The document discusses the stages of human dentition and occlusion, emphasizing the dynamic changes from birth through permanent dentition. It details the pre-dentition, deciduous, mixed dentition, and permanent dentition stages, including the eruption sequence and common abnormalities. Additionally, the author acknowledges sources, declares the work's originality, and expresses gratitude for support received during his career.

1. Ibn Sina University
Faculty of Dentistry
Department of Orthodontics
Development of
Dentition and
Occlusion
Mohanad Elsherif
BDS (U of K), MFD RCSI, MFDS RCPS(Glasg), MSc (Orthodontics), M.Orth. RCSEd

2. Introduction
 The human dentition is in a dynamic
state constantly changing throughout life.
 A knowledge of these changes assists
the clinician in determining whether or not
a specific occlusion will be sustained ,
worsen ,or self-correct over time.

3. Periods of occlusal
development
 The predentition stage.
 The deciduous dentition stage.
 The mixed dentition stage.
 The permanent dentition stage.

4. The pre-dentition stage
 From birth to 6 month of age.
 Usually there is no teeth instead there is
an upper and lower gum pads.
 The gum pads are covered with a dense
fibrous periostium and divided into
segmental elevations representing the
teeth forming below.

5.  Transverse groove:
Divides the gum pad into ten
segments representing each
deciduous tooth.
 Gingival groove:
Separates the gumpad from the
palate and the floor of the mouth.
The pre-dentition
stage

6.  Lateral sulci:
Present between the canine and
the 1st molar.
 Dental groove:
Extend from the incisive papilla
backward to touch the gingival
groove in the canine region and
continues forward in the molar
region.
The pre-dentition
stage

7.  The maxillary gum pad is
horse shoe shaped and the
palatal vault is almost flat.
 It is wider and longer
than the underlying
mandibular U shaped gum
pad.
The pre-dentition stage

8. The pre-dentition stage
 When the upper and the
lower gum pad are closed there
is a complete overjet all
around.
 In addition the lips are
incompetent.
 This infantile open bite is
considered to be normal. It
helps in sucking.

9. Gingival Cyst of infancy
 Occasionally on the alveolar
mucosa small whitish nodules
may appear, these are gingival
cysts of infancy, often called
Epstein’s pearls or Bohn’s nodules.
 Parents should be reassured
that they will spontaneously burst
and resolve within the first three
months of life.

10. Natal and Neonatal teeth
 Very rarely teeth are present at birth
called as natal teeth.
 If they erupt during the 1st 30 days
then they are called as neonatal teeth.
 Mostly located in the mandibular
incisor region and they are usually
either mandibular incisors or
supernumerary teeth.
 if they are mandibular incisors
extract only if they interfere with
breast feeding or if they are mobile and
there is a rick of there swallowing by
the infant

11. The deciduous dentition
stage
 From 6 month to 6 year of age.
 The first tooth to erupt is the mandibular
central primary incisor.
 The normal sequence of eruption is
A,B,D,C,E.
 All the deciduous teeth should be erupted
at 3 years and the root is completed 1-2 years
after eruption.

12. Features of normal deciduous
dentition
1. Spacing:
 Spacing usually exists
between the deciduous
teeth, these spaces are
called as developmental
or physiological spaces.
 Primate space is seen
mesial to the maxillary
canine and distal to the
mandibular canine.

13. Features of normal deciduous
dentition
2. Deep bite:
 The deep bite occur because
the deciduous incisors are more
upright than their permanent
counterparts.
 The deep bite reduces to an
almost edge to edge bite by 5-6
years of age due to:
 Eruption of deciduous molars.
 Attrition of incisors.
 Forward movement of
mandible due to growth.

14. Features of normal deciduous
dentition
3. Flush terminal plane
relationship:
 The distal edges of the
upper and lower second
deciduous molars are in the
same vertical plane.
 This is called flush
terminal plane relationship.

15. Abnormal features
 Eruption cyst.
 Abnormal eruption sequence.
 No spacing or crowding.
 Open bite.
 Mesial step or distal step relationships.
 Crossbite.
 Premature loss of deciduous tooth.
 Infraoccluded primary molar.

16. Mixed dentition stage
 From 6 years to 12 years of age.
 It is further subdivided into:
 First transitional stage.
 Iner-transtional stage.
 Second transitional stage.

17. First transitional stage
 Characterized by eruption of permanent
incisors and permeant first molar.
 The mandibular 1st molar usually is the first
permanent tooth to erupt.
 Mandibular teeth usually erupts a head of
maxillary teeth.
 Early mesial shift occur at this stage.

18. First transitional stage
1. Eruption of incisors:
 The collective mesiodistal
dimensions of the permanent
incisor tooth crowns are larger
than their deciduous
predecessors.
 This deficit is known as incisor
liability and it is approximately
about 5-mm in the mandible
and 7-mm in the maxilla.
A A BB
2 21 1
1 12 2
A AB B

19. First transitional stage
 This can be corrected by:
 Spacing present between the
deciduous incisors.
 Labial eruption permanent incisors
more than their deciduous
predecessors and therefore occupying
a greater arch perimeter.
 Transverse increase in the
intercanine arch width.
 Deciduous canines move distally
into primate space and Part of Lee
way space.

