The Influence of Nitrile Gloves on the Setting Behavior of Polyvinyl Siloxane Putty Impression Materials

Abstract

Objective: The purpose of this study was to assess the gelation and polymerization time of three polyvinyl siloxane (PVS) putty materials and to determine if those times were affected by nitrile gloves under different conditions.

Materials and methods: Ten specimens (n=10) were obtained for each PVS putty material (Express STD, 3M ESPE; Extrude Xtra, Kerr and Exafast, GC) and tested under different conditions (gloves washed, gloves unwashed and hands contaminated). The gelation and polymerization time were measured using an oscillating rheometer and recorded for 400 s at 37°C to simulate the oral environment.

Results: The mean gelation time of hand contaminated specimens was 157.50 minutes and was significantly slower than that by using nitrile washed gloves (mean=117.94, p=.004) and by using unwashed gloves (mean=99.46, p⟨0.001). Unwashed gloves had significantly quicker gelation times compared to washed gloves (p=.046). The gelation time was significantly delayed with Exafast compared to Extrude Xtra and Express STD across all the different types of glove conditions (p⟨0.043). No significant differences were observed between polymerization time with Exafast and Extrude Xtra Putty.

Conclusions: Extrude Xtra putty material had significantly better performance than GC Exafast and Express. Hand contaminated specimens were affected by the gelation/polymerization time.

Keywords: Gelation; Impression; Impression Material; Poly Vinyl Siloxane; Setting Time; Vinyl Polysiloxane.