This document provides an overview of occlusion and malocclusion from a dentistry lecture. It defines key terms like occlusion, malocclusion, and Angle's classifications of malocclusion. It also describes different types of malrelationships that can occur with individual or groups of teeth, like overjet, overbite, crossbites, and open bites. Additionally, it covers noncarious dental lesions such as enamel hypoplasia, fluorosis, attrition, erosion, abrasion, and fractured teeth.

1. Introduction to
Dentistry DA101
Lecture Three
Occlusion
Dr. Somaia Hasan Dashti
2017

2. SDASHTI. CHS,2017 2
Lecture Outlines
Definitions
Facial Profiles
Angle’s Classification
Malrelationships of Individual or
Groups of Teeth
Noncarious Dental Lesions

3. SDASHTI. CHS,2017 3
Definitions
Occlusion is defined as the contact
relationship between maxillary and
mandibular teeth when the jaws are in
fully closed position
Malocclusion is malportioned
relationship or deviation in
relationship between maxillary and
mandibular teeth when they are fully
in closed position

4. Normal Ideal Occlusion
All teeth in maxillary arch are in
maximum contact with all teeth in
mandibular arch in a defined pattern
Maxillary teeth slightly overlap
mandibular teeth on the facial
surfaces
SDASHTI. CHS,2017 4

5. SDASHTI. CHS,2017 5
Facial Profiles
Mesognathic (orthognathic): Protruded jaws that
gives the facial outline flat appearance ( Straight
Profile )
Retrognathic: Prominent maxilla and a mandible
posterior to its normal relationship (Convex Profile)
Prognathic: Prominent, protruded mandible and
normal maxilla(Concave Profile)

6. SDASHTI. CHS,2017 6
Angle’s Classification
Normal Occlusion
Class I Malocclusion
Class II Division 1
Class II Division 2
Class III

7. SDASHTI. CHS,2017 7
Normal Occlusion
Occlusal (Molars)
Relation-ships:
Mesiobuccal cusp of
maxillary first
premolar occludes
with buccal groove
of mandibular first
molar
Anterior (Canine)
Relation-ships:
Maxillary permanent
canine occludes with
distal half of
mandibular canine
and mesial half of
mandibular first
premolar
Facial Profile
(mesognathic)

8. SDASHTI. CHS,2017 8
Class I
Occlusal
(Molars)
Relation-ships:
(same is
normal
occlusion )
Anterior
(Canine)
Relation-ships
Facial Profile:
Mesognathic
(Orthognathich
Malpositions of
individual or
groups of teeth
may occur

9. SDASHTI. CHS,2017 9
Class II- Division 1
Occlusal
(Molars)
Relation-ships:
Anterior
Relation-ships:
Maxillary is
protruded
Facial Profile:
Retrognathic

10. SDASHTI. CHS,2017 10
Class II- Division 2
Occlusal
(Molars)
Relation-ships:
Anterior
(Canine)
Relation-ships:
Maxillary
incisor
retruded
Facial Profile:
Reterognathic

11. SDASHTI. CHS,2017 11
Class III
Occlusal
(Molars)
Relation-ships:
Anterior
(Canine)
Relation-ships
Facial Profile

12. SDASHTI. CHS,2017 12
Malrelationships of Individual or
Groups of Teeth
Labioversion
Linguoversion
Buccoversion
Supraversion
Toriversion
Infraversion
Anterior &
Posterior Crossbite
Edge-to-Edge Bite
Open Bite
Over Jet
Underjet
Overbite

13. SDASHTI. CHS,2017 13
Labioversion: A tooth assumed a
position labial to normal
Linguoversion: Position lingual to
normal
Buccoversion: Position buccal to
normal
Supraversion: Elongated above the
line of occlusion
Tersoversion: Turned or rotated
Infraversion: Depressed below the
line of occlusion

14. Crossbites
• Posterior
crossbite:
maxillary or
mandibular
posterior teeth
are either facial
or lingual to
normal position
SDASHTI. CHS,2017 14