20. First transitional stage
2. Eruption of 1st permanent molar:
 The initial occlusal relationship of the 1st
molars is directly influenced by the deciduous
second molar position.
 If these teeth are flush in the terminal plane
then the 1st permanent molars assume a cusp-
to-cusp relationship when they erupt.
 In order to establish a class I molar
relationship, some mesial movement of the
mandibular 1st permanent molar will be
required.

21. Early mesial shift
1. Flush terminal plane:
Class I can be obtained By utilization of the primate space. This is
called early mesial shift.

22. First transitional stage
Class I
Class IIIClass I
Minimal mandibular growth
Sever mandibular growth
2. Mesial step

23. First transitional stage
3. Distal step:

24. Normal features of the 1st transitional
stage
 Transient lower permanent incisors
crowding.
 Transient anterior open bite before the
eruption of maxillary permanent incisors.
 Cusp to cusp permanent first molars
relationship when they first erupt and before
early mesial shift take place.

25.  Characterize by the presence
of all permanent incisors, the
1st permanent molars and the
deciduous molars and canines.
 This phase is relatively stable
and no change occurs.
 The ugly duckling stage
(developmental stage) occur at
this stage.
Inter-transitional stage

26. The ugly duckling (developmental)
stage

27. The ugly
duckling
(development
al)stage

28. Second transitional stage
 Characterized by eruption of the premolar and canine
teeth.
 Normally takes place between the ages of 9 and 12 years
 In the mandible, the canine erupts ahead of the first
premolar and this is followed by the second premolar.
 In the maxilla, the first premolar usually erupts first,
followed by the second premolar and then canine.
 Late mesial shift occur at this stage.

29. Late mesial shift
 Unlike the anterior teeth the permanent
premolars are smaller than the primary teeth
they replace. This extra space known as the
leeway space.
 The leeway space is larger in the mandible 3.
4 mm (i.e. 1.7 mm on each half) than in the
maxilla 1.8 mm ( i.e. 0.9 mm on each half).
 This difference allow the first molars to move
a greater distance in the lower arch compared
to the upper arch leading to a class I molar
relationship, this is know as late mesial shift.
CDE
345
E D C
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30. Late mesial shift

31. Permanent dentition stage
 Start after the exfoliation of the last deciduous
tooth (usually the upper second deciduous molar)
 The sequence of eruption is as follow:
 In maxillary arch:
6-1-2-4-3-5-7 or 6-1-2-4-5-3-7.
 In mandibular arch:
6-1-2-3-4-5-7 or 6-1-2-4-3-5-7.

32. Normal Permanent dentition
 Presence of all permanent teeth.
 Class I molar, canine and incisor relationships.
 Well-aligned teeth with correct crown angulation and inclination.
 Normal and positive overbite and overjet.
 Absence of rotation.
 Tight interproximal contacts.
 Flat curve of spee.
 Correct tooth-size ratio.

33. Declaration
 The author wish to declare that; these presentations are his original work, all
materials and pictures collection, typing and slide design has been done by the
author.
 Most of these materials has been done for undergraduate students, although
postgraduate students may find some useful basic and advanced information.
 The universities title at the front page indicate where the lecture was first
presented. The author was working as a lecturer of orthodontics at Ibn Sina
University, Sudan International University, and as a Master student in Orthodontics at
University of Khartoum.
 The author declare that all materials and photos in these presentations has been
collected from different textbooks, papers and online websites. These pictures are
presented here for education and demonstration purposes only. The author are not
attempting to plagiarize or reproduced unauthorized material, and the intellectual
properties of these photos belong to their original authors.

34. Declaration
 As the authors reviews several textbooks, papers and other references during
preparation of these materials, it was impossible to cite every textbook and journal
article, the main textbooks that has been reviewed during preparation of these
presentations were:
Contemporary Orthodontics 5th edition; Proffit, William R, Henry W. Fields, and
David M. Sarver.
Handbook of Orthodontics. 1st edition; Cobourne, Martyn T, and Andrew T. DiBiase.
Essentials of orthodontics: Diagnosis and Treatment; Robert N. Staley, Neil T. Reske
Orthodontics: Current Principles & Techniques 5th edition; Graber, Lee W, Robert L.
Vanarsdall, and Katherine W. L. Vig
Orthodontics: The Art and Science. 3rd Edition. Bhalajhi, S.I.

35. Declaration
 For the purposes of dissemination and sharing of knowledge, these
lectures were given to several colleagues and students. It were also
uploaded to SlideShare website by the author. Colleagues and students
may download, use, and modify these materials as they see fit for non-
profit purposes. The author retain the copyright of the original work.
 The author wish to thank his family, teachers, colleagues and students
for their love and support throughout his career. I also wish to express
my sincere gratitude to all orthodontic pillars for their tremendous
contribution to our specialty.
 Finally, the author welcome any advices and enquires through his
email address: Mohanad-07@hotmail.com

36. Thank You