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Development of dental tissues.ppt
The document summarizes the development of dental tissues from early gestation through adulthood. It describes how at 4 weeks, the oral cavity begins forming from prominences in the face. Tooth development initiates around 6 weeks as epithelial bands thicken. Teeth then pass through stages of initiation, bud, cap, and bell formation from 6-12 weeks. This involves the epithelial and mesenchymal tissues developing and differentiating into structures that will become the enamel, dentin, cementum, and pulp of the teeth. Humans develop two sets of teeth - the primary (deciduous) set and permanent set.
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Introduction to the development of oral tissues and tooth formation processes.
Odontogenesis overview covering primary and permanent dentition timelines and their prenatal development.
Embryonic formation of the face, prominence structures, and primitive oral cavity development.
Tooth formation initiation starting from day 11, outlining the primary epithelial bands and structural development.
Details of initiation, bud, cap, and bell stages in tooth development along with key cellular processes.
Transition into bell stage with histo-differentiation in the enamel organ and papilla characterizations.
Finalization of tooth structure including ameloblasts, odontoblasts, root formation, and maturation processes.
Formation of periodontal ligament and multi-rooted teeth development in relation to root trunk differentiation.
Timing and sequence for the initiation of primary dentition and permanent teeth formation.
Recap on ectodermal origins, formations of tooth components, and associated structures in the developing process.
Conclusion of the presentation, inviting questions and discussion regarding the material presented.
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Development of dental tissues.ppt
- 1. Development of DentalTissues Development of oral tissues – Moamer Gabsa Moamer Gabsa BDS,DRM, DCL ,MSc Anatomy,MPHE,P1DPH
- 2. Introduction Development of oraltissues – Moamer Gabsa
- 3. Development of tooth •Tooth development (odontogenesis) is a complex process of tooth formation from embryonic cells, eruption, and integration with its surrounding tissues. Development of oral tissues – Moamer Gabsa
- 4. Development of tooth- Dentition • Humans have two sets of teeth in their lifetime • Primary (Deciduous) • Permanent • Primary dentition develops during prenatal period . • Permanent dentition develops as the jaw grows and matures. Development of oral tissues – Moamer Gabsa
- 5. Development of oraltissues – Moamer Gabsa
- 6. • At theend of the fourth week, the center of the face is formed by the stomodeum, surrounded by the first pair of pharyngeal arches. Moamer Gabsa - Development of head and neck 6 Oral cavity development
- 7. • When theembryo is 24 days old, five mesenchymal prominences can be recognized: • The mandibular prominences (first pharyngeal arch), caudal to the stomodeum • The maxillary prominences (dorsal portion of the first pharyngeal arch), lateral to the stomodeum • The frontonasal prominence, a slightly rounded elevation cranial to the stomodeum. front nasal Maxillary mandible Moamer Gabsa - Development of head and neck 7 Oral cavity development cont…
- 8. Front nasal Maxillary Mandible Day 24 MoamerGabsa - Development of head and neck 8 Oral cavity development cont…
- 9. • The primitiveoral cavity, or stomodeum, is lined by stratified squamous epithelium called the oral ectoderm or primitive oral epithelium. • The oral ectoderm contacts the endoderm of the foregut to form the buccopharyngeal membrane. • At about the 27th day of gestation this membrane ruptures and the primitive oral cavity establishes a connection with the foregut. Development of oral tissues – Moamer Gabsa Oral cavity development cont…
