The document discusses the development of occlusion from birth through adulthood. It covers the pre-dentate period where gum pads are present, the primary dentition period where baby teeth erupt, the mixed dentition period where permanent teeth start coming in, and the permanent dentition period when all adult teeth have erupted. Key aspects discussed include the sequence of tooth eruption, characteristics of different dentition stages like overbite and spacing, self-correcting anomalies, and factors that influence occlusion development.

1. PRESENTED BY
SHYAM A CHANDAK
I MDS
Development of Occlusion

2. Contents
• Introduction
 Why to Study
Occlusion
 Stages of Occlusal
development
 Pre Dentate
Period
 Gum Pads
 Primary Dentition
Period
 Mixed Dentition
Period
 Permanent
Dentition Period
• Self Correcting
Anomalies
• Factors Affecting
the Development
of Occlusion
 References

3. INTRODUCTION
 Development of occlusion is a genetically and
environmentally conditioned process.
 The term Occlusion is derived from the Latin word
“Occluso”.
 According to Ash & Ramfjord occlusion is defined
as “the contact relationship of the teeth in function
or Para function”.
 According to Angle occlusion is defined as “the
normal relation of the occluscal inclined planes of
the teeth when the jaws are closed.

4. Why to Study Occlusion
 Occlusion from the time of birth till the adult age is
the dynamic stage .
 A knowledge of growth and development of arches
helps to differentiate abnormal from normal relation
of teeth and helps in diagnosis.
 Helps in treatment planning.

5. Stages of Occlusal development
• Pre-Dental Stage.
• 0-6 Months
• Deciduous Dentition Period
• 6 Months -6 Years
• Mixed Dentition Period
• 6-12 Years.
• Permanent Dentition Period

6. Pre Dentate Period

7. Gum Pads
 The alveolar process at the time of birth is known as
GUM PADS.
 They are horse-shoe
shaped pads that are
pink ,firm and covered
with the layer of dense
periosteum.

8.  They are divided into Two Parts :Labiobuccal &
Lingual by dental groove.
 The gum pad is further divided
Into 10 Segments by transverse
groove; each segment has one
Developing tooth sac.

9.  The upper and lower gum pad are almost similar to
each other .
 The upper gum pad is both wider as well as longer
than the mandibular gum pad.
 Thus when upper and lower gum pad approximated,
there is complete overjet all around.

10. Maxillary Gum Pad
 The Upper gum pad is Horse-Shoe Shaped and
shows
 Gingival Groove : Separates Gum Pad From the
palate
 Dental Groove: Starts at the
Incisive papilla, extends backward
to touch the gingival groove in the
Canine region and moves laterally
to end in the molar region.

11. Mandibular Gum Pad
 The lower gum pad is ‘U’ shaped and rectangular,
Characterized by
Gingival groove : Lingual extension of the pads .
Dental groove :
Lateral sulcus :

12. Relationship of Gum Pad
 Anterior open bite is seen at rest with the contact
only at molar region.
 Complete Overjet
 Class II Pattern with maxillary gum pad being more
prominent

13. Status of Dentition at Birth

14. Natal and Neo Natal Tooth

15.  Neonate is without teeth for about 6 months of life.
 At Birth gum pads are not sufficiently wide to
accommodate the developing incisors which are
crowded in their crypts.
 During the first year of life the gum pads grow
rapidly permitting the incisor to erupt in good
alignment.
 Very rarely teeth are found to have erupted at the
time of birth or within a month after birth.

16.  The incidence of natal teeth is approximately 1:2,000
to 1:3,000 live births.
 The most commonly affected teeth are the lower
primary central incisors
 The teeth are often smaller, conical and yellowish,
and have hypoplastic enamel and dentin with poor or
absent root formation.
Reference :Leung AK, Robson WL. Natal teeth: a review. J Natl Med Assoc. 2006
Feb;98(2):226-8. PMID: 16708508; PMCID: PMC2595049.

