Removable orthodontic appl /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Removable orthodontic appl /certified fixed orthodontic courses by Indian dental academy

  1. 1. REMOVABLE ORTHODONTIC APPLIANCES INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. • Treatment with removable appliances will not provide the best answer to every orthodontic problem. Some small degree of irregularities are impossible to treat with removable appliances and some severe malocclusions respond well.“ Philip Adams Source: AJO-DO Volume 1969 Jun (10 - 19): Orthodontics in practice and perspective - Salzmann www.indiandentalacadem
  3. 3. REMOVABLE ORTHODONTIC APPLIANCES Removable orthodontic appliances are devices that can be inserted into and removed from the oral cavity by the patient at will. www.indiandentalacadem
  4. 4. . Removable appliances are considered to be of two kinds— (1) appliances which are clasped to the teeth and are referred to as fixed plates and (2) removable appliances, which are those that lie loosely in the mouth and produce their effect by modifying the pattern of activity of the orofacial musculature and hence the pressures produced on the teeth by these activities. www.indiandentalacadem
  5. 5. HISTORY:• VICTOR HUGO JACKSON was the chief proponent of removable appliance. (1904) • The crib clasp has a square form and grasps the tooth buccally and also anteroposteriorly . It is difficult to make the wire fit buccally and anteriorly and posteriorly as well, even if an accurate impression of these areas can be obtained. It is impossible to obtain a good fit if the anteroposterior surfaces are hidden by gingival tissue. It is better to use either the mesial and distal undercuts or the buccal undercut, but it is unwise to try to use them both, as in this event neither is properly effective. •Volume 1969 Jun (202 - 218): Removable appliances yesterday and today - Adams www.indiandentalacadem
  6. 6. HISTORY:•In early 1900’s, GEORGE CROZAT developed a removable appliance fabricated entirely of precious metal which consisted of an effective clasp for 1st molar modified by JACKSON’S design. He gained contact with the mesial and distal undercut areas by fixing an additional short length of wire to the loop of a plain crib clasp and causing the ends of this additional wire to run round the gingival margin and make contact with the tooth anteroposteriorly www.indiandentalacadem
  7. 7. HISTORY:• Attempts to improve the clasping of teeth on the lingual side, that is, by gaining access to the lingual undercut area by means of a fine spur which lies in the lingual gingival sulcus (Visick, 1926) or by using the anterior and posterior undercut areas from the lingual aspect by adding small spurs soldered to the tags of clasps of the crib type. Devices of this kind did certainly improve the effectiveness of crib clasps, but they also tended to be time consuming to make, delicate, troublesome to adjust, and likely to cause discomfort, and they required the use of precious metals. www.indiandentalacadem
  8. 8. HISTORY:Schwarz designed the arrowhead type of clasp, which was introduced in England by Tischler. The clasp demands considerable amount of space in the oral vestibule. Special instruments are entailed in its construction, and fabrication and adjustment are fairly complex operations. The arrowhead clasp, however, made use of the best principle of clasp design— the use of the mesial and distal undercuts— but there appeared to be room for improvement in the working out of this principle in practice. www.indiandentalacadem
  9. 9. HISTORY The modified arrowhead clasp, introduced by ADAMS in 1949 and today widely referred to as the Adams clasp, makes use of the mesial and distal undercuts of a single tooth only and can in practice be applied to any tooth, deciduous or permanent. • Since the clasp was given its definitive form in 1953, no changes in the basic principle and design have been found necessary www.indiandentalacadem
  10. 10. FUNCTIONAL APPLIANCE by definition is the one that changes the posture of the mandible, holding it open or open and forward. Passive tooth borne :- Activator, Bionator, Herbst appliance, Twin block. Active tooth borne :Modifications of Activators and Bionators. Tissue borne appliances :- Frankel appliance. www.indiandentalacadem
  11. 11. ADVANTAGES OF REMOVABLE APPLIANCES :Pt can continue oral hygiene procedures without any hindrance. Tipping movement of teeth can be carried out. Appliance more inconspicuous, hence generally more acceptable to patients. Relatively simple appliance can be delivered and monitored by general dentist. Can be removed on socially sensitive occasions, hence more acceptable to patients www.indiandentalacadem
