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Notes: Purpose: To evaluate the consistency prior to the setting of 5 elastomeric interocclusal recording materials in comparison with a wax and a zinc oxide–eugenol paste. This property is related to the viscosity as well as to the working and setting times of these materials. Materials and Methods: Testing of consistency was performed following a modification of the method described in ADA Specification No. 19, for elastomeric impression materials. Each one of the tested materials was mixed for 20 seconds and was then loaded into a 0.5 mL syringe. The material was syringed onto a 10 × 10 × 0.5 cm glass plate. A second 575 g glass plate was placed on top of the unset interocclusal registration material. A total of 10 samples were tested for each material. The surface area covered by the materials was measured with the help of a scanner and the use of appropriate computer software. Results: One-way ANOVA revealed significant differences among the materials (F = 889.493, p 〈 0.0005). According to Tukey's honest significant difference test, all materials were significantly different (p 〈 0.05) from one another. All polyvinylsiloxanes occupied a smaller area than that of the polyether and of the zinc oxide–eugenol paste. Conclusions: Zinc oxide–eugenol paste was the most fluid of all materials tested. Polyvinylsiloxanes displayed less flow properties than polyether.

Notes: Purpose: The purpose of this study was to evaluate the resistance to compression after setting of several elastomeric interocclusal recording materials. Materials and Methods: Testing of the resistance to compression after setting was performed following a modification of the method described in specification No. 19 (4.3.6) of the A.D.A., for the elastomeric impression materials—1 cylindrical stainless steel mold with an internal diameter of 20 mm and a height of 20 mm was constructed. Mixing of the interocclusal registration media was conducted according to manufacturers' instructions, and the materials were injected into the mold. Two subsequent loads, one of 100 g/cm2 and a second of 1000 g/cm2 were exerted on each sample. The deformation of each was calculated using a vertical traveling micrometer microscope with an accuracy of ± 0.001 mm. Results: One-way ANOVA revealed significant differences among the materials (F= 331.58, p 〈 0.0005). Tukey's HSD (p 〈 0.05) test was used to determine the significant differences between the materials. Conclusions: Polyvinylsiloxane Blu Mousse displayed the greatest resistance to compression, as compared to other elastomeric interocclusal recording materials tested.

Notes: Purpose: The purpose of this study was to evaluate the linear dimensional change and accompanying weight change of several elastomeric interocclusal recording media. Materials and Methods: Ten 50 mm long, 8 mm wide, 3 mm deep Teflon molds and a stainless steel die were constructed for the purposes of this study. The die was made in order to produce standardized reference lines, which were used for the measurement of the linear change. After homogeneous mixing, each material was carried from the mixing pad or directly from the mixing tip to the Teflon mold. The mold was inverted onto the stainless steel die. The materials were allowed to set for the manufacturers' suggested setting time plus an additional 3 minutes to ensure polymerization of the material. An electronic scale (Galaxy 110, Ohaus, Pine Brook, NJ) was used for the measurement of the weight change of the specimens and a traveling micrometer microscope (Griffin Ltd., London, England) was used to measure the linear changes at 5 time intervals: 0, 1 hour, 24, 48, and 72 hours. Results: Analysis of variance for a significance level of 5% revealed that there was a statistically significant effect of the “material” factor on the weight changes (F= 2229.98, p 〈 0.0005). There was also a statistically significant effect of the “time” factor on the weight changes (F= 2,332.04, p 〈 0.0005). Descriptive statistics and Tukey's Honest Significant Difference Test revealed that the elastomeric material with the greatest weight changes is polyether (Ramitec).Analysis of variance for a significance level of 5% revealed that there is a statistically significant effect of the “material” factor on the linear changes (F= 215.54, p 〈 0.0005). There is also a statistically significant effect of the “time” factor on the linear changes (F= 1,996.01, p 〈 0.0005). Descriptive statistics and Tukey's Honest Significant Difference test revealed that the elastomeric material with the smallest linear changes is polyether (Ramitec). Conclusions: Of all materials tested, Ramitec (polyether) presented the smallest linear change at all time intervals. Addition reaction silicones presented statistically significant differences in recordings of linear changes among them only at the 1st and the 24th hour. Linear changes did not seem to be associated with weight changes.