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266 PATHOLOGY OF THE HARD TISSUES OF THE TEETH.
ever, when the first molars are lost, the damage is practically
irreparable. The occlusion of the remaining teeth is necessarily
deranged by the falling backward of the bicuspids and the move-
ment forward of the remaining molars. "When they are removed
as early as the ninth or tenth year, the space of the first molars
will be closed by these movements of the teeth and the occlusion
will be better than if lost later, but the normal prominence of
the front teeth and lips will be wanting, which is a permanent
injury to the expression of the face. The occlusion will be imper-
fect at best; in many cases it will be very defective, for often
the molar teeth assume such an inclination to the mesial that
the occlusal surfaces do not meet fairly together but strike only
upon the distal cusps, rendering mastication imperfect. If one
only is lost, the incisor teeth are generally crowded to that side
in the filling of the lost space, moving away from the median
line and seriously deranging the expression of the mouth. When
two are lost on the same side, the teeth occupying the front
of the mouth generally will be thrown to that side. Both theo-
retically and practically, it seems best, when one must be lost,
to extract all four to obtain greater regularity of the features.
Few operators, however, have the moral courage to sacrifice two
or three good teeth for a possible gain in occlusion and expres-
sion in the somewhat remote future.
The time at which first molars are lost is important. They
are the first of the permanent teeth. They are placed to the
distal of the deciduous set. When they have taken their places
and the upper and lower teeth have occluded with each other,
the shedding of the deciduous teeth begins. The first molars
hold the jaws in position and preserve the symmetry of the face
while the deciduous teeth are being shed and replaced by the
permanent ones. The second molars are not erupted until the
twelfth year, and by this time the shedding and replacement
of the teeth have been nearly completed; therefore, in case
these teeth are lost before the deciduous teeth are replaced by
the permanent ones, the face is apt to be shortened because of
the lack of support for the lower jaw, the normal movement
of the front of the mouth forward is diminished and derange-
ments in the occlusion occur. All of these considerations demand
that these teeth be protected; yet children are brought to us
continually with their teeth decayed beyond all hope of repair,
and they must be removed as the lesser of two evils. In many
cases in which permanent repair is impossible, the teeth may
receive such treatment as to render them comfortable and use-