17.  If the tooth does not interfere with breastfeeding and
is otherwise asymptomatic, no intervention is
necessary.
 Tooth extraction is indicated if the tooth is
supernumerary or if the tooth is poorly implanted
and excessively mobile, which is associated with a
risk of aspiration.
Reference :Leung AK, Robson WL. Natal teeth: a review. J Natl Med Assoc. 2006
Feb;98(2):226-8. PMID: 16708508; PMCID: PMC2595049.

18. Riga-Fedes syndrome: Natal or neonatal teeth associated with tongue ulceration.
Case report
 A case of natal teeth associated with traumatic
ulceration to the ventral surface of the
tongue(Riga-Fedes syndrome ) in a four week old
boy is presented.
 On radiographic examination two teeth present at
birth, were found to be early erupted deciduous
lower central incisors.

19.  A family history of natal teeth, all involving both
lower deciduous central incisors associated with
trauma to the tongue during suckling, was elicited.
• The ulceration healed over a period of four weeks
using an innovative conservative treatment regime,
involving the use of Stomahesive Wafer.

20.  Four months later the only sign of any previous
pathosis was a fibrous scar on the ventral surface of
the tongue
Refernce:Buchanan S, Jenkins CR. Riga-Fedes syndrome: natal or neonatal teeth associated with tongue
ulceration. Case report. Aust Dent J. 1997 Aug;42(4):225-7. doi: 10.1111/j.1834-7819.1997.tb00125

21. Primary Dentition Period

22. Chronology of Primary Dentition Period
Reference :Lunt, Roger C.; Law, David B. (1974). A review of the chronology of eruption of
deciduous teeth. The Journal of the American Dental Association, 89(4), 872–
879. doi:10.14219/jada.archive.1974.0484

23. Reference :Lunt, Roger C.; Law, David B. (1974). A review of the chronology of eruption of deciduous teeth. The Journal of the
American Dental Association, 89(4), 872–879. doi:10.14219/jada.archive.1974.0484

24. Sequence Of Eruption
A B D C E

25. Rule of “7+4”
 A helpful mnemonic to remember the timing of
primary eruption is the 7+4 rule .
 At 7 months of age ,children should have their first
teeth;
 At 11 months (4months later),they should have 4
teeth.
 At 15 months of age (4months later), they should
have 8 teeth;
 At 19 months, they should have 12 teeth;

26.  At 23 months, they should have 16 teeth;
 At 27 months, they should have 20 teeth;

27. Status of Dentition

28. Characteristics of Primary Dentition
• Over bite
 Overjet
 Spacing
 Relationship of the second primary molar
Reference : Dentistry for the Child and adolescent :Jeffrey Dean, Second South Asia Edition

29. Spacing
 The presence of Spacing in the primary dentition
stage is common occurrence
 According to Foster, two generalized spacing occur
in almost two-thirds of the individuals in primary
dentition stage .
Reference : Dentistry for the Child and adolescent :Jeffrey Dean, Second South Asia Edition

30. Spacing
According to Baume 1950,deciduous dentition can
be categorized as:
Type I, with interdental spaces also referred as open
dentition.
Type II without interdental spaces also be referred as
closed dentition
Reference :Baume, L. J. (1950). Physiological Tooth Migration and its Significance for the Development of Occlusion: I.
the Biogenetic Course of the Deciduous Dentition. Journal of Dental Research, 29(2), 123–
132. doi:10.1177/00220345500290020301

31. A) Spaced Dentition
 Spaced Dentition is supposed to be good as spaces in
between the teeth can be utilized for adjustment of
permanent successors, which are always larger in
size compared to deciduous teeth.

32. Primate Space :
 Spacing seen in mesial to maxillary canine and distal
to the mandibular canines are wider than in other
spaces.
 These spaces are also called as anthropoid spaces or
simian spaces.
 They help in placement of
Canine cusp of opposing
arch.

