This document provides an overview of the development of dental and periodontal tissues. It discusses how neural crest cells give rise to dental tissues like cementum, periodontal ligament, and alveolar bone. Tooth development progresses from the bud stage to the bell stage to root formation directed by Hertwig's epithelial root sheath. Cementum develops through cellular cementoblasts on the root surface. The periodontal ligament develops from the dental follicle with fibers inserting into cementum and bone. Alveolar bone forms during root development through osteoblasts. The gingiva develops from the oral epithelium and underlying connective tissue, with the gingival sulcus forming as teeth erupt. Epithelial and

2. INTRODUCTION

4. Dr. Guru Ram Tej. K (P.G.)
Dept. of Periodontics & Implantology
Mamata Dental College

5. CONTENTS
 Overview of tooth development.
 Neural crest development.
 Development of cementum.
 Development of periodontal ligament.
 Development of alveolar bone.
 Development of gingiva.
 Conclusion
 References

6. DEVELOPMENT
Development is the progressive
evolution of a tissue and usually refers to an
increase in its complexity and specialization
Complex biologic processes
 Epithelial mesenchymal interactions
 Morphogenesis
 Mineralization

7. Neural crest development
 Dental structures (dentin and cementum,) and their
supporting tissues (periodontal ligament and alveolar
bone) are produced by cells originating in the neural
crest. Enamel from the ectodermal cells.
 By about 8 days
 By 27th day
 During the first 3 weeks
 By the third week

8. Neural crest development
 During the next few weeks, the ectoderm thickens and
forms raised margins- neural folds
 The neural tube
 Neural crest cells

9. Primary epithelial band
 After 37 days
 Continuous band of thickened epithelium
PEB
Dental lamina Vestibular lamina

10. Dental lamina
 During the 6th week of
embryogenesis, tooth
development begins with a
thickening of the oral
epithelium lining the future
dental arches to form the
dental lamina
 Fate
 Vestibular lamina

11. Tooth Development
Although tooth development
is a continuous process, the developmental
history includes several morphologic stages
including the
 GROWTH
 CALCIFICATION
 ERUPTION
 ATTRITION

13. Bud stage
 The bud stage of tooth
development is the stage
at which portions of the
epithelium in the dental
lamina first begin to
aggregate and form an
invagination underlying
connective tissue.
 At 8th week

14. Cap stage
 Proliferate forming a
parabolic- cap like structure
9th -10th week.
 Ectomesenchymal cells begin
to proliferate under the dental
papilla (ultimately give rise to
the dentin and dental pulp)

15. Bell stage.
 Bell-shaped appearance at 12th week.
 The outer enamel epithelium
 The inner enamel epithelium
 The stratum intermedium
 The stellate reticulum

16. Hertwig's epithelial root sheath
 Separates the cells comprising the dental
papilla and dental follicle.
 Cells of the inner enamel epithelium induce
adjacent cells in the dental papilla to
differentiate into odontoblasts and
subsequently deposit the root dentin.

17. Cementogenesis
 Pre functional development
 Functional development

18. HERS

19. Development of cementum
Development
cells at site of development
Disruption of HERS
Cell-cell: Cell-matrix interactions:
growth factors/ cytokines
Reorganization of cells
Migration/attachment/orientation
Proliferation factors
Progenitor Cells
Differentiation factors
Cementum

20. Initial cementum formation
 The first increment of
cementum forms
against the root
dentin surface.
Epithelial cell rests of
Malassez (remnants
of the rootsheath)
can be seen within
the follicular tissue.

21. Cementum Forming Cells
The cells responsible for cementum
formation may be
 Cementoblasts,
 Cementocytes, or
 Fibroblasts -located within the periodontal
ligament- origin in the dental follicle.

22.  Acellular afibrillar cementum
 Acellular extrinsic fiber cementum (AEFC)
 Cellular mixed fiber cementum
 Cellular intrinsic fiber cementum (CIFC)
 Intermediate cementum
TYPES OF CEMENTUM

23. Periodontal Ligament Development
Periodontal ligament fibroblasts origins in the
dental follicle and begin to differentiate during
root development (Ten Cate et al 1971).

