Effects of radio-opacifier addition in dental impression material

The aim of this in vitro study was to determine the effects of barium sulfate addition in two dental impression materials previously proved as radiolucent.

An irreversible hydrocolloid (IH) and polyether (PE) were tested for optical density, linear dimension stability and detail reproduction.

The optical density data were submitted to Kolmogorov-Smirnov normality test and compared with two-way ANOVA and Tukey (alpha=0.05).

The results of optical density (pixel) were: IH control 45.24 f (+/-7.6), PE control 54.93 e (+/-4.45), PE 5Wt% 60.43 d (+/-6.27), IH 1Wt% 61.54 cd (+/-5.3), PE 1Wt% 66.9 bc (+/-5.05), IH 5Wt% 67.17 b (+/-6.01), PE 10Wt% 84.55 a (+/-5.14), IH 10Wt% 85.33 a (+/-5.53). On detail reproduction, polyether control was able to copy the 6 microm line. Adding 1 or 5Wt% of barium sulfate have not change this characteristic. For the irreversible hydrocolloid, the control group was able to copy a line with 14 microm, however, adding 1Wt% barium sulfate, the capability decreased to 22 microm. Adding barium sulfate in the polyether promoted an increase in between the copied lines, for the control, the average distance was 931.6 microm, 936 microm to 1Wt% and 954.5 microm to 5 Wt%. For the IH, the control presented 975 microm in comparison to 987.25 microm for 1 Wt% samples.

The addition of barium sulfate was capable of increasing significantly the optical density of tested material, have changed the linear dimension stability, however, have not interfered in detail reproduction only for PE.