CHAPTER 19 Stage III checks

The inspection interval in Stage III is approximately 2 months. As the entire torquing and tip correcting process is essentially built-in, and self-limits automatically, progress and maintenance checks are normally all that is required; it is unusual for an archwire to require removal, except for running repairs or possibly upgrading a deep tunnel auxiliary.

At each check visit, the following should be observed:

• Progress of tip and torque. Both proceed concurrently. A Tip-Edge bracket can be seen to have self-limited when its upper and lower surfaces lie parallel to the archwire (Fig. 19.1). Always assess the root angulations as well as the brackets. Lack of progress is almost invariably due to inadequate mesio-distal space in the arch. It may also be due to incorrect bracket angulation, causing the bracket to self-limit before the desired root angle is achieved. An advantage of Plus is that all bracketed teeth are maintained in torque and tip control until the last one is finished. There is therefore no temptation to remove springs from the teeth that look finished, while waiting for the rest. This used to allow some individual root relapse, before Plus.

• Available space in the arch. Except towards the end of root uprighting, it is essential to ensure that up to 1 mm of space exists somewhere in each arch (Fig. 19.2). As explained previously, premolar and canine crowns require additional arch length as they upright, and failure to provide this will stifle the action of the uprighting, whether with Plus or Side-Winders. The procedure for introducing extra wire from the back is described presently. Tight or overlapping contacts are sure signs that a limited amount of extra space is needed to make further progress (Fig. 19.3).

• Unwanted space. More than 1 mm of space is wrong, and should be gathered up by running an elastomeric E-link from crimpable hook to molar hook. At the following visit, the relevant distal arch cinchback will need to be tightened. Excess space is caused by distal cinchbacks that are too slack.

• Condition of the uprighting auxiliaries. Distortion of nickel–titanium auxiliaries is seldom seen, since these are shielded by the main archwire. With Rx-1, Side-Winders are seldom lost, as they are retained by the elastic ligatures. However, the loops may become distorted labially, particularly if fiddled with by the patient, and should be bent back to correct shape or replaced. A labially displaced loop can predispose to a small mesio-palatal rotation.

• Activation of Side-Winders (Rx-1). These normally hold their activation without adjustment. However, final torque delivery and apical definition on incisors may require additional activation. ‘Hyperactivation’ for this purpose will be described shortly.

• Interarch relationship. Is the patient regulating the elastic wear adequately to maintain incisor contact, when in the retruded centric position? The possibility of adverse growth should be considered, but slippage of the interarch relationship almost always identifies a forgetful patient.

• The vertical relationship. Is overbite reduction and buccal segment interdigitation being preserved? Relapse of overbite in Stage III will most often be the result of inadequate archwire bite sweeps. In addition, vigorous activation of canine Side-Winders can cause overbite increase and infraocclusion of first molars, by reciprocal tipping of the archwire. This should obviously be avoided, but may require ‘Class II check’ elastics to rectify (Fig. 19.4).

• Molar widths. These will be well controlled by the rectangular archwires. However, in cases where crossbite correction is continuing into Stage III, an archwire may possibly need removal to check width and further adjust, or cancel, active molar torque.

• Second molars. Towards the end of Stage III, the position and function of second molars will need assessment, with a view to alignment if required. This is outlined in the following chapter.

• Profile considerations. This may require confirmation with cephalometric assessment. Is anchorage reinforcement required? A less than ideal profile may be the result of adverse growth or an inappropriate treatment plan. Too procumbent a profile may also be provoked by excessive activation of Side-Winders, particularly on canines. This is not likely with Plus, using only a .014 inch tunnel wire.