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  • 1995-1999  (6)
  • Chemistry  (3)
  • Confocal laser scanning microscopy  (2)
  • Ablation  (1)
  • 1
    ISSN: 1436-3771
    Keywords: Key words Dentine ; enamel junction ; Odontoblast processes ; Dentinal tubules ; Confocal laser scanning microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The translucency of teeth allows the non-destructive subsurface visualisation of their microstructure by confocal laser scanning microscopy (CLSM) at a level of about 150 μm below the surface. The dentine–enamel junction (DEJ) is accessible only directly adjacent to the cervix of the tooth. Therefore teeth have to be sectioned for studying marginal areas of the dental hard tissue. The potential of the technique for (pseudo) three-dimensional visualisation allows the study of an array of individual confocal images, the interpretation of which is similar to that of macroscopic tomographs (CT-scan, MRI). Additionally, the extended focus mode yields the overlay of individual confocal images in the form of a two-dimensional projection. This mode of operation proved to be particularly suited for the visualisation of odontoblast processes in their whole extension. The three-dimensional junction between enamel and dentine, the branches of the odontoblast processes and their interactions with the DEJ is demonstrable by CLSM without staining or other procedures of sample preparation. The direct microscopic comparison between samples, either fresh or kept in a humid chamber, and Technovit-embedded sample blocks gives evidence that the risk of artefacts by sample storage or by the embedding procedure is minimal. The tomographs limited to subsurface areas of the tissue also exclude mechanical surface artefacts due to grinding or cutting.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Mund-, Kiefer- und Gesichtschirurgie 2 (1998), S. 85-90 
    ISSN: 1434-3940
    Keywords: Schlüsselwörter Strahlenkaries ; In-vitro-Demineralisation ; Konfokale Laser-Scanning-Mikroskopie ; Key words Radiation caries ; In vitro demineralisation ; Confocal laser scanning microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Objective: The volume of literature on radiation-induced caries is still inconsistent as regards the state of the art. Our histotomographic studies have shown direct radiogenic effects on the dentoenamel junction (atrophy of the odontoblast processes). Whether there are direct effects of radiation on dental enamel is not yet known. Material and Method: Sound teeth (group 1, n = 10) were compared either with enamel specimens after high dose in vitro radiation (500– 2500 Gy; group 2; n = 10) and after experimental enoral in situ irradiation (60 Gy; group 3; n = 20), or with teeth from patients after cancer radiotherapy (36 Gy; group 4; n = 20) and with teeth which had obviously decayed due to cancer radiotherapy (60 Gy; group 5; n = 20). Vestibular enamel surfaces of the teeth were exposed to identical in vitro demineralizations (lactic acid gel; pH = 5.0). Each of the samples was prospectively studied histologically by confocal laser scanning microscopy (CLSM) after 90, 180 and 270 min of acid interaction. Data were interpreted micromorphometrically (width of the demineralized area) and micromorphologically. Results: The width of the demineralized area varies between the two in vivo irradiated groups of specimens (group 4: P 〈 0.01; group 5: P 〈 0.001) and the high dose in vitro irradiated teeth (P 〈 0.01) and is significantly different from the sound controls. The histological image of the demineralization in subsurface areas in the teeth of radiotherapy patients is characterized by a total loss of the prismatic structure (homogeneously, amorphous substance). Conclusions: Direct radiogenic effects at the dentoenamel junction have been described earlier. The additional information offered by this study is that there are significant micromorphometric differences in the demineralizing behaviour of irradiated enamel. Obviously, enamel is less resistant to acid attack after irradiation.
    Notes: Fragestellung: Das umfangreiche Schrifttum zur Strahlenkaries zeigt den kontroversen Forschungsstand. Eigene Untersuchungen haben direkt radiogene Veränderungen an der Schmelz-Dentin-Grenze histotomographisch nachweisen können (Atrophie der Odontoblastenfortsätze). Offen ist die Frage nach direkten Strahlenfolgen im Schmelz. Material und Methode: Gesunde Zähne (Gr. 1, n = 10) wurden mit Proben nach hochdosierter In-vitro- (500–2500 Gy, Gr. 2, n = 20) und nach experimentell-enoraler In-situ-Bestrahlung (60 Gy, Gr. 3, n = 20) sowie mit Zähnen von Patienten nach präoperativer Strahlentherapie (36 Gy, Gr. 4, n = 20) und strahlenkariösen Zähnen nach tumortherapeutischer Strahlendosis (60 Gy, Gr. 5, n = 20) verglichen. Im direkten Parallelgruppenvergleich erfolgte eine standardisierte In-vitro-Demineralisierung (Milchsäuregel pH 5,0) an den vestibulären Schmelzoberflächen. Jede Probe wurde prospektiv histologisch durch konfokale Laser-Scanning-Mikroskopie (CLSM) nach 90, 180 und 270 min Entmineralisierung untersucht. Die Auswertung erfolgte mikromorphometrisch (Breite des Demineralisationssaums) und mikromorphologisch. Ergebnisse: Die Breite des Demineralisationssaums unterschied sich sowohl bei beiden in vivo bestrahlten Probengruppen (Gr. 4: p 〈 0,01; Gr. 5: p 〈 0,001) als auch bei den hochdosiert in vitro bestrahlten Zähnen (p 〈 0,01) signifikant von den Befunden der gesunden Kontrollen. Das histologische Bild der Demineralisation an den Zahnoberflächen von Radiotherapiepatienten zeigte dabei einen völligen Verlust der Prismenstruktur (homogen amorphe Substanz). Schlußfolgerungen: Direkte Strahlenfolgen an der Schmelz-Dentin-Grenze wurden in früheren Untersuchungen dargestellt. Zusätzlich konnten jetzt signifikante mikromorphometrische Unterschiede im Demineralisierungsverhalten des bestrahlten Schmelzes gezeigt werden. Offensichtlich ist der Schmelz nach der Bestrahlung für einen Säureangriff weniger resistent.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-3940
