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Fig. 258. Fio. 259.

Figs. 258, 259, 260. Series illustrating recurrence of decay.
Fig. 258. In this case microorganisms have grown upon the filling and extended beyond its
borders, causing recurrence of decay at the gin'jival-labial and gingival-lingual margins of the filling.
These beginnings of decay ought to liave been prevented by extensions in the cavity preparation.
Fig. 259. Iri" this case there is recurrence of decay from leakage at the margin of the filling
from a fault, cither in the cavity preparation or the placing of the filling. Both of these causes of
recurrence of decay are frequent. Which may have caused the difficulty can not always be told after
more considerable decay has occurred.
Fig. 200. A photograph of a bicuspid in which there has been recurrence of decay after" filling
a cavity. When so much decay, as is shown in this, has occurred, the special marks showing the
cause of the recurrence have been obliterated. Some jud^nent may be had from the form of the
filling and the conditions presented, but this is not \ery reliable. For exactness of judgment as to
cause, these cases must be examined very early.
27a