Page 274 - My FlipBook

270 5 OPERATIVE DENTISTRY
Coacliing Into Place of the various teeth in their proper order the
position of this line A A, which bisects the jaw just at the mesial
of the first permanent molar, is not allowed to move anteriorly, there
is left just the proper space which the permanent teeth will occupy
when they replace the temporary set, provided the jaw development
is not interfered with, but if by the premature extraction of the sec-
ond temporary molar, this fir^st permanent molar is allowed to tip
forward, thereby moving line A-A anteriorly, we have encroached
just that much upon the space required by the permanent teeth.
The Irregularity Resulting From Sucli a Mistake will probably be
shown in the cuspid as this is the last of the temporary set to be

t-2-!^'-4-—

Fig. 142.—Represents the comiilete set of deciduous teeth with the first permanent molar
added. Lower row of figures represents the order the deciduou steeth generally erutp.
Upper row of figures represents the order of the replacement by the permanent set.

replaced. (See Fig. 143.) Again, if the first permanent molar is
extracted before the temporary teeth have been replaced, nature
seems to realize that further development of the jaw on this side is
not necessary, and the jaw—be it lower or upper—will generally lack
in length to correspond with its antagonist, the width of the tooth
extracted. This may not be noticed in the exhibition of faulty oc-
clusion or irregularities but a careful study of the features will
show lack of artistic contour.
Let us here consider the ortZer in wliicli tlie temporary teeth are
replaced by the permanent set. By reference to Pig. 142, you will
see that the order differs somewhat.