Physical Properties of the Zinc Oxide-Eugenol Impression Pastes

An in vitro study of a custom-made device for thermoregulation of the mixing slab on the setting properties of zinc oxide eugenol impression paste

Aim

The present study was aimed to investigate the functional relationship between the mixing temperature and properties of a commercially available zinc oxide eugenol impression paste (ZnOE paste).

Settings and Design

In-vitro study.

Materials and Methods

A custom-made simulated mixing device was indigenously designed to maintain different mixing temperatures, simulating cold, ambient, and hot weather. A commercially available ZnOE paste was mixed according to the manufacturer's instructions in the simulated mixing device at the temperatures ranging from 10°C to 50°C. Initial setting time and consistency were measured according to A. D. A. Specification No. 16 (n = 8). A stainless-steel die having 25, 50, and 75 μm lines was used for surface detail reproduction. Detail reproduction of the stone casts of the impressions was evaluated with a stereomicroscope at 30 magnification (n = 8). The shear bond strength of ZnOE paste to self-cure acrylic tray resin was measured by using the UTM at a crosshead speed of 0.5 mm/min (n = 8).

Statistical Analysis Used

Data were analyzed by using one-way analysis of variance (ANOVA) and Tukey's post hoc tests at a confidence interval of 95% (alpha =0.05).

Results

Initial setting time, consistency, and detail reproduction of the ZnOE paste were affected by the mixing temperature (P < 0.001). Mixing ZnOE paste at a lower temperature of 10°C and higher temperatures of 40°C and 50°C resulted in shorter initial setting time, thicker consistency, and poor detail reproduction. However, no significant difference was obtained in the shear bond strength among the different mixing temperatures evaluated (P > 0.05).

Conclusion

Based on this in vitro study, it is advisable to perform the manipulation of ZnOE paste at a clinical/laboratory temperature of 30°C for optimum performance. The simulated mixing device used in this study can be an alternative for extreme climatic conditions.

An In Vitro Study to Evaluate and Compare the Flow Property of Different Commercially Available Zinc Oxide Eugenol Impression Materials

Introduction:

Impression making is one of the most important steps in prosthodontic rehabilitation of edentulous patients. Zinc oxide eugenol (ZOE) impression paste is the most commonly used material for complete denture wash impression due to its cost-effectiveness and ease of manipulation, while providing the advantage of ability to record fine minute tissue details. Rheological property like flow is a critical factor influencing the success of any impression material, especially in intraoral conditions. Therefore, with so many brands of commercially available impression materials flooding the markets, the aim of this study was to evaluate and compare the flow property of four commercially available ZOE impression materials under simulated intraoral condition.

Materials and Methods:

The testing method used was according to the American Dental Association (ADA) specification no. 16 for ZOE impression pastes.

Results:

At room temperature, maximum flow was seen with Denzomix followed by Dental Product of India (DPI), Neogenate, and Cavex in descending order, respectively, at 30 s, 1 min, and 10 min of load application. At 37°C in saliva, maximum flow was seen with Denzomix followed by Neogenate, DPI, and Cavex in descending order, respectively, at 30 s, 1 min, and 10 min of load application. Of the four ZOE impression pastes, only the flow of Cavex was considerably less than ADA specified value.

Interpretation and Conclusion:

Results obtained from this study showed that there is considerable variation in the flow values of different commercially available ZOE impression materials. Change in temperature and presence of saliva had a significant influence on the flow of ZOE impression materials.

To study the flow property of seven commercially available zinc oxide eugenol impression material at various time intervals after mixing

Aims and objective of the study was to evaluate the flow property of seven commercially available zinc oxide eugenol impression materials at various time intervals, after mixing 49 samples (seven groups) were fabricated for flow property of the material. The sample were fabricated as equal length of base and accelerator paste of the test materials was taken on the glass slab and mixed with a rigid stainless steel spatula as per manufacturers recommendation till the homogenous mix was obtained. The mix material was loaded in glass syringe and 0.5 ml material was injected on a cellophane sheet placed on marked glass plate. A cellophane sheet and glass plate 70 and 500 g weight was carefully placed on freshly dispensed zinc oxide eugenol impression paste sequentially. The diameter of the mix was noted after 30 s and 1 min of load application and also after the final set of material. The diameter gives the flow of material. The samples were stored at the room temperature. The data of the flow property was analyzed with analysis of variance, Post hoc test and t test. The flow of the zinc oxide eugenol impression paste after 30 s, 1 min and final set of load application for Group A to Group G was noted. Maximum flow was seen for Group G zinc oxide eugenol impression material followed by Group F, D, E, B, C and A in descending order respectively after 30 s, where as the flow property changed after 1 min in the sequence of maximum for Group G followed by Group E, D, B, A, C, and F. Lastly after final set of the impression material the flow maximum for Group G followed by Group E, D, C, F, A and B in descending order. Based on statistical analysis of the results and within in the limitations of this in-vitro study, the following conclusions were drawn that; the flow of zinc oxide eugenol impression material after 30 s, 1 min and that after the final set was maximum for P.S.P. (Group G) and the flow for PYREX (Group A) was minimum.

The effects of different storage conditions on polyether and polyvinylsiloxane impressions

While being shipped to a laboratory, impressions can be exposed to excessive temperatures. This study compared the effects of different time and temperature storage conditions, including temperature extremes of 66 C and -10 C, on the accuracy of addition silicone and polyether impressions. The greatest distortion generally occurred as a result of the 66 C temperature extreme. The authors recommend that impressions be poured in stone according to manufacturers' specifications before being shipped to a dental laboratory.

Physical properties of some zinc oxide-eugenol cements

SYNOPSIS IN INTERLINGUA

PROPRIETATES PHYSIC DE CERTE CEMENTOS A OXYDO DE ZINC E EUGENOL.—Le hic-reporate studio esseva concernite con le consistentia, le fortia compressive, le tempores de travalio e de prisa, le spissitate de pellicula, e le duressa del materiales studiate. Lor numero esseva 6. Le valores pro le consistentia variava inter 35 e 60 mm. Le fortias compressive variava ab 6,4 ad 219 kg/cm 2. Le tempore de travalio esseva inter 3 e 21 minutas, e le tempore de prisa final esseva inter 5,5 e 20 minutas additional. Omne le cementos produceva un spissitate de pellicula de minus que 0,04 mm. Le valores del duressa post 24 horas variava inter 0,05 e 1,1 mm de penetration.