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00/25 - La sensibilità dentinale analisi al SEM degli effetti sulla dentina prodotti in vitro da quattro cementi vetroionomerici del commercio. Mirko Andreasi Bassi, Giuseppe Formisano e Salvatore Caiazza 2000, iii, 48 p.
Dentine sensitivity: an in vitro SEM analysis of the effects produced on dentin by four commercially available glass ionomer cements.
Mirko Andreasi Bassi, Giuseppe Formisano and Salvatore Caiazza
2000, iii, 48 p. Rapporti ISTISAN 00/25 (in Italian)
Glass ionomer cements (GIC) are capable to release ions in the oral environment. In the present research the effect of such release has been investigated in vitro on human dentin. On eight fresh extracted human bicuspids the vestibular and oral surfaces were cut with a diamond saw and then polished by means of a 600-grit SiC paper at the end to expose the dentinal tubules. The distance between pulp chamber and the abraded surface was 1mm. The teeth were then cut into two halves. The abraded areas were finally etched with 37 % phosphoric acid for 5s for removing the smear layer. The glass ionomer cements (GIC) tested were: Vitremer Luting Cement (3M) (VL); Vitremer Core Build up (shade A3 Vita, 3M) (VA3); Fugji I (Light Yellow, GC Corp.) (FI); Fugji IX (shade A2 Vita, GC Corp.) (FIX). One half for each tooth was used as a control, while on the other half was applied one of the materials tested (two teeth for each GIC). The GIC were prepared according to manufacturer instructions, VL, FI and FIX were self curable materials, while VA3 was light cured for 40s. After hardening, the specimens were immersed in deionized water (pH 6,4), contained in separated thermostatic tubs, at 37° C for 14 days. The water of each tub was changed every 24 hours to their ionic saturation. The specimens were then fractured into two parts and deidrated by means the critical point technique. After gold sputtering the specimens were observed using a scanning electron microscope (Stereoscan, Cambridge Instruments) at 10 kV beam acceleration. The control group showed cleaned areas with opened dentinal tubules, while all the treated areas showed the presence of a globular crystalline precipitate into the dentinal tubules. This in vitro result suggests that GIC are capable to release ions which precipitate into the dentinal tubules producing a globular crystalline layer which is probably capable, by the time, to occlude the dentinal tubules helping the physiological dentinal sclerosis in vital teeth.
Key words: Dentinal sensitivity, Glass ionomer cements
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