Summary:
The aim of the present study was the comparison of the contact angles of
distilled water over low viscosity hydrophilic polyvinylsiloxane impression
materials. The following impression materials were tested: Afinis precious,
Optimapasil Ultra Hydro, Aquasil LV, Aquasil XLV. These hydrophilic
polyvinylsiloxanes were compared with Exa'lence, a copolymer of
polyvinylsiloxane and polyaither. 10 specimens were constructed from each
impression material and their contact angles with distilled water were measured
in 2 time intervals: 10 min, and 3 h after setting.
The photographs of the contact angles were taken with a macro lens at a 1:1
ratio. Each photo was digitized and each contact angle was calculated by
measuring the base (b) and the height (h) of the meniscus and using the
following trigonometic formula: θ=2arc tan (2h/b). The statistical evaluation
of the first part of the experiment was carried out with ANOVA. For the second
part of the experiment paired samples t-test were used. The results showed that
the contact angle correlates to type the impression material that is used.
Duncan showed that Exa'lence has the lowest contact angle and Optimasil has the
greatest contact angle between all materials. These findings were statistically
significant. Afinis, Aquasil LV και Aquasil XLV did not show any statistical
significant diferrences in their contact angles. Regarding the second part of
the study, the null hypothesis is not valid, and therefore the contact angle,
i.e. the wetting capability, is not influenced by time. As a consequence, the
delay of cast construction aiming to better surfactant influence, cannot be
justified.