  12. 12. ADVANTAGES Appliance fabrication is done in specialized labs,hence chair side time is considerably less than fixed appliance. Since few movements are carried out simultaneously with these appliances the time required to activate an appliance is less. Appliance require simple inventory to be maintained as compared to complex fixed appliance. Appliance are relatively CHEAP. www.indiandentalacadem
  13. 13. DISADVANTAGES :Patient co operation. Capable of only certain types of movements. Multiple movements are difficult if not impossible. Patient has to have certain amount of dexterity and skill to remove and replace the appliance. Chances of appliance “BREAKAGE and LOSS” . AJO-DO Volume 1985 May (392 - 397): Patient cooperation in treatment with removable appliances - Gross, Samson, and Dierkes www.indiandentalacadem
  14. 14. INDICATIONS Growth modification Limited tooth movements like tipping, etc especially for arch expansion or correction of individual tooth malpositions Retention after comprehensive treatment www.indiandentalacadem
  16. 16. Components of Removable Appliances :• RETENTIVE COMPONENT • ACTIVE COMPONENT • BASE PLATE www.indiandentalacadem
  17. 17. RETENTIVE COMPONENTS www.indiandentalacadem
  18. 18. • Helps in keeping the appliance in place and resists displacement of the appliance. • Success depends to a large extent on GOOD RETENTION of appliance. • They do not bring about necessary tooth movement. • Adequate retention of a removable appliance is achieved by incorporating certain wire components in undercut area called as CLASPS. www.indiandentalacadem
  19. 19. MODE OF ACTION • Act by engaging certain areas of tooth called UNDERCUTS. • The wire is made to engage these undercuts to prevent displacement of the clasp. TYPES OF UNDERCUTS :• BUCCAL AND LINGUAL • CERVICAL UNDERCUTS. • MESIAL AND DISTAL PROXIMAL UNDERCUTS. www.indiandentalacadem
  20. 20. IDEAL REQUIREMENTS OF CLASP :Offer adequate retention. Permit usage in both fully and partially erupted teeth. Offer adequate retention even in presence of shallow undercuts. By themselves should not apply any force. Be easy to fabricate. Not impinge on soft tissues. Not interfere with normal occlusion. www.indiandentalacadem
  21. 21. DIFFERENT CLASPS :1. 2. 3. 4. 5. 6. 7. 8. Circumferential clasp. Jackson’s clasp. Adam’s clasp. South end clasp. Triangular clasp. Ball end clasp Schwarz clasp. Crozat’s clasp. www.indiandentalacadem
  22. 22. CIRCUMFERENTIAL CLASP :- • Also known as “three quarter clasp” or C clasp. • Simple clasp designed to engage bucco-cervical undercut. www.indiandentalacadem
  23. 23. • 0.9 mm stainless steel wire is engaged from one proximal undercut along the cervical margin then carried over occlusal embrasure to end as a single retentive arm on the lingual aspect embedded in acrylic base plate. • USE : - Molars and premolars, canines • ADV : - Away from occlusal contact Simplicity of design & fabrication. • DIS : - Cannot be used in partially erupted teeth as cervical undercut is not available - Cannot be used on deciduous teeth as there is no infrabulge area Skip demo www.indiandentalacadem
  24. 24. Straightened piece of wire. Skip demo www.indiandentalacadem
  25. 25. Use the pliers as a vice to bend the wire. First make a bend in the wire smoothly in a semicircularwww.indiandentalacadem shape Skip demo
  26. 26. Proceed further following the cervical margins Skip demo www.indiandentalacadem
  27. 27. Checking that the clasp fit into marked undercuts of tooth. www.indiandentalacadem Skip demo
  28. 28. Bend wire down from over contact point towards the palate www.indiandentalacadem Skip demo
  29. 29. The wire passes vertically over the occlusal embrasure Skip demo www.indiandentalacadem
  30. 30. At the level of the marginal ridge the wire is bent towrds the palatal surface www.indiandentalacadem Skip demo
  31. 31. The wire ends as a retentive arm palatally. www.indiandentalacadem Skip demo
  32. 32. JACKSON’S CLASP : - • Introduced by JACKSON in 1906. • Also called as U clasp, Full clasp www.indiandentalacadem
  33. 33. • Clasp engages bucco-cervical undercut and also mesial and distal undercut. • 0.9 mm stainless steel wire is adapted along buccocervical margin n both occlusal embrasures to end retentive arm on both sides of the molar. • USE: for retainer Molars, canine, premolars • ADV : - simple to construct and adequate retention • DIS : - inadequate retention in partially erupted teeth and deciduous teeth. www.indiandentalacadem
  34. 34. Straighten a piece of 0.9 mm stainless steel wire Skip demo www.indiandentalacadem
  35. 35. Adapt the wire to pass around the buccal surface of tooth to pass above the cervical margin www.indiandentalacadem Skip demo
  36. 36. Mark the point at the level of the bucco proximal line angle www.indiandentalacadem Skip demo
  37. 37. Bend the wire such that it passes over the occlusal embrassure www.indiandentalacadem Skip demo
