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Chapter 8
Class II malocclusions
Definition
A class II division 1 malocclusion may be
defined as one in which the lower incisor edges
occlude palatal to the cingulum plateau of the
upper incisors. The upper incisors are either of
average axial inclination or proclined. The
overjet is increased and the overbite is usually
increased (although it may be incomplete).
The buccal segment relationship reflects the
severity of the malocclusion but may be influ-
enced by crowding or spacing in either of the
arches.
Figure 8.1 (a) A class I skeletal pattern with upper
incisors proclined at the commencement of
Case selection treatment, may allow satisfactory overjet reduction
with a removable appliance, (b) If the overjet is
Dental base relationship reduced by means of tipping in a patient with a class
II skeletal pattern with upright incisors, the
Cases that are best suited to removable appli- appearance at the end of treatment will be
ance treatment will usually be those with a rela- unsatisfactory and a traumatic overbite may develop.
tively mild class II dental base relationship.
Occasionally the dental base relationship may
be class I with the overjet being due entirely to
proclination of the upper incisors. Such cases The Frankfort mandibular planes
are also often well suited to treatment with angle
removable appliances unless the incisors are
clearly over-erupted. This should be within normal limits. A very
Where the overjet is due chiefly to a class II high angle is often associated with an anterior
skeletal pattern (Figure 8.1) removable appli- open bite and gross lip incompetence so such
ances are inappropriate. In a growing patient, cases should be avoided. Similarly, a very low
treatment with a fixed appliance or functional angle is often associated with excessively
appliance may be better. In an adult, surgical increased overbite together with unfavourable
correction may sometimes be the only satisfac- soft tissues - features that will not respond well
tory solution. to the use of removable appliances.
