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

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

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

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

Color changes in resin material modified with antibacterial nanoparticles.

<p>Duplicates of all the test samples were compared with the unmodified control material. Changes in the color of the test samples are evident upon comparison of the unmodified material (control) with samples with incorporated quaternary ammonium iodide salt particles (i.e. QPEI and QASi). A relatively mild change in color is seen in samples with SiCial particles.</p

DCT procedure flowchart.

<p>A- a resin material samples allowed to polymerize onto microtite’s well sidewalls, followed by applying of bacteria suspension. B-Evaporation of suspension liquid. C- addition of growing media to agitate proliferation of survived bacteria. D- OD₆₅₀ measured as indication for survived bacteria growth.</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

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

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