  38. 38. The wire being adapted from over contact point into the palate Allowing a space of 1mm for acrylic to flow underneath the wire www.indiandentalacadem Skip demo
  39. 39. Clasp in final position Skip demo www.indiandentalacadem
  40. 40. ADAM’S CLASP • First described by PROFESSOR PHILLIP ADAMS. in 1948 • Also known as LIVERPOOL, modified arrowed, universal clasp. It is a modification of Schwartz arrowhead clasp. • This clasp provides maximum retention, when constructed properly. • Made up of 0.7 mm hard S S wire. for molars and premolars 0.6 mm wire for canine www.indiandentalacadem
  41. 41. Adam’s clasp is made up of :• 2 Arrow heads.- it engages the mesial and distal proximal undercuts • Bridge.- it connects the two arrowhead • 2 Retentive arms. www.indiandentalacadem
  42. 42. Advantages Of Adam’s clasp :It is RIGID and offers excellent retention. This clasp develops the maximum retentive potential of whatever tooth it is placed upon in the simplest and most unobtrusive way. Can be fabricated on both Deciduous and Permanent dentition. Used on partially and fully erupted teeth. Used on molars, premolars and on incisors. No specialized instrument is needed to fabricate the clasp. Auxiliaries like springs, hooks tubes can be soldered to the bridge www.indiandentalacadem
  43. 43. • It is small and occupies minimum space. • Can be modified in a number of ways. Following are Modifications of the clasp :- Adam’s with single arrow head. Adam’s with J hook. Adam’s with incorporated helix. Adam’s with additional arrowhead. Adam’s with soldered buccal tube. Adam’s with distal extension. Adam’s with incisors and premolars. skip demo www.indiandentalacadem
  44. 44. DISADVANTAGES • If not skillfully made it becomes work hardened and will be liable to fracture www.indiandentalacadem
  45. 45. Pliers required for constructing www.indiandentalacadem appliances. skip demo
  46. 46. A good quality working model cast in stone is required www.indiandentalacadem skip demo
  47. 47. ark mesial and distal undercuts for molar arrowhead placement www.indiandentalacadem skip demo
  48. 48. The position of the Adams Clasp tags drawn on t model to ensure they don't interfere with screws and springs which may be required . skip www.indiandentalacadem demo
  49. 49. www.indiandentalacadem Straightened piece of wire. skip demo
  50. 50. Use the pliers as a vice to bend the wire. First make a bend in www.indiandentalacadem the wire slightly more than a right angle . skip demo
  51. 51. Hold the wire to the mesial mark on the tooth.  www.indiandentalacadem skip demo
  52. 52. Make a second bend slightly more than a right angle .  www.indiandentalacadem skip demo
  53. 53. he wire to the model to see that the dimensions are correct www.indiandentalacadem skip demo
  54. 54. Hold in the pliers just below one of the bends www.indiandentalacadem skip demo
  55. 55. ceed with a further right angled bend . www.indiandentalacadem skip demo
  56. 56. www.indiandentalacadem Bend completed skip demo
  57. 57. Right angled bendwww.indiandentalacadem to matchskip demo on the other side
  58. 58. Tilt the wire down. www.indiandentalacadem skip demo
  59. 59. wire is locked against the beak before starting to bend the arro www.indiandentalacadem skip demo
  60. 60. Bend the arm upwards so it follows the line of th opening of the beaks of the pliers. www.indiandentalacadem skip demo
  61. 61. Turn the pliers round, then the wire is pulled back on itself forming the 'U' type of loop at the bottom of the arrowhead skip demo www.indiandentalacadem
  62. 62. he second arrowhead held in the pliers beak prior to ben www.indiandentalacadem skip demo
  63. 63. The pliers turned to show that the first arrowhead is l against the beak of the pliers www.indiandentalacadem skip demo
  64. 64. The wire is now bent upwards parallel to the opening of the beak of the pliers . www.indiandentalacadem skip demo
  65. 65. mpletion of the bend of the second arrowhead. www.indiandentalacadem skip demo
  66. 66. Arrowhead being turned in at 45o to bridge of crib.  www.indiandentalacadem skip demo
  67. 67. arrowheads are bent into 45o from the bridge head. www.indiandentalacadem skip demo
  68. 68. Turning the arrowhead to 45o to the brid www.indiandentalacadem skip demo
  69. 69. cking that the arrowheads fit into marked undercuts of www.indiandentalacadem skip demo
  70. 70. ting to bend the retention arm over the contact point of tooth. www.indiandentalacadem skip demo
  71. 71. Holding in pliers prior to bend. www.indiandentalacadem skip demo
  72. 72. Bending arm over beak of pliers. www.indiandentalacadem skip demo
  73. 73. Straightening out arm. www.indiandentalacadem skip demo
  74. 74. Put clasp back to model making sure the arrowheads go into the marked undercuts and then check the wire goes over the www.indiandentalacadem skip demo contact point between two teeth the
