Orthodontic fixed appliances

Orthodontic fixed appliance including basics,every component of fixed appliance, applied part is also included.
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1. ORTHODONTIC FIXED APPLIANCES Presented by, Dr. Sumit Rajewar BDS, MDS

2. Introduction Optimum orthodontic force Changes following application of mild forces Changes following application of extreme forces Tooth movements possible using fixed appliance Types of appliance Components of fixed appliance 1. Active components 2. Passive components Method of fixing attachment on the teeth 1. Banding 2. Bonding Contents:

3. Fixed appliance technique Edgewise Appliance Levelling and Alignment Overbite Reduction Overjet Reduction and space Closure Final Tooth position Debonding and Retention Begg appliance Preadjusted Edgewise Appliance Tip-Edge Technique

4. Appliance that are fixed or fitted onto the teeth by the operator and cannot be removed by patient is known as fixed appliance. Removable appliance are capable of only tipping type of movement, but fixed appliance can bring various type of tooth movements including bodily movement, Tipping, Rotation, Intrusion, Extrusion. Oral hygiene maintenance becomes more difficult for patient in fixed orthodontic treatment and this is the most important disadvantages of a fixed appliance. INTRODUCTION:

5. Definition: Optimum orthodontic forces is one which moves tooth most rapidly in the desired direction, with the least possible damage to tissue and with minimum patient discomfort. It is equivalent to the capillary pulse pressure that is 20-26 gm/ sq cm of root surface area. Optimum orthodontic forces:

6. When a force is applied to a tooth, areas of pressure and tension are produced. Changes on pressure side: The periodontal ligament in a direction of tooth movement gets compressed to almost 1/3 rd of its original position. Osteoclast is the bone resorbing cells that line up along the socket wall on pressure side. When forces applied within the physiologic limit the resorption seen on the alveolar plate this kind of resorption is called frontal resorption. Changes following application of mild forces

7. Changes seen on tension side: The area of tooth opposite to the direction of force is called as tension side. On application of force periodontal membrane on the tension side get stretched. Raised vascularity causes mobilization of cells such as fibroblast and osteoblast in this area. Due to this traction osteoid is laid down by osteoblast in the periodontal ligament and calcified bone forms woven bone.

8. Whenever extreme forces are applied to teeth, its results in crushing or total compression of periodontal ligament and occlusion of blood vessels and leads to hyalinization. In this case bone can not resorb in frontal portion ,it resorb in the adjacent to marrow spaces and below the alveolar plates this type of resorption is known as undermining resorption. Periodontal ligaments gets over stretched on tension side and leads to tearing of blood vessels and ischemia. Changes following application of extreme forces

9. The various tooth movements possible using fixed appliance are: Tipping Bodily movement Torquing Uprighting Rotations Extrusion and Intrusion Tooth movements possible using fixed appliance

10. 1) Tipping: It is a simplest type of tooth movement. Where single force is applied to the crown which, results in movement of crown in the direction of force and root in the opposite direction. Force needed is about 50 – 75 gm.

11. 1) Controlled tipping: In controlled tipping centre of rotation is at apex. Crown moves in one direction and here is negligible or minimal movement of root 2) Uncontrolled tipping: This kind of tipping occurs with centre of rotation is in apical area and very close to the centre of resistance Due to this crown moves in one direction and root moves in opposite direction.

12. Translation of the teeth takes place when the crown and the root of the tooth move in same direction i.e. horizontal linear direction. Here centre of rotation is at infinity. Force needed is about 100 – 150 gm 2) Bodily movement/Translation: .

