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Effect of human saliva on surface degradation of composite resins
Author(s) -
LARSEN INGE BIRK,
MUNKSGAARD ERIK GHRISTIAN
Publication year - 1991
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.1991.tb01893.x
Subject(s) - saliva , degradation (telecommunications) , composite number , dentistry , materials science , chemistry , composite material , medicine , computer science , biochemistry , telecommunications
– The amount of methacrylic acid produced by incubation of the dimethacrylate ester TEGDMA in human whole saliva was measured. The conversion rate of TEGDMA was determined in stimulated saliva from dental students and in unstimulated saliva from both dental students and patients. The differences in mean conversion rate measured in the three groups were not statistically significant ( P= 0.346). The mean conversion rate ± SD for all saliva samples was 4.54 ± 3.24 μmol MAA/L. h. The surface of BISGMA/TEGDMA‐polymer specimens treated with porcine liver esterase in activities equivalent to those found in human saliva exhibited a lower Wallace microhardness than the surface of untreated specimens. Polymer specimens incubated in human saliva exhibited a similar reduction in the microhardness. The results demonstrated that enzymes in human saliva are capable of softening the surface of dimethaerylate polymers presumably by inducing a hydrolysis of methacrylate ester bonds. The mechanical removal of a surface layer softened by hydrolases will expose a new surface layer to enzymatic attack. The enzymatic softening may thus contribute to the in vivo wear of composite restorations.