  75. 75. ting to bend the retention arm over the contact point of www.indiandentalacadem skip demo
  76. 76. wire being adapted from over contact point into the palat ing a space of 1mm for acrylic to flow underneath the w www.indiandentalacadem skip demo
  77. 77. ng on the model to check adaptation to the contact poin www.indiandentalacadem skip demo
  78. 78. Clasp in the final position with Bridge parallel with buccal cusps www.indiandentalacadem skip demo
  79. 79. Bridge halfway up crown. www.indiandentalacadem skip demo
  80. 80. ADAM’S WITH SINGLE ARROWHEAD :- www.indiandentalacadem
  81. 81. ADAM’S WITH SINGLE ARROWHEAD :• Indication -Partially erupted tooth which is usually last erupted molar. • Single arrowhead is made to engage the mesio-proximal undercut of last erupted molar. • Bridge is modified to encircle the tooth distally and ends on the palatal aspect as retentive arm. www.indiandentalacadem
  82. 82. ADAM’S WITH J HOOK : - •J hook can be soldered on to bridge of the Adam’s clasp. www.indiandentalacadem
  83. 83. ADAM’S WITH J HOOK : - USEFUL IN engaging elastics www.indiandentalacadem
  84. 84. ADAM’S WITH INCORPORATED HELIX :- www.indiandentalacadem
  85. 85. ADAM’S WITH INCORPORATED HELIX :- Helix is incorporated into the bridge of Adam’s clasp. This helps in engaging elastics. www.indiandentalacadem
  86. 86. Straighten a piece of wire www.indiandentalacadem
  87. 87. Bend the wire smoothly around the circular beak of the plier in approximately half the length of the wire www.indiandentalacadem
  88. 88. Turn the wire around the beaks to form a circular small helix www.indiandentalacadem
  89. 89. Hold the wire to the model to mark the mesial and distal under www.indiandentalacadem
  90. 90. nd the wire at the marking at slightly more than a right angle www.indiandentalacadem
  91. 91. old the wire to the model to see that the dimensions are correct www.indiandentalacadem
  92. 92. Proceed to form the arrowheads as www.indiandentalacadem in a
  93. 93. www.indiandentalacadem
  94. 94. ADAM’S WITH ADDITIONAL ARROWHEAD :- www.indiandentalacadem
  95. 95. ADAM’S WITH ADDITIONAL ARROWHEAD :- Adam’s can be constructed with an additional arrowhead. Additional arrowhead engages proximal undercut of the adjacent tooth and is soldered on to the bridge of the Adam’s. This type of clasp gives additional retention. www.indiandentalacadem
  96. 96. ADAM’S WITH SOLDERED BUCCAL TUBE :- www.indiandentalacadem
  97. 97. ADAM’S WITH SOLDERED BUCCAL TUBE :- Buccal tube is soldered on to the bridge of Adam’s clasp. This modification permits use of extra-oral anchorage using face bow-head gear assembly. www.indiandentalacadem
  98. 98. ADAM’S WITH DISTAL EXTENSION :- www.indiandentalacadem
  99. 99. ADAM’S WITH DISTAL EXTENSION :- Clasp can be modified so that the distal arrowhead has a small extension incorporated distally. Distal extension helps in engaging ELASTICS. www.indiandentalacadem
  100. 100. Follow the technique to make usual arrowheads www.indiandentalacadem
  101. 101. At the distal arrowhead, make a www.indiandentalacadem loop just above
  102. 102. Position of distal extension www.indiandentalacadem
  103. 103. www.indiandentalacadem
  104. 104. ADAM’S ON INCISORS AND PREMOLARS : - www.indiandentalacadem
  105. 105. ADAM’S ON INCISORS AND PREMOLARS : - Adam’s clasp can be fabricated on the incisors and premolars when retention in those areas are required. It can be constructed to span a single tooth or two teeth. www.indiandentalacadem
  106. 106. SOUTHEND CLASP :• Used when retention is required in anterior region. • 0.7mm stainless steel wire is adapted along the cervical margin of central incisors. • Distal ends are carried over occlusal embrassure to end as retentive arms on the palatal side. www.indiandentalacadem
  107. 107. TRIANGULAR CLASP : • They are small triangular shaped clasp that are used between two adjacent posterior teeth. • 0.7mm stainless steel wire is used • They engage the proximal undercut of two adjacent teeth. • Indicated when additional retention is needed. www.indiandentalacadem
  108. 108. BALL END CLASP :• Fabricated using S S wire having a knob or a ball like structure on one end. • Ball can be made at the end of wire using silver solder. • Preformed wires having ball at one end are also available. • Ball engages proximal undercut similar to triangular clasp. • Indicated when additional retention is required. www.indiandentalacadem
  109. 109. SCHWARZ CLASP :• SCHWARZ or ARROWHEAD clasp is said to be a predecessor of ADAM’S clasp. • Designed in such a way that number of inter-proximal undercuts between the premolars and molars are engaged. www.indiandentalacadem
