Percorrer por autor "Alves, Clara Nuno"
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- Differences in the sorption and solubility of experimental self-adhesive composites with different chemical compositionsPublication . Alves, Clara Nuno; Delgado, António SalesObjectives: The aim of this work is to assess whether systematic variations in monomer type, monomer content, powder-to-liquid ratio and filler blend of lab-based experimental self-adhesive flowable resin composites (SAFRCs) have an impact on ISO 4049:2019 water sorption (Wsp) and solubility (Wsl) parameters, over a 28-day test period. Materials and Methods: A total of sixteen experimental SAFRCs were formulated using a urethane dimethacrylate (UDMA)/polypropylene glycol dimethacrylate (PPGDMA) base matrix, combined with camphorquinone. To improve functionalization, either HEMA or 10-MDP, were incorporated at 5% or 25% mol%. Eight high-filler and eight low-filler composite formulations were tested. Standardized disc-shaped specimens were prepared, polymerized, and subjected to controlled immersion in distilled water at 37 ± 2 °C for both short- and medium-term periods. Changes in mass and volume were measured for the time periods of 1h, 24h, 7d, 15d and 28d to determine Wsp and Wsl. Results: All formulations complied with ISO 4049 at 7 days (Wsp ≤40 μg/mm³; Wsl ≤7.5 μg/mm³). Solubility ranged from 5.86–16.25 μg/mm³ and Wsl −9.36 to +1.38 μg/mm³. Four-way factorial ANOVA showed that P:L=3.2 reduced Wsp (p<0.0001), 25% concentration of functional monomer increased Wsp (p<0.0001), and a high monomer type x filler ratio interaction (p≈10⁻⁶). For Wsl, the monomer concentration dominated (p<10⁻²⁴), with strong monomer type × concentration and concentration × powder-liquid ratio interaction (p≤10⁻¹⁴). Tukey HSD separated low-Wsp formulations (e.g., H05P32FL, H05P25FL) from high Wsp ones (e.g., M25P25FL/M25P25FH/M25P32FL). At 28 days, mass increase clustered by formulation at, while volume change was modest (~0–3%), patterns that paralleled the 7-day factor effects. Conclusions: Although all materials met ISO 4049, formulation factors materially influenced water response. Increasing P:L (3.2) lowered sorption, whereas raising monomer concentration to 25% improved solubility but at the cost of higher sorption, with outcomes contingent on monomer type and filler particle ratios. Over 28 days, mass gain and swelling remained limited, but systematically favored the same factor settings that minimized Wsp. Optimizing higher P:L and moderated monomer content appears most promising to balance low sorption with acceptable solubility for long-term dimensional stability.