Microscopy of resorption of enamel and dentine from the cusp tips of the molar teeth of rats

Sutcliffe, J.E.; Owens, Phasefanie

doi:10.1016/0003-9969(81)90068-6

Cited by 9 publications

(7 citation statements)

References 17 publications

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“…The EFA epithelia in the rat and mouse, however, showed similar features a t one stage. Rat EFA cells, studied by Sutcliffe and Owens (1981), resembled ameloblasts at a n early stage of maturation (Stage IV, Reith, 1970); the epithelial cells were short columnar in shape, their distal cell membranes were folded, and the distribution and types of their organelles resembled those seen in maturation-stage ameloblasts. These ultrastructural features were also found in mouse molars examined by Diab and Zaki (1985).…”

Section: Discussionmentioning

confidence: 92%

Epithelial cytodifferentiation and extracellular matrix formation in enamel‐free areas of the occlusal cusp during development of mouse molars: Light and electron microscopic studies

1989

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Mandibular first molars in mice ranging in age from 18 days prenatal to 5 days postnatal were used for light and electron microscopic examinations of the enamel-free area (EFA) during development of the occlusal cusp (mesiobuccal cusp). Notable morphological changes in the inner enamel epithelium and the cells of the stratum intermedium were observed. At prenatal age of 18 days, the inner enamel epithelium of the EFA (EFA epithelium) was composed of a layer of columnar cells and covered by the cells of the stratum intermedium. Two days after birth, the EFA epithelium was made up largely of preameloblasts, with mitochondria located in the proximal side of the cells toward the stratum intermedium. The cells of the stratum intermedium were irregularly shaped, with wide intercellular spaces between them. At a postnatal age of 3 days, most of the EFA epithelial cells resembled maturation-stage ameloblasts, being short and columnar in shape and having nuclei located in their proximal side. Distal cell membranes were folded, and mitochondria were scattered throughout the cytoplasm. In 4-day-old mice, the EFA epithelium was found to be formed of short columnar or cuboidal cells with distinct intercellular spaces. The cells of the stratum intermedium could no longer be detected, and cells of the EFA epithelium could not be distinguished from those of the stellate reticulum. Odontoblasts of the EFA were arranged and polarized parallel to the basal lamina, and odontoblastic processes extended toward the cusp tip. The orientation of thin and thick collagen fibers within predentin and dentin was also parallel to the basal lamina. Even after dentin mineralization, disrupted basal lamina and long, aperiodic, fine fibrils were found between the epithelium and the dentin. Following the disappearance of the basal lamina and fine fibrils, stippled material and crystals appeared on the dentin surface. The mineralized matrix, which x-ray microanalytical energy peaks identified as containing calcium and phosphorus, was continuous with enamel in the distal slope of the cusp at the cusp tip. Thus, the inner enamel epithelium of the EFA differentiated into secretory cells capable of enamel-like matrix formation.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Discussionmentioning

confidence: 92%

Epithelial cytodifferentiation and extracellular matrix formation in enamel‐free areas of the occlusal cusp during development of mouse molars: Light and electron microscopic studies

1989

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“…These observations suggest that specific cell‐matrix interactions exist in the EFA, which could also intervene in modulating the phenotype of preameloblast‐like cells. Several reports indicated that preameloblast‐like cells could transitorily differentiate into secretory cells and deposit an enamel‐like amorphous matrix containing amelogenin and ameloblastin . However, the presence of amelogenin remains controversial …”

Section: Cell Differentiationmentioning

confidence: 99%

Three‐dimensional analysis of molar development in the mouse from the cap to bell stage

