MBT wire sequence during orthodontic alignment and leveling
- 1. MBT WIRE SEQUENCING DURING TOOTH LEVELING AND ALIGNING Prof dr Maher Fouda Mansoura Egypt
- 2. Reference
- 4. Molar relationship was 4 mm Class II on the right and 2 mm Class II on the left. All the teeth were developing normally, except the upper left third molar. Arch form was assessed as ovoid. It was decided to manage the case on a non-extraction basis, with upper anterior torque and lower incisor enamel reduction.
- 5. Standard metal brackets were used with .016 HANT wires to commence tooth alignment. The patient was asked to wear a combination headgear during evenings and nights. Lower enamel reduction was delayed until correct upper and lower incisor torque had been achieved, which would reveal the amount of reduction necessary.
- 7. After 3 months of treatment, upper and lower rectangular HANT wires are in place. After 6 months of treatment, steel .019/.025 rectangular wires were placed. The patient was asked to wear a right side Class II elastic (lOOgm) to commence correction of the right side occlusion and the midlines. Archwires were placed flat, without additional torque.
- 8. Subsequently, after 9 months of treatment, additional torque was added to the upper wire It became clear that lower enamel reduction was needed. Separation and then enamel reduction of lower incisors was carried out after 10 months of treatment, and first molar bands and upper canine brackets were repositioned. Upper and lower rectangular HANT wires were used for 1 month to re-level and align after enamel reduction and bracket repositioning,
- 11. Normal settling methods were used, with lower bonded and upper removable retainers.
- 13. Historical background Round and rectangular steel archwires were used with the standard edgewise appliance and during the early years with the preadjusled appliance. Round steel wires were used in sizes .014, .016, .018, and .020.
- 14. Rectangular steel wires were available in a number of sizes, with .018/025, .019/.025, and .0215/.025 being the most popular wires used with the .022 bracket slot. The authors prefer the .022 slot over the .018 slot, primarily because of the rigidity needed in the archwire during space closure with sliding mechanics.
- 15. The .014, .016, .018, and then .020 round wire sequence was used by the authors, followed by the .019/.025 rectangular steel wire . This wire allows for efficient sliding mechanics, unlike the larger .0215/.025 wire, which creates excess friction during space closure. Also, the .019/.025 rectangular wire shows less deflection than the more flexible .018/.025 wire. Round and rectangular steel wires were used during the early years w i th the preadjusted appliance.
- 16. One of the early attempts at producing archwires with greater flexibility involved twisting together strands of very small stainless steel wires . These were referred to as multistrand wires. Multistrand wires were produced to introduce greater flexibility. They are currently used as initial wires in cases w i th significant tooth malalignment.
- 17. These wires, in sizes .015 and .0175, were used as initial wires, prior to the use of the .014 round steel wire, in cases with significant tooth malalignment. Multistrand wires were produced to introduce greater flexibility. They are currently used as initial wires in cases w i th significant tooth malalignment. placement of initial .015 multistrand upper and lower aligning wires. Low-angle Class 11/1 malocclusion
- 18. Recommended sequencing The introduction of nickel- titanium wires provided a possible substitute for multistrand and steel round wires during the leveling and aligning stages of treatment. One nickel titanium wire could be used in place of approximately two sizes of stainless steel wires. The initial arch wire 0.016” NiTi was placed on both upper and lower arches .
- 19. However, given their higher cost, their significance was considered questionable by many clinicians. They were also mistakenly used during procedures that required the rigidity of a rectangular stainless steel wire, such as complete arch leveling, overbite control, space closure, and overjet reduction with inter- maxillary elastics.
- 20. The development of copper nickel-titanium wires, referred to as 'heat-activated' wires, provided wires with significantly greater flexibility. As a result, these wires could be used as a substitute for three of the traditional stainless steel wires in certain situations, which was a significant improvement.
- 21. Instead of replacing wires on a per visit basis during leveling and aligning, a coolant could be applied to the heat-activated nickel-titanium (HAN'T) wire in the areas where full bracket engagement had not been achieved, and the wire could be retied for complete engagement.
- 22. The normal warmth of the oral cavity produced significant activation of the wire-and very efficient tooth movement. Surprisingly, patients did not seem to complain of added discomfort, probably because of the light forces that were introduced.
