Structural formulas of antibacterial NPs.

<p>a–Silica particle with tertiary amine bearing two t-cial groups. b–Silica particle with dimethyl-octyl ammonium functional group. c–Quaternary ammonium polyethyleneimine particle.</p

Antibiofilm test flowchart.

<p>Polymerized samples of modified resin material were first rinsed during 7 days. Then, samples of each one of the test groups were divided into 3 subgroups for three different biofilm models. The biofilm tests were performed using MDFR.</p

Comparison of maximal stress at rupture and the youngs modulus.

<p>Unmodified resin material served as control. As can be seen, t<u>he</u> SiCial particles did not lead to a significant reduction in maximal stress or modulus. Addition of any of the quaternary ammonium-containing particles resulted in lower mechanical properties, QPEI particles causing complete destruction of the resin material.</p

Biofilm formation on the surfaces of the test materials for each microbiological model.

<p>Biofilm formation on the surfaces of the test materials for each microbiological model.</p

Antibiofilm effect.

<p>Each error bar was constructed according to 1 standard error from the mean OD values for each microbiological model. The different datasets were normalized for viable biofilm formation on the reference material,(polystyrene) of tissue-culture treated multiwall plates.</p

Representative FT-IR curves for DC calculation.

<p>Infrared spectra area focusing on characteristic peaks related to double carbon-carbon acrylic bonds (~1637nm) and carbon-oxygen double bond (~1720nm) used as normalization peaks of uncured resin material (red) and after 10 minutes of curing (blue).</p

Verification of assumptions of normality and homoscedasticity.

<p>Verification of assumptions of normality and homoscedasticity.</p

Degree of monomer conversion calculated from the data measured with infrared spectroscopy data.

<p>Ü values are expressed as mean with standard deviation. Quaternary ammonium iodide-containing particles caused a reduction in the degree of monomer conversion vs the base material. The SiCial particles preserved the Ü of the unmodified resin material.</p

Antibacterial activity against <i>S</i>. <i>mutans</i> of unmodified acrylic material and with incorporated 8% QPEI, 8% QASi or 8% SiCial.

<p>Antibacterial activity against <i>S</i>. <i>mutans</i> of unmodified acrylic material and with incorporated 8% QPEI, 8% QASi or 8% SiCial.</p

Contact angle measurements arranged in increasing order of hydrophobicity.

<p>A (unmodified, control): 59.4(±5.6)°; B (QPEI): 74.3(±5.1)°; C (QASi): 74.6(±1.9)° and D (SiCial): 111.2(±0.6)°.</p