DEVELOPMENT OF
DENTITION AND
OCCLUSION

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INDIAN DENTAL ACADEMY
Leader in continuing dental education
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DEVELOPMENT OF DENTITION
INTRODUCTION
 Embryonic cavity is lined by
oral ectoderm
 6th week of intra uterine
life(IUL) →...
DEVELOPMENT OF TEETH
Bud

stage
Cap stage
Bell stage
Root formation

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Bud stage

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Cap stage

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Bell stage

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PERIODS OF OCCLUSAL DEVELOPMENT

1.
2.
3.
4.

Pre-dental period
Deciduous dentition period
Mixed dentition
Permanent denti...
PRE-DENTAL PERIOD
 Period

after birth during which neonate does not
have teeth
 Lasts 6 months after birth

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Gum pads



1.
2.




Alveolar processes at the time of birth
Firm,pink,horse shoe shaped,covered by
fibrous periost...
 lateral

sulcus:
transverse groove
between canine and first deciduous molar
segment.
 Useful in judging inter arch rela...


birth
At birth, no teeth are
visible. Primary teeth are
at least partially formed
and development of
permanent teeth ha...
Infantile open bite






Upper and lower gum pads are similar to each other
Upper gum pad is longer and wider
When b...
STATUS OF DENTITION
 Neonate

is without teeth for 6 months of life.
 Gum pads insufficient to accommodate
developing in...
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NATAL TEETH




Teeth erupted at the
time of birth →natal teeth
Teeth erupted during 1st
month of life →neonatal
teeth

...


Natal and neonatal teeth
mostly in mandibular
incisor region and show
familial tendencies

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DECIDUOUS DENTITION PERIOD
 1st

6 weeks of IUL →initiation of tooth buds
 Primary teeth erupt at about 6 months
 Erupt...


6 months
At six months, the four
central incisors are
visible, usually appearing
two at a time and
appearing in the low...


7-8 months
At seven or eight
months, the four lateral
incisors appear next to
the central incisors. The
primary teeth a...


12 months
At around twelve
months, the primary first
molars appear, leaving
temporary spaces
between them and the
later...


16 months
At sixteen months, the
primary canines erupt
between the lateral
incisors and first molars.

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

2 years
At two years, the second
primary molars begin to
appear, completing the
primary teeth. By age
three, they appea...
SPACING IN DECIDUOUS DENTITION
 Spaces

usually exist between deciduous teeth
→physiological or developmental spaces
 Im...
Primate spaces







Also called as simian
or anthropoid spaces
Seen mesial to
maxillary canines and
distal to mandibu...
Deep bite





May occur in initial developing stages
Accentuated by the fact that deciduous incisors are
more upright...
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Flush terminal plane
 Mesiodistal

relation between distal surfaces of
upper and lower 2nd deciduous molars is called
as ...
MIXED DENTITION PERIOD

1.
2.
3.

Begins at approximately 6yrs.Classified into:
1st transitional period
Inter transitiona...
FIRST TRANSITIONAL PERIOD



1.
2.
3.

Emergence of 1st permanent molars and exchange of
deciduous incisors with perman...
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FLUSH TERMINAL PLANE
 Mesiodistal

relation between distal surfaces of
upper and lower 2nd deciduous molars is called
as ...
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 Erupting

first molars may be in a flush or end
on relation
 For transition of such an end on molar to a
Class I molar ...
EARLY SHIFT
 Occurs during early
mixed dentition period
 Eruptive force of
permanent molar pushes
deciduous 1st and 2nd
...
MESIAL STEP TERMINAL PLANE
 Distal

surface of lower 2nd deciduous molar is
more mesial than that of upper. Thus
permanen...
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DISTAL STEP TERMINAL PLANE
 Distal

surface of lower 2nd deciduous molar lies
more distal to that of upper. Thus erupting...
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INCISAL LIABILITY
 The

exchange of lower incisors take place. The
difference between the amount of space
needed for the ...
Incisal liability
Overcome by the following factors:
1. Utilization of interdental spaces seen in
primary dentition
2. Inc...
INTER TRANSITIONAL PERIOD
 Maxillary

and mandibular arches consists of
sets of deciduous and permanent teeth
 Between p...
SECOND TRANSITIONAL PERIOD
 Replacement

of deciduous molars and
canines by premolars and permanent
cuspids respectively
...
Leeway space of Nance


Combined mesiodistal
width of permanent
canines and premolars
is usually less than that
of decidu...
Leeway space of Nance




Greater in mandibular
arch [3.4mm] than in
maxillary arch [1.8mm]
This excess space is
utilize...
Ugly duckling stage


Transient or self
correcting malocclusion
seen in maxillary incisor
region b/w 8-9yrs seen
during e...


