Isfahan Dental School Pediatric Dentistry Departement Dr. S.E.Jabbarifar PRIMARY DENTITON RELATIONSHIPS GENERAL OBJECTIVES: To present the establishment of the occlusion in the primary dentition.

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Transcript Isfahan Dental School Pediatric Dentistry Departement Dr. S.E.Jabbarifar PRIMARY DENTITON RELATIONSHIPS GENERAL OBJECTIVES: To present the establishment of the occlusion in the primary dentition.

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Isfahan Dental School
Pediatric Dentistry
Departement
Dr. S.E.Jabbarifar

2009


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PRIMARY DENTITON RELATIONSHIPS
GENERAL OBJECTIVES:
To present the establishment of the
occlusion in the primary dentition.


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SPECIFIC OBJECTIVES:

1. Follow the development of occlusion from
birth – 3 years.
2. Define and illustrate all of the terminal plane
relationships for primary molars.
3. Explain canine relationships in the primary
dentition.
4. Follow the occlusion from 3-6 years.
5. Know normal anterior relationships in the
primary dentition: Overjet, Overbite.
6. Explain spacing in the primary dentition.


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I
Neutrocclusion is a maximum
intercuspidation of maxillary and mandibular
teeth with minimal overbite and overjet.
The development of occlusion is the most
dynamic phenomenon in the mouth. This is a
permanent changing process from birth to
death. It can be divided into four periods.
1.
2.
3.
4.

Primary Dentition: birth to 3 years
Mixed Dentition: 6-12 years
Young Permanent Dentition: adolescence
Adult Dentition.


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DECIDUOUS DENTITION
5 months in
utero

2 yrs
(± 6 mos.)

7 months in
utero
3 yrs

PRENATAL

(± 6 mos.)
Birth
6 mos.
(± 2 mos.)
9 mos.
(± 2 mos.)
1 year
(± 3 mos.)

4 years
(± 9 mos.)

5 yrs
(± 9 mos.)

6 years
(± 9 mos.)

18 months
(± 3 mos.)
INFANCY

EARLY CHILDHOOD
(Pre-school age)


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THE THREE TYPES OF TERMINAL PLANES

FLUSH PLANE

MESIAL STEP

TYPE

TYPE

DISTAL STEP
TYPE


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ESSENTIAL FACTORS FOR A SMOOTH
TRANSITION FROM PRIMARY TO
PERMANENT DENTITION
1. Primate space.

2. General spacing.
3. Preservation of “leeway space”.
4. Sequences of eruption.
5. Tooth size and jaw in harmony.


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PERMANENT DENTITION ESTABLISHMENT & RELATIONSHIPS
GENERAL OBJECTIVES:
Explain the establishment of the
occlusion of the permanent dentition.


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SPECIFIC OBJECTIVES:
1. Describe the eruption sequence and
timing of permanent teeth.
2. Describe the desirable eruption pattern
and identify variations of normality.

3. Explain how the inter-canine distance
changes when incisors erupt.
4. Explain temporary minor mandibular
crowding.
5. Explain the ugly ducking stage.


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SPECIFIC OBJECTIVES (con’t)
6. Explain space relationships in replacement
of canines and primary molars.
7. Describe normal closure of a maxillary
midline diastema.
8. Project from molar relationships in the
primary dentition, the type of Angle
classification that will result.
9. Describe and illustrate Angle’s classification
of occlusion: class I, class II with divisions
and subdivisions, class III.
10.Recognize acceptable overbite and overjet
relationships in the permanent dentition.


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STEPS OF TOOTH ERUPTION
1. Pre-emergent eruption - Pre-eruptive phase
a) resorption of the bone and primary tooth
roots
b) the eruption mechanism
2. Post-emergent eruption - Eruptive phase
a) post-emergent spurt - Eruptive phase
(Pre-functional)


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Steps of Tooth Eruption (con’t)
2.
b) juvenile occlusal equilibrium

Eruptive phase (Functional)

c) adult occlusal equilibrium


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Primary tooth

Bone trabeculae
at fundus

Enamel

Apex
Permanent tooth

Bone
trabeculae at
alveolar crest
Apex
Enamel

Bone
trabeculae at
fundus


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LOCAL, SYSTEMIC AND CONGENITAL FACTORS
THAT CAN INFLUENCE THE ERUPTION OF THE
TEETH.
Local






Systemic

• Primary failure of eruption
• Hypothyroidism

Congenital

• Down’s Syndrome
• Achondroplastic Dwarfism
• Cleidocranial Dysplasia

Two rows of teeth
Ectopic eruption
Infected primary teeth
Ankylosis


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ECTOPIC ERUPTION/IMPACTIONS
Primary dentition
• Extremely rare in primary dentition
Permanent dentition
• Permanent molars
– 1st > 2nd; maxillary > mandibular
– Incidence of 1st molar: - 2-3%
• Suggested etiologies include
– Small maxilla
– Posterioly positioned maxilla
relative to cranial base


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• Etiologies (continued):
– Molar path of eruption
– Mesiodistal dimension
– Asynchronization between tuberosity
growth and molar eruption
– Retarded calcification and eruption

– Genetic


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• Treatment
– Mild: observation (Pulver: 2/3 of
ecotypically erupting 1st molars will
self-correct)
– Moderate: brass ligature; spring;
distalize 1st permanent molar
–Severe: extract primary molar and

distalize 1st permanent molar.


