Research Outputs (Oral Health Sciences)

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/18776

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Subject: search.filters.subject.Microscopy, Electron, Scanning

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Now showing 1 - 4 of 4
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    Marginal adaptation in composite resin restored dentine cavities Showing gross marginal leakage
    (1986) Grossman, E. S.; Sparrius, O.
    The aim of bonding composite resin restorations to the tooth is to ensure retention and also to prevent marginal leakage at the tooth restoration interface, a process which can lead to further caries. An in vitro marginal leakage study' of composite resins in combination wTEh acid' etching and dentine and enamel bonding agents highlighted the lower sealing potential of both enamel and dentine bonding agents to dentine (36%>seal) compared to enamel (79%>seal). Several studies 2-4 suggest that if the inner surface of the resin restoration appears as a well replicated negative impression of the adjacent tooth surface, bonding has been achieved. This study was undertaken to examine the appearance of the inner surface of resin restorations which showed gross marginal leakage in restored dentine cavities to determine the degree of marginal adaptation between the restoration and cavity surface.
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    Soft-tissue specimen shrinkage during the preparation for scanning electron microscopy
    (1977) Wilton-Cox, H.; Cleaton-Jones, P.
    The amount of shrinkage and the scanning electron microscope appearance of specimens of rat tongue, soft palate and small intestine, dehydrated by air drying , the critical point technique, the camphene technique and freeze drying were compared
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    A scanning electron microscope study of the developing rat secondary palate
    (1976) Cleaton-Jones, P.
    The surfaces of the developing secondary palatal shelves and palate, in Wistar strain albino rats, were examined using scanning electron microscopy. Beginning on the 16th day after insemination there was a progressive degeneration of the cell surfaces on the medial aspect of the shelves. This took the form of a loss of surface microvilli and intercellular boundaries accompanied by the appearance of clefts between the cells. Fusion of the palate was complete by the 18th day and two epithelial zones could be recognized in the soft palate. The cell surface degeneration is possibly an essential change prior to shelf fusion.
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    Microscope observations of ART excavated cavities and restorations
    (2002) Grossman, E. S.; Mickenautsch, S.
    This in vitro light and scanning electron microscope study examined 39 extracted tooth specimens, hand excavated and restored according to atraumatic restorative treatment (ART), using 'press finger', by 'skilled' and 'novice' operators. Surface features of five excavated cavities, 12 restoration surfaces and the tooth restoration relationships of 22 bisected restored tooth crowns were examined to better understand the clinical effect of the technique. Hand-excavated cavity surfaces were rough with a complex surface arrangement of grooves, crevices, ridges, furrows and overhangs. Enamel and dentine were covered with debris except where surface fractures exposed enamel prisms and occluded dentinal tubules. Ten of the 22 bisected restored specimens had large voids (1-3 mm in length) within the glass-ionomer cement (GIC) restoration or at the tooth-restoration interface. Smaller bubbles (< 50 microns) and irregular shaped inclusions were common in all restorations. Adaptation of the GIC to the cavity margin was extremely variable and easily distinguished from the effects of dehydration shrinkage. It is thought that cavity surface irregularities could cause placement problems making it difficult to adapt the GIC to cavity peripheries. While 'press finger' enabled excellent penetration of GIC into fissures, the technique left restoration surfaces rough. At low magnification, surfaces were irregular; at magnifications higher than X500 scratches, pits, porosities, chipping and voids were evident. However, the 'press finger' technique was able to merge the GIC to a fine edge on the occlusal surface so that the restoration margin was not obvious. No apparent difference was found between the restorations placed by the 'skilled' and 'novice' operators. Tooth-restoration relationships in the ART approach are entirely different to those of traditional restorative techniques. The ART approach requires skill, diligence and comprehension to be undertaken correctly.