Page 193 - My FlipBook

EXCLUSION OF MOISTURE 189

No mechanic ever thinks of trying to accomplish his best work
with the object submerged in moistui*e. The raj'S of light are
broken, objects are distorted and distances misjudged. The dentist
who does not effectually exclude the moisture from the immediate
neighborhood of a cavity will catch only a glimpse now and then
of portions of a cavity, this being particularly true of the gingival
wall, except in cases of gum recession.
The Extent of Decalcification of both dentine and enamel is di-
agnosed only when dryness is obtained to bring out the colors and
shades of each incident to these conditions. It is impossible to
make proper cavity extension until the cavity has been made dry
and so maintained for some time, as this is often the only means of
detecting superficial caries. Semi-decalcified tooth substance, when
moist, materially resembles the healthy structures and must be
dried to detect its injured condition.
The Pain of Cavity Excavation is materially decreased by the
extraction of the moisture from the dentine. The protoplasm
within the dental tubules is the means of transmitting the sensa-
tion of pain to the vital pulp. Water is a large constituent of pro-
toplasm and the extraction of this moisture through extreme and
continued dryness removes the media of sensitiveness. It is there-
fore but humane that the cutting of dentine be done with the mois-
ture excluded.
When Using Caustic and Concentrated Drugs the moisture
should be excluded, that the drug may not be carried away to the
injury of adjacent tissues and that the drugs may not be diluted
to detract from their efficiency in accomplishing that for which they
were used. Drugs placed in the cavities of teeth with moist mar-
gins even when placed under fillings of rubber, cement or amalgam,
will follow the moisture of these margins to join that without and
great damage to the surrounding tissues often results from no other
cause than a lack of the exclusion of moisture during the operation.
As a Time Saver the exclusion of moisture should not be over-
looked. With a dry cavity the continued uninterrupted view per-
mits of more continuous Avork by the dentist. He does not have to
wait for the patient to expectorate, make a few remarks and leisurely
resume his position in the chair, not always in the position desired
for operating. The operator will also be saved much time in dry-
ing the cavity after each flooding. All this takes valuable time, much
more than is required to adjust a dam.
The Rubber Dam is the most dependable means of securing a dry