- 10. • Most ofthe connective tissue cells underlying the oral ectoderm are of neural crest or ectomesenchyme in origin. • These cells are thought to instruct or induce the overlying ectoderm to start tooth development, which begins in the anterior portion of what will be the future maxilla and mandible and proceeds posteriorly. Development of oral tissues – Moamer Gabsa Oral cavity development cont…
- 11. Oral cavity development MoamerGabsa - Development of head and neck 11
- 12. Tooth formation • Firstsigns of formation at day 11 • Thickening of the epithelium where tooth formation will occur, on the 1st branchial (pharyngeal) arch • More than 90 genes have been identified in the oral epithelium, dental epithelium and dental mesenchyme. Development of oral tissues – Moamer Gabsa
- 13. Stages of toothdevelopment (Odontogenesis) • Initiation stage – 6th to 7th week • Bud stage – 8th week • Cap stage – 9th to 10th weeks • Bell stage – 11th to 12th weeks • Apposition stage – varies per tooth • Maturation stage – varies per tooth Development of oral tissues – Moamer Gabsa
- 14. Initial stage Development oforal tissues – Moamer Gabsa
- 15. • Involves thephysiologic process of induction. • Induction of ectodermal tissues by the developing mesenchyme • Mechanisms remain unknown • At the 6th week the stomodeum is lined with ectoderm (outer portion) ( oral epithelium) • Oral epithelium that cover stomodeum gives rise to the primary epithelial bands • Also is a developing mesenchyme which contains neural crest cells that have migrated to the area of stomodeum. • The developing oral epithelium and mesenchyme separated by basement membrane. Development of oral tissues – Moamer Gabsa Initial stage
- 16. The initiation oftooth formation starts around the 37th day of gestation. - Primary epithelial bands (PEB): is a horseshoe-shaped bands that appear approximately around the 37th day of development, one for each jaw. - There are two subdivisions of PEB: Vestibular lamina and Dental lamina - The dental lamina grows deep into the mesenchyme , develops in the future spot for the Dental arches and the ingrowths represent the future sites for each deciduous tooth. - The vestibular lamina cells rapidly enlarge and then degenerate and forms a cleft that becomes the vestibule of the oral cavity Development of oral tissues – Moamer Gabsa Initial stage
- 17. Development of oraltissues – Moamer Gabsa
- 18. Stages of toothdevelopment (Odontogenesis) • Initiation stage – 6th to 7th week • Bud stage – 8th week • Cap stage – 9th to 10th weeks • Bell stage – 11th to 12th weeks • Apposition stage – varies per tooth • Maturation stage – varies per tooth Development of oral tissues – Moamer Gabsa
- 19. Bud Stage Development oforal tissues – Moamer Gabsa
- 20. • This stageis marked by the incursion of epithelium into the mesenchyme and it is a period of extensive proliferation and growth of the dental lamina forms into tooth buds or oral masses that penetrate into the mesenchyme • Each tooth bud is surrounded by the mesenchyme and separated by basement membrane. • buds + mesenchyme develop into the tooth germ and the associated tissues of the tooth. Development of oral tissues – Moamer Gabsa 1. Tooth bud 2. Oral epithelium 3. Mesenchyme Bud Stage
- 21. Development of oraltissues – Moamer Gabsa Bud Stage Tooth bud in upper jaw • Simultaneous with the differentiation of each dental lamina, round or ovoid swellings arise from the basement membrane at 10 different points, corresponding to the future positions of the deciduous teeth. • These are the primordia of the enamel organs, the tooth buds Tooth bud in upper jaw
- 22. Development of oraltissues – Moamer Gabsa Tooth Bud Bud Stage • In the bud stage, the enamel organ consists of peripherally located low columnar cells and centrally located polygonal cells . • Many cells of the tooth bud and the surrounding mesenchyme undergo mitosis. • As a result of the increased mitotic activity and the migration of neural crest cells into the area the ectomesenchymal cells surrounding the tooth bud condense. • The area of ectomesenchymal condensation immediately subjacent to the enamel organ is the dental papilla.