As developing
permanent canines
erupt, they displace
roots of lateral incisors
mesially,in turn
transmitting force to
r...
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

18 years
Last teeth to appear,
the third molars, or the
wisdom teeth, erupt at
about age 18

www.indiandentalacademy.co...
THANK YOU
www.indiandentalacademy.com
Leader in continuing dental education

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Development of dentition & occlusion /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Development of dentition & occlusion /certified fixed orthodontic courses by Indian dental academy

  1. 1. DEVELOPMENT OF DENTITION AND OCCLUSION www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. DEVELOPMENT OF DENTITION INTRODUCTION  Embryonic cavity is lined by oral ectoderm  6th week of intra uterine life(IUL) →local proliferation of oral ectoderm →formation of dental lamina  Deciduous teeth →direct proliferation of dental lamina  Permanent teeth →lingual extension of dental lamina  Permanent molars →distal proliferation of dental lamina www.indiandentalacademy.com
  4. 4. DEVELOPMENT OF TEETH Bud stage Cap stage Bell stage Root formation www.indiandentalacademy.com
  5. 5. www.indiandentalacademy.com
  6. 6. Bud stage www.indiandentalacademy.com
  7. 7. Cap stage www.indiandentalacademy.com
  8. 8. Bell stage www.indiandentalacademy.com
  9. 9. PERIODS OF OCCLUSAL DEVELOPMENT 1. 2. 3. 4. Pre-dental period Deciduous dentition period Mixed dentition Permanent dentition period www.indiandentalacademy.com
  10. 10. PRE-DENTAL PERIOD  Period after birth during which neonate does not have teeth  Lasts 6 months after birth www.indiandentalacademy.com
  11. 11. Gum pads    1. 2.    Alveolar processes at the time of birth Firm,pink,horse shoe shaped,covered by fibrous periosteum Develops in two parts Labiobuccal portion Lingual portion Both portions separated by dental groove Gum pads are divided into 10 segments by transverse grooves Each segment has one developing deciduous tooth sac www.indiandentalacademy.com
  12. 12.  lateral sulcus: transverse groove between canine and first deciduous molar segment.  Useful in judging inter arch relationship at a very early stage.  Lateral sulcus of mandibular arch is more distal to that of maxillary arch www.indiandentalacademy.com
  13. 13.  birth At birth, no teeth are visible. Primary teeth are at least partially formed and development of permanent teeth has begun. www.indiandentalacademy.com
  14. 14. Infantile open bite      Upper and lower gum pads are similar to each other Upper gum pad is longer and wider When both are approximated, there is a complete overjet all around Contact occurs between upper and lower gum pads in first molar region and space exists in anterior region This infantile open bite is considered normal and helps in suckling www.indiandentalacademy.com
  15. 15. STATUS OF DENTITION  Neonate is without teeth for 6 months of life.  Gum pads insufficient to accommodate developing incisors that are crowded in crypts  1st yr of life →gum pads grow rapidly permitting incisors to erupt in good alignment. www.indiandentalacademy.com
  16. 16. www.indiandentalacademy.com
  17. 17. NATAL TEETH   Teeth erupted at the time of birth →natal teeth Teeth erupted during 1st month of life →neonatal teeth www.indiandentalacademy.com
  18. 18.  Natal and neonatal teeth mostly in mandibular incisor region and show familial tendencies www.indiandentalacademy.com
  19. 19. DECIDUOUS DENTITION PERIOD  1st 6 weeks of IUL →initiation of tooth buds  Primary teeth erupt at about 6 months  Eruption completed by 2 ½-3 ½ yrs  Sequence of eruption →A-B-D-C-E www.indiandentalacademy.com
  20. 20.  6 months At six months, the four central incisors are visible, usually appearing two at a time and appearing in the lower jaw first www.indiandentalacademy.com
  21. 21.  7-8 months At seven or eight months, the four lateral incisors appear next to the central incisors. The primary teeth are bluish white. www.indiandentalacademy.com
  22. 22.  12 months At around twelve months, the primary first molars appear, leaving temporary spaces between them and the lateral incisors www.indiandentalacademy.com
  23. 23.  16 months At sixteen months, the primary canines erupt between the lateral incisors and first molars. www.indiandentalacademy.com
  24. 24.  2 years At two years, the second primary molars begin to appear, completing the primary teeth. By age three, they appear completely www.indiandentalacademy.com
  25. 25. SPACING IN DECIDUOUS DENTITION  Spaces usually exist between deciduous teeth →physiological or developmental spaces  Important for normal development of 2°dentition  Absence of spaces is an indication that crowding of teeth may occur in 2°dentition www.indiandentalacademy.com
  26. 26. Primate spaces    Also called as simian or anthropoid spaces Seen mesial to maxillary canines and distal to mandibular canines Helps in placement of canine cusps of opposing arch www.indiandentalacademy.com