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• Permanent mandibular incisor(s)
– Common: typically erupt lingual to overretained primary incisors
– Rationale for treatment: allow teeth
to move into area of attached gingival
– Treatment: extract primary incisors;

tongue pressure will typically push
incisors into place


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• Permanent maxillary canines

– Prevalence 1-2%
– Reported incisor root resorption - 50%
(Ericson and Kurol)

– Diagnosis
• Palpation
• Radiographic


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• Radiographic (continued)
– poor prognosis indicators
– permanent canine crown mesial of
midline of lateral incisor root
– palatal displacement of permanent
canine as viewed on cephalometric

film


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ANKYLOSIS
Primary dentition
• First molars most common
• Typically require no treatment and exfoliate
normally
• Involved second molar maybe indication of
agenesis of succedaneous tooth
• Treatment:
– Prevent space loss
»Build-up occlusion surface of
involved tooth
»Extract tooth and place space
maintainer


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Permanent dentition
• Difficult to treat ankylosed permanent teeth
– Create adequate space
– Attempt to break area of ankylosis with
luxation
– Immediately apply orthodontic traction
force (>50 G) or
– Surgically reposition tooth and hold in
position orthodontically (pulp
endodontic therapy necessary)
– Ankylosed permanent teeth tend to reankylose.


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Primary tooth

Bone trabeculae
at fundus

Enamel

Apex
Permanent tooth

Bone
trabeculae at
alveolar crest
Apex
Enamel

Bone
trabeculae at
fundus


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Chronology of Tooth Development
Permanent Dentition
C a lc ifica tio n
b e g in s

C ro w n
c o m p le te d

E ru p tio n

R o o t c o m p le te d

T o o th

M a x.

M an d .

M a x.

M an d .

M a x.

M an d .

M a x.

M an d .

C e n tra l

3 m o.

3 m o.

4 ½ yr.

3 ½ yr.

7 ¼ yr.

6 ¼ yr.

1 0 ½ yr.

9 ½ yr.

L a te ra l

11 m o.

3 m o.

5 ½ yr.

4 yr.

8 ¼ yr.

7 ½ yr.

1 1 yr.

1 0 yr.

C a n in e

4 m o.

4 m o.

6 yr.

5 ¾ yr.

1 1 ½ yr.

1 0 ½ yr.

1 3 ½ yr.

1 2 ¾ yr.

st

20 m o.

22 m o.

7 yr.

6 ¾ yr.

1 0 ¼ yr.

1 0 ½ yr.

1 3 ½ yr.

1 3 ½ yr.

nd

27 m o.

28 m o.

7 ¾ yr.

7 ½ yr.

1 1 yr.

1 1 ¼ yr.

1 4 ½ yr.

1 5 yr.

M o la r

32 w k.
in u te ro

32 w k.
in u te ro

4 ¼ yr.

3 ¾ yr.

6 ¼ yr.

6 yr.

1 0 ½ yr.

1 0 ¾ yr.

1 P re
M o la r
2 P re
M o la r
1

st

2

nd

M o la r

27 m o.

27 m o.

7 ¾ yr.

7 ½ yr.

1 2 ½ yr.

1 2 yr.

1 5 ¾ yr.

1 6 yr.

3

rd

M o la r

8 yr.

9 yr.

1 4 yr.

1 4 yr.

2 0 yr.

2 0 yr.

2 2 yr.

2 2 yr.


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ERUPTION SEQUENCE AND
TIMING
Age 6:
Age 8:
Age 11:
Age 12:

16,26,36,46,41,31
42,32,11,12,21,22
33,34,43,44,14,24,
13,23,35,45,15,25


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At dental age 9, the maxillary lateral
incisors have been in place for 1
year, and root formation on other
incisors and first molars is nearly
complete.
Root development of the maxillary canines and all second premolars is
just beginning, while about one third of the root of the mandibular
canines and all of the first premolars have been completed.


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Dental age 11 is characterized by the
more or less simultaneous eruption of
the mandibular canines, mandibular
first premolars, and maxillary first
premolars


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Dental age 12 is characterized by
eruption of the remaining
succedaneous teeth (the maxillary
canine and the maxillary and
mandibular second premolars)
and, typically a few months alter, the maxillary and mandibular
second molars.


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By dental age 15, the roots of all
permanent teeth except the third molars
are complete, and crown formation of
third molars often has been completed.


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7 years old

9 years old

14 years old

Changes in the axial inclination due to the eruption of the maxillary anterior
teeth (Broadbent, 1957).


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ERUPTION OF PERMANENT MOLARS

MESIAL STEP

DISTAL STEP

BECAUSE OF MESIAL STEP
ERUPT IN CUSP-GROOVE
RELATIONSHIP

BECAUSE OF DISTAL STEP
ERUPT IN DISTAL
RELATIONSHIP

6/6

6/6

6/6
6/6


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Primary

Permanent

Distal Step

Class II

Flush Terminal
Plane

End-End

Mesial Step

Minimal Growth Differential
Forward Growth of Mandible
Shift of Teeth

Class I

Class III


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