Page 383 - My FlipBook

THE PORCELAIN INLAY. 381

of the metal during the formation of the matrix, and it gives the entire
labial form of the tooth, so that an accurate idea may be obtained of
the desired contour of the filling.
In corners of centrals, as in Fig. 360, the platinum should be folded
well over the labial and palatal surfaces of the tooth ; then it should
Fig. 363.

A, Outline of approximal cavity ; B, ilap of platinum that had been cut away and turned back to
facilitate the removal of the matrix.
also be bent over the cutting edge, forming a sort of cap, beneath which
shows the entire contour of the tooth, and by means of which entire
Fig. 364.

A, Outline of cavity as formed in platinum matrix ; B, clamp holding platinum immovable while
the matrix is being burnished into place.
immobility may be obtained while the cavity margins are being defined
and the matrix formed.
The same principle applies in forming a half cap from a large piece
of platinum for the approximal cavities of bicusjHd.'S and molars. The
platinum should extend, as in Figs. 361 and 362, from grinding edge to
cervical margin, and along the sides of the adjacent tooth. This can be