15. SDASHTI. CHS,2017 15
• Anterior crossbite:
Maxillary incisors are
lingual to
mandibular incisors

16. Edge –to-Edge & End-to-End Bite
Incisal surfaces of
maxillary teeth occlude
with indicial surfaces if
mandibular teeth instead
of overlapping as in
normal occlusion
Molars and premolars
occlude cusp to cusp as
viewed mesiodistaly
SDASHTI. CHS,2017 16

17. Open Bite
Lack of Occlusal or
incisal contacts
between maxillary
and mandibular
Teethe cannot
brought together
SDASHTI. CHS,2017 17

18. SDASHTI. CHS,2017 18
Underjet
Maxillary teeth are
lingual to mandibular
teeth.
The horizontal distance
between labioincisal
surfaces and maxillary
incisors and
linguoincisal surface of
mandibualr incisors

19. Overjet
The horizental
distance
between
labiolincisal
surfaces of
mandibular
incisor and
linguoincisal
surfaces of
maxillary incisor
SDASHTI. CHS,2017 19

20. Overbite
Normal overbite:
When incisal
edges of
maxillary teeth
are within incisal
third of
mandibular teeth
SDASHTI. CHS,2017 20

21. Overbite
Deep (severe)
overbite:
When incisal edges of
maxillary teeth
appear within
cervical third of
mandibular teeth
SDASHTI. CHS,2017 21

22. Overbite
Moderate overbite:
When incisal edges of
maxillary teeth
appear within middle
third of mandibular
teeth
SDASHTI. CHS,2017 22

23. SDASHTI. CHS,2017 23
Noncarious Dental Lesions:
Enamel Hypoplasia
Is a defect occurs as a result of
disturbance in formation of organic
enamel matrix
Etiology could be heredity or systemic
such as severe nutritional deficiency,
fever producing diseases (measles,
chicken pox, scarlet fever, syphilis),
hypoparathyroidism, birthinjury,
prematurity, fluorosis.

24. Etiology could be local
when a single tooth is
affected due to trauma of
perapical inflammation in
primary which can injure
the adjacent permanent
developing tooth
SDASHTI. CHS,2017 24

25. SDASHTI. CHS,2017 25
Noncarious Dental Lesions:
Mottled Enamel (Fluorosis)
Form of enamel hypo
mineralization due to excessive
ingestion of fluoride during
development and mineralization
of teeth; depending on length of
exposure and ppm of fluoride,
the fluorosis area appear as
small white spot or as severe
brown staining with pitting

26. SDASHTI. CHS,2017 26
Noncarious Dental Lesions:
Attrition
Is wearing away of teeth as a result of
teeth-to-teeth contact
Found in Occlusal , incisal and
proximal surfaces
Predisposing factors include: Bruxism,
Usage (coarse food, chewing tobacco),
increase with age
Seen more in men than women at
same age
Increase with age
Staining of exposed dentin may appear

27. SDASHTI. CHS,2017 27
Noncarious Dental Lesions
Erosion
Is the loss of tooth
substance by a
chemical process
that does not involve
known bacterial
action.
Predisposing
factors include
chronic vomiting
(bulimia,
pregnancy), dietary
(carbonated drinks,
lemon juice) or
idiopathic
Usually involve
several teeth

28. Attrition appearance
Smooth, hard and
shiny
May occur in
combination of dental
caries
May progress to
involve dentine
occurs in facial or
lingual surfaces
depending on cause
but more in the facial
surfaces
SDASHTI. CHS,2017 28

29. SDASHTI. CHS,2017 29
Noncarious Dental Lesions:
Abrasion
Is mechanical
wearing away of
tooth substance by
force other than
mastication
Most common
cause is horizontal
brushing with
abrasive dentifrice
and hard tooth
brush

30. Holding pens of pipe between teeth,
usually people with this habit utilize
same tooth
Occupational causes such as
carpenters, and dressmaker
SDASHTI. CHS,2017 30

31. SDASHTI. CHS,2017 31
Noncarious Dental Lesions:
Fractured teeth
Trauma to face may involve
fractured bones and teeth in
addition to soft tissue injuries
Caused by:
Falls
Blows while fighting
Contact sports without mouth
protectors
Automobile, bicycle, and diving
accidents