Contact Angle Measurement of AdditionType Polyvinyl Siloxane Impression Materials

Objectives: To measure and compare the hydrophilicity of five commercially available polyvinyl siloxane impression materials (PVS) by measuring the contact angle made by water on the set surface of the impression material.

Methods: Five type 3 (according to ISO4823:2000) PVS impression materials were used for the present study: Standout, Examix, Aquasil Ultra, Genie, and Imprint 3. Specimens were prepared by dispensing the impression materials into a square shaped brass mold (38mmx32mmx2mm) setting on a glass slab with a plastic film separator.  Another plastic film was quickly placed on top of the mold and pressed to create a flat surface by covering the plastic film (Hostaphan RN 75, thickness 0.075mm) with a glass slab, expressing excess material and allowing the impression material to polymerize for 15min. Excess material was removed and the specimens were placed for contact angle measurement (Drop Shaped Analyses System, DSA 100 Kruss, Hamburg, Germany). A drop of distilled water measuring 5µl was dispensed onto the set impression material and contact angles were measured at 2sec and 10sec using a video camera. ANOVA and Tukey tests were used to determine intergroup differences (p<.05).

Results:                     

Contact angle at	Imprint 3	Standout	Examix	Aquasil	Genie
2sec [°]	16.4(±4.8)a	40.4(±7.1)b	36.7± (3.2)b	93.5± (2.9)c	108.7(±1.1)d
10sec [°]	6.0(±0.6)a	17.9(±2.3)b	29.1(±3. 7)c	52.5 (±1.3)d	80.9(±2.2)e

Means with the same superscripted letters are not different statistically.

Conclusions: Different PVS materials exhibited different contact angles. The lowest contact angle which indicates highest hydrophilicity. Therefore pouring a cast in a hydrophilic impression material should produce fewer voids.