Downloaded 178 times
Uploaded bySreeshma Sreekumar
Removable appliances
This document discusses removable orthodontic appliances. It describes the advantages as being able to be removed for cleaning, being less conspicuous, and allowing for treatment by general practitioners. Disadvantages include only being able to correct simple malocclusions. Indications include growth modifications and limited tooth movement needs. Components include retentive components like clasps and active components like springs. Different types of clasps and their uses are outlined, along with various spring designs and their applications.
More Related Content
Similar to Removable appliances
Removable appliances
- 2. Introduction Removable orthodonticppliances are the orthodontic appliances that can be inserted into and removed from oral cavity by patient
- 3. Advantages Disadvantages 1.Tipping movement 2.Canbe removed -for cleaning of teeth & appliance -if in pain -on socially sensitive occasion 3.Less conspicuous 4.Can be undertaken by general practitioner with adequate training 5.Manufactured in lab -less chair side time -more patients can be treated 6.Inexpensive 1.Only simple malocclusion can be corrected 2.Multiple rotations cannot be corrected 3.Uncooperative patients may leave out the applianceprolongs treatment 4.Multiple tooth movement - one at a time- prolongs Rx duration 5.Lower appliance not well tolerated 6.Cases other than I premolar extraction cannot be treated easily
- 4. Indications Growth modificationsduring mixed dentition. Limited tipping, rotation required. Arch expansion. Retention after fixed treatment.
- 5. Components of removable appliances Retentive Components Base plate Active components
- 6.
- 7. Active components Labialbow Springs Screws Elastics
- 8. CLASPS Clasps arethe retentive components of the orthodontic appliances.
- 9. IDEAL REQUIREMENTS Unobtrusive. Not impinge. Close contact to the tooth. Usable in both deciduous and permanent dentition. Adequate retention. No active force on the anchor tooth. Rigid Easy to fabricate and also replace if needed. Not interfere in the growth of jaws and eruption of teeth.
- 10. Uses To securethe appliance in position To prevent rolling of appliances To resist forces of displacement To provide retention & anchorage For engaging elastic
- 11. MODE OF ACTION Clasp engage onto the undercuts (constricted areas on the teeth.) • Two types of undercuts. – Buccal / Lingual Cervical undercuts. – Mesial / Distal Proximal undercuts.
- 12. Circumferential clasp Fabricatedusing wire 0.9mm Also known as ‘C’ clasp or Three Quarter Clasp Simple clasp used to engage buccocervical undercut Cannot be used in partially erupted teeth
- 13. Jackson’s Clasp V.H.Jackson 1906 Fabricated using 0.9mm wire Also known as Full clasp or ‘U’ clasp Engages both buccocervical undercuts Simple design Offers adequate retention Inadequate retention in partially erupted teeth
- 14. Southened clasp .7mm wire spans two adjacent margins of anterior teeth Esthetically more pleasing
- 15. Triangular Clasp Fabricatedusing 0.6mm wire used between adjacent posterior teeth Indicated for additional retention
- 16. Ball end clasp Wire having a knob or ball like structure on one end utilizes interdental undercuts Indicated when additional retention required
- 17. Delta clasp Designedby William J. Clark Similar to Adams clasp in principle Retentive loops were triangular in shape hence the name Engage interdental undercuts USED IN TWIN BLOCK APPLIANCES
- 18. Advantages Design ofthe closed loop does not open up with repeated removal. Less subject to breakage. Provides excellent retention on lower premolars. Suitable for use on most posterior teeth.
- 19. Crozat clasp Crozatin 1920 Along with the u clasp a stright wire is soldered on the base (Cresent). Strong retention is possible
- 20. Schwarz clasp Alsocalled as arrow head clasp A.M.Schwarz 1935 Mesial and distal undercuts of the teeth
- 21. Adam’s Clasp Alsoknown as Liverpool Clasp, Universal Clasp, Modified Arrowhead Clasp Parts Bridge Arrowhead Retentive arms
- 22. Adam’s Clasp C.PHILIPS ADAMS in May 1950 Most widely used clasp. Distobuccal and mesiobuccal undercuts. Does not separate teeth like a arrowhead clasp. 0.7mm posteriors 0.6mm anteriors.
- 23. Advantages Small neatand unobtrusive. Any tooth. Both deciduous and permanent dentition. Even on semi erupted tooth. No specialized pliers required. Can be modified as needed. No. of variations are available.
