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The effect of disinfectants on the properties of dental gypsum, part 2: Surface properties
Author(s) -
Abdelaziz Khalid M.,
Combe Edward C.,
Hodges James S.
Publication year - 2002
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/j.1532-849x.2002.00234.x
Subject(s) - calcium hydroxide , profilometer , materials science , mixing (physics) , surface roughness , scanning electron microscope , distilled water , gum arabic , surface finish , gypsum , dentistry , nuclear chemistry , mineralogy , metallurgy , chemistry , composite material , chromatography , medicine , organic chemistry , physics , quantum mechanics
Purpose This study is part of an ongoing investigation to evaluate the surface properties of dental stones mixed with disinfection solutions, and to determine the effect of adding gum arabic and calcium hydroxide on the same properties. Materials and Methods Aqueous solutions of 2 chemical disinfectants were used in mixing 2 types of dental stones (type III and type V). These dental stones were modified further by adding 1% gum arabic and 0.132% calcium hydroxide to their hemihydrate powders before mixing. Five specimens prepared from each type of dental stone were classified into 7 groups according to the hemihydrate powder modification and mixing liquid/powder ratio. Surface roughness was tested by 2‐dimensional profilometery and scanning electron microscopy (SEM). Knoop hardness testing was carried out, and detail reproduction was assessed using ADA specification 25 in addition to SEM and 3‐dimensional profilometer studies. Results Dental stones mixed with chemical disinfectants showed higher average roughness (R a ) values than those of the controls. However, adding gum arabic and calcium hydroxide to the hemihydrate powders before mixing restored values to the level of the control. The additives seemed to have a role in the improvement of surface hardness. There was no significant difference between the experimental and the control group in the terms of detail reproduction. Conclusions Using SEM, 3‐dimensional profilometry, and ADA testing methods, we found that the surface roughness of stone casts was adversely affected by using the disinfectant solutions as mixing water substitutes. Gum arabic and calcium hydroxide additives can yield a harder stone surface without compromising other surface properties.