The Study Of Marginal Microleakage Of Glass Ionomer Cements Fulling In Vitro

Objective: TO observe the effect of three protective agents on edge closeness of glass ionomer cements filling in vitro. To evaluate theomicroleakage in classV restrorations after use of one kind of composite and three kinds of glass ionomer cement. The mainly purpose of this experiment was to give a experimental evidence for clinical application. Methods: (1)One hundred and twenty freshly extracted human molars were randomly divided into A,B and C groups(40 molars each group). The teeth cavities were prepared at 1/3 part to buccal gingial of each molar and every cavities of A group were filled with glass ionomer cement(shanghai), B group with GC Fuiji IX and that of C group with Ketac^TM Molar Easymix. They were respectingly divided into three experiment groups and one control group.The filling surface of three experiment groups were seperately coated with vaseline(A2/B2/C2),Cocoabutter(A3/B3/C3),Biscover(A4/B4/C4).(2)Another sixty freshly extracted human molars were randomly divided into six groups(10 molars each group). A group(A1,A2) was filled with Filtek^TMZ250, B1 group was filled with Ketac^TMN100 and B4 with F2000 Compomer, the last two groups (B2, B3)were respectingly filling with Ketac^TM Molar Easymix. A2 group was coated with Adper Single Bond 2, and B3 group with vaseline. Both two parts of experiment after thermal cycling(×50, 5～55℃), the depth of dye penetrating into the teeth was observed through an optical microscope. Statistical methods used rating information on diverse groups of the rank and testing, using SPSS13.0. Result: (1)Different dye penetration degrees were shown between filling material and cavity walls among each groups, while the degrees of dye penetration of experiment groups(A2,A3,A4,B2,B3,B4,C2,C3,C4)were significantly slighter than that of corresponding control group (A1,B1,C1) (P<0.05), and there was no difference among experiment groups(P>0.05). The degrees of dye penetration of Ketac^TM Molar Easymix and GC Fuiji IX were significantly slighter than glass ionomer cement(shanghai) (P<0.05).(2)Restorative A2 group was a lesser microleakage material(P<0.05). Significant differences were observed between A2 and other four groups (A1, B1, B2, B3, B4). The microleakage of Ketac^TM Molar Easymix(B2) was more than other fiver groups(P<0.05). No statistically significant differences in microleakage were noted between B1, B4 and A1 specimens(P>0.05). Conclusions: The three protective agents can incerease the edge closeness of glass ionomer cement filling. It may be most beneficial to use Resin-modified glass-ionomer,polyacid modified resin composites and resin compsites as the restorative material of choice.