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Objective: In most clinical circumstances, secondary caries at the margin of fixed dental restorations leads to restoration failure and replacement. Accordingly, the objectives of this study were to: (1) develop a novel rechargeable nano-calcium phosphate (NACP) and nano-calcium fluoride (nCaF 2 ) resin-based cement; and (2) investigate their mechanical properties and calcium (Ca), phosphate (P), and fluoride (F) ion release, recharge, and re-release for the first time., Methods: The cement matrix consisted of pyromellitic glycerol dimethacrylate (PMGDM), ethoxylated bisphenol-A-dimethacrylate (EBPADMA) was denoted PEHB. Four cements were fabricated: (1) PEHB+0%NACP+0%nCaF 2 (experimental control); (2) PEHB+25%NACP+0%nCaF 2 , (3) PEHB+0%NACP+25%nCaF 2 ; (4) PEHB+12.5%NACP+12.5% nCaF 2 . RelyX luting cement was used as a commercial control. Mechanical properties and long-term Ca, P, and F ion release, recharge, and re-release were evaluated., Results: Adding 25% NACP, 25% nCaF 2 and adding both 12.5% NACP and 12.5% nCaF 2 to the cement matrix presented a significantly higher shear bond strength, flexural strength compared to the commercial control (p < 0.05) with a comparable outcome with no significant different (p > 0.05) compared to experimental control. The film thickness results of all cement groups met the ISO requirement (<50 µm). The resin cement group with both 12.5% NACP and 12.5% nCaF 2 successfully released Ca, P, and F ions at 3.1 ± 0.01, 1.1 ± 0.05, and 0.51±0.01 mmol/L respectively. Moreover, it showed the ability to re-release Ca, P, and F ions at 0.62±0.01, 0.12±0.01, and 0.42±0.01 mmol/L respectively., Conclusions: The resin cement group with both 12.5% NACP and 12.5% nCaF 2 demonstrated the advantages of both types of bio-interactive fillers as it could release a higher level of ions than the resin cement with 25%nCAF 2 and exhibited a better rechargeability compared to the resin cement with 25%NACP., Clinical Significance: The ability of this novel resin-based cement to release, recharge, and re-release Ca, P, and F ions could be one of the keys to lengthening the survivability of fixed dental restorations. These features could help to reduce the onset of secondary caries by enhancing the remineralization and preventing the demineralization of tooth structures., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objective: Resin cements with remineralizing and antibacterial properties are favorable for inhibition of caries. The objectives of this study were: (1) to investigate the capability of the novel dimethylaminohexadecyl-methacrylate (DMAHDM) and nano-sized amorphous calcium phosphate (NACP) containing cement to reduce saliva microcosm biofilm, and (2) to investigate the long-term ion release, recharge, and re-release of DMAHDM-NACP cement., Methods: Pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol-A-dimethacrylate (EBPADMA) were used to make PEHB monomer. Five cements were fabricated: (1) PEHB+0%NACP+0%DMAHDM (experimental control); (2) PEHB+25%NACP+0%DMAHDM, (3) PEHB+25%NACP+0%DMAHDM; (4) PEHB+25%NACP+3%DMAHDM; (5) PEHB+25%NACP+5%DMAHDM. RelyX luting cement was used as commercial control. Colony-forming units (CFU), lactic acid production, metabolic activities, and minimum inhibitory concentration (MIC) were performed. Long-term Calcium (Ca) and phosphate (P) ion release, recharge, and re-release were assessed., Results: Compared to experimental and commercial controls, the NACP-DMAHDM cement significantly reduced CFU biofilm by 2-3 orders of magnitude, metabolic activities from 0.24±0.06 A 540 /cm 2 to 0.03±0.01 A 540 /cm 2 , and lactic acid production from 27.7 ± 2.5 mmol/L to 5.4 ± 2.1 mmol/L (n = 6) (p<0.05). The DMAHDM showed an MIC value of 0.03 mg/L. However, when the DMAHDM was combined with PMGDM monomer, the MIC was greater than DMAHDM alone. The ion concentrations for the experimental groups significantly increased over time (1-84 days), indicating continuous ion release (n = 3) (p<0.05). Increasing the DMAHDM mass fraction from 0% to 5% and 3% to 5% significantly enhanced ion recharge and re-release at the third cycle (p<0.05)., Conclusions: Incorporating DMAHDM and NACP into resin-based crown cement provides strong antibacterial action against saliva microcosm biofilm and presents a high level of Ca and P ion recharge abilities, exhibiting long-term Ca and P ion release and remineralization potential., Clinical Significance: Resin based cement containing NACP and DMAHDM were developed with remineralizing and potent antibacterial effects. This cement formulation showed ion release and remineralization potential and are promising formulations to inhibit the incidence of recurrent caries and could promote remineralization and be sustainable for the long term., (Copyright © 2022. Published by Elsevier Ltd.)

Objective: Composites with remineralizing and antibacterial properties are favorable for caries inhibition. The objectives of this study were to develop a new bioactive nanocomposite with remineralizing and antibiofilm properties by incorporating dimethylaminohexadecyl methacrylate (DMAHDM) and nano-calcium fluoride (nCaF 2 )., Methods: nCaF 2 was produced via a spray-drying method and integrated at 15% mass fraction into composite. DMAHDM was added at 3% mass fraction. Mechanical properties and F and Ca ion releases were assessed. Colony-forming units (CFU), lactic acid and metabolic activity of biofilms on composites were performed., Results: The new composites had flexural strengths of (95.28±6.32) MPa and (125.93±7.49) MPa, which were within the ISO recommendations. Biofilm CFU were reduced by 3-4 log (p<0.05). The composites achieved high F releases of (0.89±0.01) mmol/L and (0.44±0.01) mmol/L, and Ca releases of (1.46±0.05) mmol/L and (0.54±0.005) mmol/L., Conclusions: New nanocomposites were developed with good mechanical properties, potent antibacterial activity against salivary biofilms, and high F and Ca ion releases with potential for remineralization., Clinical Significance: Novel nanocomposites using nCaF 2 and DMAHDM were developed with potent antibacterial and remineralizing effects and high F and Ca ion releases. They are promising to inhibit recurrent caries, promote remineralization, and possess long-term sustainability., (Copyright © 2021 Elsevier Ltd. All rights reserved.)