| Objective To evaluate the microleakage situation, shear bond strength and compressive strength of the flowable resin used as pit and fissure sealant using different etching adhesive systems.Methods Sixty caries-free were randomly divided into four groups with fifteen teeth each: Group A(Gluma, NT, 3M-Z350 flowable resin); Group B(Clearifil SE Bond adhesive, 3M-Z350 flowable resin); Group C(Gluma, 3M-Z350 flowable resin); Group D(Gluma, 3M concise sealant). A sample of ten in each group were sealed fissure, eight teeth of them were to observe the microleakage situation, the other two were to observe the morphological change of material-enamel interface by SEM. In order to test their shear bond strengths, the other five teeth of four groups were formed a certain size sample. Ten sealant cartridges and flowable resin cartridges were made to test their crushing strength.Results 1 Dye microleakage experiment: Observation under Stereomicroscope showed that four groups had a good marginal sealing ability. There was no dye penetration at the interface. Flow resin is together with the tooth surface completely without cracks, Dye was confined to the surface of flow resin without dye infiltrat into the fissure. There was no significant difference of microleakage in four groups(c2Fisher’s Exact Test=5.724,P>0.05). Observation under SEM showed that the materials of sealant combined with dental tissues closely which had a good marginal sealing ability and the resin tags were clear, long and dense in Group A. The materials of sealant combined with dental tissues were not very closely which had a not very good marginal sealing ability and the resin tags were short and sparse in Group B. Some bubbles and cracks were found on the local in both of them, the materials of sealant can ’ t combined with dental tissues which had a poor marginal sealing ability and can ’ t form resin tags. The materials of sealant combined with dental tissues closely which had a good marginal sealing ability and the resin tags were clearer, longer, thicker but sparser in Group C than those in Group D. The materials of sealant combined with dental tissues were not very closely which had a not very good marginal sealing ability and the resin tags were dim,short and dense in Group D. The materials of sealant with large amounts of impuritiesand cracks in it can ’ t infiltrate into the bottom of fissure and form good resin tags among four groups. 2 Shear bond strength test: The shear bond strength of Group E(70.22±0.98MPa) was the highest, The shear bond strength of Group G(23.17±1.35MPa)was the second, The shear bond strength of Group F(23.17±1.35MPa) was the third and the shear bond strength of Group H(22.91±2.75MPa) was the lowest. The results of one-way ANOVA show that there was significantly difference in four groups(F=837.991,P<0.001). Group E was higher than the other three groups(P<0.05), group G was higher than group F and group H(P<0.05), There was no significant difference between group F and group H(P>0.05). 3 Compressive strength test: The compressive strength of 3M Z350 flowable resin was(68.65±5.22)MPa and the compressive strength of 3M concise fissure sealant was(37.55±3.94)MPa. The results of two independent samples t-test show that the compressive strength of flowable resin was significantly higher than that of fissure sealant(P<0.05).Conclusion 1 All groups had good marginal sealing. 2 The shear bond strength and compressive strength of all-etching bonding system combined with flowable resin and combined with flowable resin directly after etching were superior to the self-etching bonding system combined with flowable resin and the traditional sealant. 3 Using Prime&Bond NT bond after acid etching could improve the shear bonding strength. 4The compressive strength of flowable resin was higher than that of fissure sealant. |
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