13. Movement of root without movement of crown is called as torque. Root movement or torque is achieved by keeping the crown of tooth stationary and applying a movement and force to move only the root. Hare centre of rotation is at incisal edge. 2) Torquing

14. In some malocclusion axial inclination is seen in the crowns. Those teeth will be tipped abnormally in mesiodistal direction and root tipped in opposite direction. Tipping of these roots back to its acceptable position is known as uprighting. 3) Uprighting

15. Rotation are labial or lingual movements of tooth around its long axis. Pure rotation requires a couple of forces . Force needed is about 50 – 100 gm. 4) Rotation

16. Extrusion is bodily displacement of tooth along its long axis in an occlusal direction. Force needed is about 50 gm. 5) Extrusion

17. Intrusion is the bodily displacement of tooth along long axis of tooth in apical direction. It require least amount of force i.e. 15 – 25 gm. 6) Intrusion

18. TYPES OF APPLIANCE: TYPES OF ORTHODONTIC APPLIANCE Removable Fixed Active Removable + Fixed Passive Active Passive

19. DEFINITION : Fixed Appliances are devices or equipment's that are attached to the teeth, cannot be removed by the patient and are capable of causing tooth movement.

20. Fixed Appliances are indicated when precise tooth movements are required Correction of mild to moderate skeletal discrepancies Correction of rotation Overbite reduction by intrusion of incisors Multiple tooth movements required in one arch Active closure of spaces: extraction spaces/hypodontia INDICATION:

21. ACTIVE COMPONENTS Separator Arch wire Elastics Springs COMPONENTS OF FIXED APPLIANCES: PASSIVE COMPONENTS Bands Brackets Molar tube Accessories Lock pins Ligature wire

22. ACTIVE COMPONENTS OF FIXED APPLIANCE

23. Orthodontic separators commonly known as spacers They are made up from rubber bands or metal. Spacers are placed between the molars at the second orthodontic appointment, before molar bands are applied. 1) Separator:

24. Purpose: Spacers are usually used to create spaces in between teeth before placement of braces. They are usually rubber, but sometimes they can be metal. S metimes very painful, they are usually in place for 1 to 2 weeks. Spacers can also cause toothache and gum pain because of the constant pressure against the teeth.

25. How to apply the separator ? Special orthodontic tools are used to stretch or open the rubber bands, depending on crowding. If the jaw is crowded, the spacers may cause intense and constant pain due to the tooth movement.

26. How to remove separator? Spacers may also fall out on their own without being removed by the patient by picking or eating sticky foods. Sometimes, a dentist may use a spacer that is similar to a metal spacer, but is removable. The spacers are taken out about a week before placing the braces.

27. An orthodontic arch wire is a wire in similar shape of the alveolar or dental arch that can be used with dental braces as a source of force in correcting irregularities in the position of the teeth. Orthodontic arch wires may be fabricated from several alloys, most commonly stainless steel, nickel-titanium alloy (NiTi), and beta-titanium alloy (composed of titanium and molybdenum) 2) Arch wire:

28. Based on material used: Gold and Gold alloys Stainless steel Nickel Titanium alloys Beta titanium Cobalt chromium nickel alloys Optiflex arch wire Based on cross section: Round Square Rectangle Twisted Coaxial Classification of arch wire:

29. Ideal requirement of orthodontic wire: Spring back: It increases range of action. Stiffness: It provide ability to provide lower and a more constant forces over time. Formability: Orthodontic wire should exhibit high formability so as to bend the arch wire into desired configuration. Resilience: Orthodontic wire should exhibit high resilience so as to increase the working range of appliance. Biocompatibility: Orthodontic wire should exhibit resistance to tarnish and corrosion and should be non-toxic. Joinability: Orthodontic wire should exhibit the property of soldering and welding.

30. Elastics are made of latex rubber and are available in various diameter. The force applied by these elastic depends on its diameter. 3) Elastics:

31. Applications of elastic: Class I elastics: They are intra arch elastics stretched between the molars and anterior. They are generally used for closer of space and retraction of teeth.

32. Class II elastics: They are intermaxillary elastics stretched between the lower molars and upper anterior. They are used in the treatment of class II malocclusion. They bring reduction of upper anterior proclination and mesial movement of lower molars.

