Development of Occlusion /certified fixed orthodontic courses by Indian dental academy

Development of Occlusion
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


1

Contents
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Introduction
Development of concepts of occlusion
Evolutionary changes
Stages of Occlusion Development
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Prenatal Dental development
Mouth of Neonate
Dev of Dentition from birth to Complete deciduous Dentition
Complete deciduous dentition
The first Transitional Period
The intertransitional period
The 2nd Transitional period
Permanent Dentition
2

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Disorders of development of Dentition
Development of Class II/1
Development of Class II div/2
Development of class III
Development of Open bite
Development of cross bite


3

Introduction to Occlusion




Oc = up Clusion = closing ; closing up
Occlusion - Relationship of dental arches

when tooth contacts are made.
Ideal occlusion in broad functional term is –






Teeth alignment is such that masticatory loads are
within physiological range and act through long axis
of as many teeth in arch as possible.
Lateral jaw movement without mechanical
interference.
When in rest position – freeway space is present
Tooth alignment is aesthetically pleasing.

4

The Anatomical alignment of teeth


The Dental Arches –





Size and shape vary
follow Catenary curve

The Neutral Zone


5

The curvatures of teeth and arches




Curve of Spee.
Curve of Wilson
Curve of Monson


6

The anatomical occlusion of teeth
Centric occlusion

Arrangement of teeth in centric occ

relation b/w teeth of both jaws
B-L relation

Centric contacts


7

Eccentric occlusion
Tooth contacts in lateral and protrusive occlusal
position


8

Andrew’s six keys of normal Occlusion
1.
2.
3.
4.
5.
6.

Molar inter arch relationship
Mesio- distal crown angulation
Labio – lingual crown inclination
Absence of rotation
Tight contacts
Curve of Spee.


9

Development of Concept of
Occlusion


10

Development of Concepts of
occlusion


It can be divided into
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


Fictional Period (prior to 1900)
Hypothetical Period (1900 to 1930)
Factual Period (1930 to present)

11

Fictional Period


Fuller Clark & Imrie talked of ‘antagonism’,
‘meeting’ or ‘gliding’ of teeth.



Talbot said it’s a historical event long since passed
in the decline of species, and possible only with an
atavism ‘throwback’ to our primitive ancestors.



The creation of a normal standard of occlusion , a
basis on which to compare departure from normal
was lacking.

12

Hypothetical Period


According to
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
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Edward H. Angel
Mathew Cryer and Calvin Case
Lischer and Paul Simon
Milo Hellman


13

Edward .H. Angle


In 1907 Angle put a hypothesis that:

“Occlusion is the basis of the science of orthodontia. The shapes of
the cusps, crowns and roots , and even the very structural material of the
teeth and attachments are all designed for the purpose of making occlusion
the one grand object…. we shall define occlusion as being normal relations
of the occlusal inclined planes of the teeth when the jaws are closed.”
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

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He described the illustration “Old glory”…. which
according to him was ideal occlusion.
Angle stated Apollo Belverdo’s straight profile as ideal
The best eg. of his hypothesis was ‘key of Occlusion’
His hypothesis was suggestive of static occlusion

14

Apollo Belverdo
Old Glory Skull


15

Mathew Cryer and Calvin case

He opposed Angle






How could one mix prognathic denture and orthognathic
profile?
How bimaxillary protrusion considered normal and
individual variation was not considered?
Then they were proved right by Turner’s illustrations

Normal occlusion
( it suits Apollo’s face better)



Case’s concept of www.indiandentalacademy.com
occlusion was static

16

Wheeler’s illustrations for normal occlusion
Prognathic

Retrognathic


17

Lischer And Paul Simon




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They tried to relate concept of occlusion by
relating teeth with rest of the face and cranium.
Lischer introduced mastication as requisite of
occlusion
Simon outlined the anthropometric approach

Milo Hellman



He showed racial variation in normal occlusion
His study was also confined to static occlusion

18

Factual Period
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

Dividing line b/w static and dynamic occlusion.
1931 Broadbent introduced Cephalometry.
With this advanced study tech the factual period
become functional period.
By now 3 components of occlusion are set up
 1. Interdigitation of teeth
 2. Status of controlling musculature
 3. TMJ integrity

19

Evolution of dentition


20

Evolution of Dentition


The mammalian dentition is 100, 000 million yrs old



The theories behind mammalian dentition are





Theory of Concrescence – derived by fusion of 2 or more
primitive conical teeth.
Theory of trituberculy – each tooth derived from single
reptilian tooth by secondary differentiation of tubercule
and root.
Theory of multituberculy – derived from reduction and
condensation of primitive multituberculate teeth.

