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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 32 (2005), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary  Dentine hypersensitivity is recognized as a pain arising from fluid movement within dentine tubules that are open to the oral environment. Blocking the tubules is considered to be the principal aim of treatment, and the accurate assessment of tubule occlusion is the primary goal of many in vitro studies. This assessment usually comprises either measuring tubule permeability or scanning electron microscope examination of the dentine surface. Several scanning microscopy studies have claimed to quantify tubule occlusion, but are descriptive, qualitative or semi-quantitative evaluations. The present study was undertaken to assess the use of digital image analysis in quantifying the effectiveness of a selected desensitizing agent from micrographs of control and treated dentine surfaces. Using a dentine disc model, an accurate methodology was sought to investigate the occluding potential of Butler Protect (J.O. Butler, Chicago, IL, USA). Subjective examination of the images indicated there was little difference after a single application, but considerable effect after 20 applications. Quantitative digital analysis of a test image, demonstrated reproducibility between two examiners when used in fully- and semi-automated mode. After a single application of Butler Protect, multilevel statistical modelling demonstrated decreases in tubule area and maximum, minimum and mean diameter measurements (P 〈 0·001), whereas single level analysis showed increases in area and maximum and mean diameters. Multiple application of Butler Protect demonstrated even greater decreases in all parameters (P 〈 0·001). This quantitative methodology was reproducible between examiners and, when combined with good controls and multilevel statistical modelling, was able to discriminate a single application of desensitizing agent.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Journal of oral rehabilitation 29 (2002), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Dentine sensitivity (DS) is a common condition which affects 8–35% of the population. Both In-Office and Over-the-Counter products have been used in treatment, usually occluding open dentine tubules on the exposed root surface. Currently there appears to be no ideal material which permanently occludes dentine tubules. Bioactive and biocompatible glasses are known to induce osteogenesis in physiological systems and may offer suitable materials for surface reactivity which could theoretically occlude tubules. A new dentifrice formulation containing a modified Bioglass® material replacing part of the abrasive silica component was compared with original 45S6 bioactive glass. Dentine discs were treated with original Bioglass®, three coded dentifrices containing 0, 2·5 and 7·5% Bioglass® and two further selected dentifrice products. These specimens were prepared for scanning electron microscopy (SEM) and viewed in a Cambridge stereoscan 90B. The results demonstrated that original bioactive glass particles covered the dentine surface and/or occluded dentine tubules, although this original formulation was easily dislodged. Dentifrice with different ratios of added Bioglass® was assessed to provide greater surface coverage and tubule occlusion than without Bioglass®. It was concluded that the inclusion of bioactive glass particles in a suitably formulated vehicle may be an effective agent for the treatment of dentine sensitivity.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of clinical periodontology 31 (2004), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: Though dental calculus is generally recognised as comprising mineralised bacteria, areas of non-mineralised bacteria may be present.Aim: To investigate the ultrastructure of non-decalcified young and mature supragingival calculus and subgingival calculus, and the possible presence of internal viable bacteria.Materials and methods: Supragingival calculus was harvested from five patients, 9–10 weeks after scaling and root debridement. Five samples of mature supragingival and subgingival calculus were taken from patients presenting with adult periodontitis. Specimens were fixed and embedded for transmission electron microscopy.Results: The ultrastructure of young and mature supragingival calculus was similar with various large and small crystal types. Non-mineralised channels were observed extending into the calculus, often joining extensive lacunae, both containing intact non-mineralised coccoid and rod-shaped microorganisms. Subgingival calculus possessed more uniform mineralisation without non-mineralised channels and lacunae.Conclusion: Supragingival calculus contains non-mineralised areas which contain bacteria and other debris. The viability of the bacteria, and their identification could not be determined in this preliminary investigation. As viable bacteria within these lacunae may provide a source of re-infection, further work needs to be done to identify the bacteria in the lacunae, and to determine their viability.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral rehabilitation 24 (1997), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: summary The dentine disc has been extensively used as a model for assessing potential desensitizing agents in vitro by scanning electron microscopy (SEM). Although the disc provides a readily available and reproducible test substrate, this paper addresses the problems associated with this model such as the natural variation in the dentine tubules and the resulting differences in surface morphology. At the ultrastructural level the surface of a single etched disc exhibits variations in the size, density, orientation and extent of etching of the cut dentine tubules. In the present study a precise control procedure was designed which allowed greater correlation between test and control surfaces. Two adjacent areas of the same disc were used, one as the test surface, the other the control. Two proprietary desensitizers were examined using this methodology. This study has shown that the dentine disc is a good, reliable model for in vitro screening and testing of potential desensitizing agents, providing such controls are applied.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford UK : Blackwell Science Ltd
    Journal of oral rehabilitation 28 (2001), S. 0 
    ISSN: 1365-2842
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 171 (1976), S. 543-549 
    ISSN: 1432-0878
    Keywords: Shell ; Centropyxis hirsuta ; Manganese ; Shell structure ; X-ray diffraction ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The proteinaceous shells of Centropyxis hirsuta contain a relatively high concentration of manganese in an amorphous state. The concentrations of manganese fill the alveoli which are characteristic of the shell structure. Observations based on cultured animals and subsequently examined by X-ray diffraction, a solid state energy dispersive X-ray analyser, and an analytical electron microscope, lead to the conclusions that manganese is selectively absorbed by Centropyxis hirsuta and deposited in the shell.
    Type of Medium: Electronic Resource
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