Oral anatomy histology and embryology – Berkovitz
21 early tooth development
Tooth development has 3 stages: initiation, morphogenesis and histogenesis.
Initiation: the sites of the future teeth are established with the appearance of the tooth germs along
the dental lamina
Dental lamina is the invagination of the oral epithelium.
Morphogenesis: the shape of the tooth is determined by a combination of cell proliferation and cell
movement.
Cell proliferation: increase in cells due to cell growth and cell division
Histogenesis: differentiation of cells proceeds to give rise to the fully formed dental
tissues (volledige gevormde denatale weefsels), both mineralized and unmineralized.
Mineralized:
Enamel is the white, compact, and very hard substance covering and
protecting the dentin of the crown of a tooth.
Dentine is the hard, calcified tissue that makes up the greater thickness of the
tooth. It is denser and harder than bone, but softer than the outer enamel
coating and contains tubules of cells which connect the inner pulp of the
tooth to the surface.
Cementum is the bonelike connective tissue covering the root of a tooth and
assisting in tooth support.
Unmineralized:
Dental pulp is the soft tissue within the pulp cavity, consisting of
connective tissue containing blood vessels, nerves, and lymphatics, and at
the periphery a layer of odontoblasts capable of internal deposition and
repair of the dentin.
Periodontal ligament is a group of specialized connective tissue fibers
that essentially attach a tooth to the alveolar bone within which it sits.[1]
It inserts into root cementum one side and onto alveolar bone on the
other.
Tooth development is characterized by complex interactions between epithelial
and mesenchymal tissues. First histological sign of tooth development is the appearance of a
condensation of mesenchymal tissue and capillary networks beneath the presumptive dental
epithelium of the primitive oral cavity.
Mesenchymal tissue is a type of connective tissue
Presumptive dental epithelium is the vermoedelijke tandepitheel
Oral cavity is the mondholte
6th week of development, the oral epithelium thickes and invaginates into the mesenchyme to form a
primary epithelial band. 7th week of, the primary epithelila band divides into two processes; a
buccally located vestibular lamina and a lingually situated dental lamina.
Mesenchym (of embryonaal bindweefsel) omvat de weefsels die ontstaan uit de mesoderm-
kiemlaag van het embryo. Uit het mesenchym ontstaan bindweefsel, kraakbeen, botweefsel,
lymfevaten, bloedvaten (endotheel, glad spierweefsel) en bijhorende organen.
, 8th week, a series of swellings develops on the deep surface of the dental
lamina. The epithelial swellings show early development of tooth germs. The
dental lamina appears as a arch-shaped band, which follows the line of
vestibular fold.
The bud stage
The enamel organ appears simple, spherical to ovoid, epithelial condensation
that is poorly morphodiffrentiated and histodiffrentiated. Surrounded by
mesenchyme. Th cells have high RNA content, lower glycogen content and
increased oxidative enzyme activity. Successful development of the tooth germ relies upon a
complex interaction of the mesenchymal and epithelial components. The epithelial component is
separated from the adjacent mesenchyme by a basement membrane.
The cap stage
11th week, morphogenesis has
progressed, the deeper the surface of
the enamel organ invaginating to form a
cap shaped structure. The enamel organ
is poorly histodiffrentiated. Greater
distinction develops between the more
rounded cells in the central portion of
the enamel organ and peripheral cells
which are becoming arranged to from
the external and internal enamel
epithelia.
External enamel epithelia is a
layer of cuboidal cells located on
the periphery of the enamel
organ in a developing tooth
Internal enamel epithelia a layer of columnar cells located on the rim nearest the dental
papilla of the enamel organ in a developing tooth and will differentiate into ameloblasts
which are responsible for secretion of enamel during tooth development.
Ameloblasts zijn cellen die het glazuur van de tand vormen (buitenste laag van de
tandkroon).
The late cap stage
12th week, the central cells of the enlarging enamel organ have become separated, maintaining
contact with desmosomes. Intercellular spaces counting significant quantities of glycosaminoglycans.
The resulting tissue is named stellate reticulum, although it is not fully developed until the later bell
stage. The cells of the external enamel epithelium remain cuboidal, those in the internal enamel
epithelium become more columnar. The latter show a increase in in RNA content and hydrolytic and
oxidative enzyme activity. The mesenchymal cells continue to proliferate and surround the enamel
organ. The part of the mesenchyme laying beneath the internal enamel epithelium is named the
dental papilla, the mesenchyme surrounding the tooth germ is called the dental follicle.
Desmosomes is a ‘tussencelbrug’
Stellate reticulum =these cells are star-shaped and synthesize glycosaminoglycans. As
glycosaminoglycans are produced, water is drawn in between the cells and stretch them
apart. As they are moved further away from one another, the stellate reticulum maintain
21 early tooth development
Tooth development has 3 stages: initiation, morphogenesis and histogenesis.