Lesot

Hovořáková

Peterka

et al. 2014

Australian Dental Journal

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During four days of prenatal development in the mouse, the morphology of the first lower molar moves from the early cap to the bell stage. Five phenomena characterize this period: growth of the tooth germ; development of the cervical loop; histogenesis of the enamel organ; folding of the epithelial-mesenchymal junction associated with cusp formation; and change in cellular heterogeneity in the mesenchyme. All these processes are controlled by epithelial-mesenchymal interactions. These complex histo-morphogenetic events have been documented using histological sections and 3D reconstructions. When combined with functional tests in vitro, this approach allowed searching for possible relationships between simultaneous changes occurring in both the epithelial and ecto-mesenchymal compartments. Parallel changes that occur in the two tissues could result from different mechanisms, as illustrated by the increasing number of pre-odontoblasts and pre-ameloblasts during crown growth. Cell division was involved mainly in the ectomesenchyme, while proliferation and cell re-organization occurred in the inner dental epithelium. 3D reconstructions also raised still unsolved questions, such as the possible relationship between cusp size and spatial specification of cell kinetic parameters, changes in cell position within the inner dental epithelium, and tracing cell migration in the mesenchyme during development.Keywords: Tooth development, mouse, molar, histo-morphogenesis, cytodifferentiation.Abbreviations and acronyms: BM = basement membrane; CL = cervical loop; ED = embryonic day; EFA = enamel free area; IDE = inner dental epithelium; PEK = primary enamel knot; OMU = Organizers of the Morphogenetic Units; PN = post-natal; SEK = secondary enamel knots; Shh = Sonic hedgehog; SI = stratum intermedium.

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“…During enamel formation, ameloblasts undergo a well‐defined sequence of differentiation events and cellular changes (see reviews by Warshawsky, 17 Nanci and Smith, 18 and Robinson et al 11 ) . In the case of rodent molars, the inner enamel epithelium (IEE) at the enamel‐free area (EFA) does not undergo the same pattern of differentiation as the enamel‐forming ameloblasts 19–24 . Although the EFA cells secrete some enamel proteins, these do not accumulate into a typically structured and full‐thickness enamel layer 23,24 .…”

Section: Introductionmentioning

confidence: 99%

Immunodetection of Enamel- and Cementum-Related (Bone) Proteins at the Enamel-Free Area and Cervical Portion of the Tooth in Rat Molars

Bosshardt

Nanci

1997

Journal of Bone and Mineral Research

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Enamel and dentin at the cervical portion of the tooth are frequently covered by a collagen-free matrix referred to as acellular afibrillar cementum (AAC). It is believed that AAC deposition occurs when the enamel organ is displaced or disrupted, and mesenchymal cells from the dental follicle gain access to the tooth surface, differentiate into cementoblasts, and secrete noncollagenous proteins typically found in collagen-based mineralized tissues. A similar thin layer of mineralized matrix is found at the enamel-free area (EFA) of rodent molars, but in this case the matrix is covered by inner enamel epithelium (IEE) throughout development. We have, therefore, used this site as a paradigm to test the hypothesis that typical mesenchymal matrix proteins can also be found in association with epithelial cells. To this end, we have analyzed the presence and distribution of enamel-and cementum-related matrix proteins at the EFA and at the cervical portion of the tooth. Rat mandibular molars were processed for colloidal gold immunolabeling with antibodies to amelogenins, bone sialoprotein (BSP), osteopontin (OPN), osteocalcin (OC), and dentin sialoprotein (DSP), and the plasma proteins ␣ 2 HS-glycoprotein and albumin. The EFA matrix was immunoreactive for amelogenins as well as for BSP, OPN, OC, and ␣ 2 HS-glycoprotein, but not for albumin and DSP. The AAC was, similar to the EFA matrix, labeled for BSP, OPN, OC, and ␣ 2 HSglycoprotein. These data show for the first time that the EFA matrix is comprised of a mixture of enamel-and cementum-related proteins, a situation that parallels the distribution of matrix constituents at the cervical portion of the tooth. Since the EFA matrix is deposited on top of the mineralized dentin, and since the enamel organ seals off the forming matrix, it is concluded that EFA cells are responsible for the production of these proteins. Consistent with previous reports showing that epithelial cells can produce both BSP and OPN in some circumstances, the data also suggest that AAC may be deposited by cells of epithelial origin. Furthermore, they lend support to the possibility that cells derived from Hertwig's epithelial root sheath may likewise be capable of producing cementum matrix proteins. (J Bone Miner Res 1997;12:367-379)

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Microscopy of resorption of enamel and dentine from the cusp tips of the molar teeth of rats

Cited by 9 publications

References 17 publications

Epithelial cytodifferentiation and extracellular matrix formation in enamel‐free areas of the occlusal cusp during development of mouse molars: Light and electron microscopic studies

Epithelial cytodifferentiation and extracellular matrix formation in enamel‐free areas of the occlusal cusp during development of mouse molars: Light and electron microscopic studies

Three‐dimensional analysis of molar development in the mouse from the cap to bell stage

Immunodetection of Enamel- and Cementum-Related (Bone) Proteins at the Enamel-Free Area and Cervical Portion of the Tooth in Rat Molars

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