  110. 110. Disadvantages of this clasp :• • • • Needs special arrowhead forming pliers to fabricate. Occupies a large amount of space in the buccal vestibule. Arrowheads can injure the inter-dental dental soft tissues. Difficult and time consuming to fabricate. www.indiandentalacadem
  111. 111. CROZAT CLASP :• Resembles a full clasp but has an additional piece of wire soldered which engages into the mesial and distal proximal undercuts. • Offers better retention than full clasp. www.indiandentalacadem
  112. 112. ACTIVE COMPONENT Components which exert force to bring about necessary tooth movement. www.indiandentalacadem
  113. 113. Active components include :BOWS SPRINGS SCREWS ELASTICS www.indiandentalacadem
  114. 114. Bows:Active component that are mostly used for incisor Following is a list of commonly used bows: Short Labial Bow. Long Labial Bow. Split Labial Bow. Reverse Labial Bow. Robert’s Retractor. Mill’s Retractor. High Labial Bow With Apron Springs. Fitted Labial Bow. www.indiandentalacadem
  115. 115. SHORT LABIAL BOW :• It is constructed using 0.7 mm hard round S S wire. • It consists of a bow that makes contact with most prominent labial teeth and 2 U loops that end as retentive arms distal to canines. • This type of labial bow is very stiff and exhibits low flexibility. www.indiandentalacadem
  116. 116. • Activated by compressing the U loops. • Indicated in cases of minor overjet reduction and anterior space closure • Used for the purpose of retention at the termination of fixed orthodontic therapy. www.indiandentalacadem
  117. 117. LONG LABIAL BOW :• It is similar to short labial bow except that it extends from one premolar to the opposite premolar. • Distal arms of U loop are adapted over the occlusal embrasure between the two premolars to get embedded in the acrylic plate. Activation similar to short labial bow. Modified form of long labial bow can be made by soldering distal arm o the bridge. www.indiandentalacadem
  118. 118. Indications : Minor anterior space closure.  Minor overjet reduction .  Closure of space distal to canine.  Guidance of canine during canine retraction .  As a retaining device at the end of fixed orthodontic treatment. skip demo www.indiandentalacadem
  119. 119. mark the position of the labial bow on the model. skip demo www.indiandentalacadem
  120. 120. skip demo www.indiandentalacadem
  121. 121. skip demo www.indiandentalacadem
  122. 122. tart with a piece of wire approximately 20cm long to form a mooth curve, using the fingers to ensure that it touches www.indiandentalacadem l the teeth from canine to canine
  123. 123. ark the centre of the canine where you wish to bend the 'U' loo www.indiandentalacadem skip demo
  124. 124. mark the centre of the canine where you wish to bend the 'U' l www.indiandentalacadem skip demo
  125. 125. Using the round beak to form the 'U' loop www.indiandentalacadem skip demo
  126. 126. skip demo The completed 'U' loop. www.indiandentalacadem
  127. 127. Place the wire on the model. www.indiandentalacadem skip demo
  128. 128. Commence bending the retention leg. www.indiandentalacadem skip demo
  129. 129. Bend a small loop at the end of the retention leg www.indiandentalacadem skip demo
  130. 130. skip The completed retention leg replaced on model. www.indiandentalacadem demo
  131. 131. SPLIT LABIAL BOW :• This is a labial bow that is split in middle ,that results in 2 separate buccal arms having a U loop each. • This type of labial bow exhibits flexibility. USE:  For anterior retraction  Modified form of split bow used for closure of midline diastema. ACTIVATION: By compressing U loop 1-2 mm at a time. www.indiandentalacadem
  132. 132. NORMAL SPLIT LABIAL BOW Used for correction of diastema www.indiandentalacadem
  133. 133. REVERSE LABIAL BOW:• Also called Reverse loop labial bow. • U lops are placed distal to canine and the free ends of the U loops are adapted occlusally between 1st premolar and canine. USE • Anterior reduction and anterior space closure. ACTIVATION • done by first opening the U loop and then compensatory bend given at the base. www.indiandentalacadem
  134. 134. ROBERT’S RETRACTOR: • This is a labial bow made up of thin gauge S S wire having a coil of 3 mm internal diameter mesial to canine. • Use of 0.5 mm stainless steel wire along the incorporation of a coil makes the labial bow highly flexible. • As bow is highly flexible,it lacks adequate stability in vertical plane. www.indiandentalacadem
  135. 135. • Distal part of retractor is supported in a S S tubing of 0.5 mm internal diameter. USE: • Indicated in pts having severe anterior proclination with overjet of 4 mm. • As bow is flexible, it generates lighter forces hence can be used in adult pts whom lighter forces are desirable. www.indiandentalacadem
  136. 136. MILL’S RETRACTOR • Labial bow has extensive looping of the wire so as to increase flexibility and range of action. • Indication- Large overjet • Disadvantages : • Difficulty in construction and poor patient acceptance due to complicated design. www.indiandentalacadem