- 24. Disadvantages Unwanted palataltipping if gets activated. May lead to elongation of tooth if is fitting tightly. Can be repaired only if fractured through the arrowheads. Cannot be given on proclined anteriors.
- 25. Modifications Adams claspwith single arrowhead Adams clasp with J hook Adams clasp with additional arrowhead Adams clasp with distal extension Double clasp on maxillary central incisors Anterior Adams Adams with single arrowhead Adams with soldered buccal tube
- 26. Duyzings Clasp Simpledesign engages buccal undercut of molars half clasp can also be constructed
- 27. Active component ofremovable orthodonticappliances Theyare components of the appliances that exertforces to bring about the necessarytooth movements . The active component includes : (a)bows (b)springs (c)screws (d)elastics
- 28. Bows Bows areactive components that are mostly used forincisor retraction .
- 29. Typesof the bows: (a)Short labial bows : Theyare constructed using 0.7mm hard round stainless steel wire . It consist of bow that make contact with the most prominent labial teeth and two Uloops that ends as retentive arms distal to the canine . Theshort labial bow is activated by compressing the Uloop. Indication: Minor overjet reduction and anterior space closure.
- 30. Long labial bow Thislabial bow is similar to the short labial bow except that it extends from one first premolar to opposite first premolar . The distal arms of the Uloops are adapted over the occlusal embrasure between the two premolars to get embedded in the acrylic plate .
- 31. Indications : Minoranterior space closure Minor overjet reduction Closure of space distal to canine Guidance of canine during canine retraction using palatal retractor As a retaining device at the end of fixed orthodontic treatment
- 32. Split labialbow •Thisis alabialbow that is split in the middle . •Thisresult in two seprate buccal arms having aUloop each . •Thistype of labial bow show the increase flexiblity ascompared to the conventionalshort labial bows. •This type of labial bow is used for anterior retraction . •Thesplit bow is activated by compressing the Uloop 1-2mm ata time .
- 33. Reverselabialbow Thisis alsocalled reverse loop labial bows Here the Uloop is placed distal to the canine and the free end of the Uloop are adapted occlusally between the first premolar and canine . Indication are similar to that of short labial bow . Activation is done in two step . First the U-loop is opened resulting in lowering of the labial bow in incisor region . The compensatory bend is then made at the base of U loop to maintain proper level of the bow .
- 35. Highlabial bow withapronsprings It consistof heavywirebowof 0.9 mm thicknessthat extends into the buccalvestibule. Apronspring madeof 0.4mmwire isattached to high labial bow . Theapronspringcanbedesignedfor retraction of oneor more teeth . Thistype of labial bow ishighly flexible and isthus used in casesof largeoverjet . Theapronspring isthe activecomponent that isactivated bybending it towards the teeth , activation of upto 3mm canbedone.
- 37. Robert’s retractor This isalabial bow made of thin guage stainless steel wire having a coil of 3mm internal diameter mesial to the canine . Asvery thin wire is used for its fabrication ,the bow is highly flexible and lacks adequate stability in the vertical plane . Thusthe distal part of the retractor is supported in astainless steel tubing of 0.5 mm internal diameter .
- 38. Indications:- Patienthaving severe anterior proclination with over jet ofover 4mm .
- 39. Mills retractor Thisis a labial bow having extensive looping of the wire so as to increase the flexibility and range of action . Mills retractor are indicated in patient with alarge overjet . Disadvantage :- Difficult in construction Poor patient acceptance
- 40. Springs Springs arethe active component of removable orthodontic appliance that are used toeffect various tooth movements .
- 41. Classification ofsprings– (1) Basedon the presenceor absenceof helix theycanbe classified as simple –without helix compound –with helix (2) Basedon the presence of loop or helix they canbe classified as helical springs – haveahelix looped springs – havealoop (3) Basedon the nature of stability of the springs they canbe classified as: self –supported spring supported springs
- 42. Ideal requisites ofaspring:- It should be easily adjustable. The spring should be simple to fabricate It should fit into the avilable space with out discomfort to the patient . It should be easyto clean. It should apply force of required magnitude and direction . It should not slip or dislodge when placed over asloping tooth surface . It should be roust. It should remain active over along period of time .
