Oral Mucosa And Underlying Bone

Contact between the appliance and the labial or lingual mucosa can increase anchorage considerably for either fixed or removable appliances. Contact between an orthodontic appliance and the vault of the palate provides resistance to mesial movement of the posterior teeth. The anchorage provided by this means is considerably greater if there is a high vaulted palate as shown in Figure 5a, which will produce a greater buttressing effect. A shallow vaulted palate (Fig. 5b) will provide much less anchorage control because the appliance will simply tend to slide down the inclined plane of the palate.

The mucosa and underlying bone can also be used when fixed appliances are used, for example a Nance palatal arch (Fig. 5c). This is an acrylic button that lies on the most vertical part of the palate behind the upper incisors and is added to a trans-palatal arch. These buttons are again of more limited use if the palatal vault is shallow.

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