  137. 137. HIGH LABIAL BOW WITH APRON SPRINGS • Consists of a heavy wire bow of 0.9 mm thickness into buccal vestibule. • Apron spring made up of 0.4 mm wire attached to the high labial bow. • Designed for retraction for 1 or more teeth,being highly flexible are thus used in cases of large overjet . www.indiandentalacadem
  138. 138. • Apron spring is an active component that is activate by bending it towards the teeth. • Being flexible, activation is done up to 3 mm at a time. • Disadvantage is Difficulty in construction and Risk of soft tissue injuries. www.indiandentalacadem
  139. 139. FITTED LABIAL BOW :• In this type , the wire is adapted to confirm to the contour of the labial surface. • U loop is usually small and cannot be used to bring about active tooth movement. • Used as fixed retainers at the completion of fixed orthodontic therapy. www.indiandentalacadem
  140. 140. SPRINGS They are active component of removable orthodontic appliance. CLASSIFICATION :1] Based on presence or absence of HELIX a) Simple – without helix. b) Compound – with helix. 2] Based on presence of LOOPS or HELIX a) Helical spring. b) Looped spring. 3] Based on the NATURE of stability a) Self supported spring. www.indiandentalacadem b) Supported spring.
  141. 141. Ideal requirements of a spring • • • • • • Simple to fabricate Easily fit. Easy to clean Apply force of required magnitude and direction. Should fit into available space without discomfort to the pt. Should not slip or dislodge when placed over a sloping tooth surface. • Should be strong and sturdy. • Should remain active over a long period of time. www.indiandentalacadem
  142. 142. Factors To Be Considered In Designing A Spring :• According to McKeag I926 ,the laws which regulate the stresses and bending of orthodontic springs can be embodied in a formula which describes the relationship between the length of a spring, its thickness, the pressure which is required to deflect it, and the amount of deflection produced. • The formula states that Force generated is F α D4 L3 where P is pressure exerted upon the spring, l is the length of the spring, t is its thickness (for a wire of round section), and D is the deflection produced. • Volume 1969 Jun (202 - 218): Removable appliances yesterday and today - Adams www.indiandentalacadem
  143. 143. • DIAMETER OF WIRE :- Flexibility depends upon diameter of wire used. Thicker wire --> Decrease flexibility of spring and apply greater force. Doubling Diameter --> Force increases by 16 times. Decreasing diameter  Force applied is lesser, spring remains more flexible and active over a longer period. www.indiandentalacadem
  144. 144. LENGTH OF WIRE :Force decreased length of wire increases Longer spring , more flexible and remain active for a longer duration of time. Helices and Loops incorporated in the spring make them more active. Doubling the length the force can be reduced by 8 times. Force to be applied :Force that should be generated by the spring is calculated by Number of teeth to be moved ,Root surface area and Patient comfort . On average, force of about 20 gm/cm2 root area is recommended. www.indiandentalacadem
  145. 145. PATIENT COMFORT :Spring should offer any patient discomfort by way of its design ,size and force that it generates. Patient should be able to insert the appliance with the spring in the proper position so as to bring the desired tooth movement. DIRECTION OF TOOTH MOVEMENT Direction of tooth movement is determined by the point of contact between spring and tooth. Palatally placed are used for labial and mesio-distal tooth movement. Buccally placed springs are used when the tooth is to be moved palatally and in a mesio-distal direction. www.indiandentalacadem
  146. 146. FINGER SPRING :• Also called SINGLE CANTILEVER SPRING as one end is fixed in acrylic and other end is free. • Constructed in 0.5-0.6 mm hard round S S wire. • Used for mesio-distal movement of teeth and can be used in teeth that are placed correctly in buccolingual direction. www.indiandentalacadem
  147. 147. FINGER SPRING :• Finger spring consists of an active arm of 12 – 15 mm which is towards the tissue , a helix of 3 mm internal diameter and a retentive arm of 4 – 5 mm length which is kept away from the tissue and ends in small retentive tag. • The coil lies along the long axis of tooth to be moved, perpendicular to the direction of movement. • Coil is in direction opposite to that of tooth surface. www.indiandentalacadem
  148. 148. • Prior to acrylisation,the helix and the active arm are boxed in wax so that the spring lies in an recess between the mucosa and base plate. • Finger spring is activated by moving the active arm towards the teeth intended to be moved. • Activation of 3 mm is considered ideal,when 0.5 mm wire is used. • Whenever 0.6 mm of wire is used the activation should be half of that. www.indiandentalacadem
