Residual Monomer Elution From Conventional and CAD/CAM Polymers During Aging

Objectives: The aim of this study was to analyze and quantify the residual monomer elution of 9 conventional and CAD/CAM dental polymers during artificial aging.
Methods: 360 square-shaped specimens (14x12x2 ± 0.05mm) were fabricated from eight CAD/CAM polymer blanks (n=40): (a) Avadent Base material (AVADENT), (b) Avadent Teeth material (AVADENT), (c) PMMA Multi blank A3 (AnaxDENT), (d) PMMA Mono blank A1 (AnaxDENT), (e) Temp Premium (Zirkonzahn), (f) Telio CAD (Ivoclar Vivadent), (g) Ceramill Temp (Amann Girrbach), (h) Shofu Block HC (SHOFU Dental Corporation) and a conventional polymer (i) PalaXpress (Heraeus Kulzer). Specimens were aged in distilled water for 60 days at 37°C and the evaluation of the residual monomer content/elution was made through UV-spectrophotometry (Perkin Elmer Inc.) at 1, 2, 3, 4, 5, 6, 7, 15, 20, 30, and 60 days. Statistical analysis was carried out in the SPSS software. One-way ANOVA and Scheffé post-hoc test were used for comparison of results (α<0.05).
Results: Aging time had an impact on the elution for all groups, except for PalaXpress. Statistically significant differences of elution were also found between the materials. Shofu Block HC presented the highest, whereas PMMA Multi blank A3 and Mono blank A1 presented the lowest elution after the 60^th day of aging.
Conclusions: CAD/CAM dental polymers as well as the conventional polymer PalaXPress eluted residual monomer within aging time. The differences in elution were material-dependent; still, the maximum elution found is below the specified threshold of the ISO standard.