[Experimental research on the finishing and polishing of amalgam fillings]

In an in-vitro study occlusal amalgam restorations were finished and polished with four different methods. The quality of the restorations were evaluated according to the surface homogeneity and marginal adaptation. Additionally, the loss of substance due to the finishing and polishing process was determined. The results can be summarized as follows: The use of carbide finishing burs in combination with silicon polishing instruments (method A) results in rather smooth surfaces with numerous defects in the marginal area. The maximum loss of substance was about 160 microns in the filling material and about 110 microns in the adjacent enamel. Diamond finishing burs (grain size 30 microns = method B; grain size 15 microns = method C) in combination with silicon polishing instruments lead to rougher surfaces. The marginal areas, however, showed less deficiencies compared with method A. The maximum loss of substance in the adjacent enamel was about 220 microns (method B) and about 200 microns (method C), respectively, and in the amalgam area about 200 microns (method B) and 90 microns (method C), respectively. When finishing and polishing was done with a brush and a polishing paste (method D), the surface homogeneity and marginal adaptation of the restorations showed poor results. However, the maximum loss of substance was strongly decreased compared with methods A, B and C to an average of about 40 microns in the adjacent enamel and to about 75 microns in the amalgam. In conclusion, the application of the finishing and polishing methods A, B and C leads to a higher quality of the amalgam restoration than that, which can be achieved by applying method D.(ABSTRACT TRUNCATED AT 250 WORDS)