  149. 149. Straighten ed piece of wire www.indiandentalacadem
  150. 150. Position the wire in the plier www.indiandentalacadem
  151. 151. Bend the wire around the the round beak of the plier www.indiandentalacadem
  152. 152. Turn the wire around the beak to form a www.indiandentalacadem
  153. 153. www.indiandentalacadem
  154. 154. www.indiandentalacadem
  155. 155. Position it on the cast www.indiandentalacadem
  156. 156. Adapt thewww.indiandentalacadem the palatal retentive arm to
  157. 157. www.indiandentalacadem Mark the position on active arm
  158. 158. Bend the wire www.indiandentalacadem the such that it engages
  159. 159. www.indiandentalacadem
  160. 160. www.indiandentalacadem
  161. 161. Z SPRING :• Also called DOUBLE CANTILEVER SPRING. • Used for labial movement of incisors and bringing about minor rotation of incisors. • Made up of 0.5 mm hard round S S wire. • Springs can be made for the movement of of a single or two incisors. www.indiandentalacadem
  162. 162. • Spring consists of two coils of very small internal diameter. • It should be parallel to the palatal surface of the tooth. • It has a Retentive arm of 10 – 12 mm length that gets embedded in acrylic. • Z spring is activated by opening both the helices by about 2-3 mm at a time,incase of minor rotation correction, one of the helices is opened. www.indiandentalacadem
  163. 163. www.indiandentalacadem Take a straightened piece of wire.bend one end and
  164. 164. Mark the www.indiandentalacadem position distal contact point on wire
  165. 165. Form www.indiandentalacadempoint a Helix at that
  166. 166. The arms should be parallel to each other. Make www.indiandentalacadem another helix at a point such that both arms are
  167. 167. www.indiandentalacadem
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  169. 169. Completed Z Spring in position www.indiandentalacadem
  170. 170. T SPRING :• The spring consist of a T shaped arm whose ends are embedded in acrylic. • Buccal movement of premolars and sometimes canines can be brought about using a T spring. • It is made of 0.5 mm hard round stainless steel wire. • Loops can be incorporated in both the arms of the T so that as the tooth moves buccally. The head of the T can be made to remain in contact with the crown by slightly opening the loops. • The spring is activated by pulling the free end of the T towards the intended direction of tooth movements. www.indiandentalacadem
  171. 171. COFFIN SPRING :• This is a removable type of arch expansion spring that was introduced by Walter Coffin. • It is used to bring about slow dento-alveolar arch expansion in patients where the upper arch is constricted or there is a unilateral cross bite. • The Coffin spring is made of 1.2 mm hard round stainless steel wire. • It consists of a U or omega shaped wire placed in the mid-palatal region with the retentive arms incorporated into base plates. www.indiandentalacadem
  172. 172. • The appliance gains retention from Adam’s clasps on the first molars and the first premolars or deciduous molars. • The Coffin spring can be activated manually by holding both the ends at the region of the clasps and pulling the sides gently apart. • Activation of 1-2 mm at a time is considered appropriate. www.indiandentalacadem
  173. 173. CANINE RETRACTORS :They are springs used to move canines in distal direction. CLASSIFICATION :A) Based on their LOCATION :-Buccally placed or Lingually placed. B) Based on the presence of HELIX or LOOP:- Canine retractor with or without HELIX C) Based on their MODE OF ACTION :- Push type or Pull type. www.indiandentalacadem
  174. 174. • Mechanically it is least effective and is used when minimal retraction of 1-2 mm is required. • It is activated by closing the loops by 1-2 mm or cutting the free end of the active arm by 2 mm and readapting it. • Advantages of this retractor are case in fabrication and less bulk. www.indiandentalacadem
  175. 175. U LOOP CANINE RETRACTOR:• • • • It is made of 0.6 mm or 0.7 mm wire. It consists of a U loop, an active arm and a retentive arm which is distal. The base of the loop should be 2-3 mm below the cervical margin. The mesial arm of the U loop is bent at right angles and adapted around the canine below its mesial contact point www.indiandentalacadem
  176. 176. HELICAL CANINE RETRACTOR:• It is also called reverse loop canine retractor and is made of 0.6 mm wire. • It consists of a coil of 3 mm diameter , an active arm and a retentive arm. • The mesial arm is adapted between the premolars. • The distal arm is active and is bent at right angles to engage the canine below the height of contour. www.indiandentalacadem
