2Removable appliances Work by simple tipping movements of the crowns of the teeth about a fulcrum close to the middle of the tooth also allow differential eruption of teeth, for example by using bite planes. They differ from fixed appliances, which are capable of complex movements of multiple teeth, including bodily movement, root torque and rotation.
4Function/Role Interceptive treatment during mixed dentition Eg : crossbite correctionspace maintainerexpansion to reopen spaceFacilitate of distal movement of the molars using headgear.As an adjunct to fixed appliance tx.Eg : anterior bite planes for overbite reductionMaxillary restrainEg: maxillary intrusion splintAssess motivation and compliance before more complex tx.
5INDICATIONS &CONTRAINDICATIONS Growth modification during mixed dentitionLimited (tipping) tooth movements desired (arch expansion, individual tooth mal position).Retention following orthodontic treatmentAdjunct to fixed orthodontic appliances,Interfere with (or prevent the development of) abnormal orofacial habitsSevere skeletal discrepancyUpper and lower arch correlate treatmentSevere rotationBodily movement neededVertical discrepancySevere crowdingVery dense bone
6ADVANTAGES & DISADVANTAGES Removable for social functionSuitable for simple malocclusionSmaller anchorage requirementUncompromised oral hygieneShort chair-side timeEase of adjustmentRequire less training for managementDependent on patient complianceLess precise control of tooth movementUnable to perform complex tooth movementDifficult to control space closureFewer tooth movementMore difficult to correct rotationAffect speechRetention poor in lower archProne to breakage and loss
7RETENTIVE ANCHORAGE BASEPLATE ACTIVE URA DESIGN PRINCIPLESRETENTIVEClaspANCHORAGESimpleReciprocalStationaryIntermaxillaryBASEPLATEHeat cureCold cureAutoresinACTIVESpringsScrewsElastics
8Springs Screws Elastics ACTIVE COMPONENTSSpringsScrewsElastics
9Z-spring Stainless steel wire 0.5mm diameter Function: -proclination of 1 or 2 incisors-to correct mild rotation if only 1 helix is activated
10T-spring For incisor, 0.5mm diameter stainless steel(SS) wire For premolar, 0.6mm diameter SS wireFunction:-for proclination of incisors or premolar
11Finger spring For incisor, 0.5mm SS wire For canine and premolar, 0.6mm SS wireFunction:-for mesial or distal movement
12Labial bow 0.7mm diameter SS wire Function: -for retraction of anterior teeth
13Split labial bow 0.7mm diameter SS wire Function: -retraction of anterior teeth-to close diastema
14Robert retractor 0.5mm diameter SS with sleeve Function: -retraction of anterior teeth
15Buccal canine retractor 0.7mm diameter SS wireFunction:-palatal and distal movement of mesially angulated canine
16Coffin spring 1.25mm diameter SS wire Function: -transverse expansion -buccal crossbite correction
17Screw Function: -for expansion of arch -for distalization of molar teeth1 turn / week = 0.25mm(1/4 turn)
18Elastics Rubber or latex rings Function: -extra-oral traction -inter-maxillary tractionHowever, it depends largely on the patient cooperation
20Adam’s Clasp The most useful clasp in removable appliances. It is designed to engage the MB, DB undercuts of posterior teeth.Advantage, it does not separate teeth and has excellent retention.
21Adam’s Clasp fabrication Components of Adam’s Clasp1- Arrow heads2- Bridge3- Tags4- Retentive partsIt is made of 0.7 mm diameter hard St. round wire
22Adam’s Clasp Design modifications Long bridge One arrow head Solder a HG tube to the bridgeSolder hook to he bridge
23Adam’s clasp adjustment 1. To tighten/loosen: Adjust the arrowhead to grip the undercut of the tooth. Hold arrowhead with pliers at A and bend using finger inwards in direction shown.
242. To adjust the height: Hold adams clasp wire the wire exits the acrlyic at pint B and bend the wire up or down to adjust verical position of arrowhead.
25Circumferential clasp Useful for second molars and caninesEasier to keep it out from occlusal contactIt is only supportive, not as retentive as Adam’s claspIt can be adequate for a retainer, but not for an active appliance
26Ball Clasp Ball Clasp It like Adam, extends across the embrasure Uses buccal undercuts for retentionEasy to fabricateIt is stiff that could not be extended deep into the undercuts
27Lingual Extension Clasp It works only from the lingual aspect without crossing the occlusal surface or embrasuresShort loop of (0.4 mm) wireCan be placed in the first molar second premolar lingual embrasureDifficult to adjustBreak easilyMay cause tissue irritationCan separate teeth if activeCan be used for retainers,not for active appliance
28ANCHORAGEResistance to unwanted tooth movement BY equal in magnitude and opposite in direction
29Types of intra-oral anchorage Simple-active movement of few teeth versus several anchor teethReciprocal-when 2 teeth or 2 sets of teeth move to an equal extent in an opposite directionStationary-bodily movement of 1 group of teeth against tipping of anotherIntermaxillary- when the anchorage units situated in 1 jaw used to provide the force required to move teeth in opposing jaw
30BASEPLATE It must be: -hold components -clear acrylic = heat cure, cold cure polymethyl-methacrylate, autoresin-comfortable-good fit-can be active as additional functions-act as bite plane
31References http://www.retainerlab.com/Pages/Springs.htm Lecture by Dr. Norzakiah(principles of removable appliance therapy-part 1)Lecture by Dr. Fitri Octavianti(types of orthodontic appliances)