PRENATAL AND
POSTNATAL
DEVELOPMENT
OF MANDIBLE

INDIAN DENTAL ACADEMY

Leader in continuing dental education
www.indianden...
PRENATAL
DEVELOPMENT
OF MANDIBLE

www.indiandentalacademy.com
CONTENTS
1. Period of Ovum
2. Period of Embryo
3. Period of Fetus
4. Meckel’s cartilage
5. Neonatal mandible
www.indianden...
Period of Ovum
• 2 weeks
• 1.5 mm in length
• Cephalad differentiation not begun

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Embryonal Period
• 14th to 56th day
• 3rd week- 3 mm
• 4th week- 5mm

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4 week embryo
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Contents of Mandibular Arch
1. Meckel’s cartilage
2. Musculature
3. Mandibular nerve
4. Maxillary and External Carotid Art...
www.indiandentalacademy.com
Fetal period
• 8th week till birth
• Tremendous acceleration is the theme
• Meckel’s cartilage- precursor of
mandibular me...
Mandibular changes
•

STUDY OF HUMAN FETAL MANDIBLE
—Ingham, J. Dent. Res, 1932

• Observations:1. The alveolar plate leng...
3. The width of the alveolar plate shows a
more rapid increase than does total
width
4. The ratio of the width between the...
www.indiandentalacademy.com
Meckel’s Cartilage
• 41st – 45th day of IUL
• Template
• Otic capsule - Symphysis

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Ossification of Meckel’s
cartilage
• Mandibular nerve

Neurotrophic
factor
Osteogenesis
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Ossification of Meckel’s
cartilage
Ectomesenchymal condensation at 36-38 days

Osteogenic membrane

Primary ossification

...
Ossification of Meckel’s
cartilage
• Begins during 7th week
Woven bone

Lamellar bone

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Haversi...
Fate of Meckel’s Cartilage
1. Disappears by 24th week
2. Sphenomandibular ligament
3. Resorbs on lateral surface dorsal to...
www.indiandentalacademy.com
Fate of Meckel’s Cartilage

10th & 14th week
Sec. accessory
cartilages appear

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Condylar Cartilage
Growth rate increases at
puberty(12 1/2-- 14 yrs) and
ceases by 20 yrs

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Types of Ossification
•

1st one to ossify- 6th week of I.U.L

•

Two types of ossification:-

1. INTRAMEMBRANEOUS
2. ENDO...
Parts of Mandible derived from
• INTRAMEMBRANEOUS Ossification
1. Whole of body except anterior part
2. Ramus as far as ma...
NEONATAL MANDIBLE
• Low and wide ascending ramus
• Coronoid process is large
• Body- open shell
• Mandibular canal runs lo...
NEONATAL MANDIBLE
www.indiandentalacademy.com
Differential Growth

At Birth

Fetal life
8 weeks– mandible>maxilla

Mandible retrognathic

11 weeks– mandible=maxilla

Ea...
POST NATAL GROWTH OF
MANDIBLE

www.indiandentalacademy.com
Contents
1.
2.
3.
4.
5.
6.
7.

Theories of growth
Mechanisms of bone growth
Skeletal units of mandible
Main sites of growt...
Theories of Growth
1. Genetic theory- Brodie,1941
2. Scott’s hypothesis, 1953
3. Sutural dominance theory- Sicher, 1955
4....
Mechanisms of Bone Growth
1. REMODELING

2. DISPLACEMENT:• Primary displacement
• Secondary displacement

www.indiandental...
www.indiandentalacademy.com
Enlow’s “V” Principle
• Growth movement
and enlargement
of many facial and
cranial bones or
parts of bones
occur towards t...
Enlow’s Counterpart Principle
• Growth of any given facial or cranial part
relates specifically to other structural and
ge...
Growth Timings
•

Overall growth of mandible takes place
at different stages

•
1.
2.
3.

