contour can be
produced, but the contour will not have the hardness or strength of
gold, so in many cases it would not be practicable to make extensive
contours with tin, owing to its physical characteristics.

No. 10 will answer for all cases, and it is not as liable to be torn or
cut by the plugger as a lower number, but one need not be restricted to
it, as good fillings can be made with Nos. 4, 6, or 8. More teeth can be
saved with tin than with any other metal or metals, and the average
dentist will do better with tin than with gold. It is invaluable when
the patient is limited for time or means, and also for filling the first
permanent molars, where we so often find poor calcification of
tooth-structure. In cases of orthodontia, where caries has attacked a
large number of teeth, it is well to fill with tin, and await further
developments as to irregularity and caries.

If cavities are of a good general retaining form, that will be
sufficient to hold the filling in place; but if not, then cut slight
opposing angles, grooves, or pits. Cavities are generally prepared the
same as for gold, except where there is a great deal of force brought
upon the filling; then the grooves or pits may be a little larger;
still, many cavities can be well filled with less excavating than
required for gold, and proximal cavities in bicuspids and molars, where
there is sufficient space, can be filled without removing the occlusal
surface, and here especially should the cavities be cut square into the
teeth, so as not to leave a feather edge of tin when the filling is
finished, as that would invite further caries and prove an obstruction
to cleansing the filling with floss.

In proximal cavities involving the occlusal surface, cut the cervical
portion down to a strong square base, with a slight pit, undercut, or
angle, at the buccal and lingual corners; where there is sufficient
material, a slight groove across the base, far enough from the margin so
that it will not be broken out, can be made in place of the pit,
undercut, or angle; then cut a groove in the buccal and lingual side
(one or both, according to the amount of material there is to work
upon), extending from the base to the occlusal surface; in most of these
cases the occlusal grooves or pits would have to be excavated on account
of caries; thus there would be additional opportunity for anchorage. In
place of the grooves the cavity may be of the dovetail form. In nearly
all