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Can remineralization be proven under a conventional
glass ionomer restorative material?
Remineralization of carious dentine exposed to
a glass ionomer, an in-vivo study. 17
The aim of this study was to investigate
the remineralizing effect in vivo of a glass ionomer on the
affected zone as described by Massler (1967) and Ogawa(1983).
This was a collaborative project between the Adelaide Dental
School and the Fiji Dental School. Volunteers were sought
from patients of the Department of Dentistry of the Fiji School
of Medicine. Each volunteer had at least one badly decayed,
asymptomatic, permanent first molar, for which extraction
was the treatment of choice based on criteria set by the Fiji
Dental School. After consent was obtained, 50 teeth were restored
according the Atraumatic Restorative Treatment (A.R.T) technique.
A high speed hand piece was used to gain access to the carious
lesion and provide sound enamel to ensure a good seal around
the periphery.
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Lesion before cavity preparation
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Cavity before placement of Fuji IX showing
the extent of soft dentine left behind for internal
remineralization
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Finished restoration
(Dr Hien Ngo) |
Hand instruments were used to remove the very soft dentine
around the walls with some soft dentine remaining on the floor.
The cavity was then filled with Fuji IX. The teeth were reviewed
after 1 and 3 months and those that still warranted extraction
(15 teeth) were collected and sent to Adelaide for analysis.
The teeth were sectioned and prepared for microanalysis using
EPMA. Analysis of the specimens determined the concentration
profiles of calcium, phosphorus, strontium and fluorine in
both the soft demineralized and the sound dentine. Remineralization
was demonstrated as a significant increase, in all 15 samples,
of strontium and fluorine in the demineralized dentine under
the Fuji IX. From this study, it is evident
that there is ionic exchange between the affected dentine
and Fuji IX. The pattern of uptake of strontium and fluorine
by the demineralized dentine suggests that this is due to
a remineralizing process which is dependent on the nature
of the diseased dentine left behind.
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Figure 1 : Cross section of Fuji IX restored
tooth (Fiji study) after 3 months showing the extent
of demineralized dentine.
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Figure 2 : A chemical micrograph of tooth
and restoration showing different mineral levels. The
brighter the area, the more mineral.
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Figure 3 : Higher magnification of Figure
2.
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Figure 4 : An illustration of the 3 different
zones. Non remineralize, mineralizable, hypermineralized.
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Figure 5 : EPMA analysis quantifying
mineral deposition in each of the different zones.
(Dr Hien Ngo)
17. Ngo H, Mount GJ, Morris M, Mclntyre J, Tuisuva
J, Von Doussa R. Journal of Dental Research 2001 ; Spec
issue 80 (abst no 919) |
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