First there is increase in its
W...
Skeletal Units of Mandible

www.indiandentalacademy.com
Main sites of growth of Mandible
•

Mandible undergoes largest amount of
growth postnatally and exhibits largest
variabili...
www.indiandentalacademy.com
Symphysis Menti
• 4-12th month after birth, syndesmosis is
converted to synostosis
• No widening after fusion

www.indiand...
Mental Foramen

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Alveolar Process
• Adds to height of mandible
• Tooth absent- process fails to develop
• After tooth extraction, alveolar ...
Alveolar Process
• Buffer zone
• Adaptive
remodeling
makes
orthodontic tooth
movement
possible
www.indiandentalacademy.com
Ramus
• Bridges pharyngeal
compartment
• Mandible in
occlusion with
maxilla
• Remodeled in a
posterosuperior
manner
www.in...
Ramus to Corpus Remodeling
Bicondylar dimension established early
in childhood

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Ramus to Corpus Remodeling
• Making room for
molars

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Ramus and Middle Cranial Fossa
• Provides developmental potential for
adaptations required to place the corpus
in a contin...
• Antegonial notch• Single field of
resorption
• Mandibular foramen• Relocates backward
and upwards
• Sustains midway
loca...
Size of notch
depends
On angle

www.indiandentalacademy.com
Lingual tuberosity
• Anatomic equivalent of maxillary
tuberosity
• Boundary between ramus and corpus
• Remodels in posteri...
www.indiandentalacademy.com
www.indiandentalacademy.com
Coronoid Process
• Propeller like twist

www.indiandentalacademy.com
Vertical V

Horizontal V
www.indiandentalacademy.com
www.indiandentalacademy.com
The Mandibular Condyle
• Historically- regarded as kind of
cornucopia
• No longer believed as a pacesetting
“master centre...
The Mandibular Condyle
• Dual function1. Articular
2. Growth
Not a primary center of growth but rather
1. Secondary in Evo...
Condylar Growth Mechanism
• Special non vascular tissue
• Firm hydrophillic intercellular matrix
• Endochondral growth mec...
Histology of Condyle
• Capsular layerpoorly vascularised
• Proliferative layerprechondroblasts
closely packed with
scanty ...
• Proliferative process
produces upward
and backward growth
movement
• Multidirectional
proliferative capacity

www.indian...
Neck of the Condyle
• Lingual and buccal
surfaces resorptive
• Condyle becomes
neck after
remodeling
• Endosteal surfaces
...
The Condylar Question?
•
•

Mandibles totally lacking condyles exist
in nature
Occupy normal anatomic position and
proper ...
The Condylar Question?
•
•
•
•

1955- Weinmann and Sicher
Major growth center
Explanation seems to be logical
Charlier and...
The Condylar Question?
• 1962- Moss, Functional matrix Hypothesis
• Questions the primacy of Sicher theory
• Condyle is un...
The Condylar Question?
•
•
•
•

1963- Koski et al
Transplanted mandibular ramus of the rat
Recovered tissue was same as or...
Current concept
•
•

Enlow
Condyle does have intrinsic genetic
programming but extra condylar factors
are needed
• Extra c...
• More recent studies involve NerveMuscle-Connective tissue pathways
• Periodontal membrane and soft tissue
matrix--- sens...
Adaptive Role of Condyle
• Multidirectional growth potential
• If growth of mandible were
preprogrammed within condyle, ma...
Chin
• Protrusive chin is characteristic of humans
• Males- more prominent
• Females- less prominent

www.indiandentalacad...
Mental Protuberance
• Formed by mental
ossicles
• Poorly developed in
infants
• Forms by osseous
deposition
• Reversal lin...
Factors affecting mandibular
growth
•
1.
2.
3.
4.

Systemic factors
Genetic
Hormonal
Nutritional
Illness

www.indiandental...
Factors affecting mandibular
growth
•
1.
2.
3.
4.

Local factors
Ankylosis
Trauma
Birth injury
Ear infection

www.indiande...
Anomalies of mandible
•

Syndromes associated with mandible
1. Pierrie robin syndrome
2. Treacher collins syndrome
3. Marf...
Anomalies of mandible
•

Congenital anomalies
1. Agnathia
2. Micrognathia
3. Macrognathia

www.indiandentalacademy.com
Anomalies of mandible
•
1.
2.
3.
4.

Developmental anomalies
Torus mandiularis
Stafne’s cyst
Achondroplasia
Odontogenic cy...
Touras mandibularis

Stafne’s cyst

www.indiandentalacademy.com
Age changes of Mandible
At birth

Adult

Old age

1 Mental
foramen

Near the lower
border

Midway b/n upper
& lower border...
References
1. Human anatomy- B.D. Chaurasia
2. Human Embryology- I.B Singh
3. Craniofacial embryology – SPERBER
4. CranioF...
5. Contemporary orthodontics – PROFFIT
6. Principles and practice of orthodontics –
T.M GRABER
7. Study of human fetal man...
There is
nothing
new under
the sun

But there are
lot of old
Things we
don’t know

Thank You
www.indiandentalacademy.com
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Prenatal and postnatal development of mandible /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.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
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Transcript of "Prenatal and postnatal development of mandible /certified fixed orthodontic courses by Indian dental academy "

