In vitro characterization of a novel resin-based restorative material containing alkaline fillers

Abstract

Objective: In this study, a comparative evaluation of the physicochemical properties of Cention N and other direct restorative materials was performed. Three restorative materials—a resin-modified glass ionomer (Fuji II LC), an alkasite-based resinous material (Cention N), and a resin composite (Tetric N Ceram)—were characterized in terms of degree of conversion, Knoop hardness number (KHN) ratio, flexural strength, elastic modulus, water sorption, water solubility, microshear bond strength to dentin, immediate microleakage, and radiopacity. Methodology: The microshear bond strength to dentin and microleakage of Cention N were evaluated with and without the application of an adhesive system (Tetric N Bond Universal). A one-way ANOVA test was used to analyze the data in terms of degree of conversion, KHN ratio, water sorption, water solubility, microshear bond strength to dentin, and radiopacity. A two-way ANOVA test (carried out considering the material type and ethanol aging as factors) was used to analyze the data in terms of flexural strength and elastic modulus. The Kruskal–Wallis test was used to statistically analyze the data on microleakage. A significance level of α=0.05 was used for all tests. Results: Fuji II LC was found to have the highest degree of conversion, water sorption, and microleakage, as well as the lowest flexural strength. Cention N had the highest solubility; when used with an adhesive system, it achieved bond strength and microleakage similar to those of the Tetric N Ceram composite. Tetric N Ceram had the highest degree of conversion, KHN ratio, and radiopacity. Conclusion: The properties of Cention N validate its efficacy as an alternative direct restorative material when used in conjunction with an adhesive system.

Mechanical Properties of Alkasite Material with Different Curing Modes and Simulated Aging Conditions

“…In that study, only the top surface of the light-cured specimens was evaluated, and the reported MH ratio was 48%, which was considerably lower compared to the MH ratios of the light-cured specimens obtained in our study (72–76%). Considering the methodological differences and the unknown material modifications that occurred during the development of Cention N, tested in the aforementioned study [ 33 ], to Cention Forte, which was tested in our study, it is not possible to discuss these differences in more detail.…”

“…There is only one published study on ethanol softening of an early version of the alkasite material (Cention N) in which the Knoop hardness was compared after and before ethanol immersion to indirectly assess the crosslink density [ 33 ]. In that study, only the top surface of the light-cured specimens was evaluated, and the reported MH ratio was 48%, which was considerably lower compared to the MH ratios of the light-cured specimens obtained in our study (72–76%).…”

“…Hence, it is possible that these modifications have reduced the ability of the self-curing mechanism in newer versions (Cention and Cention Forte), so that the self-cured specimens had a lower degree of conversion [ 46 ] and, consequently, lower mechanical properties [ 19 ] than light-cured specimens. On the other hand, there are also reports of high FS values even for the early version of the alkasite (Cention N) in the range of 100–120 MPa [ 27 , 33 ], suggesting that the differences in the measured values may be due to methodological particularities rather than some concrete trends in the improvement of the mechanical properties of alkasite due to the development of newer versions. The inconsistencies in the results for macro-mechanical properties for different “generations” of the alkasite material are compounded by a study showing that the FS and FM of Cention N were significantly higher for the self-cured mode than for the light-cured mode [ 50 ].…”