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CAEIES AS A WHOLE. ITS CLINICAL FEATURES. 97
well to notice that the very heavy enamel cap shown in Figure
111 has been no bar to the invasion of caries, but that, on the
other hand, has been rather a menace in that the failure to break
away early has kept the cavity hidden and maintained condi-
tions favorable to the rapid advance of caries of the dentin.
Occlusal and Proximal Surface Decays in Bicuspids.
ILLUSTRATIONS: FIGURES 112-118.
(1.) In pit and fissure decays,
Principal clinical features :
the danger of undermining the mesial and distal marginal ridges
by extension of caries along the dento-enamel junction, involving
also the enamel of the proximal surfaces. (2.) In proximal sur-
face cavities the clinical characters are the same as in proximal
surfaces of the molars.
The positions in which pit decays occur in the bicuspids
are well shown in Figure 112. The occurrence of these, inde-
pendent of caries of the proximal surfaces, is not nearly as
frequent as in the molars, yet a considerable number are met
with. If these are treated before considerable progress has been
but, as decay progresses,
made, they are very simple cases ; it
quickly undermines the marginal ridge and is liable to weaken
the enamel of the proximal surface to such an extent that this
must be cut away to make a safe treatment by filling. In the
illustration, Figure 112, which presents decays of the enamel in
each pit and in its distal surface, it will be noted that, as these
progress in the dentin, they will quickly undermine the enamel
of both the marginal ridge and the proximal surface, and the
enamel of these parts will be weakened by backward decay.
This undermining often makes a proximo-occlusal filling neces-
sary even though there may have been no proximal decay.
Many of the proximal decays in bicuspids begin near the
marginal ridges, as in the molars. This is illustrated in the
beginning of decay of the enamel in the distal surface in Figure
112. These undermine the marginal ridges and disclose the cavi-
ties early in their progress. In Figure 113 the beginning of the
decay has been farther toward the gingival, and spreading on
the surface of the enamel toward the occlusal has occurred.
This is seen also in Figure 114 in the decay on the right side of
the figure and is much more plainly seen in the photomicrograph
of the same decayed area in Figure 116. The excellent photo-
graph of the split bicuspid in Figure 117, shows the most usual
points of beginning and direction of progress of these decays to