- 23. Development of oraltissues – Moamer Gabsa
- 24. Stages of toothdevelopment (Odontogenesis) • Initiation stage – 6th to 7th week • Bud stage – 8th week • Cap stage – 9th to 10th weeks • Bell stage – 11th to 12th weeks • Apposition stage – varies per tooth • Maturation stage – varies per tooth Development of oral tissues – Moamer Gabsa
- 25. Cap Stage Development oforal tissues – Moamer Gabsa
- 26. • Characterized bycontinuation of the ingrowth of the oral epithelium into the mesenchyme. • Tooth bud of the dental lamina proliferates unequally in different parts of the bud forms a cap shaped tissue attached to the remaining dental lamina. • This stage marks the beginning of histo- differentiation (differentiation of tissues) • The tooth germ also begins to take on form start of morpho-differentiation Development of oral tissues – Moamer Gabsa Cap shape Cap Stage
- 27. Development of oraltissues – Moamer Gabsa Vestibular lamina Dental Organ Cap Stage 9th week 10th week Dental Organ
- 28. • A depressionforms in the deepest part of each tooth bud and forms the cap or Enamel organ (or dental organ) produces the future enamel (ectodermal origin) • Below this cap is a condensing mass of mesenchyme Dental papilla produces the future dentin and pulp tissue (mesenchymal origin) • The basement membrane separating the dental organ and the dental papilla becomes the future site for the Dentinoenamel junction (DEJ) • Remaining mesenchyme surrounds the dental/enamel organ and condenses to form the Dental sac or the Dental follicle Development of oral tissues – Moamer Gabsa Cap Stage
- 29. • Together theenamel organ + dental papilla + dental follicle is considered the developing Tooth germ. • These germs are found in the developing dental arches and will develop into the primary dentition. Development of oral tissues – Moamer Gabsa Cap Stage
- 30. Development of oraltissues – Moamer Gabsa
- 31. Stages of toothdevelopment (Odontogenesis) • Initiation stage – 6th to 7th week • Bud stage – 8th week • Cap stage – 9th to 10th weeks • Bell stage – 11th to 12th weeks • Apposition stage – varies per tooth • Maturation stage – varies per tooth Development of oral tissues – Moamer Gabsa
- 32. Bell Stage Development oforal tissues – Moamer Gabsa
- 33. • Continuation ofhistodifferentiation and morpho-differentiation (Early stage) • Cap shape then assumes a more bell-like shape • Differentiation produces four types of cells within the enamel organ 1. Inner enamel epithelium 2. Outer enamel epithelium 3. Stellate reticulum 4. Stratum intermedium Development of oral tissues – Moamer Gabsa Bell Stage
- 34. • The dentalpapilla undergoes differentiation and produces two types of cells 1. Outer cells of the DP forms the dentin- secreting cells (odontoblasts) 2. Central cells of the DP forms the primordium of the pulp • Dental sac/follicle increases its collagen content and differentiates at a later stage than the EO and DP Development of oral tissues – Moamer Gabsa DP: dental papilla EO: enamel organ Bell Stage
- 35. Histo-differentiation of theEnamel organ Development of oral tissues – Moamer Gabsa
- 36. Histo-differentiation of theEnamel organ • At early stage of bell stage the enamel organs cell are differentiate into: 1. Inner enamel epithelium 2. Outer enamel epithelium 3. Stellate reticulum 4. Stratum intermedium Development of oral tissues – Moamer Gabsa
- 37. • Outer enamelepithelium (OEE) • Cuboidal cell • Protective barrier during enamel production • Other name outer dental epithelium • Inner enamel epithelium (IEE) • Short columnar cells • Differentiates into the enamel secreting cells Ameloblasts • Separated from the dental papilla below it by a basement membrane • Other name inner dental epithelium • The IEE and OEE are continuous the Region where they connect curved rim of the enamel organ called cervical loop Development of oral tissues – Moamer Gabsa Cervical loop IEE OEE Histo-differentiation of the Enamel organ
- 38. • Stellate reticulum •Star-shaped cells in many layers • Center of the enamel organ • Forms a network (Reticulum) • Supports production of enamel • Stratum intermedium • Inner layer of compressed flat to cuboidal cells • Supports production of enamel Development of oral tissues – Moamer Gabsa Histo-differentiation of the Enamel organ
- 39. Development of oraltissues – Moamer Gabsa Histo-differentiation of the Enamel organ
- 40. Late Bell Stage Developmentof oral tissues – Moamer Gabsa