Initiation: the sites of the future teeth are established with the appearance of the tooth germs along
the dental lamina
Dental lamina is the invagination of the oral epithelium.
Morphogenesis: the shape of the tooth is determined by a combination of cell proliferation and cell
movement.
Cell proliferation: increase in cells due to cell growth and cell division
Histogenesis: differentiation of cells proceeds to give rise to the fully formed dental
tissues (volledige gevormde denatale weefsels), both mineralized and unmineralized.
Mineralized:
Enamel is the white, compact, and very hard substance covering and
protecting the dentin of the crown of a tooth.
Dentine is the hard, calcified tissue that makes up the greater thickness of the
tooth. It is denser and harder than bone, but softer than the outer enamel
coating and contains tubules of cells which connect the inner pulp of the
tooth to the surface.
Cementum is the bonelike connective tissue covering the root of a tooth and
assisting in tooth support.
Unmineralized:
Dental pulp is the soft tissue within the pulp cavity, consisting of
connective tissue containing blood vessels, nerves, and lymphatics, and at
the periphery a layer of odontoblasts capable of internal deposition and
repair of the dentin.
Periodontal ligament is a group of specialized connective tissue fibers
that essentially attach a tooth to the alveolar bone within which it sits.[1]
It inserts into root cementum one side and onto alveolar bone on the
other.
Tooth development is characterized by complex interactions between epithelial
and mesenchymal tissues. First histological sign of tooth development is the appearance of a
condensation of mesenchymal tissue and capillary networks beneath the presumptive dental
epithelium of the primitive oral cavity.
Mesenchymal tissue is a type of connective tissue
Presumptive dental epithelium is the vermoedelijke tandepitheel
Oral cavity is the mondholte
6th week of development, the oral epithelium thickes and invaginates into the mesenchyme to form a
primary epithelial band. 7th week of, the primary epithelila band divides into two processes; a
buccally located vestibular lamina and a lingually situated dental lamina.
Mesenchym (of embryonaal bindweefsel) omvat de weefsels die ontstaan uit de mesoderm-
kiemlaag van het embryo. Uit het mesenchym ontstaan bindweefsel, kraakbeen, botweefsel,
lymfevaten, bloedvaten (endotheel, glad spierweefsel) en bijhorende organen.
, 8th week, a series of swellings develops on the deep surface of the dental
lamina. The epithelial swellings show early development of tooth germs. The
dental lamina appears as a arch-shaped band, which follows the line of
vestibular fold.
The bud stage
The enamel organ appears simple, spherical to ovoid, epithelial condensation
that is poorly morphodiffrentiated and histodiffrentiated. Surrounded by
mesenchyme. Th cells have high RNA content, lower glycogen content and
increased oxidative enzyme activity. Successful development of the tooth germ relies upon a
complex interaction of the mesenchymal and epithelial components. The epithelial component is
separated from the adjacent mesenchyme by a basement membrane.
The cap stage
11th week, morphogenesis has
progressed, the deeper the surface of
the enamel organ invaginating to form a
cap shaped structure. The enamel organ
is poorly histodiffrentiated. Greater
distinction develops between the more
rounded cells in the central portion of
the enamel organ and peripheral cells
which are becoming arranged to from
the external and internal enamel
epithelia.
External enamel epithelia is a
layer of cuboidal cells located on
the periphery of the enamel
organ in a developing tooth
Internal enamel epithelia a layer of columnar cells located on the rim nearest the dental
papilla of the enamel organ in a developing tooth and will differentiate into ameloblasts
which are responsible for secretion of enamel during tooth development.
Ameloblasts zijn cellen die het glazuur van de tand vormen (buitenste laag van de
tandkroon).
The late cap stage
12th week, the central cells of the enlarging enamel organ have become separated, maintaining
contact with desmosomes. Intercellular spaces counting significant quantities of glycosaminoglycans.
The resulting tissue is named stellate reticulum, although it is not fully developed until the later bell
stage. The cells of the external enamel epithelium remain cuboidal, those in the internal enamel
epithelium become more columnar. The latter show a increase in in RNA content and hydrolytic and
oxidative enzyme activity. The mesenchymal cells continue to proliferate and surround the enamel
organ. The part of the mesenchyme laying beneath the internal enamel epithelium is named the
dental papilla, the mesenchyme surrounding the tooth germ is called the dental follicle.
Desmosomes is a ‘tussencelbrug’
Stellate reticulum =these cells are star-shaped and synthesize glycosaminoglycans. As
glycosaminoglycans are produced, water is drawn in between the cells and stretch them
apart. As they are moved further away from one another, the stellate reticulum maintain