    Keywords: Schlüsselwörter CO2-Laser ; Scanner ; Ablation ; Ratten ; Histologie ; Key words CO2 laser ; Scanner ; Ablation ; Rats ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Introduction: Laser systems are frequently used in dentistry. New laser scanner technologies are promising more homogeneous ablation of pathological ablations of the skin and mucosa. The theoretical advantages of these systems have not yet been sufficiently evaluated by histological findings. For this reason, we compared two laser scanners with different scanning patterns in this study (Silktouch® and Swiftlase®, by Sharplan®, Germany). Materials and Methods: In this animal study (79 male Osborn-Mendel rats), skin defects of 3-mm diameter were lasered on to the backs of the animals, one for each method mentioned above (defocused laser, Swiftlase®, and Silktouch®). The histological investigations were conducted, depending on the time after surgery (9 h, 1, 2, 3, 4, 5, 6, 7, 9, 11, or 13 days). On the clinical site, we evaluated the visible ablation rate, homogeneity and morphology of the wound surface and the degree of carbonization. In the histomorphological investigations, we determined the degree of thermal damage as well as the morphology of the necrotic area and reepithelization pattern of the surface. Results: The Silktouch® scanner clinically showed a homogeneous ablation rate with less carbonization than the Swiftlase® scanner. In the histological specimen, this correlated with an increase in the tissue ablation rate and decreasing thermal damage to the surrounding tissue. Especially in the early wound-healing period, there was a more rapid reepithelization after the use of the Silktouch scanner. These differences could not be evaluated in the later wound-healing period. Compared to the defocused laser ablation, both scanning systems seem to have benefits within these parameters. Conclusions: The results of this study seem to show a diminished perifocal damage and reduced clinical postoperative morbidity achieved by using laser scanning systems. Compared to the Swiftlase® laser, the Silktouch® seems to deliver better results.
    Notes: Fragestellung: Lasersysteme finden in der Zahn-, Mund- und Kieferheilkunde zunehmend Anwendung. Laser-Scanner versprechen von ihrem methodischen Ansatz eine gleichmäßige Ablation von Haut- oder Schleimhautveränderungen, die theoretischen Vorteile derartiger Systeme sind aber bislang nicht ausreichend histologisch verifiziert. Daher wurden in dieser Studie 2 CO 2 -Laser-Scanner (Silktouch ® , Swiftlase ® ) unterschiedlicher Scanmuster diesbezüglich verglichen. Material und Methoden: In einem Tiermodell (79 Osborn-Mendel-Ratten) wurden je 3 mm große kutane Defekte durch CO 2 -Laser-Anwendung auf der Rückenhaut gesetzt. Die histologische Aufarbeitung erfolgte zu verschiedenen Zeitpunkten der Wundheilung. Klinische Zielparameter waren Ablationsrate, Homogenität und Morphologie der Wundoberfläche sowie das Ausmaß der Karbonisation. Die histologische Auswertung betrachtete das Ausmaß der Schädigung des Umgebungsgewebes sowie die Reepithelisierungsgeschwindigkeit der Oberfläche. Ergebnisse: Der Silktouch ® -Scanner zeigte klinisch eine gleichmäßigere Ablationsrate bei größerer Homogenität und verminderter Karbonisation als der Swiftlase ® -Scanner. Als histologisches Korrelat dieser klinischen Eigenschaften zeigte sich eine Steigerung des intendierten Gewebeabtrags bei gleichzeitig verminderter thermischer Schädigung des Umgebungsgewebes und exakt definierter lateraler Begrenzung der thermischen Schädigungszone. Insbesondere in der frühen Phase der Wundheilung zeigte sich eine beschleunigte Reepithelisierung nach Anwendung des Silktouch ® -Scanners. Diese Unterschiede waren in der Spätphase der Wundheilung kaum mehr nachweisbar. Im Vergleich zur defokussierten Gewebeablation zeigten beide Scanner deutliche Vorteile bezüglich der genannten Parameter. Schlußfolgerungen: Diese experimentellen Ergebnisse können als Hinweis auf eine Verminderung der perifokalen Schädigung mit reduzierter klinischer perioperativer Morbidität durch den Einsatz von Laserscannern gewertet werden. Im direkten Vergleich der beiden Scanner scheint der Silktouch ® günstigere Ergebnisse zu erzielen.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie in unserer Zeit 29 (1995), S. 337-337 
    ISSN: 0009-2851
    Keywords: Chemistry ; Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 68 (1996), S. 1100-1101 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 70 (1998), S. 1198-1199 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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