33. Class III elastics: It is intermaxillary elastics stretched between the upper molar and lower anterior. They are used in class III malocclusion to bring mesial movement of upper teeth and retraction of lower anterior.

34. Cross bite elastics: It is Intermaxillary elastics used to treat molar cross bite. They extend between the palatal surface of the upper molar and buccal surface of lower molar.

35. Box elastics: This form of elastic used to correct anterior open bites and open bite gets corrected by forced eruption of upper and lower anterior.

36. It is used to bring about various tooth movement. Types of spring: Uprighting springs: This type of spring move the root in mesial or distal direction. 4) Springs:

37. Open coil springs: This type of spring that are compressed between two teeth to open up space between them.

38. Closed coil springs: They are stretched between teeth to close space.

39. PASSIVE COMPONENTS OF FIXED APPLIANCE

40. 1) Bands: It helps in fixing the various attachments on to the teeth. The are made of from soft stainless steel. The attachments like molar tube and brackets are soldered or welded on to the band and band will be cemented around the teeth. Prefabricated band are also available. The use of these bands reduces the chair side time by eliminating tedious procedure like pinching.

41. 2) Brackets Brackets acts as handles to transmit the force from the active component to the teeth. Brackets have one or more slots that accept the arch wire. Types of brackets: Edgewise brackets: Ribbon arch brackets: Weldable and bondable brackets: Metallic brackets: Ceramic brackets: Plastic brackets:

42. 1) Edgewise type of bracket: (The bracket with rectangular slot facing labially ) Bracket used in Edgewise and straight wire technique have a horizontal slot facing labially. They accept wires of rectangular cross section. These bracket provide greater control over tooth movement and do not permit tipping of tooth.

43. 2) Ribbon arch brackets: (The bracket with vertical slot facing occlusal or gingival direction) The slot is narrow mesio -distally. This type of brackets usually receive round wire to bring tipping of tooth labio-lingual as well as mesio-distal direction. It is used in Begg-fixed appliance.

44. 3) Weldable and bondable brackets: Those brackets are welded over the band are called weldable bracket. Those bracket directly bonded over the enamel are called bondable brackets. Bondable bracket has a meshwork or grooves to help in interlocking with the adhesives.

45. 4) Metallic brackets: Mostly in use Advantages of metallic brackets: They can be recycled They can be sterilized They resist deformation and fracture They exhibit the least friction at the wire bracket interface. They are not expensive Disadvantages of metallic brackets: They are aesthetically not pleasing. The can corrode and cause staining of teeth.

46. 5) Ceramic brackets: Introduced in 1980’s They are made up from aluminium oxide or zirconium oxide Advantages of Ceramic brackets: They are dimensionally stable They are durable and resist staining in the oral environment Disadvantages of Ceramic brackets: The are very brittle To compensate their brittleness, their size is increased which tends to increase their bulk

47. Ceramic brackets Metallic brackets

48. 5) Plastic brackets: Made up from Polycarbonate Introduced to improve the aesthetic value of appliance Available in tooth colored or transparent forms Disadvantages of Plastic brackets: They tend to become discoloured due to smoking and coffee etc. They having poor dimensional stability. Their slots tend to distort.

49. 2) Molar tube / Buccal tube: Buccal tube can be weldable on to the bands or they can be bondable directly to the teeth. Buccal tube can be round or rectangular. The buccal tube sometimes have double or triple tubes. These additional tubes for additional wires.

50. 2) Accessories: 1) Lock pins It is small pins that are used to secure the arch wire into the bracket with vertical slot such as ribbon arch brackets. It is usually made of brass

51. 2) Ligature wire They are soft stainless steel wire of 0.009 to 0.011 inches in diameter and are used to secure the arch wire to the bracket and it is known as ligation Ligation is necessary in edgewise type of brackets because it have labially facing slot Elastic ligature can also used to secure wire into the brackets

52. 1 ) Banding: Banding involves the use of thin stainless steel strips called bands that are pinched tightly around the teeth and then cemented to the teeth. The stainless steel tape is available in different width and thickness to suit different teeth. The molar band material is wider and stiffer A nterior band material is thinner and narrower. Method of fixing attachment on the teeth

53. Indications for banding Banding is preferred over bonding in case of posterior teeth the Banded attachment are better capable of resisting occlusion forces than bonded attachment. It is preferable to band a tooth that requires buccal as well as lingual attachments. Bands are better likely to resist heavy forces as in the case of extra oral devices such as headgear.

