Page 220 - My FlipBook

110 PATHOLOGY OF THE HAED TISSUES OF THE TEETH.
decays on the mesial and distal surfaces. (4.) In many cases of
this class of caries the disposition is seen to spread quickly from
tooth to tooth, or to attack a number of teeth at the same time.
(5.) Yields to prophylactic treatment by the patient, when prop-
erly instructed, more readily than any other class of decay.
(6.) Protection from recurrence of decay after making fillings
is had only by extension of cavities nearly to the angles of the
teeth in the ordinary cases. (7.) Attacks fewer persons than
other classes of caries, but is often very destructive when a
beginning is once made. (8.) The most general rule is that gingi-
val third decays occur later in the life of the person than the
other classes, but attacks in early youth are not very infrequent.
Gingival third decays in the labial or buccal surfaces, or in
both together, have been much dreaded by dentists because of
persistent recurrence to the mesial and the distal of the margins
of fillings, or to the gingival when these have been made for
young people. This difficulty has arisen from a failure to study
the clinical characters and conditions of occurrence closely
enough to properly direct the treatment for its eradication and
cure. If the conditions which have given rise to the beginning
of the decay are not materially modified by prophylactic meas-
ures, or spontaneous cessation, the disposition to spread mesially
and distally is one of its most persistent characters. Nothing
less than the extension of cavities very nearly to the angles of
the teeth attacked, will be effective.
Figure 134 is a photograph of a cuspid with a gingival third
decay which began before the tooth fully reached its position
in the arch, or when the crown had yet more than one third of
its length covered by the free margin of the gum. Decay spread
rapidly across the surface mesially and distally from the begin-
ning point and became established in tbe dentin. In the process
of growth, more of the crown of the tooth was uncovered to the
gingival of this decay, the conditions which caused the first
beginning remaining or recurring. The result is another whit-
ened band of enamel, a new beginning of decay, to the gingival
of the first. This is what may be expected to occur when such
decays are treated by filling, when they occur in young persons,
unless the free margin of the gum is pushed well away and the
cavity margin extended so far to the gingival as to include the
new area of liability that must become exposed. In early youth
the sufficient persistence of attention to prophylactic measures
for the prevention of such extensions is not likely to be so well
kept up as to be a very safe protection.