The document discusses key concepts related to occlusion, including: 1. Occlusion refers to the relationship between the upper and lower teeth during activities like chewing and swallowing. This includes static occlusion when teeth are closed and dynamic occlusion during jaw movements. 2. Centric occlusion is the tooth-to-tooth relationship when teeth are in maximum intercuspation and the condyles are in their most retruded position in the mandibular fossae. 3. The first permanent molars, due to their eruption pattern and position, serve as the "key of occlusion" that guides relationships between other teeth.

1. {

2. Occlusion
Is the relation of the upper
and lower teeth during various
activities of the mandible as in
mastication and swallowing

3. Contact of teeth in opposing
dental arches:
When the jaws are closed=
"static occlusal relationships“
During various jaw movements=
"dynamic occlusal relationships".
Occlusion

4. Centric occlusion
Is a tooth-to-tooth relationship
(interdigitation of teeth) when:
1 - Upper and lower teeth are in
maximum intercuspation.
2 - Condyles are resting in the most
etruded -unstrained- position in
mandibular fossae.

5. Centric Occlusion
maximum
inter-
cuspation
most retruded unstrained position
of condyles in glenoid fossa
GLENOID
FOSSA
TOOTH –TO- TOOTH RELATIONSHIP
1
2

6. 1.First permanent teeth to erupt
in the oral cavity.
2.Occupy a central position in the jaw
(antro-posteriorly).
Key of Occlusion:
Maxillary & mandibular
1st permanent molars
serve as “Key of
occlusion”:
Why?

7. 3- Their positions in the jaws
are guided by the presence of
the deciduous molars preceding
them.
4- Their eruption is not disturbed as
they have no predecessors.
5- 6 is considered more accurate than
6 as it is attached to a bone fixed to
the base of the skull.

8. MB cusp 6
MB groove 6
Classification of Occlusion
Class I :
Centric occlusion:
Angle’s Classification:
MB
MB groove

9. MB cusp 6 MB groove 6
Class I : centric occlusion
Orthognathic profile
Classification of Occlusion

10. Class I
Class II
Class III
Angle’s Classification:

11. Class II malocclusion
Retrognathic profile
Classification of Occlusion

12. Class III malocclusion
Anterior cross bite

13. 6
6
6
6
Malocclusion
6
6
Malocclusion
Centric occlusion

14. 1- Opposing teeth:
I) Centric Occlusion of Permanent Teeth
Each tooth in a dental arch
occludes with two teeth in
the opposing arch ,
except:
the mandibular central incisor
the maxillary third molar.
General Concepts:
1
1 2
5
5
4

15. *The neighboring teeth
migrate, to fill the
space.
Loss of tooth leads to:
* The opposing tooth
may elongate.
This results in: disturbance in the centric
occlusion, caries and periodontitis.

16. 2-Maxillary anterior teeth
overlap mandibular teeth:
 Horizontal overlap: “Overjet”
Incisal edges of maxillary
anterior teeth are labial to
incisal edges of mandibular teeth
 Vertical overlap: “Overbite”
Incisal edges of the maxillary teeth
extend below the incisal edges of mandibular
teeth
Relationship of
Anterior teeth
General Concepts:

17. Overbite

18. Overjet

20. Vertical overlap:
“overbite”
Horizontal overlap:
“overjet”
General Concepts:

21. Relationship of
Individual Teeth
in
Centric Occlusion

22. Maxillary posterior teeth
are slightly buccal to
mandibular posterior teeth:
Relationship of
Posterior Teeth
•The lingual cusps of the
maxillary teeth rest in the
occlusal fossae of the
mandibular teeth.
General Concepts:
•The buccal cusps (free of
contact)

23. • Buccal cusps of mandibular teeth
rest in occlusal fossae
of maxillary teeth.
• Lingual cusps
(free of contact)
.
Relationship of
Posterior Teeth
The mandibular posterior teeth:
General Concepts:

24. The buccal cusps (free of contact)
MBC Free, in the opposing B groove
DBC Free in the opposing embrassure between their
antagonistic teeth and the distal one
8……. DB slope of DBC of 8
MBC DBC
Maxillary molars

25. MLC Opposing central fossa
DLC 6…….. MMR 7
7 ……..DMR of 7
8 (if present) ……... DMR of 8
Lingual relation of maxillary molars

26. Forms of Malocclusion
Anterior
open bite
Crowding
Cross bite