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  • 1
    Electronic Resource
    Electronic Resource
    Establishment of acellular extrinsic fiber cementum on human teeth (1991)
    Springer
    Cell & tissue research 263 (1991), S. 325-336 
    Details
    ISSN: 1432-0878
    Keywords: Cementum ; Fiber fringe ; Periodontal ligament fibers ; Dentino-cemental junction ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study describes for the first time the development of early acellular extrinsic fiber cementum (AEFC) until its establishment on human teeth. Precisely selected premolars with roots developed to 50%–100% of their final length were prefixed in Karnovsky's fixative and most of them were decalcified in EDTA. Their roots were subdivided into about 10 blocks each, cut from the mesial and distal root surfaces. Following osmication, these blocks were embedded in Epon and sectioned for light-and transmission electron microscopy. Some blocks were cut non-demineralized. From semithin stained sections, the density of the collagenous fiber fringe protruding from the root surface was measured by using the Videoplan-system. After initiation of this fiber fringe and its attachment to the dentinal root surface followed by mineralization, the fringe gradually increased in length and subsequently became mineralized. Fringe elongation and the advancement of the mineralization front appeared to progress proportionally. Thus, in all stages of AEFC development, a short fiber fringe covered the mineralized AEFC. Its density remained constant, irrespective of AEFC thickness. The latter gradually increased and reached an early maximum of 15–20 μm in the cervical region. At this stage, the AEFC fringe appeared to fuse with the future dentogingival or other collagen fibers of the tooth supporting apparatus. Mineralization of the fringe commenced with isolated, spherical or globular centers, which later fused with the mineralization front and became incorporated in AEFC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318774
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  • 2
    Electronic Resource
    Electronic Resource
    Initiation of acellular extrinsic fiber cementum on human teeth (1991)
    Springer
    Cell & tissue research 263 (1991), S. 311-324 
    Details
    ISSN: 1432-0878
    Keywords: Dental root surface ; Periodontal fiber fringe ; Dentino-cemental junction ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of acellular extrinsic fiber cementum (AEFC) has never before been studied in human teeth. We have therefore examined the initiation of AEFC in the form of a collagenous fiber fringe and its attachment to the underlying dentinal matrix, in precisely selected, erupting human premolars with roots developed to 50%–60% of their final length. Freshly extracted teeth were prefixed in Karnovsky's fixative, decalcified in EDTA and subdivided into about 10 blocks each, cut from the mesial and distal root surfaces, vertical to and along the root axis. The blocks were postfixed in osmium tetroxide, embedded in Epon and cut for light- and electron-microscopic investigation. Starting at the advancing edge of the root, within a region extending about 1 mm coronal to this edge, fibroblast-like cells were seen closely covering the external root surface. Along the first 100 μm from the root edge, these cells extended cytoplasmic processes and contacted the dentinal collagen fibrils. Between these cells and the dentinal matrix, new collagen fibrils and very short collagen fibers gradually developed. Within the second 100 μm from the root edge, this resulted in the formation of a cell-fiber fringe network. Newly formed fibers of the fringe were directly attached to the non-mineralized matrix containing dentinal collagen fibrils and could be distinguished from the latter by differences in fibril orientation. During the process of dentin mineralization, the transitional zone between the fiber-fringe base and the dentinal matrix, i.e., the future dentino-cemental junction, also mineralized. It is suggested that this fiber fringe is the base of AEFC, which later increases in thickness by fiber extension and subsequent mineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318773
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  • 3
    Electronic Resource
    Electronic Resource
    Attempts to label matrix synthesis of human root cementum in vitro (1993)
    Springer
    Cell & tissue research 274 (1993), S. 343-352 
    Details
    ISSN: 1432-0878
    Keywords: Teeth ; Cementum ; Autoradiography ; Cementoblasts ; Fibroblasts ; Matrix production ; In vitro analysis ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The present study describes the dynamic process of both acellular extrinsic (AEFC) and acellular/cellular intrinsic fiber cementum (AIFC/CIFC) matrix production on growing human teeth. Selected erupting maxillary and mandibular premolars with roots grown to about 70%–95% of their final length were placed in organ culture immediately following extraction. Twelve teeth for short-time labeling were pulse-incubated for 15 min in medium containing 3H-proline and chased for various times in order to follow the migration and secretion of the tracer. Eight teeth for long-time incubation were labeled continuously for 5 h before being chased for 1–8 days in order to label cementum matrix accumulation. After decalcification in ethylene diaminetetraacetic acid (EDTA), their roots were subdivided into about 20 slices each. Epon-embedded sections were prepared for light- and electron-microsopic as well as autoradiographic examination. During CIFC-formation, cementoblasts revealed high intracytoplasmic silver grain concentrations within the first hour after 3H-proline administration. The release of the tracer occurred between 60 to 120 min after administration. After 2 h, cementoblasts and the cementum matrix appeared to be labeled