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Anchorage control during tooth leveling and aligning

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ANCHORAGE CONTROL

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Anchorage control during tooth leveling and aligning

  1. 1. Presenting by: Dr. Rahul Tiwari
  2. 2. Successful tooth alignment depends on recognizing that unwanted tooth movements can occur early in treatment, mainly owing to the tip built in to the preadjusted brackets. During leveling and aligning, therefore, all tooth movements should be carried out with the final treatment goal in mind, and anchorage control measures should be used to restrict unwanted tooth movements. the term 'anchorage control during tooth leveling and aligning' will have the following meaning:
  3. 3. EFFECT OF ANCHORAGE LOSS “The maneuvers used to restrict undesirable changes in teeth position during the treatment, and leveling and aligning are achieved without key features of the malocclusion becoming worse”
  4. 4.  There are two main aspects to anchorage control:  1. Reduction of anchorage needs during leveling and aligning. 'There is a need to minimize the factors which threaten anchorage and which produce unwanted tooth movements. This reduces the demands on anchorage.  2. Anchorage support during tooth leveling and aligning. Where necessary, there is a need to use anchorage support, such as palatal or lingual bars, to help to control certain teeth, or groups of teeth. Anchorage control needs will differ from case to case. it is important to identify the needs for each individual case.
  5. 5.  At the diagnosis and treatment planning stage for each case, a goal will be set for incisor position in the facial complex at the end of treatment. The anchorage control needs of a case, early in treatment, can be decided by comparing the starting position of upper and lower incisors with PIP ('planned incisor position‘) at the end of treatment. During tooth leveling and aligning, the anchorage control should be managed to ensure that the upper and lower incisors either show no change, or they should move favorably relative to PIP. (PIP-The intended end-of-treatment position for upper incisors. )
  6. 6.  At the start of treatment, the upper incisors are normally in front of PIP, and full A/P anchorage control will be required to restrict mesial movement and an increase in overjet. Lower incisors will normally be on or behind PIP. Anchorage will need to be managed to prevent undue proclination during alignment.
  7. 7.  the upper incisors are behind PIP al the start of treatment, although in other Class III cases they may be on PIP or even in front of it. Lacebacks and bendbacks will therefore be contraindicaied in the upper arch in many Class III cases, to allow upper incisors to procline and show favorable torque changes towards PIP and to allow upper arch development. Lower incisors will typically be in front of PIP in a Class 111 case. The lower arch will therefore normally require full anchorage control .
  8. 8.  Normally full anchorage control will be required in both arches for this type of case, because upper and lower incisors will be in front of PIP at the start of treatment.
  9. 9. LACEBACKS FOR A/P CANINE CONTROL: Lacebacks are .010 or .009 ligature wires which extend from the most dislally banded molar to the canine bracket. They restrict crowns from lipping during leveling and aligning. They are placed before the archwire. At monthly adjustment visits, the lacebacks are normally loose, and require 1-2 mm of lightening.
  10. 10. The archwire is bent back immediately behind the tube on the most distally banded molar, this serves to minimize forward tipping of incisors. The ends of the NITI wires and round steel wires need to be flamed and quenched in cold water before placement, to allow accurate bendbacks.
  11. 11.  Lingual arches should also be considered for maximum anchorage premolar extraction cases. This will include many bimaxillary proclination cases and also cases with severe lower anterior crowding. In both these types of problem, it is necessary to consider using a lingual arch throughout the early stages of leveling and aligning. This will restrict the mesial movement of lower molars, and in the bimaxillary proclination cases, it will ensure that most of the premolar extraction space is available at the end of leveling and aligning.
  12. 12.  This is normally placed when the upper molars have been properly rotated and are situated in a Class I relationship to the lower molars. The palatal bar can be constructed of heavy (19 gauge)round wire extending from molar to molar with a loop placed in the middle of the palate and the wire about 2 mm from the roof of the palate. It is soldered to the molar bands.
  13. 13. Vertical control of the incisors : Anterior control is needed to restrict the tendency to temporary increases in overbite, especially in deep-bite cases. The effect of bracket tip is more extreme in the upper arch, and care is needed if the canines are distally tipped in the starting malocclusion. If the wire is fully engaged into the incisors, it will tend to cause extrusion of these teeth, This effect can be avoided either by not bracketing the incisors at the start of treatment, or by not tying the archwire into the incisor bracket slots, until the canine roots have been uprighted and moved distally, under the control of the lacebacks.
  14. 14.  It is important to avoid early arch wire engagement of high labial canines so that unwanted vertical movement of lateral incisors and premolars does not occur. High labial canines may be loosely tied to the NITI wire in the early stages of treatment
  15. 15. When treating high-angle cases, the following methods of vertical molar control should be considered: 1.Upper second molars are not initially banded or bracketed, to minimize extrusion of these teeth. 2. If the upper first molars require expansion, an attempt is made to achieve bodily movement rather than tipping, to avoid extrusion of the palatal cusps. 3. Palatal bars should be used. 4. An upper or lower posterior biteplate in the molar region is helpful to minimize extrusion of molars. 5. When headgears are used in high-angle cases, either a combination pull or a high-pull headgear is used. The cervical pull headgear is avoided.
  16. 16. Attention needs to be paid to inter-canine width in all treatments, and molar crossbites are important in certain treatments. 1. Upper and lower inter-canine width should be kept as close as possible to starting dimensions for stability. 2. Molar crossbites should be corrected by bodily movement. IF THE BONE IS TOO NARROW early rapid expansion should be considered as a separate procedure prior to leveling and aligning. IF ADEQUATE MAXILLARY BONE EXISTS, a fixed quadhelix expander can be effectively used. MINIMAL MOLAR CROSSBITES can be corrected in final stage of leveling and aligning using rectangular steel wires which are slightly expanded from the normal form and which carry buccal root torque.
  17. 17.  Cases with unerupted teeth, or teeth significantly out of the arch form.Such teeth can be left unbracketed until adequate space is provided for their movement and positioning.  In High-angle deep-bite cases in which the upper incisors interfere with bracket placement on the lower incisors the upper incisors can be bracketed and the lower incisors left unbracketed at the start of treatment. After leveling and aligning have occurred and the upper incisors have been slightly advanced, the lower incisors can then be bracketed.  In low-angle deep-bite cases, a biteplate can be placed.
  18. 18. At the end we must understand Tooth leveling and aligning is normally the first orthodontic objective during the initial stage of treatment. The tooth movements needed to achieve passive engagement of a steel rectangular wire of .019/. 025 dimension and of suitable arch form, into a correctly placed preadjusted .022 bracket system. Successful tooth alignment depends on recognizing that unwanted tooth movements can occur early in treatment, mainly owing to the tip built in to the preadjusted brackets. These unwanted tooth movements need to be controlled, or the underlying malocclusion will worsen during tooth alignment. This will increase the time and effort needed to complete the case, later in treatment.

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