24. Orientation Of The Early Periodontal
Ligament

25. Intermediate Plexus
 Fiber insertion occurs along the lining of
the bony socket wall.
 Root surface-derived and bone-derived
fibers ultimately coalesce in the middle
third of the ligament space to form the
intermediate plexus.

26. Schematic representation of the
sequential organization of the
periodontal ligament fibers in
developing marmoset teeth. G,free
gingival fibers; A, alveolar crest fibers;
H, horizontal fibers;0, oblique fibers.
(From: Levy BM, Bernick )

27. Development of oxytalan fibres and the
ground substance
Fullmer et al.

28. The alveolar bone
 Formed during root
development
 OSTEOBLASTS
 Development is independent of
other portions of the alveolar
process

29.  Succedaneous tooth germs are located within the same
osseous cavity as their deciduous precursors
 During the eruption of a succedaneous tooth: resorption
of
 the walls of the bony crypt,
 the roots of the superficial primary tooth,
 and the alveolar bone housing the primary tooth.
 With the loss of the primary tooth
 With the emergence of succedaneous teeth
 complete deposition of new alveolar bone
 significant remodeling of the whole alveolar process

30. Development of Gingiva
 Composed of a superficial epithelium of
ectodermal origin and an underlying connective
tissue of mesodermal origin. (Listgarten 1972;
Mackenzie 1988).

31. Epithelial Attachment

32. Formation of Gingival Sulcus
 Begins to form as the
tooth erupts,
 A separation occurs
between the attached
epithelium and the tooth
surface.
 Epithelial cells derived
from stratum intermedium
also begin to form into
cells with the appearance
of junctional epithelium.

33. Modalities of tooth-tissue
interface
 Gingival tissues (both epithelial and
connective tissue) associate with the tooth
via separate mechanisms.
 Epithelial tissues
 via an epithelial attachment called the
junctional epithelium
 in health, is usually located at, or coronal to,
the CEJ
 Gingival tissues
 attach to the root surface at or below the CE]
 via fiber insertion into the cementum of the root
source.

34. Summary

35. EPITHELIAL - MESENCHYMAL TISSUE
INTERACTIONS

36. Role of Epithelial-Mesenchymal Tissue
Interactions in Maintaining Tissue Phenotype
 Junctional epithelium is initially derived from the
reduced enamel epithelium,
 Gingival epithelium originates from the ectodermal
tissues covering the maxillary and mandibular
arches.
 Two tissues considered to have
 distinct origins, phenotypes, and function.

37. Controlling Influence Of Connective
Tissue Substrate On Epithelial
Phenotype
 Connective tissues are considered to play in
important role in regulating the adjacent
epithelial phenotype.
 If components of palatal and buccal mucosa
are cross-grafted, the pattern of epithelial
differentiation is controlled by the underlying
connective tissue (Ten Cate 1994).

38.  The connective tissue of the gingival tissues
does permit epithelial growth and proliferation
 Periodontal ligament connective tissue
suggested to be non permissive for epithelial
growth and differentiation (Mackenzie 1988,
1990).
 explains the inability of junctional epithelium to extend
apically beyond its periodontal connective tissue interface
with the tooth,

39. Conclusion
Knowledge about the development of these
tissues is important since it will help us understand
better the mechanisms required for inducing repair
and regeneration of damaged tissues.

40. References
 Carranza, Newman, Takei, Klokkevold:
carranza’s clinical periodontology, 10th Ed. Pg-
53, Elsevier
 Inderbir Singh: Human embryology: 6th Ed.
 A R Tencate. Oral Histology- Development,
structure and function. 3rd Ed.
 Connective tissues of the periodontium:
periodontology 2000; Vol 24: 2000
 Regeneration of periodontal tissues:
cementogenesis revisited: periodontol 2000.
2006;41:196-217
 Mark Bartold, Sampath Narayanan: Biology
of periodontal tissues: pg 151-161

41. THANK YOU