33.  Primate spaces are present in 87% of the maxillary
arches usually between the lateral incisors and canines.
 The primate spaces are also present in 78% of the
mandibular arches, usually between the canines and first
primary molars.
 The amount of primate space in maxilla is around
1.7mm and in mandible is 1.5 mm
 These space is used for early mesial shift
Reference :Textbook : Dentistry for the Child and adolescent :Jeffrey Dean, Second South Asia Edition
Textbook : Bhalajhi, S.I. (2006) Orthodontics: The Art and Science. 3rd Edition, Arya (Medi) Publishing House, New Delhi

34. Physiologic Spaces
 Frist described by Dellabare 1819.
 These spaces are present in between the primary teeth
and plays an important role in normal development of
permanent dentition
 The total space present vary from 0 to 8 mm with an
average 4 mm in maxillary arch and 1-7 mm with an
average 3 mm in mandibular arch
Reference : Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition

35. B} Non-Spaced Dentition:
 Teeth are present
without any spaces in
between the teeth.
 Due to narrow dental
arches or if teeth are wider
than usual.
 May indicate crowding
in developing permanent
dentition.
Reference : Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition

36. Shallow overjet & overbite
 Initially a deep bite may occur due to the fact that
the deciduous incisors are more upright than their
successors. The lower incisal edges often contact the
cingulum area of the maxillary incisors . This deep
bite is later reduced by:
 Eruption of deciduous molars.
 Attrition of incisors.
 Forward movement of the mandible due to growth.

37. Development of Molar Relationship
 The cone-shaped cusps of the maxillary posterior
teeth and the crater-like occlusal anatomy of their
antagonists are held responsible for a guided
emergence toward each other by the so-called cone-
funnel mechanism . (Schwarz, 1951)
 In most instances, the large palatal cusp of maxillary
first deciduous molar arrives with its cone shaped
within the fossa of the mandibular first molar.

38.  The fossa will function as a funnel by which both the
teeth are directed towards each other in proper
position.
Reference :J. M. Ostyn, I. Hons, J. C. Maltha, M. A. van 't Hof, F. P. G. M. van der Linden, Contribution of
interdigitation to the occlusal development of the dentition in Macaca fascicularis, European Journal of
Orthodontics, Volume 19, Issue 5, October 1997, Pages 531–542

39. Molar Relationship
 The mesio-distal relation between the distal surface
of maxillary and mandibular 2 nd deciduous molar is
called as terminal plane .
 This is of three types

40. Flush Terminal Plane
 If the distal surface of maxillary
and mandibular deciduous second
molars are in same vertical plane;
Then it is called as flush terminal
Plane.
 It is a normal molar relationship
in the primary dentition, because
the mesiodistal width of the mandibular molar
is greater than the mesiodistal width of maxillary
molar.

41. Mesial Step:
 Distal surface of mandibular deciduous second
molar is mesial to the distal surface of maxillary
deciduous second molar.
 It can processed to end on/half cusp relationship or
classIII relationship with continued
mandibular growth.

42. Distal Step
 Distal surface of mandibular second deciduous molar
is more distal to the distal surface of the maxillary
second deciduous molar.
 It is prognostically unfavourable as it guide the
permanent molar in class II malocclusion
Reference :Reference : Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition page no 177

43.  Nanda et al.reported that 52% of Indian children had
flush terminal relationship,25.5% had mesial step,
9 % had distal step and 7.5% had asymmetric molar
relationship.
Nanda RS, Khan I, Anand R. Age Changes in the Occlusal Pattern of Deciduous Dentition. Journal of Dental Research. 1973;52(2):221-224.
doi:10.1177/00220345730520020601

44.  According to study by Bishara et al, the distribution
of terminal plane realtionship was found to be :
Distal Step :10%
Flush Terminal Plane -29%
Mesial step of 0-1 mm -42%
Mesial step of more than 1 mm -19%
Reference :Bishara, Samir E.; Hoppens, Brad J.; Jakobsen, Jane R.; Kohout, Frank J. (2014). Changes in
the molar relationship between the deciduous and permanent dentitions: A longitudinal study. , 93(1),
19–28. doi:10.1016/0889-5406(88)90189-8

45. Development of Primary Occlusion
 Teeth are guided into their occlusal position by
functional matrix of muscles during the active
growth of facial skeleton.
 Low cusp height and occlusal surface wear
contribute to the adaptability of primary occlusion.
 With the functioning of peri-oral muscle the arch
shape is altered by muscular activities.
 Primary dental arch is ovoid and tounge plays a role
in shaping of dental arches in early stages.