21

Evolution of Dentition


Non mammalian vertebrates – Polyphyodonty
(many dentitions)



In mammals –Diphyodonty (2 dentitions )



During growth of the animal – increase in the jaw
size is associated with tooth size

22

Dentition of fishes ( Agnatha)
Eg - Sea lamprey & hag fishes


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No true calcified teeth
Arranged circumferentially
Horny teeth are also seen on the tongue

23

Chondrichthyes (carrtilagenous fishes)
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Large no. of teeth are present
Homodont & polyphyodont
Teeth are covered by enameloid
lower jaw of shark


24

Osteichthyes
(bony fishes)


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Haplodont – conical shape
prehension
Polyphyodont
Teeth- vomer, palatine bones roof of the mouth &
tongue

25

Amphibia




Small, homodont, polyphyodont
prehension
In the frog – small teeth on the upper jaw
& no teeth on the lower jaw


26

Reptiles

Homodont & polyphyodont
 Tend to be tricuspid or cone shaped
 Egg teeth – in embryos of lizards & snakes
- used to break the shell



27

Dentition of mammals




Heterodont ( 4 types )
Restricted to 2 rows
Ability to masticate – improves digestive
efficiency for high rate of metabolism


28

Other features
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TMJ articulation
Salivary glands
Prismatic enamel
Diphyodonty
Secondary palate
Significant muscle development


29

Dentition of protheria


Spiny ant eater – edentulous



Duck billed platypus – 3 functional
posterior teeth in each jaw quadrant



No. of additional teeth develop but do not
erupt but rapidly resorb

30

Metatheria
(Marsupials)


Eg. Red Kangroo



Dental formula – 3/1, 0/0, 1/1, 4/4 .
Feed on various plant.
Anterior teeth allow the food to be firmly
grasped.
Marsupials have no. of dental features
which distinguish them from placental
animals.






31

Eutheria
Eg - hedge hog

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
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Insectivoral
Incisors form a forcep like mechanism to pick
preys.
Molars – primitive tritubercular with sharp cusps
Suitable for crushing the shells of insects


32

Rodentia
Eg - rat



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Heterogenous , Monophyodont
Continuously growing incisors
DF 1/1, 0/0, 0/0, 3/3
Rat & mice are widely used as experimental
animals in Dental sciences

33

Carnivora

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Incisors are small and arranged in line.
Enlarged canines – offensive weapons
Incisors and canine – tearing flesh

34

Primates


Classified in to –
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Prosimii or Lemur type
Anthropoidea

Mainly herbivorous sometimes
insectivorous

35

Prosimii or Lemur type

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
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DF – 2/2, 1/1, 3/3, 3/3
incisors & canines are procumbent and
form dental comb.
mid line diastema .
Upper canine is blade like
Upper molar tritubercular


36

Anthropoidea
(monkey, apes & Man)

Eg -Macaca monkey
 DF – 2/2, 1/1, 2/2, 3/3
 Canines are long & prominent ( esp. in male )
 Lateral diastema



37

Chimpanze


Resembles permanent teeth of man


38

Homosapiens


Modern man – existed 100,000 yrs. ago


39

Stages of
Occlusal development


40

Stages of occlusal development
from clinical view ( Barnett)


41

According to Vander Linden
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Dev of Dentition from birth to Complete
deciduous Dentition
Complete deciduous dentition
The 1st Transitional Period
The intertransitional period Mixed Dentition
The 2nd Transitional period
Permanent Dentition


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43

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Prenatal beginning of the dentition
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Initiation of odontogenesis
bud stage
cap stage
bell stage

Spatial patterns

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Arch shape
Spacing

44

Initiation of odontogenesis



3rd week of IUL - first sign of tooth dev.
Epithelial thickening seen
IL border of maxilla

SL border of mandible



6 wk IUL Dental lamina is formed.

