In vitro antibacterial activity of a novel resin-based pulp capping material containing the quaternary ammonium salt MAE-DB and Portland cement.
BACKGROUND
Vital pulp preservation in the treatment of deep caries is challenging due to bacterial infection. The objectives of this study were to synthesize a novel, light-cured composite material containing bioactive calcium-silicate (Portland cement, PC) and the antimicrobial quaternary ammonium salt monomer 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB) and to evaluate its effects on Streptococcus mutans growth in vitro.


METHODS
The experimental material was prepared from a 2 : 1 ratio of PC mixed with a resin of 2-hydroxyethylmethacrylate, bisphenol glycerolate dimethacrylate, and triethylene glycol dimethacrylate (4 : 3 : 1) containing 5 wt% MAE-DB. Cured resin containing 5% MAE-DB without PC served as the positive control material, and resin without MAE-DB or PC served as the negative control material. Mineral trioxide aggregate (MTA) and calcium hydroxide (Dycal) served as commercial controls. S. mutans biofilm formation on material surfaces and growth in the culture medium were tested according to colony-forming units (CFUs) and metabolic activity after 24 h incubation over freshly prepared samples or samples aged in water for 6 months. Biofilm formation was also assessed by Live/Dead staining and scanning electron microscopy.


RESULTS
S. mutans biofilm formation on the experimental material was significantly inhibited, with CFU counts, metabolic activity, viability staining, and morphology similar to those of biofilms on the positive control material. None of the materials affected bacterial growth in solution. Contact-inhibition of biofilm formation was retained by the aged experimental material. Significant biofilm formation was observed on MTA and Dycal.


CONCLUSIONS
The synthesized material containing HEMA-BisGMA-TEGDMA resin with MAE-DB as the antimicrobial agent and PC to support mineralized tissue formation inhibited S. mutans biofilm formation even after aging in water for 6 months, but had no inhibitory effect on bacteria in solution. Therefore, this material shows promise as a pulp capping material for vital pulp preservation in the treatment of deep caries.
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Yanwei
Y
Yang
State Key Laboratory of Military Stomatology, Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Li
L
Huang
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Yan
Y
Dong
Department of Clinical Nursing, School of Nursing, Fourth Military Medical University, Xi'an, China.
Hongchen
H
Zhang
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Wei
W
Zhou
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Jinghao
J
Ban
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Jingjing
J
Wei
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Yan
Y
Liu
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Jing
J
Gao
State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Jihua
J
Chen
D017607:Aluminum Compounds / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D017610:Calcium Compounds / Q000737:chemistry; D002126:Calcium Hydroxide / Q000737:chemistry; D015169:Colony Count, Microbial; D003188:Composite Resins / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry / Q000494:pharmacology*; D003785:Dental Pulp Capping; D004338:Drug Combinations; D006801:Humans; D008689:Methacrylates / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010087:Oxides / Q000737:chemistry; D010933:Plankton / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000494:pharmacology*; D017640:Silicates / Q000737:chemistry; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
C560118:2-methacryloxylethyl dodecyl methyl ammonium bromide; D017607:Aluminum Compounds; D000900:Anti-Bacterial Agents; D017610:Calcium Compounds; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D004338:Drug Combinations; D008689:Methacrylates; D010087:Oxides; D011109:Polymethacrylic Acids; D000644:Quaternary Ammonium Compounds; D017640:Silicates; C086631:mineral trioxide aggregate; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; C005044:hydroxyethyl methacrylate; D002126:Calcium Hydroxide