Ml. Hutchings et al., IMMERSION DISINFECTION OF IRREVERSIBLE HYDROCOLLOID IMPRESSIONS IN PH-ADJUSTED SODIUM-HYPOCHLORITE .2. EFFECT ON GYPSUM CASTS, The International journal of prosthodontics, 9(3), 1996, pp. 223-229
Lowering the pH of sodium hypochlorite has been shown to greatly impro
ve its efficacy as a disinfectant for irreversible hydrocolloid. This
study evaluated the surface roughness and detail reproduction of gypsu
m casts recovered from impressions disinfected with sodium hypochlorit
e at altered pH levels. The experimental disinfectants were sodium hyp
ochlorite 0.525% (10-minute immersion) at pH 11.5 (unaltered), pH 10,
and pH 8. An additional group was tested at pH 10 for 5 minutes. There
was a trend toward increased surface roughness as the pH was lowered,
but a 5-minute immersion of impressions in sodium hypochlorite at pH
10 produced casts of equivalent surface roughness to impressions rinse
d in water and poured immediately. The test for surface detail reprodu
ction produced similar results.