scholarly journals Daughters of the Enamel Organ: Development, Fate, and Function of the Stratum Intermedium, Stellate Reticulum, and Outer Enamel Epithelium

2016 ◽  
Vol 25 (20) ◽  
pp. 1580-1590 ◽  
Author(s):  
Hui Liu ◽  
Xiulin Yan ◽  
Mirali Pandya ◽  
Xianghong Luan ◽  
Thomas G.H. Diekwisch
Keyword(s):  
Enamel Organ ◽  
Organ Development ◽  
Enamel Epithelium ◽  
Stellate Reticulum ◽  
And Function

Lesions of the Enamel Organ of Developing Dog Teeth following Experimental Inoculation of Gnotobiotic Puppies with Canine Distemper Virus

1981 ◽  
Vol 18 (5) ◽  
pp. 684-689 ◽  
Author(s):  
R. R. Dubielzig ◽  
R. J. Higgins ◽  
S. Krakowka
Keyword(s):  
Canine Distemper Virus ◽  
Giant Cells ◽  
Enamel Organ ◽  
Post Inoculation ◽  
Canine Distemper ◽  
Experimental Inoculation ◽  
Enamel Epithelium ◽  
Viral Inclusions ◽  
Reduced Enamel Epithelium ◽  
Multinucleate Giant Cells

Ten 7-day-old gnotobiotic Beagle puppies were inoculated intraperitoneally with virulent canine distemper virus (R252-CDV). The dogs were killed and perfused with paraformaldehyde/glutaraldehyde from eight to 36 days after inoculation. The developing teeth of the mandibles were examined by light microscopy, and the teeth from three dogs were examined by electron microscopy. Necrosis of individual cells in the stratum intermedium of the developing tooth was the first change, detectable at day 9 post-inoculation. At day 16 post-inoculation, there was disorganization of the ameloblasts. In the stratum intermedium, multinucleate giant cells and large eosinophilic cytoplasmic viral inclusions were prominent. Ultrastructurally, these inclusions consisted of clusters of tubular aggregates typical of canine distemper virus nucleocapsids. At 28 to 36 days post-inoculation, the changes were seen in the reduced enamel epithelium. Multinucleate cells were seen, but no inclusions. Some necrotic cells were seen. In these teeth, ameloblastic cells of the root were morphologically normal. Our results suggest that distemper virus affects developing teeth by direct infection of the enamel organ.

scholarly journals Management of Dentigerous Cyst: A Review Article

2021 ◽  
Vol 2 (1) ◽  
pp. 01-04
Author(s):  
Nanda Gofur
Keyword(s):  
Epithelial Cells ◽  
Dentigerous Cyst ◽  
Inflammatory Cells ◽  
Cyst Fluid ◽  
Enamel Organ ◽  
Fluid Accumulation ◽  
Venous Flow ◽  
Dentigerous Cysts ◽  
Enamel Epithelium ◽  
Reduced Enamel Epithelium

Introduction: Dentigerous cyst is a pathological epithelial cavity that surrounds an unerupted tooth crown. Dentigerous cysts are usually associated with impacted teeth, mandibular third molars, first and second premolars and canines. Dentigerous cysts can occur at any age, but most cases of these cysts occur at the age of approximately 20 years. Men are affected more often than women. Purpose.To find out how the mechanism of dentigerous cysts. The cyst cavity is lined with epithelial cells derived from the epithelial enamel that is reduced from the tooth-forming organs. According to its pathogenesis, the pressure exerted by an erupted tooth on the follicle can block venous flow leading to accumulation of exudate between the reduced enamel epithelium and the crown of the tooth. These cysts are mostly due to fluid accumulation either between the reduced enamel epithelium and the enamel or between the layers of the enamel organ. This fluid accumulation occurs as a result of the pressure exerted by the erupting tooth on the affected follicle, which blocks venous flow, thus inducing rapid transudation of serum in the capillary walls. Discussion: The expansion of the dentigerous cyst causes the release of bone resorbing factor and an increase in the osmolarity of the cyst fluid as a result of the discharge of inflammatory cells, the discharge of residual epithelial enamel and tooth enamel, and desquamation of epithelial cells into the lumen of the cyst. In theory, the fluid will cause cystic proliferation. because the hyperosmolar content produced by cellular breakdown and cell products causes an osmotic gradient to pump fluid into the lumen of the cyst or it can also be said that an increase in the osmolarity of cyst fluid is the result of a shortcut to inflammatory cells and desquamation of epithelial cells into the lumen of the cyst resulting in a dentigerous cyst. Conclusion: The dentigerous cysts that surround the unerupted dental crowns are caused by the accumulation of fluid either between the reduced enamel epithelium or between the layers of the enamel organs. Dentigerous cysts can cause infection, pain, swelling, root dislocation, and resorption of adjacent tooth roots.

scholarly journals Msx2 Prevents Stratified Squamous Epithelium Formation in the Enamel Organ