- 23. The archwire sequence shown has been employed by the authors. It has significantly reduced chairside time and increased the efficiency of tooth movement, owing to the minimizing of permanent archwire deflection. In some cases, the authors can follow sequence B to complete a treatment with very efficient mechanics and few archwire changes. However, in many treatments it is necessary to use some wires from the more traditional sequence A,
- 24. Heat activated superelastic NiTi archwires (Nickel Titanium) Body-Heat-Activated Nickel Titanium (ca 37°) Extremely easy to ligate with lower ligating forces Transforms to a super elastic state inside the mouth Offering gentle continuous tooth-moving force
- 25. HE AT-ACTIVATED NICKEL- TITANIUM (HANT) OR STAINLESS STEEL? Because of their flexibilily, there are clinical situalions where heat-activated wires are not recommended, or where some stainless sleel wires should also be used. These clinical situations are described below: .Mid-sized brackets were placed wiih a .014 sectional steel upper wire, and a .016 lower round HANT wire lo commence tooth movements.
- 26. • Initial wires in cases with severe malalignirient of teeth. It is a service to the patient to place a multistrand wire as the first wire in such cases. The permanent deflection that occurs with these wires reduces the overall force levels and produces less discomfort during the initial 'experience with braces'. Also, some wire bending in addition to the normal arch form may be required, and is easily accomplished with multistrand wires. Upper archwire was .016 HANT. Lower archwire was .015 mullislrand, with offset bends for the buccally placed lower canines. The upper left canine bracket was lassoed with a module.
- 27. When using lacebacks for cuspid retraction in crowded extraction cases. The use of lacebacks minimizes the tipping of the cuspids into the extraction sites. However, with prolonged use of flexible heat-activated wires, some tipping can occur. To reduce this possibility, a .018 or .020 stainless steel wire should be used as early as possible when using lacebacks. Lacebacks are routinely used to assist control of canine crowns in premolar extraction cases, and in some nonextraction cases. :Canine retraction with Mulligan bypass arch
- 28. When using open coil spring in the anterior or posterior segments to create space for blocked-out teeth. Because of their flexibility, the use of open coil springs on heatactivated wires can cause significant distortions in arch form. Thus, open coil springs should not be used until .018 or .020 round steel wires are in place.
- 29. For complete arch leveling and overbite control. While heat-activated wires are excellent for individual tooth alignment, they are not effective for complete arch leveling and subsequent bite opening. The opening wires were .016 HANT to an ovoid arch form. The .016 HANT wires in the ovoid form were followed by .019/.025 rectangular IIANT wires, with the selected tapered arch form. The .019/.025 rectangular HANT wires were followed by .019/.025 rectangular stainless steel wires, with tapered arch form, and with soldered hooks.
- 30. Hence, the transition from even the rectangular heat- activated wires to the rectangular stainless sleel wire is sometimes impossible. A .020 round steel wire is often required before the rectangular stainless steel wire. The opening upper arch wire was .0175 multistrand, with a bend in the upper left central incisor region to reduce force. This was replaced 1 month later by a .016 HANTwire. During the first 2 months, a .016 HANTwire was used in the lower arch. The lower left first molar band was repositioned at the second adjustment visit. At 2 months, upper and lower rectangular HANT wires were placed,
- 31. For torque control. Rectangular heat- activated wires commence the process of torque control, but this difficult tooth movement is best completed by using a rectangular stainless steel wire. Standard metal brackets were used with .016 HANT wires to commence tooth alignment. Molar relationship was 4 mm Class II on the right and 2 mm Class II on the left. After 3 months of treatment, upper and lower rectangular HANT wires are in place. After 6 months of treatment, .steel .019/.025 rectangular wires were placed. The patient was asked to wear a right side Class II elastic (lOOgm) to commence correction of the right side occlusion and the midlines.
- 32. • For the treatment stages of space closure and overjet reduction. The major tooth movements that occur during these stages of treatment require the rigidity of a rectangular stainless sleel wire, as opposed to the flexibility of a heat-activated wire. Closing loop archwires were part of traditional edgewise treatment mechanics. They were individually made for each patient, and had a limited range of action before the omega loop came into contact with the molar tube. A lower type one active tieback. This shows minimal activation of the elastomeric, and slightly more stretching could be used.
- 33. In summary, the introduction of heat-activated wires has provided a beneficial substitute for a number of traditional stainless steel wires, and can dramatically improve the efficiency of orthodontic treatment. This substitution is, however, beneficial for initial tooth alignment procedures only.
