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The objective was to evaluate new commercially available ion-releasing restorative materials and compare them to established anti-cariogenic materials. Four materials were tested: alkasite Cention (Ivoclar Vivadent) in self-cure or light-cure mode, giomer Beautifil II (Shofu), conventional glass-ionomer Fuji IX (GC), and resin composite Tetric EvoCeram (Ivoclar Vivadent) as a control. Flexural strength, flexural modulus, and Weibull modulus were measured one day, three months, and after three months with accelerated aging in ethanol. Water sorption and solubility were evaluated for up to one year. Degree of conversion was measured during 120 min for self-cured and light-cured Cention. In this study, Beautifil II was the ion-releasing material with the highest flexural strength and modulus and with the best resistance to aging. Alkasite Cention showed superior mechanical properties to Fuji IX. Weibull analysis showed that the glass-ionomer had the least reliable distribution of mechanical properties with the highest water sorption. The solubility of self-cured alkasite exceeded the permissible values according to ISO 4049. Degree of conversion of light-cured Cention was higher than in self-cure mode. The use of alkasite Cention is recommended only in the light-cure mode.

Introduction: To evaluate flexural strength (FS) and flexural modulus (FM) of dual-cure resin cements polymerized using different curing protocols. Materials and methods: Four dual-cure cements and one light-cure cement were investigated. The specimens for the three-point bending test (2x2x16 mm) were prepared using the following three curing protocols: (I) 1200 mW/cm2 for 10 s immediately adjacent to the specimen surface, (II) 1200 mW/cm2 for 20 s through a 1-mm layer of disilicate ceramics, and (III) without light illumination. The specimens were artificially aged using 30-day immersion in water followed by 7-day immersion in absolute ethanol. Mechanical testing was performed in a universal testing machine at a crosshead speed of 1 mm/ min until fracture. Results: The investigated materials demonstrated a wide range of FS (11.4– 111.1 MPa) and FM (0.65–5.5 GPa). FS and FM values were notably material-dependent and significantly affected by curing protocols in all tested materials. The self-curing protocol resulted in up to 25% poorer mechanical properties compared to the corresponding maximum values attained by the maximum light exposure provided by curing protocol (I). In addition to being significantly affected by curing protocols, mechanical properties of the lightcure resin cement were at the low-end of all investigated materials. For all materials, FM was more affected by different curing protocols than FS. Conclusions: The dual-cure resin composite cements should be additionally light-cured in order to attain optimal mechanical properties. Also, direct exposure to the curing light resulted in improved mechanical properties compared to the light exposure through a 1-mm thick ceramic layer.

Introduction: The aim of this study was to investigate mass changes of experimental composites over a long-term immersion in distilled water. Materials and methods: Two series of experimental composites were prepared by replacing their reinforcing fillers (total: 70 wt%) with 0, 5, 10, 20, and 40 wt% of either bioactive glass 45S5 or a low-sodium fluoride-containing bioactive glass. Three ion-releasing commercial materials were used as references. A gravimetric method adapted from the ISO 4049 protocol was used to evaluate mass changes of cured material specimens after water immersion for 1, 28, 42, 63, and 180 days. Results: Mass changes during immersion were generally more pronounced for the composite series functionalized with bioactive glass 45S5. Within both experimental composite series, the materials with the highest bioactive glass amount (40 wt%) showed a time- dependent mass decrease, indicating a solubilization that continued beyond the 180-day observation period. The final weight changes were as follows: 1.8% for the control composite, 1.4– 3.0% for the experimental composites containing bioactive glass 45S5, and 0.6– 2.1% for the experimental composites with low-sodium bioactive glass. Among the reference materials, the glass ionomer increased its mass for 5.6%, while the weight changes for the giomer and the alkasite were comparatively lower (1.1% and 0.7%, respectively). Conclusions: Both series of experimental composites demonstrated a higher extent of water sorption and solubility compared to the control composite, whereas the composite series with the low-sodium fluoride-containing bioactive glass showed lower extents of water sorption and solubility compared to the composites with bioactive glass 45S5. This study was supported by Croatian Science Foundation, project IP-2019-04-6183.