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FIXED APPLIANCE Prepared by Dr. Hana Omar AL. Balbeesi Orthodontic consultant Fixed Appliances : Are appliances attached to the teeth surfaces &are capable to generate a range of tooth movement more than RA. Brackets + Arch wires {generate force that can move teeth in three planes of space vertically , apically & rotationally }. Edge Wire Brackets : Fixed appliances achieve tooth movement in 3 spatial planes First-order bends. Compensate tooth widths. Second-order bends . Achieve correct angulations or tilt of the tooth. Third-order bends . Only for rectangular arch wires. It exert bucco-lingual force on the tooth apex to torque it . Indications for the use of FA: 1. 2. 3. Correction of mild to moderate skeletal discrepancies. Intrusion/extrusion of teeth . Correction of rotations . 4. Overbite reduction . 5. Multiple tooth movement . 6. Closure of extraction spaces ,or spaces due to hypodontia . FA close the spaces + produce good contact between teeth. Patient selection: 1. 2. 3. 4. Patient maintain good oral hygiene . Avoid hard or sticky food . Cooperative patient . Attend appointments regularly to adjust the appliance . Components of fixed appliance : 1. Bands : a. Seated on molars or any tooth especially in crossbites . b. Headgear can be used with them . c. Separation is a must . d. Approximate the size in a study models . e. The edges should be flushed with marginal ridges . f. Bracket in the midpoint of the clinical crown or 90 % to the long axis of the tooth . g. Glass ionomer is used . 2. Bonds : a. Acid etch and composite is used . b. Mechanical interlock between bracket mesh & the composite . c. They are made of metal or ceramic . Disadvantages of Ceramic Brackets: 1. 2. 3. 4. Chemical bond between bracket & enamel surface causing tooth Fx during debonding . Brittle they break easily & wings breaks, so tying of the wire is very difficult . Hardness of it cause notching of the arch wire which make sliding of teeth difficult . Wearing of opposing teeth not advisable to be used in the lower incisors . 3. Orthodontic adhesives : a. b. Cementation with glass ionomer because it can release fluoride & better affinity to stainless steal & enamel surface . Bonding with composite is better than glass ionomer . c. Light-cure or self-cure acrylic resin . d. No mix-orthodontic composite . e. Despite any material used excess should be removed . 4. Auxiliaries : a. b. c. d. Elastomeric modules are easier to place & more comfortable to the patient . Ligatures are better in the late stages of treatment . Intra-oral elastics in 2, 3.5, & 4.5 oz strengths & a variety of sizes 1\8 or 3\4 inches changed every day . Palatal & lingual arches ,quad helix some are preformed or made in the laboratory. 5. Arch wires : Presented in different cross sectional diameters , &/or different material construction a. b. Flexible wires in initial stages or alignment stage . Rigid wires in the late stages of treatment . Arch Wires Physical Properties : 1. 2. 3. Spring back : wire returns to original shape & resist deformation . Stiffness : greater diameter stiffness . Formability : bending of the wire to any desirable shape . 4. Resilience : the stored energy after deflection without deformities . 5. Biocompatibility . 6. Joinability : if the material can be soldered or welded . 7. Frictional characteristics: wires with low surface friction is preferred . Types of wires : 1. 2. Stainless steal : preferred in later stages of treatment (multi-strand & or twistflex ). Nickel titanium : more flexible , greater resistance to deformation but expensive . 3. Cobalt chromium (can be readily formed & R & S by heat ). 4. TMA or B-Titanium . 5. They are either round (0.016 = 0.4 mm) or rectangular (0.016 × 0.022 = 0.4 × 0.55 mm, can be straight or coil in a spool or preformed . Treatment planning for fixed appliances : 1. 2. Anchorage is important headgear &/or a palatal or lingual arch should be placed . Lower arch form should be preserved . Practical procedures : 1. 2. 3. 4. Pre-adjusted system brackets will be in the middle of the tooth along the long axis . Improper bracket position incorrect tooth position,& affect function & esthetics . Mesiodistal movement of the teeth can be achieved by sectional or sliding teeth along the arch wire . Patient should be seen every 4-6 weeks. Fixed Appliance System : 1. 2. 3. Pre-adjusted appliance or straight wire appliance (Andrews’ & Roth systems are the best) . Begg appliance . Tip edge appliance . Tip edge appliance : It combines the advantages of both Straight Wire & Begg systems . It allows tipping of the tooth in the initial stages with round wires & better tooth positioning in the final stages with rectangular arch wires . Decalcification of fixed appliance : Fixed appliance plaque accumulation demineralization by 15-85 % . Approaches to Reduce Decalcification 1. 2. 3. Fluoride mouth rinses regularly. Fluoride containing cements & bonding adhesives . Dietary advise chewy sweets, sugared beverages & fizzy drinks between meals should be avoided during treatment . Starting with Fixed Appliance Skillful orthodontist : Knowledge with diagnosis & treatment planning before treating any patient . THANK YOU