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Appliances Xi’an Jiao tong University Stomatology Hospital Orthodontic Division Wang Xiaorong Removable appliances Functional appliances Fixed appliance No bracket appliance Implant appliance Questions • • • • • What are appliances? What to do? What is the influence to treatment? Where to go? Why to study appliances? Overview 1.The definition of appliance The equipment to treatment the malocclusion Request: • Patients:efficient, aesthetic, comfortable, without adversely affect • Doctor :easy operation, the tooth move according to plan, use force stable, no or little hurt 2.The source of power • Materials have the ability to returned to their original shape. As we say: elastic properties. Flexible role • • • stress strain stress-strain curves Correction wire • At flexible framework, stress-strain curve should become a linear relationship. Rubber products stress-strain curve do not become a linear relationship. • For example : chain band、 orthodontic elastics Biology Organization Between mechanical properties of elastic solids and viscous liquids, and that means also shown to demonstrate the flexibility of the mechanical properties of viscosity, known as viscoelasticity. Strain lags behind the stress, strain and stress set up the balance of the need for a transitional phase, which is visco-elastic. Ideal for the requirements of orthodontic arch wires • Good biocompatibility • Good formability • Good flexibility 3.Appliance Classification • Retention mode removable appliance, fixed appliance. • The source of power mechanical force, magnetic force,function • The purpose of the role correction, prevention, retention Categories removable appliance fixed appliance removable appliance • Attached to the teeth and mucous membranes, you can pick to wear. fixed appliance • Cement on the teeth, removal of after the treatment. 4. The basic requirements of appliance • Non-toxic harmless to humans, does not affect the growth and development and function. • Wear comfortable, little impact on the appearance . • Does not affect the oral hygiene. • Treatment effective and efficient. Anchorage • The term anchorage, in its orthodontic application, is defined in an unusual way: the definition as “resistance to unwanted tooth movement” includes a statement of what the dentist desires. Lose anchorage Lose anchorage can lead: 1.occlusal relationship disorder 2.using space Type of anchorage • To provide anchorage in accordance with the site: Intermaxillary anchorage Intramaxillaty anchorage Extraoral anchorage Intramaxillaty anchorage Intermaxillary anchorage Intermaxillary elastics Class Ⅱ elastics Class Ⅲ elastics Extraoral anchorage To provide anchorage in accordance to the mode of action classification • Easy anchorage • Reciprocal anchorage In accordance with the anchorage teeth and non-anchorage tooth movement ratio moderate anchorage maximum incisor retraction:maximum anchorage minimum incisor retraction moderate anchorage maximum anchorage minimum retraction (3)ways to strengthen anchorage • Used to increase the number of anchorage teeth • Anchorage teeth will be linked one to enhance the overall role of Anchorage • Appliance increased activity of the base area, to maintain secret noodle and organizations together ways to strengthen anchorage • Use of jaw teeth to strengthen the anchorage, transpalatal arch, Nance arch, lingual arch • Devices to enhance the use of extraoral anchorage (J hook, face-bow) • Implant anchorage ways to strengthen anchorage using the appropriate power ways to strengthen anchorage The type of tooth movement ways to strengthen anchorage Intermaxillary anchorage The function of Class Ⅱ elastics • Backward upper anterior teeth, forward lower • • • • • posterior teeth. Elongate upper anterior teeth and lower posterior teeth. Increase anchorage. Correct the class Ⅱ molar relationship. Mandibular advancement, maxillary orthopedic minor inhibition Skeletal Class III patients went to compensatory before surgery. ways to strengthen anchorage Extraoral anchorage Anchorage Noodles ways to strengthen anchorage Implant anchorage Removable appliance Attached to the teeth and mucous membranes, you can pick to wear. The applications of removable appliance • All the easy malocclusion correction • Mechanical retainer • Get rid of bad habits appliance • Function appliance • Assistive devices of fixed appliance Advantages • They can be removed on socially sensitive • • • occasions, which makes them more acceptable to patients. They are fabricated in the laboratory rather than directly in the patient’s mouth. Reducing the dentist’s chair time during the initial part of treatment. They allow some types of growth guidance treatment to be carried out more readily than is possible with fixed appliances. Disadvantages The response to treatment is heavily dependent on patient compliance, since the appliance can be effective only when the patient chooses to wear it. It is difficult to obtain the two-point contacts on teeth necessary to produce complex tooth movements. Removable appliance 1.Retention device 2.Force part 3.Connecting part (1) Retention device • Adams crib • Circumferential molar clasp • Ball clasp • Labial bow • Baseplate Adams crib • Adams designed in 1957. • Most used in first molars. • Diameter is 0.8—0.9mm Circumferential molar clasp • Permanent teeth • • 0.9~1.0mm Other teeth 0.7~0.8mm Extending into the mesio-buccal undercut Ball clasp • Between premolar • • and molar 0.8mm Extending into the buccal embrasure Labial bow • 0.8—0.9mm Baseplate • Plastic • Thickness 2—2.5mm • Organize noodle base soft tissue and hard work closely fitting (2) Force part 1)Spring :double helical spring, longitudinal spring. 2)Bow spring :Labial bow, spring Expansion 3)Orthodontic elastics 4)Permanent magnet 5)Guide plate (3)Connecting part • Baseplate Will appliance parts and the retention Afterburning even as a part of the overall The function of base • Basic role • Increase anchorage • Afterburning part 2. Activity commonly used mechanical appliance • All pad-type maxillary appliance Removable retainer • Expansion Appliance • Magnetic Appliance • Get rid of bad habits appliance Removable retainer (Hawley) Maintained after the completion of dental treatment does not shift. All pad-type maxillary appliance Removable retainer • component: • Adams crib, double helical spring, baseplate function: to correct upper anterior crossbite expansion appliance Get rid of bad habits appliance • oral screen • Palate gill Magnetic Appliance • Frame:retention device, magnetic materials, baseplate. • Function:Elongation and low teeth, correction of anterior openbite. The removable appliance wear and referral Check the quality of appliance Teach patients to wear Appliance afterburning: Forces - orthodontic force 2 weeks, 4 weeks, 3 months Summary • Anchorage: “resistance to unwanted tooth movement” • Easy anchorage, Reciprocal anchorage • Maximum anchorage, minimum anchorage, moderate anchorage. • Extraoral anchorage, internal anchorage. • Intermaxillary anchorage, intramaxillary anchorage. • Retention device, force part, connecting part.