45


46



Morphologic changes - 6wks IUL till 4-5 yrs.



Occurs in 3 main phases





Initiation of entire deciduous dentition at 2nd
month IUL
Initiation of permanent teeth in successional
lamina from 5th month IUL
The dental lamina elongates distal to 2nd decid.
Molar and give rise to permanent molar tooth
germs

47

Bud Stage


Seen at 7th wk IUL



Increased mitotic activity at specific sites in DL
produces 10 knob like tooth buds



Stage of proliferation with no
morphodifferentiation of cells


48

Bud Stage
Early bud stage
Dental lamina
Enamel organ
Mesenchymal condensation
Late bud stage


49

Cap Stage


At end of 8th wk concavity appears on deep surface of
bud – cap shape



Epithelium enlarges and proliferates in to
deeper ectomesenchyme



Its stage of morphodifferentiation


50

Cap Stage
Early cap stage
External dental epith.
Dental follicle
Inner enamel epith.
Dental papilla

Late cap stage

Enamel cord
Enamel knot
Dental
papilla

51

Bell stage


Enlargement of tooth germ and deepening of its undersurface



Germ looses connection with oral epith.



Stage of Histodifferentiation



Determine crown shape initate dentin
and enamel formation


52

Bell stage

Bell stage
outer enamel epith.
Stellate reticulum
Dental follicle
Stratum intermedium
Inner enamel epithelium
Dental papilla

Advanced Bell stage

Ameloblasts
Enamel matrix
Dentin
Predentin
Odontoblasts

53

Advanced Bell stage


Inner dental epithelium – Ameloblasts – Enamel



Outer dental epith. – dental cuticle



Transition zone b/w IDE & ODE – cervical loop



Neighboring cells of IDE in dental papilla –
Dentinoblasts/odontoblasts – Dentin

.


Hertwig’s rootsheath proliferate from CL which
initiates radicular odontoblasts.

54

Arch Shape

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At 6 to 8 weeks it’s A-P flattened.
By bell stage or 4mth IUL – Catenary pattern.
Cleft lip and palate arrest this development.
Lateral shift of deciduous lat. incisor is seen.

4 diff arrangements of deciduous teeth in both jaws before
birth

55

Graphic Reconstruction of prenatal
Dental arch quadrant


56

Frontal sec through face of 24 wk fetus showing linear
distance from midline to points on tooth germs


57

Spacing


Decid. anterior teeth appear crowded.



Lateral incisor is seen out of alignment
before birth but usually erupt in good
alignment.
Summed crown size increases eight
fold but summed interdental spacing
shows little correlatin with it.




58

The mouth of the Neonate


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The mouth of the Neonate


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The gum pads
Neonatal jaw relationship
Status of dentition


60

Gum Pads


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At birth alveolar processes are covered by firm and pink
gum pads
Divided in to 10 segments by transverse
grooves.
Groove b/w canine and dm1 crypt –
lateral sulcus – assessing relation of jaws.
Maxillary arch is horse shoe shape and
extend buccally and labially
Mandibular arch is posterior to max. arch

61

Neonatal jaw relationship




Anterior openbite is seen.
Contact mainly occur at dm1 region.
Infantile open bite is normal as it helps in
suckling.


62

The status of dentition



Neonates are without teeth for 6mths.
Occasionally teeth seen in this period –





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Natal
Neonatal
Pre-erupted

These teeth are always mandibular incisors.
Familial tendencies.


63

Tooth Eruption



Two types Preemergent eruption



Eruption before emergence of tooth in oral cavity.
Two processes involved –





Resorption of the overlying bone (and primary tooth root).
Eruption mechanism itself then move the tooth in cleared
path.