54. Although it is not possible to Bond attachments on teeth that have porcelain or gold restorations on crowns, banding is preferred in these case. It is preferable to band teeth that show recurrent breakage of the bonded attachments due to bond failure. It is preferable to use Banded attachments whenever they are likely to connect the opposing dentition when the jaws are closed.

55. Steps in banding: Separation of teeth Selection of band material Pinching of the band Fixing the attachments Cementation of band

56. Separation of teeth Due to the presence of tight inter-dental contact between the teeth, it may not be possible to force the band through contact point. Hence tight contact should be broken with the help of separator prior to band adaptation. Selection of band material Based on which tooth is being banded, the band material of appropriate thickness and width is selected.

57. Pinching of the band Band material of adequate length is taken and two end are welded together and band is now passed through the separated interdental contact around the teeth to be Banded using band pinching pliers. The band is tightly drawn around the tooth to form a ring the neck of the band is spot welded to retain the tight fit the excess band material is then cut off and the end are adapted close to the band.

58. The bend portion is spot welded and the gingival margins of the band are trimmed to conform the contour of the gingival margin. The weld spots and rough margin are then smoothened and polish.

59. Fixing the attachment Once the band pinching is completed the appropriate attachments are fixed on to the band. The attachments include brackets for the anterior teeth and buccal or molar tube for the posterior teeth The attachments are fixed to the band by spot welding by soldering.

60. Cementation of the band The final step involves cementation of the band around the tooth. The inner surface of the band is rough in order to add retention.

61. A well pinched band is one that has adequate retention even without the use of cement but Cementation is required to eliminate the space between the band and tooth into which cariogenic material may seep. cements that can be used includes zinc polycarboxylate , zinc phosphate, glass ionomer cement etc

62. Band thickness in inches Band width in inches Incisor 0.003 0.125 Canine 0.003 0.150 Premolar 0.004 0.150 Molar 0.005 0.006 0.180 Band sizes

63. Causes of band failure 1. Patient factors Eating hard and sticky food Bruxism Use of phenolic mouthwashes Biting nails chewing pen or pencil 2. Dentist factor Poor moisture control Insufficient etch time Application of high force to engage the arch wire.

64. 2 ) Bonding: The method of fixing attachments directly over the enamel using adhesive resins is called bonding Introduced by buonocore . [ in 1955 ]

65. Advantages of bonding It is aesthetically superior. It is faster to Bond than to pinch band around the teeth. It enables maintenance of better oral hygiene. It is possible to Bond on teeth that have aberrant shape or form. It is easier to Bond than band in case of partially erupted and fracture teeth. The risk of caries under band is eliminated. Interproximal areas are accessible for restoration and proximal stripping.

66. Disadvantages of bonding Bonded attachments are weaker than Banded attachments. Bonding involves etching of enamel with an acid which may lead to enamel loss and an increased risk of demineralization. Chances of enamel fracture can occur during the debonding.

67. Steps in bonding: 1. Teeth which are to be bonded cleaned with the help of pumice and brush to remove plaque. After cleaning teeth are washed and dried. During bonding procedure adequate moisture control should be maintained with the help of saliva ejector and cotton rolls.

68. 2. 35-50% phosphoric acid in gel or liquid form is used to etch enamel. This etching is done for 45-60 seconds after that etchant is washed of with water. Teeth are then dried and sealant is applied onto the etched enamel surface.