- 41. • The dentalpapilla is separated from the enamel organ by a basement membrane • Immediately below this BM is a region called the acellular zone this is where the first enamel proteins will be laid down • The dental lamina begins to break up into discrete islands of epithelial cells (epithelial pearls) that separates the oral epithelium from the developing tooth. • The inner enamel epithelium completes its folding and you can begin to identify the shape of the future crown pattern. Development of oral tissues – Moamer Gabsa Late Bell Stage- early crown formation
- 42. • The cellsin the center of the enamel organ begin to synthesize and secrete GAGs (glycosaminoglycan's) • This pulls water into the enamel organ, Increasing amount of fluid in the enamel organ forces the central cells apart • However, they remain connected via cellular processes which makes them star shaped stellate reticulum . B = inner dental epithelium (inner enamel epithelium) Development of oral tissues – Moamer Gabsa Late Bell Stage
- 43. Tooth development Development oforal tissues – Moamer Gabsa
- 44. Development of oraltissues – Moamer Gabsa Tooth development
- 45. Cap and Bellstages & Permanent teeth ( Successedenous ) Development of oral tissues – Moamer Gabsa
- 46. • During thecap stage the development of the permanent dentition begins • The primordia for these teeth appears as an extension off the developing dental lamina • Its site of origin is called the successional dental lamina • These permanent teeth are called succedanuos teeth (anterior teeth and the premolars) teeth that form with the primary tooth buds (primary predecessors) Development of oral tissues – Moamer Gabsa Cap and Bell stages & Permanent teeth ( Successedenous )
- 47. Stages of toothdevelopment (Odontogenesis) • Initiation stage – 6th to 7th week • Bud stage – 8th week • Cap stage – 9th to 10th weeks • Bell stage – 11th to 12th weeks • Apposition stage – varies per tooth • Maturation stage – varies per tooth Development of oral tissues – Moamer Gabsa
- 48. Appositional stage • Itcharacterized by secretion of hard tissues of tooth: Enamel, Dentin and Cementum. • These tissues are initially secreted as a matrix that is partially calcified serves as a framework for later calcification • Varies per tooth Development of oral tissues – Moamer Gabsa
- 49. Stages of toothdevelopment (Odontogenesis) • Initiation stage – 6th to 7th week • Bud stage – 8th week • Cap stage – 9th to 10th weeks • Bell stage – 11th to 12th weeks • Apposition stage – varies per tooth • Maturation stage – varies per tooth Development of oral tissues – Moamer Gabsa
- 50. Maturation stage • Characterizedby the completion of calcification. Development of oral tissues – Moamer Gabsa
- 51. Development of oraltissues – Moamer Gabsa
- 52. Ameloblasts and Odontoblasts formation Developmentof oral tissues – Moamer Gabsa
- 53. • Ameloblasts • Thecells of the IEE assume a more columnar shape or they elongate • Differentiate into pre-ameloblasts • The pre-ABs induce the cells of the dental papilla to differentiate also • Odontoblasts • Differentiation by the mesenchyme of the dental papilla • Occurs after differentiation of pre-ABs begins • Results because the pre-ABs induce differentiation of the mesenchymal cells also • After differentiation – the ODs then start Dentinogenesis Development of oral tissues – Moamer Gabsa ODs : odontoblasts ABs : Ameloblast Ameloblasts and Odontoblasts formation
- 54. • Before dentinforms – cells of the EO receive blood supply from vessels of the dental lamina • As dentin forms, it cuts of this papillary source of blood/nutrients • This causes a drastic reduction in the amount of nutrients that reach the EO • But the ABs require extensive nutrients to form enamel – stellate reticulum collapses and invagination of the OEE – this brings in blood supply from peripheral vessels found outside the tooth Development of oral tissues – Moamer Gabsa OEE :outer enamel epithelium EO : enamel organ Ameloblasts and Odontoblasts formation
- 55. Development of oraltissues – Moamer Gabsa
- 56. ROOT FORMATION Development oforal tissues – Moamer Gabsa
- 57. • Takes placeas the crown is completely shaped and the tooth begins to erupt • Therefore the tooth forms from the “top down” – i.e. crown to root • Root formation is through the formation of a cervical loop • The CL is the most cervical portion of the enamel/dental organ – two layers consisting of IEE and OEE • the CL begins to grow down into the dental sac • it forms a Hertwig's root sheath Development of oral tissues – Moamer Gabsa CL: cervical loop ROOT Formation