46.  With the eruption of the primary first molar the first
three dimensional occlusal relationship is
established.
 All the primary teeth expect mandibular central
incisors and maxillary 2 nd molar occlude with two
tooth of opposing jaw.

47. In maxilla :
 Increased intermolar width of 2mm between 3-5 years.
 Palatal vault increases from birth to about 12 months and
remains relatively constant throughout the first 2 years.
In Mandible:
 Increased intermolar width of 1.5mm between 3-5 years
 Increase in height of alveolar bone .
Reference : Development of the Human Dentition - An Atlas by Frans P G M van der Linden DDS PhD and Herman S
Duterloo DDS PhD

49. Self Correcting Anomalies
 Anterior deep bite
Correction:
Forward and Downward growth of mandible.
Attrition of incisal edges
Eruption of permanent molars
Reference : Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition

50.  Primate spaces
 Early Mesial Shift
 Flush Terminal Plane
Early Mesial Shift
Late Mesial Shift
 Physiologic Spaces
Permanent incisor accommodation.
Reference : Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition

51. Mixed Dentition Period
 Around 6 years - 12 years age

52. Successional teeth: Those permanent teeth that
follow into a place in the arch once held by primary
tooth
Eg : Incisors, Canine ,Premolar
Accessional teeth : Those permanent teeth that
erupt posteriorly to the primary teeth
Eg: Molars

53. Mixed dentition period can divided into Three
phases :
 First Transitional period (6 to 8 year age)
 Inter Transitional period.
 Second Transitional period (10to 12 year age)

54. First Transitional Period
Emergence of the First Permanent Molar Exchange Of Incisors

55. A) Emergence of the First Permanent Molar:
 Permanent First Molar erupt at the age of 6 years .
 They are guided into position by
the distal surface of the primary second
molar.
 The future molar relationship of the permanent
dentition depends upon the distal relationship of
upper and lower primary second molar.
First Transitional period

56.  Shift in lower molar from the initial relation to the
final occlusion can occur in two ways.
 Designated as Early and Late mesial Shift .
 Early Shift Uses Primate Space.

57.  Late Shift Uses Leeway Space.

58. Occlusion of first permanent molar when
deciduous molars are in flush terminal plane
relation :
 Erupting first permanent molars may also be in a
flush or end on relation .
 For transition into Class I molar relation it utilizes
primate space and by differential forward growth of
mandible
 Early shift occurs during early mixed dentition
period.

59.  In absence of primate space, after exfoliation of
primary second molar the mandibular permanent Ist
molar utilizes the leeway space of Nance and drift
mesially.
 This occurs in late Mixed dentition period and it is
called as late mesial shift.

60. Occlusion of first permanent molar when
deciduous molars are in mesial terminal plane
relation :
 In such case permanent molars erupt directly into
Angle Class I occlusion.
 Mesial Step terminal plane occurs due to early
forward growth of mandible.
 If the differentiated growth of the mandible is in a
forward direction, it can lead to an Angle Class III
molar relation.

61.  If it is minimal it can establish a Class I molar
relationship.

62. Occlusion of first permanent molar when
deciduous molars are in distal step terminal
plane relation :
 The erupting permanent molars may be in Angle
Class II occlusion.
 Later the relation may be shift to class I if the
forward mandibular growth is extensive.

63. Ref : Moyers RE.Handbookm of orthodontics,edition 3,1973

64. B} The Exchange of Incisors:
 During the first transitional period the deciduous
incisors are replaced by the permanent incisors.
 The permanent incisors are considerably larger than
the deciduous teeth they replace.
 This difference between the amount of space needed
for the accommodation of the incisors and the
amount of the space available for this is called as
Incisal liability described by Warren Mayne 1969
 7.6 mm in Maxillary and 6 mm in Mandibular arch.