69. 3. Adequate amount of bonding adhesive is placed on the base of brackets, then bracket is placed on the tooth Excessive adhesive is removed by using scaler.

70. FIXED APPLIANCE TECHNIQUES Edgewise appliance Begg appliance or light force technique or differential technique Preadjusted Edgewise Appliance or Straight Wire appliance Tip Edge technique

71. Introduced by EH Angle in 1928 It utilizes both rectangular slot brackets as well as rectangular wire Rectangular wire in rectangular slot able to control tooth movement in all the tree planes of space Edgewise appliance:

72. Angle devised a metal bracket having rectangular slot with 0.022’’ * 0.028’’ dimension facing labially . The slot receive rectangular wire of 0.022’’ * 0.028’’ Rectangular wire is inserted into bracket slot in such way that the narrower dimension is placed oclusogingivally and the larger dimension extends depth wise labiolingually into the slot. This mode of incretion is called edgewise hence this technique is known as Edgewise technique.

73. Bends in fabrication of edgewise appliance:

74. Levelling and Alignment: This is the major objective during the early stage of treatment In this all the teeth are brought in same vertical and horizontal planes of space. Any rotation, crowding, intrusion and extrusion are corrected in this stage. It is achieved by round Ni-Ti wire or stainless steel wire which apply gentle forces without distortion. This is followed by sequentially increasing diameter of wire from 0.012’’ to 0.020’’ or 0.016’’ * 0.016’’ to 0.018’’ * 0.018’’ square wire

75. Overbite reduction: Deep bite are corrected by intrusion of the anterior or extrusion of posterior teeth That depends upon the number of factors such as skeletal and dental growth pattern of individual, lip configuration and inter- occlusal clearance.

76. Incisors can be intruded by using intrusion utility arches, with incorporating anchor bends in wire and arch wires with reverse Spee in the mandiblular and curve of spee in maxillary arch. Posterior extrusion can be achieved by use of bite planes and vertical elastics. In some cases headgears may be used.

77. Overjet reduction and space closer: It is necessary to establish normal relationship between the upper and lower arches. There are two types of mechanisms used for anterior retraction. Friction or sliding mechanisms: Frictionless or loop mechanisms:

78. 1. Friction or sliding mechanisms: After proper alignment of the bracket [teeth], arch wire easily slides through the buccal tube. Rectangular stainless steel wire with 0.18’’ * 0.025’’ or 0.019’’ * 0.025’’ dimension are used for the purpose of anterior retraction.

79. Hocks are soldered on the arch wire either mesial or distal to the canine. Sometimes elastic, either fixed or removable and NiTi coil springs can be used. This result in retraction of anterior teeth by arch wire sliding through the slot of the posterior brackets and buccal tube.

80. 2. Frictionless or loop mechanisms: This is based on the spring and loop design incorporated into the main arch wire. The spring can be modulated for anterior retraction or posterior protraction depending upon the anchorage need of patient. Various design of loop are available such as T-loop, Omega loop, key hole loop, tear drop loop, mush-room loop etc.

81. Final tooth position: The final phase involves finishing and occlusal detailing . During this phase of treatment smaller diameter wires are used in the initial phases such as 0.016’’ stainless steel wires as they are more flexible and allow precise finishing. Debonding and Refraction: Once the occlusion is settled, the appliance is debonded. This is followed by appropriate retention.

82. Introduced by Raymond Begg . Begg modified the angles ribbon arch technique and introduced begg light wire differential force technique. Tipping rather than bodily movement . Begg appliance technique is carried out in three different stages. Begg appliance or light force technique or differential force technique:

83. 1. Stage one: It is concern with alignment, correction of crowding, rotation, closer of anterior spaces and achiving edge-to-edge anterior bite . The bite is open in order to reduce the overjet Usually 0.016’’ stainless steel round arch wire that will be plane or with loops is used. Intermaxillary elastics are used in this stage

84. 2. Stage two: The remaining extraction spaces are closed in this stage Usually 0.018’’ stainless steel round arch wire is used. Both intermaxillary and intramaxillary elastics is used. 3. Final stage: Uprighting and torquing is carried out in this stage to achieve normal axial inclination of teeth. Usually 0.020’’ stainless steel round arch wire is used. Uprighting springs also used in this stage.