- 34. It is important that the orthodontist separates the situations that require archwire flexibility from those in which archwire rigidity is needed. upper and lower rectangular HANT wires are in place,
- 35. CLINICAL PROCEDURES IN LEVELING AND ALIGNING - IMPROVING PATIENT COMFORT AND ACCEPTANCE At the start of treatment, every effort should be made to ensure that discomfort and inconvenience for patients are minimized. This will normally be their first experience of orthodontic treatment, and there are opportunities for the orthodontic team to make it a good experience. The initial lower archwire was .016 IIANT,
- 36. For many cases, the opening wires will be .016 HANT, but if there are major tooth malalignmenis, a multistrand .015 wire is preferable. Bends can be introduced into .015 multistrand wires, and these reduce the force applied to the teeth at the outset (Case JN, p. 120 and Case DO, p. 208). The opening wires should not be tied in tightly. Plastic sleeving should be used lo make lengthy stretches of archwire more comfortable. .016 HANT ARCH WIRE a .015 Multist rand arch wire
- 37. As leveling and alignment progresses, there will be a switch into rectangular HANT wires. This can typically follow directly from the .016 round HANT in many cases. The rectangular HANT wires are most useful and patient-friendly, and the switch is therefore seldom accompanied by discomfort. Any brackets which are wrongly positioned should be repositioned at the rectangular HANT wire stage, or earlier. Commencing upper and lower arch wires were .016 HANT. the molars are half a unit Class II bilaterally. The lower midline was 1 mm to the right. The initial .016 HANT wires were followed by rectangular .017/.025 HANT wires.
- 38. The patient should be given proper instruction on the use of wax and mild analgesics A good supply of wax should be provided, and it should be made clear that most discomfort will disappear after the first few days. In this very crowded Class I case, the first premolars had previously been extracted. The upper right lateral incisor was in crossbite, and there was 2 mm of displacement at terminal closure Initial alignment was commenced with a .015 multistrand upper archwire and a .016 HANT lower archwire. A band with an eyelet was placed on the upper right lateral incisor. This was loosely tied.
- 39. Archwire ends should be carefully turned in, and particular care is needed with multistrand wires. Multistrand wires may be carefully turned into a small circle distal to the molar tube to create a bendback. Bendbacks are possible when using .016 HANT wires, providing the terminal 3 mm is flamed and quenched in cold water before placement of the archwire.
- 40. Steel and HANT wireends should be flamed and quenched, to allow accurate turning in, and also ease of removal at the first adjus tment appointment. Molar hooks should be turned in . It is helpful to flame the end of all archwires, except steel rectangular and multistrand wires, and then quench them in cold water before placement. This allows accurate bendbacks. Steel and HANT wires should have the terminal 3 mm flamed and quenched before placement. The softened end of the archwire can easily be turned in to form a bendback. The softening facilitates removal of the archwire at the subsequent adjustment visit.
- 41. Two months later. The upper right lateral incisor bracket was not inverted because the root position of this tooth was good, and special torque control was not required. A multistrand wire was used t o continue tooth leveling and aligning in the upper, with a .014 round steel wire in the lower. After 4 months of treatment, it was possible to place upper and lower rectangular .019/.025 HANT wires. These very effective wires were used for several months, changing elastomeric modules and re- tying as necessary.
- 42. Much can be made of selecting colored modules at the first visit, for those patients who like the idea of colors. There is a colored module culture among some groups of youngsters. Self-ligaiing brackets may be an inevitable development in the future, but this will be a concern for many younger patients, who look forward to choosing colors at each visit. Here the case is seen at completion of tooth leveling and aligning. Steel rectangular wires, .019/025 in dimension and of ovoid arch form, are passively engaged in a correctly placed preadjusted .022 bracket system. The case after settling and appliance removal. Good tooth f i t was assisted by the large size of the upper lateral incisors.
- 43. It is correct to have a senior assistant make a follow-up phone call a few days after placement of the initial appliances .This will show that the practice is concerned to know that all is going well, and it is a chance to offer advice and encouragement. During this call, the patient or parent will often raise minor queries, which are important to them, although they 'didn't want to bother the doctor'.
- 44. Although there have been many technical advances in orthodontics, there is a continuing need to ensure good patient cooperation, in order to reach treatment goals. Care and consideration from the outset will provide a sound basis for the treatment relationship. This should lead on to better cooperation in many cases.