Tuning Nano-Amorphous Calcium Phosphate Content in Novel Rechargeable Antibacterial Dental Sealant

Abstract

Dental sealants with antibacterial and remineralizing properties are promising for caries prevention among children and adolescents. The application of nanotechnology and polymer development have enabled nanoparticles of amorphous calcium phosphate (NACP) and dimethylaminohexadecyl methacrylate (DMAHDM) to emerge as anti-caries strategies via resin-based dental materials. Our objectives in this study were to (1) incorporate different mass fractions of NACP into a parental rechargeable and antibacterial sealant; (2) investigate the effects on mechanical performance, and (3) assess how the variations in NACP concentration would affect the calcium (Ca) and phosphate (PO4) ion release and re-chargeability over time. NACP were synthesized using a spray-drying technique and incorporated at mass fractions of 0, 10, 20 and 30%. Flexural strength, flexural modulus, and flowability were assessed for mechanical and physical performance. Ca and PO4 ion release were measured over 70 days, and three ion recharging cycles were performed for re-chargeability. The impact of the loading percentage of NACP upon the sealant’s performance was evaluated, and the optimized formulation was eventually selected. The experimental sealant at 20% NACP had flexural strength and flexural modulus of 79.5 ± 8.4 MPa and 4.2 ± 0.4 GPa, respectively, while the flexural strength and flexural modulus of a commercial sealant control were 70.7 ± 5.5 MPa (p > 0.05) and 3.3 ± 0.5 GPa (p < 0.05), respectively. A significant reduction in flow was observed in the experimental sealant at 30% NACP (p < 0.05). Increasing the NACP mass fraction increased the ion release. The sealant formulation with NACP at 20% displayed desirable mechanical performance and ideal flow and handling properties, and also showed high levels of long-term Ca and PO4 ion release and excellent recharge capabilities. The findings provide fundamental data for the development of a new generation of antibacterial and rechargeable Ca and PO4 dental sealants to promote remineralization and inhibit caries.

Tooth sealing formulation with bacteria‐killing surface and on‐demand ion release/recharge inhibits early childhood caries key pathogens

“…The composition, percentages, and the mass ratio of resin to glass filler (1:1) of the parental formulations were optimized and based on our previous report (Ibrahim et al, 2018) to impart rechargeability of calcium and phosphate ions released by NACP and physical and mechanical properties suitable for sealing/sealant applications. DMAHDM was synthesized via a modified Menschutkin reaction method (Antonucci et al, 2012).…”

“…Still, its performance on ECC‐linked key pathogens is not investigated yet. We have reported screened formulations that reach acceptable rates for physical and mechanical properties using DMAHDM and amorphous calcium phosphate nanoparticles (NACPs), respectively (Ibrahim et al, 2018). Furthermore, we have suggested a role of DMAHDM in the reduction of S. mutans virulence factors (Ibrahim et al, 2019).…”

Applications of nano-materials in diverse dentistry regimes

“…In (B), the TEM image of NACP from the spray-drying technique, having sizes of about 100-300 nm. 103 which affirms that there is minor environmental and human exposure from the toothbrushes; however, the safe levels of Ag NP exposure is still unanswered. 102 Salem Ibrahim et al designed novel anti-bacterial resinbased sealants including NPs of amorphous calcium phosphate (NACP) for PO 4 and Ca ion release and re-charge characteristics ( Fig.…”

“…It appears that the addition of an enhanced percentage of NACP had satisfactory physical and mechanical functions, while generating considerable initial ion release and a lengthy iterated recharge ability. 103 Wassel and Khattab proposed that applying the naturallyoccurring products experimentally may be an efficient strategy to prevent caries; Varnish is a mix of natural products with optimum concentrations of uoride in chitosan NPs (CS-NPs) and potential for ion release, re-mineralization potential, and clinical efficacy. The procured dental varnishes with miswak, propolis, and CS-NPs with or without sodium uoride (NaF) have been evaluated in terms of the anti-bacterial effects against Streptococcus mutans employed in the disk diffusion test.…”

Dental Sealant Empowered by 1,3,5-Tri Acryloyl Hexahydro-1,3,5-Triazine and α-Tricalcium Phosphate for Anti-Caries Application

“…The effectiveness of sealants mainly depends on their retention and sealing; there is strong evidence that the rate of remained intact resin decreases over time [4], leading to the need for the development of novel materials with better mechanical properties. Furthermore, the current trend in material science involves the incorporation of copolymerizable antimicrobial agents and bioactive remineralizing fillers [5].…”