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Objective. The aim of this study was to perform an in vitro
evaluation of the demineralization on perimarginal enamel of composite
resin restorations after storage in cariogenic solutions. Method.
The material used in the research were 56 extracted human molars. Class
V cavities were prepared with margins in enamel. Cavities were restored
with various composite materials and appropriate adhesive systems: (1)
Single Bond/Z 250, (2) Prompt-L-Pop/Z 250, (3) Single Bond/Filek flow
and (4) Prompt-L-Pop/Filtek flow. After the restorative procedure, the
restorations were submitted to demineralization during the first and the
fourth week. Samples were stored in a demineralizing- cariogenic
solution (lactic acid, pH 4.5, 0,1M) at 370Cor in distilled water
(control group). The margins of restorations and perimarginal enamel
were examined by scanning electron microscope (SEM). The widht of
demineralized zone and marginal fissures around restaurations were
measured at cervial, occlusal and approximal margin.
Results. The enamel close to composite restoration margins was
strongly affected by acidic cariogenic solution and was marked as
perimarginal demineralized enamel zone. The typical ultrastructural
patterns of the perimarginal enamel zone were erosions of intraprismatic
enamel, porosities, fissures and fractures. The peripheral zone showed
only minimal alteration by cariogenic solution. There was no
statistically significant difference (p<0.05) between restorative
materials concerning the approximate width of demineralized perimarginal
enamel zones.
Conclusion. Deterioration of perimarginal enamel zone caused by
cariogenic solution could be seen around all composite fillings and did
not depend on adhesive treatment and restorative materials.
Key words: enamel, composite resins, demineralization, scanning
electron microscopy
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