85. Stages in begg appliance treatment:

86. Introduced by Lawrence F Andrews in 1970. It is the a modification of the edgewise appliance and it is based on the Andrews six keys to normal occlusion. Preadjusted Edgewise Appliance or Straight Wire appliance

87. Bracket have rectangular slots similar to standard edgewise bracket. The first-order, Second-order and Third-order components are built in the bracket itself. So it eliminates the need of wire to have any complex bending as required in standard edgewise appliance. Hence it is called preadjusted appliance

88. Tip-Edge Technique: It was introduced by Peter C. Kesling. This is the combination technique which utilises the advantages of both the edgewise and begg appliance. The bracket design has both vertical and horizontal slot. It can create rapid opening of bite as well as reduced treatment time and at the same there is good control over tooth movements.

89. Advances in orthodontic brackets: Ceramic Bracket: Ceramic brackets were introduced in the 1970’s All currently available ceramic brackets are composed of aluminium oxide in two forms i.e. polycrystalline or monocrystalline, depending on their method of fabrication. Plastic Bracket: Plastic brackets were marketed in the early 1980’s. Initially constructed from acrylic and later by polycarbonate. Recent advances in orthodontics:

90. Self- ligating Bracket: A self- ligating bracket is a ligature less system with a mechanical device built-in to close-off the bracket slot. Secure engagement of the main arch wire into bracket may be produced by a clip mechanism replacing the stainless steel or elastomeric ligature. Features of Self- ligating bracket 1. Speed brackets: Earlier brackets had clips which could too easily be displaced or distorted. These drawbacks have been taken care into these bracket.

91. 2. Activa brackets: Activa brackets had a rotating slide, which therefore gave a concave inner radius to the labial surface of the slot. These increased slot depth reduced the labio -lingual alignment efficiency. The bracket is wider than the average bracket. Tie-wings were absent and a different bonding base made bracket positioning more difficult.

92. 3. Time 2 bracket: The time 2 bracket has a clip that rotates into position around the gingival tie wing and rotates towards the occlusal rather than the gingival wall of the slot.

93. 4. DAMON SL Brackets: Damon SL brackets had a slide that wrapped around the labial face of the bracket. The slides sometimes opened inadvertently and they were prone to breakage

94. 5. DAMON 2 Brackets: Introduced to overcome the imperfections of Damon SL. Damon 2 brackets are almost completely free from inadvertent slide opening or slide breakage. However, the brackets were not immediately and consistently very easy to open.

95. 6. DAMON 3 and DAMON 3MX Brackets: Damon 3 and Damon 3MX brackets have a different location and action of the retaining spring, and this has produced a very easy and secure mechanism for opening and closing. Damon 3 brackets have three significant problems: a high rate of bond failure, separation of metal from reinforced resin components, and fractured tie wings.

96. 7. Basis of Butterfly system: The Butterfly System is based on low-profile pre-adjusted bracket that features a vertical slot. The vertical slot permit the addition of a variety of auxiliaries. Hook or T-pins for elastics can be added to the vertical slot during treatment whenever they are needed. A further enhancement to patient comfort and aesthetics is derived from the reduced profile or thickness of the bracket.

97. Emoyers , handbook of orthodontics 4h edition, year book medical publisher, inc 1988 Profit, Contemporary orthodontics, Elsevier India 3ed 2000. Begg PR, KeslingPC , begg orthodontic theory and technique, St Louis Mosby 1985 Kesling PC, Tip-edge guide and diffren . Stratight arch technique 1988 Andrew LF. Straight wire appliance explaned and compared. J clin orthod 1976;10:174-95 References:

98. TH AN K Y OU