- 43. Factor to beconsidered in designing a spring . Diameter of wire :- flexibility of the spring to a large extent depends upon diameter of wire F= D4/l3 F= force applied by spring D=diameter of wire L= length of wire
- 44. b)Length of wire:- force can be decreased by increasing the length of wire . Thus springs that are longer are more flexible and remains active for long duration of time . By doubling the length of wire force can be reduced by eight times. c)Patient comfort :- spring should be comfortable to patient in design , shape , size orforce generation . The patient should be able to insert the appliance with spring in proper position. d)Direction of tooth movement :- the direction of tooth movement is determined by the point of contact between the spring and the tooth . Palatally placed spring are used for labial and mesio – distal tooth movement .buccally placed spring are used when the tooth is to be moved palatally and in a mesio-distal direction .
- 45. Fingerspring Fingerspringisalsocalledsinglecantileverspringasoneend isfixedin acrylicandthe otherend isfree . It isconstructed using0.6mm wire . It consistof activearmof 12-15mmlength ,ahelixof 3mm internal diameterandretentivearmof 4-5mmlength. It isusedfor mesiodistal tooth movementwhen teeth arelocated correctly in buccolingual direction it isactivated bymovingactivearm toward the teeth intended tobe moved.
- 47. Cranked single cantileverspring It is constructed with 0.5mm wire . The spring consist of coil , close to its emergence from base plate . The spring is crankedto keep it clear of the other teeth . It is used to move teeth labially .
- 49. Zspring The‘z’ springisalsocalleddoublecantileverspring . It ismadeupof 0.5mm wire . Thespringconsistof two coil of verysmall internal diameter .it should beplaced perpendicularto palatal surfaceof tooth . Thespringcanbemadefor movementof singleincisor or two incisor. It isactivated byopening helicesbyabout 2-3 mmata time .
- 51. Tspring It ismade of 0.5 mm wire . The spring consist of t shaped arm whose arm are embedded in acrylic. It is used for buccal movement of premolar and some canine . It is activated by pulling the free end of the t toward the intended direction of tooth movement.
- 53. Coffin spring Itismadeof 1.2mmwire . It consistof au or omegashapedwire placed in the midpalatal region with retentive arm incorporated in baseplates . It isretended byadamsclaspin molar . It isused in slow dentoalveolararchexpansionin patient withupperarchconstriction or in unilateral crossbite
- 55. Canineretractors a) Basedontheir location buccalcanine retractor canineretractor a) Basedonthe presenceof helixor loop canine retractor with helix canine retractor with loop c) Basedontheir modeof action Push type pull type
- 56. U loop canineretractor It is made up of 0.6 or 0.7 mm wire . It consist of u loop , an active arm and a retentive arm that is distal . It is used when minimum retraction of 1-2mm is required . It is activated by closing loop by 1-2mm or cutting the free end of active arm by 2mm and readapting
- 58. Helical canine retractor It is also called reverse loop canine retractor and is made of 0.6 mm wire . It consist of acoil of 3mm diameter , an active arm and a retentive arm . It is activated by opening helix by 1mm or by cutting 1mm of free end and readapting it around the canine
- 59. Buccalcanineretractor Itis indicatedin bucally placed canine and canines placed high in the vestibule . They are used to move canine in distal aswell as palatal direction . It consist of acoil of 3mm diameter , an active arm and a retentive arm .
- 60. Buccal canineretractor are of two types Supported self supported
- 61. Self supportedare made of thicker gauge wire(0.7mm) so that the spring can support itself and supported are made of thinnergauge wire (0.5mm) thus they are more flexible and mechanicallyefficient
- 62. Palatal canine retractor It is made up of 0.6mm wire . It consist of coil of 3mm diameter , an active arm a guide arm . It is indicated in canine that are palatally placed.
- 63. Screws Screw areactive component that can be incorporated in a removable appliance . Screw can be activated by the patient at regular intervals using akey. Removable appliances having a screw usually consist of split acrylic plate and adams clasps on the posterior teeth. The screw is placed connecting the split acrylic plate.
- 64. Screw can bringabout three types of movement Expansion of arch Movement of one or a group of teeth in a buccal or labial direction . Movement of one or more teeth in a distal or mesial direction
- 65. Elastics Elastics asactive components are seldom used along with removable appliances . They are mostly used in conjunction with fixed appliances
- 66. Baseplate The bulkof removable appliance is made of the acrylic base plate . The prime function of the base plate is to incorporate all the components together into the single function unit .