Dimensional changes in stone casts resulting from long-term immersion of addition-type silicone rubber impressions in disinfectant solutions

Abstract

There is a concern that long-term immersion of impressions in disinfectant solutions may cause changes in the dimensions of the resulting stone casts. This study investigated the dimensional changes in stone casts resulting from immersion of five brands of addition-type silicone rubber impressions in disinfectant solutions for 30 min and 24 h. Impressions of a master cast designed to simulate an abutment tooth were immersed in 2% glutaraldehyde and 0.55% ortho-phthalaldehyde. The diameter of the stone cast was measured using a laser scan micrometer. For four brands of impression materials, 30-min immersion in disinfectant solutions produced no dimensional changes in the stone casts. For four brands of impression materials, 24-h immersion caused a significant decrease in the stone cast dimensions.

Dimensional changes in stone models simulating full crown preparations with adjacent teeth resulting from long-term immersion of medium-viscosity additiontype silicone rubber impressions in disinfectant solutions

“…It has been reported that the accuracy of hydrophilic additiontype silicone rubber impression materials is adversely affected by 18-h immersion in 2% glutaraldehyde solution, and shows decreases in the mesiodistal and buccolingual dimensions 5) . A previous study 8) has also reported that 24-h immersion of low-viscosity additiontype silicone rubber impression materials in disinfectant solutions caused a significant decrease in the dimensions of the resulting stone models. However, the effects varied according to the brand of impression material and the disinfectant solution employed [5][6][7][8] .…”

“…A previous study 8) has also reported that 24-h immersion of low-viscosity additiontype silicone rubber impression materials in disinfectant solutions caused a significant decrease in the dimensions of the resulting stone models. However, the effects varied according to the brand of impression material and the disinfectant solution employed [5][6][7][8] . Therefore, detailed investigation of the effects of long-term immersion of hydrophilic addition-type silicone rubber impression materials might help to devise methods of long-term disinfection that are clinically acceptable.…”

“…It has been reported that there are no differences in the dimensional changes in stone models after immersion of addition-type silicone rubber impression materials in glutaraldehyde solution for less than 30 min in comparison with no immersion [13][14][15] . A previous study 8) investigating the effects of 30-min immersion disinfection of four brands of low-viscosity hydrophilic addition-type silicone rubber impression materials, including those with enhanced hydrophilicity, on the dimensional accuracy of the resulting stone models found no difference between the use of 2% glutaraldehyde solution and 0.55% orthophthalaldehyde solution. In the present study, for medium-viscosity impression materials, there were no significant differences in the dimensional changes in the mesiodistal and buccolingual dimensions among stone models obtained from impressions subjected to immersion disinfection for 30 min (GA0.5, PA0.5) and no disinfection (C24) at any of the measurement positions.…”

“…A previous study 8) has reported that immersion of low-viscosity hydrophilic addition-type silicone rubber impression materials in 2% glutaraldehyde or 0.55% ortho-phthalaldehyde solution for 24 h caused a significant decrease in the dimensions of stone models 8) . On the other hand, a previous study has shown that the degree of imbibition of hydrophilic additiontype silicone rubber impression materials after 18 h of immersion in 2% glutaraldehyde solution varied according to the brand 7) .…”

“…If impression materials could be immersed for a longer period, for example overnight, then this form of disinfection would become easier to apply. Some studies [5][6][7][8] have reported the effects of long-term immersion of impression materials in disinfectant solutions on the dimensional accuracy of the resulting stone models. However, no studies have investigated the effects of long-term immersion of addition-type silicone rubber impression materials in ortho-phthalaldehyde solution, which has become attention for the toxicity of glutaraldehyde solution.…”