Occlusion

2. OCCLUSION
> may mean the
contact relationship
of the teeth in
function or
parafunction.

3.  > It refers not only to contact of the
arches at an occlusal interface but
also to all those factors concerned
with the development & stability of
the masticatory system & with the
use of the teeth in oral motor
behavior.

4. SUGGESTED TOPICS FOR THE
STUDY OF OCCLUSION:
1. Development of
Occlusion
Primary Dentition
– development of
occlusion begins with the
occlusion of the deciduous
teeth.

5. Permanent Dentition
– there are significant
differences in the
eruption sequences
between the maxillary
arch & the mandibular
arch that do not appear
in the eruption of the
primary dentition.

6. Sequence of eruption in the maxillary
arch:
6 – 1 – 2 – 4 – 3 – 5 – 7 – 8
Sequence of eruption in the mandibular
arch:
6 – 1 – 2 – 3 – 4 – 5 – 7 – 8

7. 2. Dental Arch Form
- the basic pattern of
tooth position is the
arch.
- The form is largely
determined by the
shape of the
underlying basal
bone.

8. 3. Compensating
Curvatures of the
Dental Arches
Curved Occlusal Plane
– mandibular arch
conforms generally to
one or more curved
planes which appear
concave, & the
opposing maxillary arch
appears convex.

9. Von Spee noted that the
cusps & incisal ridges
of the teeth tended to
display a curved
alignment when the
arches were observed
from a point opposite
the first molars.

10. This alignment is
within the sagittal
plane only & is
known as the
Curve of Spee.

11. 4. Angulation of the
Individual Teeth in
Relation to Various
Planes
Root form – each tooth
must be placed at an
angle that best withstands
the lines of forces brought
against its function.

12. 5. Functional Form of the
Teeth at their Incisal &
Occlusal Thirds
- the incisal & occlusal
thirds of the tooth crown
present a convex &
concave surface at all
contacting occlusal
areas.

13. - a convex surface, representing a
segment of the occlusal third of one
tooth may come into contact with a
concave segment of another tooth.

14. 6. Facial & Lingual
Relations of Each
Tooth in one Arch to
its Antagonists in the
Opposing Arch in
Centric Occlusion
- Each tooth has two
antagonists, the loss of
one still leaves one
antagonist remaining.

15. - This will keep the tooth in occlusal
contact with the opposing arch &
keep it in its own arch relation at the
same time by preventing elongation
& displacement through the lack of
antagonism.

16. 7. Occlusal Contact &
Intercusp Relations of
all the Teeth of one
Arch with those in the
Opposing Arch in
Centric Occlusion
- Centric occlusion is
frequently the position of
the jaw for bracing during
swallowing & the terminal
position of the
masticatory stroke.

17. - When the teeth of both jaws come
together in centric occlusion, forces
should be equalized so that the teeth
are stabilized by all forces acting on
them.

18. ARTICULATION
- used to describe contacts between
the teeth in opposing dental arches
during mandibular movements.

19. Articulators – mechanical device by
which the occlusal relationship
during mandibular movements may
be copied.

20. POSITION
- the relationship of the maxilla &
the mandible when the teeth are in
occlusion.

21. Five Positions in which occlusion
takes place:
1. Intercuspal occlusion
2. Protruded occlusion
3. Retruded occlusion
4. Left lateral occlusion
5. Right lateral occlusion

22. POSTURAL OR MANDIBULAR REST
POSITION
- teeth not in function, mouth is
closed by the tonic contraction of the
muscles of mastication & facial
expression & the teeth are not in
contact.
- there is intercuspal or freeway
space of 2-5mm between teeth.

23. REST VERTICAL DIMENSION
- the face is in an involuntary relaxed
state.
- a distance measured from the
inferior border of the nose to the
point of the chin.

24. OCCLUSAL VERTICAL DIMENSION
- teeth are in intercuspal occlusion.
(* The difference between the RVD &
OVD represents the freeway space.)

25. DISTURBANCE
- alteration in the established form of
the teeth or in occlusal function.

26. Example:
1. overcrowding
2. rotation/displacement of teeth from
the dental arches
3. increase overbite/overjet
4. posterior open bite
5. anterior open bite
6. missing, painful, sharp teeth

27. DISORDER
- disturbances that cause pathological
alterations in the masticatory system.

28. Example:
1. bruxism
2. attrition
3. cracked tooth syndrome
4. mandibular pain dysfunction
syndrome

29. IDEAL OCCLUSION
- is a perfect dentition which can be
rarely found.

30. NORMAL OCCLUSION
- takes into account the ability of the
masticatory system to adapt or
compensate for some deviations
within the range of acceptable
variation without producing
disturbances or disorders

31. ANGLE’S CLASSIFICATION OF
OCCLUSION
Normal Occlusion/ Ideal Occlusion
- the MB cusp of the maxillary first
molars occlude with the MB groove
of the mandibular first molars.

33. - the DB cusp of the maxillary first
molar occlude with the distal cusp of
the mandibular first molar & with the
MB cusp of the mandibular second
molar.

34. - each tooth occludes with 2 teeth in
the opposing dental arch with
exception to the mandibular central
incisors & the maxillary third
molars.

35. OVERBITE
- vertical relation
between the upper and
lower incisors.
OVERJET
- horizontal relation
between the upper and
lower incisors.

36. OCCLUSAL PLANE
- imaginary plane that passes
through the incisal edges of the
mandibular central incisors & curves
gently upwards through the tips of
the buccal cusps of the premolar &
molar teeth to the tip of the DB cusps
of mandibular second molars.

37. Slope of the Curve – Compensating Curve

38. CLASSIFICATION OF
MALOCCLUSION:
1. NEUTROCCLUSION /
ANGLE’S CLASS I
- antero-posterior relationship of
dental arches are normal.

39. - malocclusion found is due to
discrepancies between the length of
the two dental arches & tooth size.
- spacing/ crowding/ crossbite may
be present.

41. 2. DISTOCCLUSION/
ANGLE’S CLASS II
- mandibular first molars lie in distal
relationship to the maxillary molars.

43. Division I - maxillary incisors proclined
- increase overjet
Division II - maxillary incisors are
retroclined and crowded
maxillary incisors are proclined
& overlap the central incisors.

44. 3. MESIOCCLUSION /
ANGLE’S CLASS III
- mandibular molars lie mesial to the
maxillary molars
- negative overjet

46. Pseudo – Class III
- the incisors have negative overjet
but the molar relationship is Class I.

47. Treatment for Malocclusion:
1. Orthodontic treatment
2. Surgery

49. Functional Movement of the Mandible
1. Bilateral Movement
- bilaterally symmetrical, both head
and condyle are involved
- example:
a. depression
b. elevation
c. protrusion
d. retrusion

50. 2. Unilateral Asymmetrical Movement
- one head of the condyle moves
in one direction while the other head
stays in position as seen during the
chewing cycle of mastication.

51. 3. Balancing Bite / Position
- static relationship of the
mandibular & maxillary teeth to one
another on one side of the dental
arch when closure is made and the
mandible moved laterally to the
opposite side.

52. 4. Balancing Occlusion
- dynamic relationship of
mandibular & maxillary teeth to one
another during the excursion of the
mandible for balancing position to
centric occlusion.

53. 5. Working Bite / Position
- static relationship of the
mandible & maxillary teeth to one
another on one side of the dental
arch when closure is made with the
mandible moved laterally to that side.

54. 6. Working Occlusion
- dynamic relationship of
mandibular & maxillary teeth to one
another during the excursion of the
mandible for working position to
centric occlusion.