[Effect of three protective agents on edge closeness of glass ionomer cements].

Purpose: To observe the effect of three protective agents on edge closeness of glass ionomer cements filling in vitro.
Methods: Eighty freshly extracted human molars were randomly divided into A and B groups(40 molars each group). The teeth cavities were prepared at 1/3 part to buccal gingiva of each molar and those of A group were filled with GC Fuji IX and those of B group with another glass ionomer cement. A and B groups were respectively divided into three experiment groups and one control group(A1/B1). The filling surfaces of three experimental groups were separately coated with vaseline(A2/B2), cocoa butter(A3/B3), biscover (A4/B4). After thermal cycling(x 30, 5-55 degrees centigrade), the depth of dye penetrating into the teeth was observed through an optical microscope. The data was analyzed with rating information on diverse groups of the rank and testing, using SPSS13.0 software package.
Results: Different dye penetration degrees were shown between filling material and cavity walls among each group, while the degrees of dye penetration of experimental groups were significantly slighter than those of corresponding control group(P<0.05), and there was no difference among experimental groups (P>0.05).
Conclusion: The three protective agents can increase the edge closeness of glass ionomer cement filling.