  1. 1. PRENATAL AND POSTNATAL DEVELOPMENT OF MANDIBLE INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. PRENATAL DEVELOPMENT OF MANDIBLE www.indiandentalacademy.com
  3. 3. CONTENTS 1. Period of Ovum 2. Period of Embryo 3. Period of Fetus 4. Meckel’s cartilage 5. Neonatal mandible www.indiandentalacademy.com
  4. 4. Period of Ovum • 2 weeks • 1.5 mm in length • Cephalad differentiation not begun www.indiandentalacademy.com
  5. 5. Embryonal Period • 14th to 56th day • 3rd week- 3 mm • 4th week- 5mm www.indiandentalacademy.com
  6. 6. 4 week embryo www.indiandentalacademy.com
  7. 7. Contents of Mandibular Arch 1. Meckel’s cartilage 2. Musculature 3. Mandibular nerve 4. Maxillary and External Carotid Artery www.indiandentalacademy.com
  8. 8. www.indiandentalacademy.com
  9. 9. Fetal period • 8th week till birth • Tremendous acceleration is the theme • Meckel’s cartilage- precursor of mandibular mesenchyme www.indiandentalacademy.com
  10. 10. Mandibular changes • STUDY OF HUMAN FETAL MANDIBLE —Ingham, J. Dent. Res, 1932 • Observations:1. The alveolar plate lengthens more rapidly than ramus 2. The ratio of alveolar plate length to total mandibular length is reasonably constant www.indiandentalacademy.com
  11. 11. 3. The width of the alveolar plate shows a more rapid increase than does total width 4. The ratio of the width between the mandibular angle to the total width is relatively constant during fetal life www.indiandentalacademy.com
  12. 12. www.indiandentalacademy.com
  13. 13. Meckel’s Cartilage • 41st – 45th day of IUL • Template • Otic capsule - Symphysis www.indiandentalacademy.com
  14. 14. Ossification of Meckel’s cartilage • Mandibular nerve Neurotrophic factor Osteogenesis www.indiandentalacademy.com
  15. 15. Ossification of Meckel’s cartilage Ectomesenchymal condensation at 36-38 days Osteogenic membrane Primary ossification Intramembraneous bone lateral to cartilage www.indiandentalacademy.com
  16. 16. Ossification of Meckel’s cartilage • Begins during 7th week Woven bone Lamellar bone www.indiandentalacademy.com Haversian system– 5th month
  17. 17. Fate of Meckel’s Cartilage 1. Disappears by 24th week 2. Sphenomandibular ligament 3. Resorbs on lateral surface dorsal to mental foramen 4. Ventrally- Accessory Endochondral www.indiandentalacademy.com Ossicles
  18. 18. www.indiandentalacademy.com
  19. 19. Fate of Meckel’s Cartilage 10th & 14th week Sec. accessory cartilages appear www.indiandentalacademy.com
  20. 20. Condylar Cartilage Growth rate increases at puberty(12 1/2-- 14 yrs) and ceases by 20 yrs www.indiandentalacademy.com
  21. 21. Types of Ossification • 1st one to ossify- 6th week of I.U.L • Two types of ossification:- 1. INTRAMEMBRANEOUS 2. ENDOCHONDRAL www.indiandentalacademy.com
  22. 22. Parts of Mandible derived from • INTRAMEMBRANEOUS Ossification 1. Whole of body except anterior part 2. Ramus as far as mandibular foramen • 1. 2. 3. 4. ENDOCHONDRAL Ossification Anterior part of mandible Ramus above mandibular foramen Coronoid process www.indiandentalacademy.com Condylar process
  23. 23. NEONATAL MANDIBLE • Low and wide ascending ramus • Coronoid process is large • Body- open shell • Mandibular canal runs low www.indiandentalacademy.com
  24. 24. NEONATAL MANDIBLE www.indiandentalacademy.com
  25. 25. Differential Growth At Birth Fetal life 8 weeks– mandible>maxilla Mandible retrognathic 11 weeks– mandible=maxilla Early post natal life Becomes orthognathic 13-20 weeks– maxilla>mandible www.indiandentalacademy.com
  26. 26. POST NATAL GROWTH OF MANDIBLE www.indiandentalacademy.com
  27. 27. Contents 1. 2. 3. 4. 5. 6. 7. Theories of growth Mechanisms of bone growth Skeletal units of mandible Main sites of growth of mandible Condyle and great puzzle Current concept Age changes in mandible www.indiandentalacademy.com
  28. 28. Theories of Growth 1. Genetic theory- Brodie,1941 2. Scott’s hypothesis, 1953 3. Sutural dominance theory- Sicher, 1955 4. Functional matrix theory- Moss, 1962 www.indiandentalacademy.com 5. Van limborgh theory- 1970
  29. 29. Mechanisms of Bone Growth 1. REMODELING 2. DISPLACEMENT:• Primary displacement • Secondary displacement www.indiandentalacademy.com
  30. 30. www.indiandentalacademy.com
