Simple occlusion basics.

1. Milan Chande

2.  Definitions
 Classifications
 Guidance
 Basic Mandibular movements

3.  Overjet – The horizontal distance between the
labial surface of the lower incisor and the upper
incisal edge
 Overbite -The vertical distance between the lower
incisal edge and the upper incisal edge - the
amount that the upper incisor overlaps the lower
incisor.
 Openbite - The failure of some opposing teeth to
occlude when others are in maximum
intercuspation.

4.  Angle’s Incisal Classification
 Angle’s Molar Classification

5.  The incisal edge of the lower incisor occludes
with, or is directly below, the cingulum plateau of
the upper incisors

6.  The incisal edge of the lower incisors lies behind
the cingulum plateau of the upper incisors. The
upper incisors are of average inclination or
proclined, with an increase overjet.

7.  The incisal edge of the lower incisors lies behind
the cingulum plateau of the upper incisors. The
upper incisors are retroclined, with minimal overjet
although overjet maybe increased.

8.  The incisal edge of the lower incisors lies in front
of the cingulum plateau of the upper incisors; the
overjet may be reduced or reversed.

9.  The mesio-buccal cusp of the upper first
permanent molar occludes with the mesio-buccal
groove of the lower first permanent molar.

10.  The mesio-buccal cusp of the upper first
permanent molar occludes anterior to the mesio-
buccal groove of the lower first permanent molar.

11.  The mesio-buccal cusp of the upper first
permanent molar occludes posterior to the mesio-
buccal groove of the lower first permanent molar.

12.  Static occlusion - Static occlusion is the study
of contacts between the teeth when the jaw is not
moving. The contacts are points (seen as dots
when articulating paper is used).

13.  Freedom In Centric - occlusion occurs when
the mandible is able to move anteriorly for a short
distance in the same horizontal and sagittal plane
while maintaining tooth contact.

14.  Dynamic occlusion - Dynamic occlusion is the
study of the contacts that teeth make when the
mandible is moving – contacts when the jaw
moves sideways, forwards, backwards, or at an
angle. The contacts are not points, they are lines.

15.  If the mandible moves to the right, the right is the
working side (and left is non-working).
 If the mandible moves to the left, the left is the
working side (and right is non-working).

16. If you slide you teeth to your right, and
only your right canines contact during this
lateral excursion, then you have canine
guidance.

17. When you slide laterally a number of teeth on
your working side are in contact at the same
time, all sharing the load, this is called group
function. This might happen if your canines have
worn down over time, or are crooked.

18. When you move your jaw laterally, if the first contact
is just on a single tooth near the back (on the
working side), this is called a working side
interference. For example, perhaps there is an upper
molar which has tilted into an adjacent extraction
space.

19. A non-working side interference is when any tooth on
the opposite side makes the first contact.

20.  Centric Relation - CR
 Retruded Contact Position - RCP
 Intercuspal Position - ICP

21.  Centric Relation can be described as the position
of the mandible to the maxilla, with the intra-
articular disc in place, when the head of the
condyle is against the most superior part of the
distal facing incline of the glenoid fossa.
 The teeth may be touching in CR, or they may be
apart in CR. It is important to understand the jaw
has an arc of positions in which the condyles are
in Centric Relation. Centric Relation is a dynamic
state.

22.  The static position of first tooth contact on CR.
 RCP occurs at a specific occlusal vertical
dimension (OVD).

23.  The static position of maximum intercuspation.

26.  http://www.nature.com/bdj/journal/v191/n5/full/4801151
 Introduction to Orthodontics – Laura Mitchell
 http://www.nature.com/bdj/journal/v196/n7/fig_tab/4811
 Orthodontic Clinical Skills