetic brackets led to the introduction of brackets made of ceramic. Ceramic brackets were first introduced in 1987 and have practically replaced most other type of esthetic brackets used today. The ceramic brackets developed initially had some shortcomings ; which included-excessive bond strength (resulting in enamel fracture on debonding ) brittleness of the bracket and surface finish ( rough finish increases friction ). These have been largely add ressed in the second generation of ceramic brackets and they rarely pose any problems now. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Advantages of ceramic brackets 1. The brackets are extremely esthetic. Ceramic brackets are either transparent ( monocrystalline ) or opaque (polycrystalli.ne) which accounts for their " invisibil ity ". 2. They resist discoloration unlike polycarbonate brackets. 3. Marginal benefits include use in patients undergoing magnetic resonance imaging and also in patients who are allergic to nickel. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Disadvantages of ceramic brackets 1. Enamel abrasion of opposing teeth as in deep bite cases. 2. Brittleness of the bracket material makes it more prone to fracture. 3. High bond strength particularly with silane primed ceramic bases leading to enamel fracture on debonding. 4. Brittle, fracture of the bracket on debond ing makes debonding, technique sensitive. 5. Due to the inherent nature of the material accurate bracket positioning is demanding. 6. High cost of the material. Textbook of Orthodontics. Gurkeerat Singh. 2007.
These are in vogue because of their possible reduction it, enamel damage during debonding. The brackets with metal ( stainl ss steel) slots also decrease the friction values, which are comparable to other stainless steel brackets. Textbook of Orthodontics. Gurkeerat Singh. 2007.
Titanium is the latest metal to be used for the manufacture of brackets. It is more biocornpatible and allows superior finish thereby decreasing friction. Titanium brackets are single piece cast brackets. They are ideal for use in patients with nickel hypersensitivity. Titanium brackets are more expensive than stainless steel brackets. Textbook of Orthodontics. Gurkeerat Singh. 2007.