  31. 31. Enlow’s “V” Principle • Growth movement and enlargement of many facial and cranial bones or parts of bones occur towards the wide ends of “V” www.indiandentalacademy.com
  32. 32. Enlow’s Counterpart Principle • Growth of any given facial or cranial part relates specifically to other structural and geometric “counterparts” in the face and cranium Regional part Counter part Balanced growth www.indiandentalacademy.com
  33. 33. Growth Timings • Overall growth of mandible takes place at different stages • 1. 2. 3. First there is increase in its Width Length Height www.indiandentalacademy.com
  34. 34. Skeletal Units of Mandible www.indiandentalacademy.com
  35. 35. Main sites of growth of Mandible • Mandible undergoes largest amount of growth postnatally and exhibits largest variability in morphology • Principal growth sites are:1. Posterior surface of ramus 2. Condylar process 3. Coronoid process/ alveolar process www.indiandentalacademy.com
  36. 36. www.indiandentalacademy.com
  37. 37. Symphysis Menti • 4-12th month after birth, syndesmosis is converted to synostosis • No widening after fusion www.indiandentalacademy.com
  38. 38. Mental Foramen www.indiandentalacademy.com
  39. 39. Alveolar Process • Adds to height of mandible • Tooth absent- process fails to develop • After tooth extraction, alveolar process resorbs www.indiandentalacademy.com
  40. 40. Alveolar Process • Buffer zone • Adaptive remodeling makes orthodontic tooth movement possible www.indiandentalacademy.com
  41. 41. Ramus • Bridges pharyngeal compartment • Mandible in occlusion with maxilla • Remodeled in a posterosuperior manner www.indiandentalacademy.com
  42. 42. Ramus to Corpus Remodeling Bicondylar dimension established early in childhood www.indiandentalacademy.com
  43. 43. Ramus to Corpus Remodeling • Making room for molars www.indiandentalacademy.com
  44. 44. Ramus and Middle Cranial Fossa • Provides developmental potential for adaptations required to place the corpus in a continuously functional position because of variations elsewhere in the face and neurocranium. www.indiandentalacademy.com
  45. 45. • Antegonial notch• Single field of resorption • Mandibular foramen• Relocates backward and upwards • Sustains midway location www.indiandentalacademy.com
  46. 46. Size of notch depends On angle www.indiandentalacademy.com
  47. 47. Lingual tuberosity • Anatomic equivalent of maxillary tuberosity • Boundary between ramus and corpus • Remodels in posterior and medial direction • Resorptive field below forms Lingual www.indiandentalacademy.com Fossa
  48. 48. www.indiandentalacademy.com
  49. 49. www.indiandentalacademy.com
  50. 50. Coronoid Process • Propeller like twist www.indiandentalacademy.com
  51. 51. Vertical V Horizontal V www.indiandentalacademy.com
  52. 52. www.indiandentalacademy.com
  53. 53. The Mandibular Condyle • Historically- regarded as kind of cornucopia • No longer believed as a pacesetting “master centre” • Functions as regional field growth www.indiandentalacademy.com
  54. 54. The Mandibular Condyle • Dual function1. Articular 2. Growth Not a primary center of growth but rather 1. Secondary in Evolution 2. Secondary in Embryonic origin 3. Secondary in Adaptive responses www.indiandentalacademy.com
  55. 55. Condylar Growth Mechanism • Special non vascular tissue • Firm hydrophillic intercellular matrix • Endochondral growth mechanism- specific response to particular local circumstance www.indiandentalacademy.com
  56. 56. Histology of Condyle • Capsular layerpoorly vascularised • Proliferative layerprechondroblasts closely packed with scanty matrix • Zone of Deposition and Resorption www.indiandentalacademy.com
  57. 57. • Proliferative process produces upward and backward growth movement • Multidirectional proliferative capacity www.indiandentalacademy.com
  58. 58. Neck of the Condyle • Lingual and buccal surfaces resorptive • Condyle becomes neck after remodeling • Endosteal surfaces faces growth direction • Periosteal surface points away from it • V principle www.indiandentalacademy.com
  59. 59. The Condylar Question? • • Mandibles totally lacking condyles exist in nature Occupy normal anatomic position and proper occlusion • 2 conclusions1. Not the master center 2. Displaced Anteriorly and Inferiorly without a push www.indiandentalacademy.com