Failure of tooth eruption –



Failure of bone resorption (Cleidocranial dysplasia)
Primary failure of eruption.


64



Postemergent eruption



Eruption after emergence of tooth in oral cavity.
Postemergent spurt
 Rapid eruption from a time tooth penetrates the
gingiva till tooth reaches occlusal level.
 Eruption - During critical period b/w 8 PM to 1 AM.
 After it attain occlusal contact ,occlusal forces
opposes further eruption




65



Juvenile Occlusal equilibrium
 Slow phase
 Teeth erupt to fill the space created by vertical
growth of mandibular ramus.



Adult occlusal equilibrium
 Compensate for occlusal and proximal wear

66

Mechanism of tooth movement





Bone remodelling of crypt wall
Root formation
Vascular pressure
Periodontal ligament traction


67

Development of the Dentition from
Birth to complete Deciduous
dentition


68

Development of the Dentition from
Birth to complete Deciduous dentition





After birth jaws grow considerably for 6-8 mths.
Lower jaw more dorsally placed irt upper.
Ventral dev takes place during 1st yr – A-P relation
Transverse dev –





median suture in maxilla
Synchondrosis in mandible (till 6 mths.)

Eruption sequence is A B D C E

69

Dev of dental arches and dev of deciduous teeth
A.

At birth

B.

Mand. Central
incisor- 6 to 8 mths

C.

Max. central incisor
7-9 months

D.

U & L lateral
incisors – 1 yr.


70

E.
F.
G.
H.


1st molar – 16 mth.
Canine – 20 mth.
2nd molar – b/w 24 &
30 mths.
Complete deciduous
dentition with
successors within the
jaws.

71

Displacement of U & L Dm1 to establish
occlusion : Cone-funnel mechanism





Palatal cusp of
max. 1st molar –
cone
Crater in mand.
1st molar –funnel

72

The Complete Deciduous
Dentition
ABCDE
ABCDE


73

The Complete Deciduous Dentition


Competed at 2.5 yrs of age after dm2 erupts and
lasts till 5 yr of age



Physiological spaces in primary
dentition


Primate spaces
Developmental spaces


74

Spacing in Deciduous dentition

 Gap toothed smile - normal
 Hollywood smile with teeth in contact - not normal

75

Occlusal relationship of U & L Dm2


3 types of terminal planes –
 Flush terminal plane
 Mesial step
 distal step


76

Normal situation of the Deciduous dentition
in occlusal, anterior and lateral view


77

The first Transition period


78

The First transition period


The emergence of 1st permanent
molar A B C D E 6
ABCDE6



Transition of the incisors


79

The emergence of 1st permanent molar




1st teeth to emerge in permanent dentition.
In mand. 6 –7 yr In maxillary arch 7- 8 yr
The A-P relation b/w two opposing permanent
molars depend upon –




Their previous position within the jaw
Sagittal relation b/w maxilla and mandible
Terminal planes of 2nd decid molars.


80

Influence of terminal plane on the
position of 1st permanent molar


81

Exchange of Incisors




After eruption of Pm1 , primary incisors exchange
with permanent incisors.
Incisal Liability





7 mm in maxilla
5 mm in mandible

The factors controlling the arrangement of
permanent incisors are -


82



Interdental spaces in deciduous dentition





Increase of inter-canine width






physiological & primate spaces are utilized
If closed space – crowding occur
Increases 3 mm in both jaws at time of eruption
Increases1.5 mm when canine erupts
So the clasps on canine attached as space maintainer
should be cut off at this time

Increase of anterior length


Increase in length of arch in A-P dimension


83



Change of tooth axis of incisor







Permanent incisor erupt labially by 2 – 3 mm, attain
overjet and over bite
Pressure by tongue , lip and perioral musculature
Interincisal angle  150 degree in decid. Incisors.
 123 degree in perm. Incisor
It increases arch circumference


84



Ugly duckling stage


Child look unusual due to
Too large permanent incisor compared to primary.
 Flared incisors with midline diastema.
 Transitional malocclusion – called ugly duckling
stage - broadbent



85

Sequence of normal transition of incisors
At 5 yr.

