[The influence of disinfectants on colloidal impression materials and dental stones]

In view of prophylaxis against hospital infections, following tests were performed: Two kinds of alginate impression materials (ALGIACE and Aligix-S) and two kinds of agar impression materials (CARTRIILLOID and RUBBERLLOID) were immersed for 30 minutes in the following six kinds of disinfectants; 0.1% benzethonium chloride (benzethonium), 1% chlorhexidine gluconate (hexidine), 1% chlorhexidine gluconate added with surfactants (hexidine surfactant), 1% sodium hypochlorite (hypochlorous acid), 2% glutaraldehyde (glutaral) and 1% formaldehyde (formalin). Changes in size of the impression materials with time were then measured. Three kinds of dental stones (SHIMOMURA DENTAL PLASTER, NEW PLASTONE and SURSTONE) were infused into the impression surfaces after treatment with disinfectants, and the surface roughness and hardness of the yielded surfaces of the samples were measured. The results obtained are as follows: 1) As to ALGIACE, although the rates of changes in size lay within the range of +/- 0.3% when immersed in hexidine, hexidine surfactant and hypochlorous acid, the infusion of either one of SHIMOMURA DENTAL PLASTER, NEW PLASTONE or SURSTONE into the impression showed an effect on the stone surface. 2) As to Algix-S, the rate of changes in size lay within the range of +/- 0.3% when immersed in all the disinfectants, and the influsions of NEW PLASTONE and SURSTONE after immersing in benzethonium, hexidine surfactant and glutaral gave a slight effect on the stone surface. 3) As to CARTRILLOID, the rates of change in size lay within the range of +/- 0.3% except for the immersion in hexidine; the influsion of SHIMOMURA DENTAL PLASTER into the impression, the influsion of NEW PLASTONE after immersing in benzethonium and formalin and the influsions of NEW PLASTONE and SURSTONE after immersing in glutaral gave a slight effect on teh stone surface. 4) As to RUBBERLLOID, the rates of changes in size lay within the range of +/- 0.2% when immersed each disinfectant; the influsion of SHIMOMURA DENTAL PLASTER after immersing in hypochlorous acid and that of either one of SHIMOMURA DENTAL PLASTER, NEW PLASTONE or SURSTONE after immersing in benzethonium, glutaral and formalin gave a slight effect on the stone surface.