65. Incisal liability is overcome by 3 Mechanisms :
Inter dental physiological spacing in the primary
incisor region .
4 mm in maxillary arch and 3 mm in mandibular arch

66. Increase in inter-canine arch width :
 During the Period of Permanent Incisor eruption,
significant amount of increase in intercanine arch.

67. Change in inclination of permanent incisors:
 When the permanent incisors erupt, they are assume
somewhat more anteriorly inclined position than
deciduous incisors.
 Primary teeth are upright but permanent teeth are
incline to the labial surface thus decreasing the inter
incisal angle from about 151 degree to 124 degree in
permanent dentition.
 This increases the arch perimeter

68. Inter Transitional Period
 This is the Stable phase, little changes take place in
the dentition.
 The teeth present are the permanent incisors and
first molar along with the deciduous canine and
molars.
 This phase prepares for the second transitional
phase.

69. Some of the features of this stage are:
 Any asymmetry in emergence and corresponding
differences in height levels or crown lengths between
the right and left side teeth are made up.
 Root formation of emerged incisors, and molars
continues along with concomitant increase in
alveolar process height.
 Resorption of roots of deciduous canine and molars.

72. Second Transitional Period
 The second transitional period is characterized by
the replacement of the deciduous molars and canine
by the premolars and permanent canines
respectively.
 The features of second transitional period are :
Leeway Space of Nance
Ugly Duckling Stage

73. Leeway Space Of Nance
 The combined mesio-distal
width of the permanent
canine and premolars
is usually less than
that of the deciduous
canine and molars .
 This surplus space is called Lee-
way space of nance.

74.  Maxilary arch =1.8mm (0.9mm on each side )
 Mandibular arch =3.4mm (1.7mm on each side )
 Utilized for the mesial drift of the mandibular molars
to establish Class I molar relation.
 Leeway space is greater in the mandible than in the
maxilla and facilitates a greater mesial movement of
he lower permanent molar in relation to upper ones,
which results in change from possible cusp to cusp
molar relationship to a normal molar interrelation.
Reference :Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition Page no 181

75. Ugly Duckling Stage

76.  It is a transient or self correcting malocclusion
seen in the maxillary incisor region
 Seen in the children between 8-9 years of age,
during eruption of permanent canine.
 Its typical features are:
-- Flaring of the lateral incisors.
--- Maxillary midline diastema

77. How it Develops ????
 Crowns of canine in
young jaw impinge on
developing lateral incisor
roots, thus driving the roots
medially and causing the
Crowns to flare laterally.

78.  The roots of the central incisors are also forced
together, thus causing a maxillary midline diastema.

79.  With the eruption of the canine,
the impingement from the
root shifts incisally
thus driving the
incisor crowns medially,
Resulting in closure
of the diastema as well as
the correction of the flared
lateral incisors.

80.  Hence this unaesthetic
metamorphosis,
eventually leads
to an aesthetic results.

82. Favourable occlusion in this period is largely
dependent on:
 Favourable eruption sequence.
 Satisfactory tooth size to available space ratio.
 Attainment of normal molar relation with minimum
diminution of space available for the bicuspids

83. Permanent Dentition Period
 The entire permanent dentition is formed within the
jaws after birth expect for the cusps of the first molar
which are formed before birth.

84. Chronology of Eruption

85. Eruption of Permanent Second Molar :
 Before emergence, second molar are oriented in a
mesial and lingual direction.
 Teeth- formed palatally,guided into occlusion by
Cone Funnel Mechanism, Upper palatal cusps (cone)
slides into the lower occlusal fossa (funnel).
 Arch length is reduced by mesial eruptive forces.
 Thereby, crowding if present is accentuated.

86.  At approximately 13 years of age all permanent teeth
expect third molars are fully erupted.

87. Key of Occlusion :
 Permanent dentition after establishing itself is
governed by various factors.
 These were underlined as
ANDREW SIX KEY OF OCCLUSION
 Put forward by
Dr Lawrence F Andrew
in 1972 he hypothesized
that the presence of these
features is necessary
for an ideal occlusion.