about equally. After 5 h, most of the labeled proteins appeared to be localized in the cementoid. Silver grains increased in number over the cementum matrix from 5–24 h. Very high intracellular grain concentrations within very large cementoblasts corresponded to regions of rapid cementum formation. Tracer-halos around entrapped cells lend support to a multipolar mode of matrix production during CIFC-initiation. The fate of the tracer during the development of early AEFC-matrix was less clear. However, fibroblasts revealed dense intracytoplasmic grain accumulations within the first hour after 3H-proline administration. Thereafter, the tracer localization was vague. This indistinct grain localization reflected the particular mode of AEFC-matrix production characterized by addition of new fibril segments to pre-existing fibers of a collagenous fringe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318753
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  • 4
    Electronic Resource
    Electronic Resource
    Initial formation of cellular intrinsic fiber cementum in developing human teeth (1992)
    Springer
    Cell & tissue research 267 (1992), S. 321-335 
    Details
    ISSN: 1432-0878
    Keywords: Teeth ; Cementum ; Cementoblasts ; Matrix production ; Electron microscopy ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study describes the formative process of the initiation of cellular intrinsic fiber cementum (CIFC) in still growing human teeth. From 29 premolars and molars with incomplete roots developed to 60–90% of their final length, 8 premolars (with roots formed to three quarters of their final length) were selected for electron-microscopic investigation. All teeth were clinically intact and prefixed in Karnovsky's fixative immediately after extraction. Most of them were decalcified in ethylene diaminetetraacetic acid (EDTA), and the apical part of the roots was divided axially into mesial and distal portions that were subdivided in about 5 slices each. Following osmication and embedding in Epon, these blocks were cut for light- and electron-microscopic examination. In addition, 5 teeth with incomplete roots were freed from organic material and processed for scanning electron microscopy. It was found that CIFC-initiation commenced very close to the advancing root edge and resulted in a rapid cementum thickening. Thereafter, appositional growth continued on the already established cementum surface. Large, basophilic and rough endoplasmic reticulum-rich cementoblasts, some of which became cementocytes, were responsible for both fast and slow CIFC-formation. The CIFC-matrix was free of Sharpey's fibers and composed of more or less organized intrinsic collagen fibrils, in part fibril bundles, that ran roughly parallel to the root surface. Initially, the cementum fibrils intermingled with those of the dentinal collagen fibrils, which were not yet mineralized. This boundary subsequently underwent calcification. The development of collagen fibril bundles and their extracellular arrangement were associated with cytoplasmic processes probably involved in fibril formation and fibril assembly. Many cementoblasts contained intracytoplasmic, membrane-bounded collagen fibrils, which probably were related to fibril formation rather than degradation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302971
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  • 5
    Electronic Resource
    Electronic Resource
    In-vitro formation of a new fibrous attachment to human dental roots in the presence of autologous serum (1989)
    Springer
    Cell & tissue research 258 (1989), S. 125-135 
    Details
    ISSN: 1432-0878
    Keywords: Periodontal ligament cells ; Alveolar bone cells ; Autologous serum ; Cementum ; Dentin ; Cell culture ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Recent studies have accomplished the establishment of a collagenous fiber-fringe matrix upon dental root surfaces in vitro. The present study was undertaken to follow the development of such a matrix in vitro and to test the possible effects of root surface treatments upon this matrix. Periodontal ligament cells, 0.1 to 0.2-mm thick dental root discs, and alveolar bone cells were derived after extraction from four partially erupted third molars and the accompanying interradicular bony septa of 1 male patient. Autologous serum was obtained by venipuncture. Cultures were initiated by delivering a 1-ml suspension of 50000 tritiated thymidine-labeled periodontal ligament cells and 50000 alveolar bone cells onto each of 42 culture sets. The following day, demineralized or non-demineralized root discs treated with autologous serum, fibronectin or complete medium were placed in pairs, separated by a 0.1–1.0 mm gap, upon the initial cell layer. Representative cultures were terminated after 2, 3, 4, 5 and 6 weeks, and processed for light- and electron microscopy, morphometric analysis and autoradiography. An outstanding feature of the early cultures (2, 3 and 4 weeks) was a patchwise, random distribution of matrix making a precise developmental study impossible, although collagen fibrils were produced within the first 2 weeks. Some 3-week cultures already demonstrated a mature fiber-fringe characterized electron-microscopically as oriented, densely packed collagen fibrils closely abutting the cementum-lined root discs. The treatments (including autologous serum) used in this study had no appreciable morphologic or morphometric effect upon the fiber-fringe formed. Because none of the cultures in the present or past studies have demonstrated a true cementoid matrix, this model may not be suitable for the in-vitro study of cementum formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00223152
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  • 6
    Electronic Resource
    Electronic Resource
    Formation of a new fibrous attachment to human dental roots (1988)
