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are not detected and referred during this period of development. Further,
from the time when deciduous molars have lost a considerable portion
of their roots, due to normal absorption, to the time when the premolars
have well erupted, treatment by general expansion, so often needed, is
very limited.
The routine school dental inspection of about 100 children (with
parents) per session, often carried out in poor light, is, I feel, too great
a number to permit adequate examination for dental caries, gingival
conditions and malocclusion together with its predisposing causes. It
may be argued that about 60 per cent, of those inspected will be seen
again by the dental officer at treatment visits to the clinic, but this
still leaves about 40 per cent, who will not be seen again for another
year.
Malocclusion: I would venture to state that all types of malocclusion
are produced by one or more of the following causes:—
1. Dental caries.
2. Untimely loss of permanent deciduous teeth.
3. Habits.
4. Obstructions.
5. Imperfect nutrition.
6. Genetic factors.
7. Endocrine disfunction or over function.
1. Dental caries: Through loss of tooth substance, deciduous
teeth become more closely packed and cause loss of space for their
permanent successors.
2. Untimely loss of deciduous and permanent teeth: Premature
loss of deciduous teeth causes severe loss of space, especially
when it can be least afforded, for the permanent successors. Overretention
of deciduous teeth may result in deflection of the permanent
successors and/or an upset in the articulation. Premature loss of
permanent teeth may slightly or seriously affect the articulation, depending
upon which teeth are lost.
3. Habits: Habits which can result in malocclusion are too
numerous to detail in this report, but I have met three interesting ones
which are worthy of note.
(a) Tongue thrusting. This by no means unusual habit, though
not always caused by thumb sucking, often follows that habit. The
thumb or finger which is sucked may result in an anterior open bite,
into which space the tongue finds ready access. It is often said, and
it is quite true, that the malposition of the anterior teeth, due to thumb
sucking, is easy to rectify, but this is not so if the tongue has found
the gap. In such cases we have a child who has developed an abnormal
swallow, as far as the tongue is concerned, and probably a decided lisp.
(b) Occupational habit. Recently a girl aged 12 presented a
slewed mandible, over to the right side, and no cause could at first be
found. Later the mother thought of the violin which the child had
played for the last four years. Fortunately quite good articulation can
be obtained in the normal central position.
(c) Position of comfort. At the Potters Bar Clinic, a child aged
5 presented a prenormal occlusion. On enquiry it was found that when
aged about 2½ years a plaster collar was fitted on the child's neck to