  27. 27. Deep bite     May occur in initial developing stages Accentuated by the fact that deciduous incisors are more upright Lower incisal edges often contact cingulum area of maxillary incisors Later reduced by 1. Eruption of deciduous molars 2. Attrition of incisors 3. Forward growth of mandible www.indiandentalacademy.com
  28. 28. www.indiandentalacademy.com
  29. 29. Flush terminal plane  Mesiodistal relation between distal surfaces of upper and lower 2nd deciduous molars is called as flush terminal plane  Normal feature of deciduous dentition where second deciduous molars are in same vertical plane www.indiandentalacademy.com
  30. 30. MIXED DENTITION PERIOD  1. 2. 3. Begins at approximately 6yrs.Classified into: 1st transitional period Inter transitional period 2nd transitional period www.indiandentalacademy.com
  31. 31. FIRST TRANSITIONAL PERIOD    1. 2. 3. Emergence of 1st permanent molars and exchange of deciduous incisors with permanent incisors 1st permanent molar erupts at 6yrs-guided into the dental arch by distal surface of 2nd deciduous molar Mesiodistal relation between distal surfaces of upper and lower deciduous molars are of 3 types Flush terminal plane Mesial step terminal plane Distal step terminal plane www.indiandentalacademy.com
  32. 32. www.indiandentalacademy.com
  33. 33. www.indiandentalacademy.com
  34. 34. FLUSH TERMINAL PLANE  Mesiodistal relation between distal surfaces of upper and lower 2nd deciduous molars is called as flush terminal plane.  Normal feature of deciduous dentition where second deciduous molars are in same vertical plane. www.indiandentalacademy.com
  35. 35. www.indiandentalacademy.com
  36. 36.  Erupting first molars may be in a flush or end on relation  For transition of such an end on molar to a Class I molar relation, lower molar has to move forward by about 3-5mm relative to upper molar  This can occur in 2 ways. By early shift or late shift www.indiandentalacademy.com
  37. 37. EARLY SHIFT  Occurs during early mixed dentition period  Eruptive force of permanent molar pushes deciduous 1st and 2nd molars in the arch to close primate space and establishing Class I LATE SHIFT  Occurs during late mixed dentition period  In children who lack primate space, when the deciduous molars exfoliate the permanent 1st molars drift mesialy utilizing leeway space. www.indiandentalacademy.com
  38. 38. MESIAL STEP TERMINAL PLANE  Distal surface of lower 2nd deciduous molar is more mesial than that of upper. Thus permanent molars directly erupt into Angles Class I occlusion  Occurs due to early forward growth of mandible www.indiandentalacademy.com
  39. 39. www.indiandentalacademy.com
  40. 40. DISTAL STEP TERMINAL PLANE  Distal surface of lower 2nd deciduous molar lies more distal to that of upper. Thus erupting permanent molars maybe in Class II relation www.indiandentalacademy.com
  41. 41. www.indiandentalacademy.com
  42. 42. INCISAL LIABILITY  The exchange of lower incisors take place. The difference between the amount of space needed for the accomodation of incisors and the space available for this →incisal liability  It is roughly 7mm in upper arch and 5 mm in lower arch www.indiandentalacademy.com
  43. 43. Incisal liability Overcome by the following factors: 1. Utilization of interdental spaces seen in primary dentition 2. Increase in inter- canine width 3. Change in incisor inclination www.indiandentalacademy.com
  44. 44. INTER TRANSITIONAL PERIOD  Maxillary and mandibular arches consists of sets of deciduous and permanent teeth  Between permanent incisors and permanent 1st molars are deciduous canines and molars  This phase during mixed dentition stage is relatively stable and no change occurs www.indiandentalacademy.com
  45. 45. SECOND TRANSITIONAL PERIOD  Replacement of deciduous molars and canines by premolars and permanent cuspids respectively www.indiandentalacademy.com
  46. 46. Leeway space of Nance  Combined mesiodistal width of permanent canines and premolars is usually less than that of deciduous canines and molars, this is Leeway space of Nance www.indiandentalacademy.com
  47. 47. Leeway space of Nance   Greater in mandibular arch [3.4mm] than in maxillary arch [1.8mm] This excess space is utilized for mesial drift of mandibular molars to establish Class I molar relation www.indiandentalacademy.com
  48. 48. Ugly duckling stage  Transient or self correcting malocclusion seen in maxillary incisor region b/w 8-9yrs seen during eruption of permanent canines www.indiandentalacademy.com
  49. 49.  As developing permanent canines erupt, they displace roots of lateral incisors mesially,in turn transmitting force to roots of central incisors which gets displaced mesially. Resultant divergence of crown causes midline spacing www.indiandentalacademy.com
  50. 50. www.indiandentalacademy.com
  51. 51. www.indiandentalacademy.com
  52. 52.  18 years Last teeth to appear, the third molars, or the wisdom teeth, erupt at about age 18 www.indiandentalacademy.com
  53. 53. THANK YOU www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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