At 6 –7 yr.

At 7 –8 yr.

At 8 – 9 yr


86

Transition of incisors









Loss of decid. tooth is caused by Resorption of its root
 By reduction of bone cervically
Several week passes b/w shedding of decid and eruption
of successor.
In the interval reconstruction of alveolar process and
healing of gingival defect occur
A perm. teeth starts eruption after ¼ of its root formed
Perm .teeth emerge in oral cavity when ¾ root is formed.


87

The inter transitional Period
12CDE6
12CDE6


88

The inter transitional period









Consist of both decid. & perm. teeth
Teeth present are 1 2 C D E 6
12CDE6
Ugly duckling stage persists in upper incisors.
Under influence of tongue mand incisor attain
proper sites from their lingual position.
The decid teeth present are worn out at this stage.
It is a stable phase with little changes in dentition.

89

The inter transitional period


90

The Second Transition Period


91

The Second transitional period



Transition of Lateral teeth
Eruption of Second permanent molar


92

Transition of lateral teeth



Transition of C D E with 3 4 5 .
For smooth exchange following are
conditions–


Leeway space of Nance





Sum M-D width of 3, 4 & 5 < C D & E
Space available is
22.3 – 21.5 = 0.8 (U)
23.5 – 21.1 = 2.4 (L)


93



Order of exchange of lateral teeth





It takes 1 ½ yrs. to complete exchange of
lateral teeth.
Sequence of eruption is –
4 5 3 in maxillary and 3 4 5 in mand.


94

Eruption of second Permanent teeth




After exchange of lateral teeth 2nd permanent
molar erupts. i.e after loss of all deciduous teeth.
Sometimes it erupts before E sheds – leads to
crowding


95

Transition of lateral teeth and
eruption of 2nd perm molar
At 9- 10 yrs

At 10 – 11 yrs.

At 10 – 12 yrs.

At 11 – 12 yrs

At 12 – 13 yrs.

96

The Permanent Dentition
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97

The Permanent Dentition


At around 13 yr of age all permanent teeth
(except 3rd molar) are erupted.

Situation

in normal
permanent dentition


98

Normal bucco-lingual inclination of
perm teeth in both jaws


99

Disorders in development of
Dentition


100

Disorders in development of
Dentition


At time of eruption of Deciduous dentition –




Anomolies




Teething disorder - most of infants exhibit fever,
diarrohea, vomiting , irritability etc before tooth
eruption.
Its rare for primary teeth to be congenitally missing.

Primary tooth resorption



Hastened by inflammation and occlusal trauma
Delayed by splinting and absence of successor

101



Ankylosis of primary teeth




In Primary molars, esp during physiologic
resorption

Disorders of primary Occlusion –



Its less compared to permanent occlusion.
Thumb sucking and other oral habits
Posterior crossbite
 Open bites
 Class II malocclusion
 Excessive overjet




Bruxism – functional malocclusion

102



Factors affecting transition of teeth






Dental caries in primary teeth
Disturbance in root resorption due to pulpal or
periodontal disturbances
A periapical lesion
Premature loss of primary molar


103



Anomolies in Permanent dentition







Microdontia, macrodontia
Gemination ,Fusion, Dilaceration, Talon
cusp, Dens evaginatus
Supernumerary roots
Dentinogenesis & Amelogenesis imperfecta
Enamel Hypoplasia


104

Abnormalities in dental arch
1.

2.

Arch Length Discrepancy
1. Crowding
2.
Spacing
Deviation in no. of teeth1. Absence of teeth ( Agenesis)
2. Supernumerary teeth


105

Absence of teeth ( Agenesis)


Sequece of agenesis is –


3rd molar > Mand. 2nd premolars > Max
Lateral Incisors > Max. 2nd Premolar


106

Absence of teeth ( Agenesis)


107

Supernumerary teeth


108

Deviation in tooth size



Its relative in nature
All teeth combined > or < relative to size of
jaws or head.