88. Andrews 6 Keys to Normal Occlusion
Key I-Molar Relationship :
 MB cusp of the max 1st molar
falls into the mesio-buccal
groove of the mandibular
1st molar and that the distal
surface
of the DB cusp of the upper first
permanent molar should make
contact and occlude with mesial
surface of the MB cusp of lower second molar.

89. Key II-Crown Angulation :
 The gingival portion of
the long axis of all the
Crowns must be distal
Than the incisal portion.
 The angulation of the facial
Axis of every clinical crown
Should be positive.

90. Key III-Crown Inclination :
 Cervical area of the crown
is lingually placed then it
is called as
Positive crown inclination
and if it is more buccally then
it is called as negative crown inclination.
 Maxillary incisors : + ve
 Mandibular incisors and maxillary and mandibular
Posterior :- ve

91. Key IV-Rotations:
 The fourth key to normal occlusion is that teeth
should be free of undesirable rotations.

92. Key V-Tight Contacts :
 Contact points should be tight (No Spaces).
 In absence of abnormalities
Such as genuine tooth size discrepancies,
Contact point should be tight.

93. Key VI-Curve of Spee:
 The curve of Spee should have no
more than a slight arch.
(not exceeding 1.5mm)
 Intercuspation of teeth is best
when the plane of occlusion is relatively
flat.
 A deep curve of spee results in a more
contained area for the upper teeth, making
normal occlusion impossible.

94. Key VII-Correct tooth size or the Bolton ratio:
 Bennett and Mc Laughlin in 1993 gave seventh key of
normal occlusion i.e the upper and lower tooth size
should be correct.
Reference : Deepti S. Fulari, Sangamesh G. Fulari, Vishwal A. Kagi, Jiwanasha M. Agrawal. Seventh key of occlusion.
International Journal of Contemporary Medical Research 2016;3(7):2108-2110.

95. Changes in Permanent Occlusion
Arch Dimensional Changes :
 Arch length decreases to a surprising amount during
the late adolescent period.
 Fish found that Mandibular arch perimeter decrease
by 0.5mm between 9-16 years whereas maxillary
arch perimeter decreased by about half the amount
as it was in the mandibular arch.

96. Occlusal changes :
 Both the overjet and overbite decreases throughout the
second decade of life.
 It is due to greater forward growth of the mandible and
eruption of permanent molar.
 Overbite decreases up to the age of 18 years by 0.5mm
 Overjet decreases by 0.7mm between 12 and 20 years of
age.
 The alveolar process may grow in height beyond 16 years
of age .
Reference:Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition page no 184

97. Self Correcting Anomalies
Reference : Textbook of Pediatric Dentistry ,Shobha Tandon ,Third Edition Page no 183

98. Factors Affecting the Development of Occlusion
General Factors:
 Skeletal Factors : the position, size and relation of bone
in which the tooth develops.
 Muscle Factors : the form and function of the muscle
which surrounded the teeth.
 Dental Factors : the size of the dentition in relation to the
size of the jaws.
 The position and relationship of teeth within the bone
Reference :American Academy of Pediatric Dentistry. Management of the developing dentition and
occlusion in pediatric dentistry.The Reference Manual of Pediatric Dentistry. Chicago, Ill.: American
Academy of Pediatric Dentistry; 2021:408-25.

99. Local Factors:
 Aberrant developmental position of teeth.
 The presence of supernummery teeth.
 Hypodontia – Congenital absence of certain teeth.
 Localized soft tissue anomalies – labial frenum
Reference :American Academy of Pediatric Dentistry. Management of the developing dentition and
occlusion in pediatric dentistry.The Reference Manual of Pediatric Dentistry. Chicago, Ill.: American
Academy of Pediatric Dentistry; 2021:408-25

100. References
 Textbook-Dentistry for the Child and Adolescent –
MC Donald
 Hadbook of Orthodontics : Robert Moyers
 Orthodontics Art and Science : S I Bhalajhi
 Textbook of Paediatric Dentistry : S. J Damle
 Textbook of Paediatric Dentistry: Shobha Tandon
 Textbook of Dental Anatomy,Physiology and
Occlusion : Wheelers