    Springer
    Cell & tissue research 254 (1988), S. 659-670 
    Details
    ISSN: 1432-0878
    Keywords: Periodontal ligament cells ; Cementum ; Cell culture ; Regeneration ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study was performed to improve currently employed in vitro models for the study of periodontal regeneration by using a porous filter upon which periodontal ligament cells were grown. Periodontal ligament cells were harvested and 0.3 mm root discs cut from three partially erupted and extracted third molar teeth of one patient. Experimental culturing was performed by seeding periodontal ligament cell suspensions on Puropor-200 filters supported by wire-mesh grids in Grobstein Petri dishes. The following day, an interdental space of 0.1 to 0.3 mm was created by gently placing two dental root discs upon the filter. Cultures were terminated after 42, 56, 112 and 124 days, and processed for light- and electron microscopy. Collagen fibril diameters were measured. Adjacent and often attached to large areas of cementum-lined root discs, a dense fiber fringe developed. This fiber fringe was not found on dentinlined root discs. Although less organized, older cultures demonstrated a similar disc-culture interface, which depended upon the presence or absence of original root cementum. Collagen fibrils of early cultures had a mean diameter of about 42 nm, while in older cultures the diameters ranged from 47 to 68 nm. It is concluded that the fibrous matrix attached to cementum-lined root discs somewhat resembles the initial stages of the formation of dental root cementum in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226517
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  • 7
    Electronic Resource
    Electronic Resource
    In-vitro formation of a collagenous matrix upon previously diseased and experimentally treated cemental root surfaces (1990)
    Springer
    Cell & tissue research 259 (1990), S. 603-606 
    Details
    ISSN: 1432-0878
    Keywords: Periodontal ligament cells ; Alveolar bone cells ; Cementum ; Cell culture ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A diseased and mechanically treated surface of root cementum is known, clinically, to favor periodontal regeneration. The present investigation was undertaken to test whether previously diseased and experimentally treated root surfaces can support the in-vitro formation of a new collagenous matrix. Three teeth extracted for advanced periodontitis were treated first with 5% sodium hypochlorite for 2 h to remove all organic material from the root surface. After the healthy, apical one third of the root was cut off, the roots were scaled with moderate pressure to remove visible calculus. Non-demineralized root discs were cut and placed on a co-culture of periodontal ligament- and alveolar bone-derived cells. After 7 weeks in culture, either one of two matrix types was found along the root surface. The most frequent matrix consisted of clusters of cells layered within densely aggregated collagen fibrils. The other, less frequent matrix consisted of loosely arranged collagen fibrils adjacent to the cemental surface. The findings support the notion that, in vitro, a collagenous matrix is formed in contact to diseased and experimentally treated root surfaces. However, the smooth, non-demineralized and scaled cemental surface does not appear to be a suitable substrate for interdigitation with newly produced collagen fibrils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01740790
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  • 8
    Electronic Resource
    Electronic Resource
    Formation of a new fibrous attachment to human dental roots (1989)
    Springer
    Cell & tissue research 255 (1989), S. 631-639 
    Details
    ISSN: 1432-0878
    Keywords: Periodontal ligament cells ; Alveolar bone cells ; Cementum ; Cell culture ; Regeneration ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Human periodontal ligament cells have been shown to produce a new fibrous attachment at the surface of scaled dental root discs in vitro. The purpose of this investigation was to answer the question whether cells derived from human alveolar bone would enhance this attachment. Three partially erupted third molars were extracted and collected from one female patient and used for harvesting periodontal ligament cells as well as for cutting 0.3 mm dental root discs. Cells derived from alveolar bone were obtained by enzymatic digestion of bone chips harvested after extraction of wisdom teeth from three additional patients. Experimental cultures were prepared by seeding 1.0 × 106 suspensions of periodontal ligament cells onto five Puropor-200 filters. The following day, root disc pairs were placed on the cell layer, leaving a gap (interdental space) of 0.1–0.3 mm. Five days later, all cultures received equal aliquots of alveolar bone cells. The cultures were terminated and processed for microscopic and morphometric evaluation after 56, 112 and 124 days. All cultures demonstrated a dense fiber-fringe attachment along most of the cementum-lined surfaces of root discs. Adjacent to other root-disc surfaces, cells were surrounded by halos of their collagenous product. Mean diameters of collagen fibrils for the 56-, 112- and the two 124-day cultures were 64.6, 48.9 and 62.6 nm, respectively. Compared to results obtained in this system with periodontal ligament cells alone (Bernstein et al. 1988), the fiber fringe in this experiment was denser, composed of collagen fibrils with a larger diameter, and maintained for longer duration in culture. These findings support the hypothesis that cells from the alveolar bone participate, as a normal component of the periodontal ligament, in the maintenance and repair of periodontal ligament attachment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218801
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