  60. 60. The Condylar Question? • • • • 1955- Weinmann and Sicher Major growth center Explanation seems to be logical Charlier and Petrovic supported this theory • If correct then condyle would grow by 2 mechanisms1. Interstitial proliferation 2. Appositionalwww.indiandentalacademy.com growth
  61. 61. The Condylar Question? • 1962- Moss, Functional matrix Hypothesis • Questions the primacy of Sicher theory • Condyle is under influence of the growth of orofacial capsular matrices • Concept of dominance of epigenetic and www.indiandentalacademy.com environmental factors is supported
  62. 62. The Condylar Question? • • • • 1963- Koski et al Transplanted mandibular ramus of the rat Recovered tissue was same as original Condyles with part of ramus transplantedmeasurable growth • 1968- Rankow and Moss • Condylectomy in young femaleimmediate downward and forward growth seen along with basal mandibular www.indiandentalacademy.com translation and increase in vertical height
  63. 63. Current concept • • Enlow Condyle does have intrinsic genetic programming but extra condylar factors are needed • Extra condylar factors are1. Intrinsic and extrinsic biomechanical forces 2. Physiologic inductors www.indiandentalacademy.com
  64. 64. • More recent studies involve NerveMuscle-Connective tissue pathways • Periodontal membrane and soft tissue matrix--- sensory input– higher centers– motor input to muscles– repositions mandible– affects growth and remodeling of condyle www.indiandentalacademy.com
  65. 65. Adaptive Role of Condyle • Multidirectional growth potential • If growth of mandible were preprogrammed within condyle, mandible cannot fit into maxilla and basicranium www.indiandentalacademy.com
  66. 66. Chin • Protrusive chin is characteristic of humans • Males- more prominent • Females- less prominent www.indiandentalacademy.com
  67. 67. Mental Protuberance • Formed by mental ossicles • Poorly developed in infants • Forms by osseous deposition • Reversal line www.indiandentalacademy.com
  68. 68. Factors affecting mandibular growth • 1. 2. 3. 4. Systemic factors Genetic Hormonal Nutritional Illness www.indiandentalacademy.com
  69. 69. Factors affecting mandibular growth • 1. 2. 3. 4. Local factors Ankylosis Trauma Birth injury Ear infection www.indiandentalacademy.com
  70. 70. Anomalies of mandible • Syndromes associated with mandible 1. Pierrie robin syndrome 2. Treacher collins syndrome 3. Marfan’s syndrome www.indiandentalacademy.com
  71. 71. Anomalies of mandible • Congenital anomalies 1. Agnathia 2. Micrognathia 3. Macrognathia www.indiandentalacademy.com
  72. 72. Anomalies of mandible • 1. 2. 3. 4. Developmental anomalies Torus mandiularis Stafne’s cyst Achondroplasia Odontogenic cyst www.indiandentalacademy.com
  73. 73. Touras mandibularis Stafne’s cyst www.indiandentalacademy.com
  74. 74. Age changes of Mandible At birth Adult Old age 1 Mental foramen Near the lower border Midway b/n upper & lower border Near the upper border 2 Angle of the mandible 3 coronoid & condyloid processes Obtuse Right angle Obtuse Coronoid is larger & above condyle Condyle is above the coronoid 4 Mandibular canal Runs little above the mylohyoid line Present; two halves united fibrous tissue Runs parallel to the mylohyoid line Condyle is above the coronoid but in extreme old age –bent backwards Runs close to the upper border 5 Symphysis menti Represented by faint ridge only in the upper part www.indiandentalacademy.com Not recognizable or absent
  75. 75. References 1. Human anatomy- B.D. Chaurasia 2. Human Embryology- I.B Singh 3. Craniofacial embryology – SPERBER 4. CranioFacial growth – ENLOW www.indiandentalacademy.com
  76. 76. 5. Contemporary orthodontics – PROFFIT 6. Principles and practice of orthodontics – T.M GRABER 7. Study of human fetal mandible– INGHAM, J Dent Resarch, 1932 8. Text book of oral pathology- SHAFER’S www.indiandentalacademy.com
  77. 77. There is nothing new under the sun But there are lot of old Things we don’t know Thank You www.indiandentalacademy.com

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