- 58. A, The rootis beginning to form as an extension of the inner and outer dental epithelia in the cervical loop region (circles) which form a bilayered structure called Hertwig’s epithelial root sheath. B. Formation of dentin by odontoblasts above the root sheath Development of oral tissues – Moamer Gabsa
- 59. • Grows downto encompass all but the basal portion of the pulp • This sheath shapes the root and induces dentin formation in the root area by the ODs of the dental papilla • This sheath lacks the stellate reticulum and stratum intermedium • Is capable of differentiating into ODs BUT NOT ABs Development of oral tissues – Moamer Gabsa ODs : odontoblasts ABs : ameloblasts ROOT Formation
- 60. Root Dentin Development oforal tissues – Moamer Gabsa
- 61. • The rootof the tooth is composed by dentin and cementum • Dentin forms when the outer cells of the dental papilla are induced to differentiation into ODs • Similar to what occurs at the crown area • Influenced by Hertwig’s root sheath • The ODs then undergo Dentinogenesis and secrete predentin • After dentin formation – the BM disintegrates along with the Hertwig’s sheath Development of oral tissues – Moamer Gabsa ABs : ameloblasts ODs : odontoblasts BM : basement membrane Root Dentin
- 62. Cementum and Pulpformation Development of oral tissues – Moamer Gabsa
- 63. • Cementogenesis inthe root area also occurs upon degradation of the H. root sheath • The degradation allows contact of the dental sac cells with the dentin surface – induces the formation of cementoblast cells • The CBs cover the root dentin and undergo Cementogenesis – laying down cementoid • Only upon mineralization of the cementoid can it be called cementum • The region of contact between cementum and root dentin = dentinocemental junction or DCJ • While the cementum is forming - the central cells of the dental papilla form the pulp Development of oral tissues – Moamer Gabsa CBs : cementoblast Cementum and Pulp formation
- 64. Periodontal ligament formation Developmentof oral tissues – Moamer Gabsa
- 65. • The surroundingtissues of the tooth also develop as the crown and root form • The mesenchyme of the dental sac condenses to form the periodontal ligament • Forms adjacent to the new cementum • Ends of these fibers insert into the outer layer of cementum and surrounding alveolar bone • The cells of the disintegrating H. root sheath develop into discrete islands of epithelial cells • Become epithelial rests of Malassez • Unknown function • They can be identified in the periodontal ligament and are responsible for the development of radicular cysts. Development of oral tissues – Moamer Gabsa Periodontal ligament formation
- 66. Multirooted teeth • Anteriorteeth, premolars and molars all begin as a single root – root trunk • Root of the posterior teeth divides from the trunk into the correct number of root branches • Differential growth of the H. root sheath results in the division of the root trunk into two or three roots Development of oral tissues – Moamer Gabsa
- 67. Timetable for toothdevelopment Development of oral tissues – Moamer Gabsa
- 68. • Entire primarydentition initiated between 6 and 8 weeks of embryonic development. • Successional permanent teeth initiated between 20th week in utero and 10th month after birth • Permanent molars between 20th week in utero (first molar) and 5th year of life (third molar) Development of oral tissues – Moamer Gabsa Timetable for tooth development
- 69. Development of oraltissues – Moamer Gabsa
- 70. Development of oraltissues – Moamer Gabsa Two years old
- 71. Development of oraltissues – Moamer Gabsa Five years
- 72. Development of oraltissues – Moamer Gabsa 8 years
- 73. Summary Development of oraltissues – Moamer Gabsa
- 74. Ectoderm of first arch Toothgerm Ectomesenchyme from neural crest Origin Enamel organ Dental papilla Dental follicle Periodontal ligament Fibroblast Pulp Cementum Products Root form Primary epithelium attachment Enamel Crown pattern Dentin Cementoblast Cells of tooth germ Odontoblast Component of tooth germ Ameloblast Cervical loop Outer dental epithelium Stellate reticulum Stratum intermedium Inner dental epithelium Undifferentiated mesenchymal cells fibroblast Alveolar bone Osteoblast Reduced dental epithelium Hertwig's root sheath
- 75. Development of oraltissues – Moamer Gabsa
- 76. Development of oraltissues – Moamer Gabsa
- 77. Any questions ? Developmentof oral tissues – Moamer Gabsa
- 78. Development of oraltissues – Moamer Gabsa