Stage III archwires

CHAPTER 15 Stage III archwires

Choice of archwires 135
Arch width 135
Identifying the ‘landmarks’ 135
Archform 135
Traction hooks 136
Preparation of arch ends 137

At the setting up visit for Stage III, the patient may be only halfway through treatment, in terms of time taken. The orthodontist will be thinking up to 9 months ahead, since he will effectively be programming the final result. Care and attention at this point will be amply rewarded; once correctly set up, the third stage will progress and self-limit automatically, with a minimum of supervision and adjustment.

The various steps will be described in turn as a clinical sequence. In this and the following chapter, we begin with tailoring the archwires to shape and size, subsequently adjusting the passive torque setting to which the brackets will be conformed. There is, incidentally, no difference between Rx-1 and Plus in respect of the main archwires. The preparation is exactly the same for both.

Choice of archwires

Only one size of rectangular wire is ever used in Stage III. This is .0215 × .028 inch ‘Shiny Bright’ stainless (the lateral dimension is actually .027 inch, to facilitate insertion in the molar tubes). However, such archwires come in two formats: plain or pretorqued. The choice between these will be described later and is summarized at the end of the next chapter. Basically, pretorqued will be indicated when bite sweeps are used, cancelling out the labial crown torque that would otherwise result from the sweeps, which would cause incisor proclination. These arches are also used for different reasons in Class III cases, where an atypical torque prescription may be appropriate to the anterior segments to maintain a positive overjet.

Arch width

The Standard (straight leg) arch shape should be used as the starting point. This will almost invariably be too narrow for the patient. However, it is easier to expan/>

Related posts:

  1. Differential tooth movement
  2. Precision finishing
  3. Stage II checks
  4. The non-compliant patient
  5. Stage I
  6. Setting up Stage I

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Dec 31, 2014 | Posted by in Orthodontics | Comments Off on Stage III archwires

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