These appliances are attached to the crowns of teeth and allow correction of rotations, bodily movements of teeth and alignment of ectopic teeth. They have increased in sophistication enormously over the past 10-15 years and together with advancements in arch wire technology are capable of producing a very high level of treatment result. Simultaneous multiple
tooth movements can be achieved, invariably creating a better treatment outcome than can be achieved with removable appliances. Although there are a variety of fixed appliances available they all operate in a similar way producing a fixed point of attachment to control the position of the teeth. Brackets are attached to the teeth and wires (arch wires) are placed in the bracket slots to move the teeth. The closer the fit of rectangular arch wires in a rectangular slot on the bracket the greater the control of the teeth (Fig 11). As treatment progresses, thicker rectangular wires are used to fully control the teeth in three dimensions. Fixed appliances are the appliances of choice for most orthodontic treat ment because the results are far more predictable and of a higher standard achieved than by other means. However, they are relatively complex appliances to use and further training in these devices is essential. An example of a case treated with fixed appliances is shown in Figure 12a-j. The anchorage requirements for the bodily movement of teeth are considerably greater than for tipping movements (Fig. 13).
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