2018 ◽  
Vol 97 (12) ◽  
pp. 1355-1364 ◽  
Author(s):  
M. Nakatomi ◽  
H. Ida-Yonemochi ◽  
C. Nakatomi ◽  
K. Saito ◽  
S. Kenmotsu ◽  
...  
Keyword(s):  
Squamous Epithelium ◽  
Developmental Stages ◽  
Tooth Enamel ◽  
Cyst Formation ◽  
Underlying Mechanism ◽  
Enamel Organ ◽  
Loss Of Function ◽  
Ectopic Mineralization ◽  
Enamel Epithelium ◽  
Stratified Squamous Epithelium

Tooth enamel is manufactured by the inner enamel epithelium of the multilayered enamel organ. Msx2 loss-of-function mutation in a mouse model causes an abnormal accumulation of epithelial cells in the enamel organ, but the underlying mechanism by which Msx2 regulates amelogenesis is poorly understood. We therefore performed detailed histological and molecular analyses of Msx2 null mice. Msx2 null ameloblasts and stratum intermedium (SI) cells differentiated normally in the early stages of amelogenesis. However, during subsequent developmental stages, the outer enamel epithelium (OEE) became highly proliferative and transformed into a keratinized stratified squamous epithelium that ectopically expressed stratified squamous epithelium markers, including Heat shock protein 25, Loricrin, and Keratin 10. Moreover, expression of hair follicle–specific keratin genes such as Keratin 26 and Keratin 73 was upregulated in the enamel organ of Msx2 mutants. With the accumulation of keratin in the stellate reticulum (SR) region and subsequent odontogenic cyst formation, SI cells gradually lost the ability to differentiate, and the expression of Sox2 and Notch1 was downregulated, leading to ameloblast depolarization. As a consequence, the organization of the Msx2 mutant enamel organ became disturbed and enamel failed to form in the normal location. Instead, there was ectopic mineralization that likely occurred within the SR. In summary, we show that during amelogenesis, Msx2 executes a bipartite function, repressing the transformation of OEE into a keratinized stratified squamous epithelium while simultaneously promoting the development of a properly differentiated enamel organ competent for enamel formation.

Jaw cysts and odontogenic tumours

2018 ◽  
Author(s):  
Max Robinson ◽  
Keith Hunter ◽  
Michael Pemberton ◽  
Philip Sloan
Keyword(s):  
Enamel Organ ◽  
Odontogenic Cysts ◽  
Epithelial Lining ◽  
Jaw Cysts ◽  
Dental Lamina ◽  
Odontogenic Tumours ◽  
Jaw Bones ◽  
Root Sheath ◽  
Odontogenic Origin ◽  
Enamel Epithelium

Odontogenic cysts and tumours arise from inclusion of tooth-forming epithelium and mesenchyme in the jaw bones during development. Cysts also arise from non-odontogenic epithelium trapped during fusions or from vestigial structures. In addition, bone cysts that can arise at other skeletal sites may also occur in the jaws. Odontogenic cysts and tumours may be classified according to their putative developmental origins and biology. The classification of jaw cysts is shown in Fig. 6.1. Odontomes are hamartomatous develop­mental lesions of the tooth-forming tissues. Odontogenic tumours are uncommon and are usually benign. Ameloblastoma is the most com­mon odontogenic tumour and is described in detail. The other odon­togenic tumours are rare and only the principal features are presented. Very rare congenital lesions of possible odontogenic origin are men­tioned in the final section. A cyst may be defined as pathological cavity lined by epithelium with fluid or semi-fluid contents. However, clinically, the term encompasses a broader range of benign fluid-filled lesions, some of which do not possess an epithelial lining. The preferred definition is, therefore, ‘a pathological cavity having fluid or semi-fluid contents that has not been created by the accumulation of pus’. Cysts are commonly encountered in clinical dentistry and are generally detected on radiographs or as expansions of the jaws. Most cysts have a radiolucent appearance and are well circumscribed, often with a corticated outline. At least 90% of jaw cysts are of odontogenic origin. The clinico-pathological features of jaw cysts are summarized in Table 6.1. The incidence of the four most common jaw cysts are provided in Table 6.2. The epithelial lining of odontogenic cysts originates from residues of the tooth-forming organ. • Epithelial rests of Serres are remnants of the dental lamina and are thought to give rise to the odontogenic keratocyst, lateral periodon­tal, and gingival cysts. • Reduced enamel epithelium is derived from the enamel organ and covers the fully formed crown of the unerupted tooth. The dentiger­ous (follicular) and eruption cysts originate from this tissue, as do the mandibular buccal and paradental cysts. • Epithelial rests of Malassez form by fragmentation of Hertwig’s epi­thelial root sheath that maps out the developing tooth root. Radicular cysts originate from these residues.

Reciprocal expressions between α-dystroglycan and integrin β1, perlecan receptors, in the murine enamel organ development

2013 ◽  
Vol 13 (8) ◽  
pp. 293-302 ◽  
Author(s):  
Hiroko Ida-Yonemochi ◽  
Hidemitsu Harada ◽  
Hayato Ohshima ◽  
Takashi Saku
Keyword(s):  
Enamel Organ ◽  
Organ Development ◽  
Integrin Β1
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