15

Concavities in the denture base should be avoided whenever possible. Because of the form of the tooth to be clasped, a concavity in the area of the clasp is usually unavoidable (Fig. 15).

16

Underneath the clasp, however, concavities are unnecessary. In fact, their presence makes an ideally polished surface unattainable (Fig. 16).

17

This is especially true in cases where various types of materials are present at the tooth- denture interface; for example, acrylic, artificial tooth and metal (Fig. 17).

18

When the dental denture surface at the tooth-denture interface consists totally of metal, the saddle is best kept plaque-free with the aid of a faultless finish.

19

The base of the framework under the first denture tooth is designed as if it were a veneered pontic. Thereafter begins the usual saddle retentive element with its lingual bar connection (Fig. 18,19,20).

20

21

With tooth-supported saddles the entire saddle can be designed as a veneered bridge, especially in the upper arch.

22

Technically there is no stress disadvantage, since a precision tooth- supported saddle transfers only very little, if any, force to the underlying ridge (Fig. 21, 22).