Page 32 - COS-FOD2015

Compend. Oral Sci:vol1(4);2015;21-31

In this study, the mean difference in depth was pression materials, its viscosity selection and
chosen to represent the ability of the test im- the presence of moisture.
pression materials to wet and flow thus repro-
The results of this study showed that impres-
ducing the surface detail of master dies. The
sion materials were not dependent on the type
smaller the mean difference in depth, the better
of grooves. It was expected that Impregum Me-
the surface detail reproduction, suggesting that
dium would exhibited high accuracy due to its
the material has good flow and wetting proper-
inherent hydrophilicity, however this was not
ties. Therefore, one may indirectly conclude
observed. Polyether impression materials can
that a material exhibit hydrophilic characteris-
swell when they come into contact with water
tics. It can also be anticipated that the con-
unlike polyvinylsiloxane as shown by previous
sistency of the pastes might have an impact on
study Nissan et. al (2000) (22)
the reproduction of the grooves. In general, the
The most accurate surface detail reproduction
mean difference in depth produced by dual mix
was obtained from dual phase materials; Aqua-
polyvinylsiloxane (Express™ XT Light Body /
sil Putty-Light and Express-Putty-Light. The
Express™ XT Putty Soft and Aquasil Ultra LV
hydrophilic behaviour of these materials is at-
Smart Wetting® Regular Set / Aquasil Soft Put-
tributed to the presence of surfactant (12).
ty-Regular Set) were lower compared to those
Among surfactants used in polyvinylsiloxane as
obtained from single mix polyvinylsiloxane
non-ionic surfactant are nonylphenoxyl poly
(Aquasil Ultra Monophase Smart Wetting®
(ethyleneoxy) ethanol and ethoxylated long-
Regular Set). Meanwhile, the reverse was ob-
chain alcohol (24).
served for polyether. The results of this study
contradict those of other studies that have been Although the mean difference in depth between
reported in the literature (12,21) and polyether these materials was not significant, Express-

has been reported to consistently produced bet- Putty-Light exhibited the highest accuracy.
ter results compared to polyvinylsiloxane in the Thus, further study is necessary to determine
reproduction of surface details due to its inher- the effect of different type of surfactant in differ-
ent hydrophilic nature (21). ent type of impression materials.

In this study only single mix technique impres- The results of this study indicated incorporation
sion materials which is a medium-bodied was of a non-ionic surfactant into polyvinylsiloxanes
used. However, in the present study, both sin- enhanced their hydrophilicity and led to the sig-
gle and dual mix technique were used to simu- nificant reduction in the contact angles (1,5,12).
late clinical application as the difference in the
Nevertheless, further investigation should be
components of each impression materials may
carried out to empirically verify the observation
influence the outcome. Furthermore, different
of this study. The exact type of surfactant also
types of surfacant added to polyvinylsiloxane by
needs to be identified in each impression mate-
different manufacturers also may affect the re-
rial as Express Putty-Light showed significantly
sults. This was highlighted by Johnson et al
lower mean difference in depth compared to
(2003) who showed that mean roughness of
Aquasil Putty-Light. Furthermore, the result of
impressions was influenced by the type of im-

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