Crowding
Spacing

Deviation in size of individual teeth


Tooth size Discrepancy


109

Tooth size Descrepancy


110

Deviation in individual teeth position


111

Ankylosis



Frequent in mand deciduous molars.
In permanent 2 types




Due to abnormal position within jaw
 Max perm. Canine
Due to lack of space
 Mand 3rd molar


112

Angle’s classification of Malocclusion



Class I
ClassII


Class II div 1




Class II div 2




Class II div 1 subdivison
Class II div 2 subdivison

Class III


113

The Development of Occlusion in
Class II/ 1 malocclusion


114

In Deciduous dentition
Limited increase in
overbite

Mand dental arch
dorsally placed irt
maxillary

Distal step

115

In Intertransitional period
Increased overbite

Mand dental arch dorsally
placed, large overjet

Mand 1st perm molar
occludes dorsally to max


116

In Permanent Dentition
Increased overbite

Mand dental arch dorsally
placed, large overjet
Class II molar relation


117

The Development of Occlusion in
Class II/2 malocclusion


118

Change in Incisor and Molar region in Class
II /2 , from deciduous to permanent
In Decid. Dentition
Overjet less,high lip
line

Mand incisor erupt
Normally Max erupting
slightly upright

Lower lip – lingual
tipping of L. Incisor

Lower lip – lingual tipping
of U. Incisor

In adult, U. C. Incisor
tipped severly palatall

Continued erution
– till vertical contact

119

Class II /2 with more space in anterior
segment
Lingual tipping ( By L Lip)
U C P incisor - Continous
Arch with B & C

U L P incisor Erupt in
normal orientation as
sufficient space available

•Lingual tipping of U L P
incisor by L lip.
•Lingual tipping of lower
incisors.
•Rectangular arch form

120

Class II /2 with less space in anterior
segment
•Lingual tipping ( By L Lip)
•U C P incisor - Continous
Arch with B & C

• Already limited space,
reduced further by palatal
tipping of centrals .
• Lateral erupts labially
• L lip placed lingual to laterals
•Max. laterals rest on the L lip.
•Max Central and Mand incisors
are perpendicular to Occ plane

121

The Development of dentition in
Class III


122

In Deciduous dentition
Lower ant placed ventrally to
max. less overbite

Mand dental arch ventrally
placed, reverse overjet

Large mesial step


123

In Intertransitional period
Incisal surface of
U incisor contact ligual
surface of lower


Mand perm !st molar
occludes too far
mesially to max


124

In Permanent dentition
Incisal surface of U incisor
contact ligual surface of
lower

Mand perm !st molar
occludes too far
mesially to max


125

Development of Open bite


126

Anterior open bite
Asymmetrical open bite
due to thumb sucking
in Deciduous dentition

Open bite due to abnormal
Tongue position
(symmetrical)


127

Posterior open bite
Open bite due to incomplete
eruption of teeth.Resulting
from interpositioning
of tongue

Open bite combined with
inadequate contacts.


128

ClassII /1 Subdivison

•

•
•

Class I on right side, class II on left
Overjet overbite too large
Midline shift.

129

ClassIII Subdivison

•

•
•

Class I on right side, class III on left
Anterior crossbite exists
Midline shift.

130

Unilateral Crossbite

Maxillary dental arch crosses the mandibular
one distal to maxillary left canine

131

Bilateral Crossbite

On both sides maxillary molars occlude with their
buccal cusps instead of their palatal ones

132

Total exo-occlusion in ClassII/1





All

maxillary teeth positioned exteriorly to mandibular
Brodie Syndrome or Telescope bite

133

Total endo-occlusion in Class III

All maxillary teeth positioned interiorly to mandibular
ones

134

Refrences :










Oral Anatomy - Berkovitz
Development of Dentition – Van der Linden
Transition of human Dentition – PGM Vander Linden
Handbook of orthodontics – Moyers
Contemporary orthodontics –Proffit
Orthhodontics - T. M. graber
Oral histology – Tencate
Dental Anatomy – Wheelers
Dentistry for child – Mc Donald


135

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136

Development of Occlusion /certified fixed orthodontic courses by Indian dental academy

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