الفهرس 
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Abstract
Aim: The aim of this study is to assess the effect of addition of a synthesized antibacterial
quaternary ammonium (QA) compound and bioactive glass nanoparticles on the antibacterial
properties and bioactivity respectively of the experimental dental adhesive system.
Methodology: A QA compound was synthesized from 2-(Dimethylamino) ethyl methacrylate and 1-
Bromobutane and characterized using CHN, FTIR and H+NMR analyses. The synthesized QA was
assessed for its cytotoxicity using MTT assay, and its antibacterial activity using disc diffusion
method, measurement of minimum inhibitory concentration and minimum bactericidal
concentration, time kill test, and TEM imaging. The QA compound was added to the primer of a
commercially available adhesive (Optibond XTR) by two concentrations 20 mg/mL and 40 mg/mL
representing the MIC and MBC, respectively., while 5% bioglass fillers were added to the adhesive
bottle. Then, the experimental adhesives were characterized by measurement of pH and degree of
conversion. Comparison was made between the experimental adhesive, commercial antibacterial
adhesive Clearfil SE Protect (CP) containing MDPB antibacterial monomer and fluoride fillers, and
commercial vehicle (Optibond XTR) regarding antibacterial properties using time kill test, and
bioactivity through quantifying Calcium and Phosphorus ion release using Inductive couple plasma,
and observation of apatite formation by scanning electron microscope, followed by elemental
analysis by EDX and calculation of Ca/P ratio. Statistical analysis by ANOVA followed by tukey
post-hoc test (P˂0.05).
Results: Disc diffusion and time-kill kinetics tests showed potent antibacterial properties of the
synthesized QA compound against S. mutans both in the unpolymerized and the cured forms. MIC
and MBC were 20 and 40 mg/mL respectively. There was no statistically significant difference
between experimental adhesives and CP with more than 99% reduction in bacterial count, while
OptiBond XTR showed no bacterial killing up for up to 10 hours. The experimental adhesive
samples showed a statistically significant higher calcium release after 2 weeks than the control
groups. The Ca/P ratio was statistically significantly higher on dentin discs with the experimental
adhesive and the plain commercial adhesive compared to CP. Also, this ratio increased after 2 weeks
follow up for all materials. SEM images revealed mineralizing deposits on the tested adhesive
surfaces, compared to the untreated teeth discs which showed open dentinal tubules.
Conclusions: The synthesized QA compound can be used as an affordable additive for imposing
antibacterial properties for adhesive systems. Bioglass nanoparticles fillers impart significant
remineralizing abilities to the adhesive in vitro.
Keywords: Antibacterial, Streptococcus mutans, Quaternary Ammonium Compounds, Dental
Adhesives, Minimum Inhibitory Concentration, Minimum Bactericidal Concentration, Time-kill
kinetics, Bioglass