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Influence of curing method, sealer, and water storage on the hardness of a soft lining material over time
Author(s) -
Polyzois Gregory L.,
Frangou Mary J.
Publication year - 2001
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.2001.00042.x
Subject(s) - curing (chemistry) , materials science , soft water , composite material , indentation hardness , chemistry , microstructure , organic chemistry
Purpose The purpose of this study was to determine the hardness of plasticized acrylic resin soft lining materials over time when curing procedures were modified and when surface sealers were either used or omitted. Materials and Methods A chairside plasticized acrylic resin material and a heat processed plasticized resin material were made into disks 40 mm in diameter and 10 mm in thickness. Materials were cured by processing at an elevated temperature or at mouth temperature. Five samples were used with each processing method. Half of all samples were treated with a surface sealer, whereas the other samples received no surface treatment. After processing, the samples were immersed in 37°C water for a total time of 1 year. Specimens were tested to determine hardness on a monthly basis. Testing was accomplished using a Shore A durometer. Results Hardness testing showed differences relative to material and to time after processing. The heat‐processed plasticized resin material showed significantly higher Shore A hardness values than the chairside over the entire experimental period ( p < .01 ). Increased hardness was seen for all materials over time, but this was more pronounced with plasticized acrylic resin in which the hardness increased from 28.4% to 115.8% depending on processing method and surface treatment. Surface treatment showed significant softening only when the samples were cured at simulated mouth temperature ( p < .05 ). Conclusions Processing method and time after processing have an effect on surface hardness of the tested materials, but neither of these effects is as profound as the initial choice of material.