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Objectives: To compare residual monomer levels of a heat-cure and a self-cure injection-molding denture base materials after immersing in distilled water for 7 days. The curing process of the self-cure material was modified from that recommended by the manufacturer
Materials and methods: Two denture base polymers, heat-cure SR IvocapÒ High Impact (Ivocap wet curing) and self-cure IvoBaseÒ Hybrid (IvoBase dry curing), were selected for this study, Three disc shaped specimens of each brand (50 mm. diameter 3 mm. thickness) were prepared from separate mixes. The mixing ratios and processing methods were achieved according to the manufacturer’s instruction. Modification of the curing process of IvoBase® Hybrid was achieved by wet curing at 100 OC (IvoBase wet curing). Each specimen was immersed in 37°C distilled water at 7 days. Residual monomer was extracted from the immersed specimen and determined by gas chromatography following ISO 20795-1:2013. The freshly prepared specimens were also determined for residual monomer.
Non-parametric independent sample test (Kruskal-Wallis test and Mann-Whitney U test) was used to analyze the data at a=0.05.
Results: SR IvocapÒ High Impact showed significantly higher residual monomer level than IvoBaseÒ Hybrid after 7 days water immersion. No different residual monomer level was found when IvoBaseÒ Hybrid was polymerized wet or dry. The residual monomer level of the specimens decreased when they were immersed in water 7 days compared to when they were not.
Conclusions : Different curing technique (wet and dry curing) for IvoBaseÒ Hybrid could not reduce the residual monomer level. Water immersion in SR IvocapÒ High Impact (wet curing) and IvoBaseÒ Hybrid (wet curing) significantly decrease residual monomer level. Water immersion in IvoBaseÒ Hybrid (dry curing) was no different residual monomer level.
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