Tooth root caries account for 10.1% of all dental caries in the USA. This study developed a multifunctional resin coating with calcium (Ca) and phosphate (P) ion release and antibacterial properties to combat root caries. The effects of nano-sized amorphous calcium phosphate (NACP) and dimethylaminohexadecyl methacrylate (DMAHDM) on mechanical, physical, and antibacterial properties against Streptococcus mutans, and cytotoxicity on dental pulp stem cells and gingival fibroblasts were evaluated. A coating resin combining urethane dimethacrylate (UDMA), triethylene glycol divinylbenzyl ether (TEGDVBE), DMAHDM, and NACP was synthesized and compared with Seal&Protect and Vanish XT. Experimental groups (UV + 5% DMAHDM + 10%, 15%, and 20% NACP) showed flexural strength (70.9 ± 8.0 to 81.1 ± 6.0) MPa, significantly higher than Seal&Protect (48.2 ± 7.2) MPa (p < 0.05) and comparable to Vanish XT (70.2 ± 13.6) MPa, (p > 0.05). Elastic modulus (2.2 to 3.3) GPa was lower than Vanish XT (9.4 ± 1.1) GPa (p < 0.05). Experimental groups showed an 8 log CFU reduction, 96% reduction in metabolic activity and 87% in lactic acid production, and increased Ca (1.25 ± 0.03) mmol/L and P (0.8 ± 0.001) mmol/L release over 35 days. Cytotoxicity for experimental groups against dental pulp stem cells and human gingival fibroblast was low and matched those of commercial controls already used in clinic. The resin demonstrated potent antibacterial properties, high ion release, low cytotoxicity, and maintained physical and mechanical integrity, offering potential to prevent root caries formation and progression.

Recurrent caries remain a persistent concern, often linked to microleakage and a lack of bioactivity in contemporary dental composites. Our study aims to address this issue by developing a low-shrinkage-stress nanocomposite with antibiofilm and remineralization capabilities, thus countering the progression of recurrent caries. In the present study, we formulated low-shrinkage-stress nanocomposites by combining triethylene glycol divinylbenzyl ether and urethane dimethacrylate, incorporating dimethylaminododecyl methacrylate (DMADDM), along with nanoparticles of calcium fluoride (nCaF₂) and nanoparticles of amorphous calcium phosphate (NACP). The biofilm viability, biofilm metabolic activity, lactic acid production, and ion release were evaluated. The novel formulations containing 3% DMADDM exhibited a potent antibiofilm activity, exhibiting a 4-log reduction in the human salivary biofilm CFUs compared to controls (p < 0.001). Additionally, significant reductions were observed in biofilm biomass and lactic acid (p < 0.05). By integrating both 10% NACP and 10% nCaF₂ into one formulation, efficient ion release was achieved, yielding concentrations of 3.02 ± 0.21 mmol/L for Ca, 0.5 ± 0.05 mmol/L for P, and 0.37 ± 0.01 mmol/L for F ions. The innovative mixture of DMADDM, NACP, and nCaF₂ displayed strong antibiofilm effects on salivary biofilm while concomitantly releasing a significant amount of remineralizing ions. This nanocomposite is a promising dental material with antibiofilm and remineralization capacities, with the potential to reduce polymerization-related microleakage and recurrent caries.

Provisional crowns are often used in dentistry for prolonged periods, but bacterial attachment and dental plaque often lead to gingival inflammation and secondary caries. The aims of this research were to develop a novel resin-based antibacterial provisional crown coating to prevent secondary caries and investigate the physical properties and antibacterial efficacy. The resin-based coating was prepared by addition of triethylene glycoldivinylbenzyl ether and urethane dimethacrylate, with the antibacterial monomer dimethylaminododecyl methacrylate (DMADDM) incorporated at different mass fractions. Surface characteristics including surface roughness and contact angle were assessed. The antibacterial effects were evaluated by 48 h biofilms of Streptococcus mutans (S. mutans) on provisional crowns coated with the resin-based coating. No statistically significant difference was observed in surface roughness across all groups (p > 0.05), showing that adding DMADDM did not have a negative impact on surface roughness. The contact angle results revealed a significant difference in hydrophilicity between different concentrations of DMADDM (p < 0.01), but overall hydrophilicity did not negatively affect the performance of the coating. The incorporation of 5% DMADDM demonstrated a significant antibiofilm effect on S. mutans biofilm CFU with a 4-log reduction compared to controls (p < 0.01). Significant reductions of 4–5 folds were observed in biofilm metabolic activity and lactic acid production (p < 0.01). The findings suggest that the novel coating material could enhance the long-term performance and clinical outcomes of provisional crowns, contributing to better patient oral health.

Traditional pulp-capping materials like mineral trioxide aggregate (MTA) offer excellent biocompatibility and sealing, but limitations such as prolonged setting time, low bioactivity, and high costs persist. Metformin, with its potential in craniofacial regeneration, could enhance dentin synthesis by targeting pulp cells. This study aimed to: (1) develop a calcium phosphate cement with chitosan (CPCC) with improved physio-mechanical properties; (2) incorporate metformin (CPCC-Met) to assess release; and (3) evaluate human dental pulp stem cells (hDPSCs) response. CPCC was mixed at different powder-to-liquid ratios to evaluate physio-mechanical properties compared to MTA. The optimized CPCC formulation was loaded with 0, 50, 100, and 150 µg of metformin to measure release and assess hDPSCs attachment and proliferation (1, 4, and 7 d) via live/dead imaging and SEM. One-way ANOVA was used for statistical analysis. Results showed CPCC at a 3.25:1 ratio significantly reduced setting time to 41.5 min versus 123 min for MTA (p < 0.05). Metformin release correlated with concentration, and SEM confirmed the presence of a porous, hydroxyapatite-rich surface. Cell viability was consistently high across groups (>93% at 1 d, >95% at 4 d, ≈98% at 7 d), with no significant differences (p > 0.05). These findings suggest that the novel CPCC-Met demonstrates promise as a fast-setting, cost-effective pulp-capping material, offering metformin delivery to enhance dentin repair.

Root caries caused by cariogenic bacteria are a burden on a large number of individuals worldwide, especially the elderly. Applying a protective coating to exposed root surfaces has the potential to inhibit the development of caries, thus preserving natural teeth. This study aimed to develop a novel antibacterial coating to combat root caries and evaluate its effectiveness using the antibacterial monomer dimethylaminohexadecyl methacrylate (DMAHDM). DMAHDM was synthesized and incorporated into a resin consisting of 55.8% urethane dimethacrylate (UDMA) and 44.2% TEG-DVBE (UV) at a 10% mass fraction of glass filler. Multiple concentrations of DMAHDM were tested for their impact on the resin’s mechanical and physical properties. S. mutans biofilms grown on resin disks were analyzed for antibacterial efficacy. Cytotoxicity was assessed against human gingival fibroblasts (HGFs). The results showed an 8-log reduction in colony-forming units (CFUs) against S. mutans biofilm (mean ± sd; n = 6) (p < 0.05) when 5% DMAHDM was incorporated into the UV resin. There was a 90% reduction in metabolic activity and lactic acid production. A low level of cytotoxicity against HGF was observed without compromising the physical and mechanical properties of the resin. This coating material demonstrated promising physical properties, potent antibacterial effects, and low toxicity, suggesting its potential to protect exposed roots from caries in various dental procedures and among elderly individuals with gingival recession.