Resin-based reconstructive/restorative materials with antibacterial effects are potentially useful for preventing dental and oral diseases. To this end, the immobilization of an antibacterial component on the surface of a resin by incorporating polymerizable bactericide such as a quaternary ammonium compound-monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) is an effective technique. However, the effectiveness of immobilized bactericide is reduced by salivary protein coverage. We address this issue by utilizing 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, which exhibits protein repellency, with MDPB to fabricate a novel copolymer, which served as a surface coating on a methacrylate-based resin. This coating provided a more hydrophilic surface than that provided by MDPB coating and reduced the adsorption of bovine serum albumin and salivary protein. To evaluate bacterial growth on the contact surface, Streptococcus mutans suspension was placed on the coated specimen. After 24-h incubation, MDPB/MPC copolymer exhibited killing effects against S. mutans. Moreover, confocal laser scanning microscopy and scanning electron microscopy were used to evaluate biofilm formation after 48-h incubation in S. mutans suspension, which revealed sparse biofilm and dead bacteria in biofilm on the surface coated with MDPB/MPC. Overall, the proposed surface coating on dental resins exhibited protein-repellent ability and inhibitory effects against bacteria and oral biofilms.

An antibacterial monomer 12-methacryloyloxydodecylpyridinum bromide (MDPB)-containing experimental, chemically cured primer was prepared to develop a new resin-based root canal filling system. This study investigated the antibacterial effects of the MDPB-containing primer (experimental primer [EP]) against Enterococcus faecalis and assessed the in vitro bonding and sealing abilities of the filling system, consisting of EP and a Bis-GMA-based sealer resin. Antibacterial effects of EP were evaluated by contact with planktonic or adherent bacteria for 30 or 60 sec, and the viable bacterial number was counted. The antibacterial effects against E. faecalis in dentinal tubules were also assessed, according to a root canal infection model. Bonding and sealing abilities of the experimental filling system were examined by microtensile bond strength tests and leakage tests based on fluid filtration methods. Significantly greater reduction in viable bacteria in planktonic and adherent form was obtained by short-period contact with EP compared with the control primer (without MDPB) or with the proprietary (Epiphany) primer (p < .05). Significantly greater bactericidal effects of the EP inside the dentinal tubule of root, as opposed to the control primer or Epiphany primer, were confirmed according to a root canal infection model (p < .05), and 100% killing of E. faecalis could be obtained by the application of EP after irrigation with a 5% sodium hypochlorite solution.The experimental endodontic filling system demonstrated significantly greater bond strength to root dentin than Epiphany sealer system (Epiphany primer and Epiphany Root Canal Sealant; p < .05), showing formation of resin tags and a hybridized layer. Leakage tests clarified that the experimental system provided excellent sealing. This study confirmed that the MDPB-containing experimental antibacterial primer has the ability to effectively disinfect the root canal. Additionally, the experimental root canal filling system employing this primer and the Bis-GMA-based sealer resin is useful for achieving good sealing, suggesting its possible benefit for successful endodontic treatments.

An experimental cavity disinfectant (ACC) that is intended to be used for various direct and indirect restorations was prepared by adding an antibacterial monomer 12-methacryloyloxydodecylpyridinum bromide (MDPB) at 5% into 80% ethanol. The antibacterial effectiveness of ACC and its influences on the bonding abilities of resin cements were investigated. To examine the antibacterial activity of unpolymerized MDPB, the minimum inhibitory and bactericidal concentrations (MIC and MBC) were determined for Streptococcus mutans, Lactobacillus casei, Actinomyces naeslundii, Parvimonas micra, Enterococcus faecalis, Fusobacterium nucleatum, and Porphyromonas gingivalis Antibacterial activities of ACC and the commercial cavity disinfectant containing 2% chlorhexidine and ethanol (CPS) were evaluated by agar disk diffusion tests through 7 bacterial species and by MIC and MBC measurement for S. mutans The effects of ACC and CPS to kill bacteria in dentinal tubules were compared with an S. mutans-infected dentin model. Shear bond strength tests were used to examine the influences of ACC on the dentin-bonding abilities of a self-adhesive resin cement and a dual-cure resin cement used with a primer. Unpolymerized MDPB showed strong antibacterial activity against 7 oral bacteria. ACC produced inhibition zones against all bacterial species similar to CPS. For ACC and CPS, the MIC value for S. mutans was identical, and the MBC was similar with only a 1-step dilution difference (1:2). Treatment of infected dentin with ACC resulted in significantly greater bactericidal effects than CPS (P < 0.05, analysis of variance and Tukey's honest significant difference test). ACC showed no negative influences on the bonding abilities to dentin for both resin cements, while CPS reduced the bond strength of the self-adhesive resin cement (P < 0.05). This study clarified that the experimental cavity disinfectant containing 5% MDPB is more effective in vitro than the commercially available chlorhexidine solution to eradicate bacteria in dentin, without causing any adverse influences on the bonding abilities of resinous luting cements.

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The 12-methacryloxydodecylpyridium bromide (MDPB) has been reported to act as a matrix metalloprotease (MMP) inhibitor. In this study, the effects of application of MDPB on resin-dentin bonds were evaluated. The resin-dentin bonded specimens were prepared with a commercial MDPB-containing self-etching primer or a self-etching primer without MDPB, and stored 24 h or 1 year. Surfaces were pretreated with chlorhexidine or MDPB-containing cavity disinfectant. Additionally, we compared the degradation patterns between the two self-etching adhesives and etch and rinse system. Water tree formations were observed as the typical morphological phase of the two tested self-etching adhesives for both 24 h and 1 year groups. The degradation phase of collagen network depletion was observed in the adhesive interface of the etch-and-rinse system in the 1 year group. Pretreatment with chlorhexidine did not prevent bond strength reduction after 1 year. The cavity disinfectant improved the bond durability for the self-etching adhesive.

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The aim of this study was to evaluate the antibacterial activity and dentin bonding ability of a commercial self-etch adhesive Clearfil SE Protect (Kuraray Noritake Dental, Tokyo, Japan) in combination with sodium hypochlorite (NaOCl). Agar disc diffusion tests and measurement of minimum inhibitory/bactericidal concentrations (MIC/MBC) against Streptococcus mutans were performed to evaluate antibacterial effects. The mixture solution of 5.25% NaOCl and the primer of Clearfil SE Protect demonstrated less antibacterial activity than primer only. In microtensile bond strength tests using non-carious human molars, pretreatment with 5.25% NaOCl aqueous solution had no influence on the bond strength of Clearfil SE Protect. These results indicate that pretreatment with NaOCl does not influence the bonding ability of Clearfil SE Protect, while their combined use does not enhance cavity disinfecting effects.

Composite resin blocks for computer-aided design/computer-aided manufacturing (CAD/CAM) applications have recently become available. However, CAD/CAM composite resins have lower wear resistance and accumulate more plaque than CAD/CAM ceramic materials. We assessed the effects of SiO2-nanocomposite film coating of four types of CAD/CAM composite resin blocks: Cerasmart, Katana Avencia block, Lava Ultimate, and Block HC on surface hardness and bacterial attachment. All composite blocks with coating demonstrated significantly greater Vickers hardness, reduced surface roughness, and greater hydrophobicity than those without coating. Adhesion of Streptococcus mutans to the coated specimens was significantly less than those for the uncoated specimens. These reduced levels of bacterial adherence on the coated surface were still evident after treatment with saliva. Surface modification by SiO2-nanocomposite film coating has potential to improve wear resistance and susceptibility to plaque accumulation of CAD/CAM composite resin restorations.