A long term study on residual monomer release from denture materials.

The aim of this long term study was to investigate the release of residual monomer from different denture materials, throughout a 38 months time period after curing and storage in water Specimens made of four denture base resins (three heat polymerizing, one auto polymerizing) and one hard liner were subjected to residual monomer determination using gas liquid chromatography. The residual monomer estimation carried out on three occasions: one week, 12 months and 38 months after curing. The data obtained were analyzed using two-way Anova followed by Scheffe's test for post hoc multiple comparisons at alpha=0.05. Heat polymerized denture base acrylic resins showed less residual monomer than auto polymerized ones (p<0.001) and released no statistically significant amounts of monomer (p>0.05), during the 38 months storage time period. Auto polymerized denture materials, which had higher residual monomer content, released statistically significant amounts of monomer (p<0.001) during the first twelve months storage, but not during the last twenty six months period (p>0.05). Heat polymerized denture base acrylic resins released insignificant amounts of residual monomer during the storage period, whereas both the auto polymerized denture base resin and the hard liner released significant amounts of residual monomer during the initial storage time period but insignificant ones during the remainder of the storage period.