  177. 177. • The coil is placed 3-4 mm below the gingival margin. • It is activated by opening the helix by 2 mm or by cutting 2 mm of the free end and readapting it around the canine. • It is indicated in patients with shallow sulcus. www.indiandentalacadem
  178. 178. BUCCAL SELF SUPPORTED CANINE RETRACTOR :• It is made of 0.7 mm wire. • It consists of a helix of 3 mm diameter, an active arm and a retentive arm. • The coil is placed distal to the long axis of canine. www.indiandentalacadem
  179. 179. • It is indicated in case of bucally placed and canines placed high in the vestibule. • It is called self-supported because it is made of thicker diameter wire which can resist distortion. • It is activated by closing the helix 1 mm at a time. www.indiandentalacadem
  180. 180. PALATAL CANINE RETRACTOR • It is made up of 0.6 mm stainless steel wire. • It consists of a coil of 3 mm diameter, an active arm and guide arm. • The active arm is placed mesial to canine. • The helix is placed along the long axis of canine. • It is indicated in retraction of canines that are palatally placed. • Activation is done by opening the helix 2 mm at a time. www.indiandentalacadem
  181. 181. SCREWS:• Screws are active components that can be incorporated in a removable appliance. • Used to bring about many types of tooth movements. • Activated by pts at regular intervals using a key. • They are valuable aid in pts who cannot visit dentist frequently. • Appliance with screws usual consist of a split acrylic plate and Adam's clasp on posterior teeth. www.indiandentalacadem
  182. 182. • Screw is placed connecting the split acrylic plate, can bring about various types of movements based on the location of acrylic split,the location of screw amd number of screw used in appliance. • Removable appliance using screws bring about 3 types of movements : > Expansion of arch. > Movement of one or a group of teeth in buccal or labial direction. >Movement of 1 or more teeth in a distal or mesial direction. www.indiandentalacadem
  183. 183. ELASTICS :• They are active component which are seldom used with removable appliance. • Mostly used in conjunction with fixed appliance. • Appliance using elastics for anterior retraction making use of a labial bow with hooks placed distal to the canines. • Disadvantages are elastics tend to slip gingivally causing trauma and risk of arch form getting flattened. www.indiandentalacadem
  184. 184. BASE PLATES www.indiandentalacadem
  185. 185. USES OF BASE BLATES :• • • • • Unites all components of the appliance into one unit. Helps in anchoring the appliance in place. Provides support for the wire components. Helps in distributing the forces over a larger area. Bite planes can be incorporated into the plate to treat specific orthodontic problems. www.indiandentalacadem
  186. 186. THICKNESS OF BASE PLATE Base plate should have minimum thickness to help in patient acceptance. Thick plates are less tolerated by pts. Base plate of 1.5 – 2 mm thickness offers adequate strength and is well tolerated by the patient. EXTENSION OF BASE PLATE :- Maxillary base plate usually covers the entire palate till the distal of the 1st molar.Full coverage helps in gaining adequate strength. Narrow maxillary base plate resembling a horse shoe are less stable and likely to get dislodged during movement. Mandibular base plate is usually shallow to avoid irritation to the lingual sulcus. To compensate for this,plate is made thicker to increase strength. www.indiandentalacadem
  187. 187. Materials used for base plate:• COLD CURE ACRYLIC. • HEAT CURE ACRYLIC. www.indiandentalacadem
  188. 188. Factors to be considered at the time of delivery of removable appliance :• Tissue surface of appliance should not have any sharp areas or nodules. • Base plate may need some trimming to help in ease of insertion and removal. • Clasp should be examined for adequate retention,should be engaged in undercut if not retentive. • Active components should rest at desired location. • Patient should be educated on how to insert and remove the appliance. • Active components can be activated after few days once the patient gets used to the appliance. www.indiandentalacadem
  189. 189. Instruction to the patient :• Pt instructed on number of hours of wear,to be worn day n night. • Appliance and teeth to be clean after every meal. • Pt is asked to clean the appliance using detergent solution and brush. • In case of appliance with screws,pt and parents should be given clear instruction on how to activate the appliance. • Pt instructed to report immediately to the clinic in case of appliance damage or other problems. • Pt instructed not to leave the appliance out of mouth for a long period. www.indiandentalacadem
  190. 190. Problems encountered in removable appliance therapy:• • • • • Oral hygiene maintenance. Soft tissue irritation. Caries. Pain. Tooth mobility. www.indiandentalacadem
  192. 192. “THANK YOU“