Page 427 - My FlipBook

423

come before it, whilst the other central incisor keeps its
proper place, standing before the under teeth.
The second is, when both the incisores are turned in, and
go behind the under teeth ; but the lateral incisores stand out
before the under teeth.
The third variety is, when the central incisores are placed
properly, but the lateral incisores stand very much in ; and
when the mouth is shut, the under teeth project before them
and keep them backward.
The fourth is, when all the incisores of the upper jaw are
turned in, and those of the under jaw shut before them.
This is sometimes occasioned by too great a length of the
under jaw, in consequence of which it projects considerably
forwarder than the upper jaw. But the majority of such
cases originate entirely from neglect, and may be completely
remedied by early assistance.
The time to affect any material alteration in the position
of the teeth, is before thirteen or fourteen years of age, and
as much earlier as possible ; for after that time the sockets
of the teeth acquire a degree of strength, and the teeth are
so fixed that they cannot be moved without much difficulty.
If the irregularity be left to a much later period, it becomes
a great deal more difficult to produce any alteration, and
frequently all attempts are fruitless.
To remove the kind of irregularity above mentioned, two
objects must be accomplished ; one, to apply a force which
shall act constantly upon the irregular tooth, and bring it
forward ; the other to remove that obstruction which the un-
der teeth, by coming before the upper, always occasion.
The first of these objects may be attained by the applica-
tion of an instrument adapted to the arch of the mouth,
which, being attached to some strong teeth on each side, will
furnish a fixed point in front, to which a ligature previously