To Study The Efficacy Of Reciprocating Single File System And Multifile Rotary Systems In Elimination Of Root Canal Bacteria And Endotoxins

AIM: To study the efficacy of reciprocating single file system and multifile rotary systems in elimination of root canal bacteria and endotoxins. MATERIAL AND METHOD: Forty permanent single rooted mandibular premolars with straight canals inoculated with Escherichia Coli suspension for 21 days were selected for the study. Teeth were randomly divided into four groups (n=10) according to instrumentation system: Grp. A–Reciproc (VDW); Grp. B–WaveOne (Dentsply Maillefer); Grp. C–MTwo (VDW); and Grp. D–K3( Sybron Endo); Bacterial and endotoxin samples were collected with a sterile paper point before instrumentation  and after instrumentation. Culture methods estimated the colony-forming units (CFU) and the Limulus Amebocyte Lysate test was used for quantification of endotoxins. Results so obtained were calculated and statistically analysed.  RESULT: Results at S1 concluded that bacteria and endotoxins were found in all of the investigated root canals. After instrumentation all systems were associated with the significant reduction of the bacterial load and endotoxins respectively: Grp. A– Reciproc (88.25% and 89.10%); Grp. B– WaveOne (83.53% and 80.59%); Grp. C– MTwo(79.41% and 75.84%) and Grp. D– K3 (67% and 74.4%). Statistically no difference was found amongst the instrumentation systems regarding bacteria and endotoxin elimination (P <0.05).  CONCLUSION: The reciprocating single file, Reciproc and WaveOne were as effective as the multifile rotary systems for the eradication of bacteria and endotoxins from root canals

Photosynthetic electron transport system promotes synthesis of Au-nanoparticles.

In this communication, a novel, green, efficient and economically viable light mediated protocol for generation of Au-nanoparticles using most vital organelle, chloroplasts, of the plant system is portrayed. Thylakoids/chloroplasts isolated from Potamogeton nodosus (an aquatic plant) and Spinacia oleracea (a terrestrial plant) turned Au³⁺ solutions purple in presence of light of 600 µmol m⁻² s⁻¹ photon flux density (PFD) and the purple coloration intensified with time. UV-Vis spectra of these purple colored solutions showed absorption peak at ∼545 nm which is known to arise due to surface plasmon oscillations specific to Au-nanoparticles. However, thylakoids/chloroplasts did not alter color of Au³⁺ solutions in dark. These results clearly demonstrated that photosynthetic electron transport can reduce Au³⁺ to Au⁰ which nucleate to form Au-nanoparticles in presence of light. Transmission electron microscopic studies revealed that Au-nanoparticles generated by light driven photosynthetic electron transport system of thylakoids/chloroplasts were in range of 5-20 nm. Selected area electron diffraction and powder X-ray diffraction indicated crystalline nature of these nanoparticles. Energy dispersive X-ray confirmed that these nanoparticles were composed of Au. To confirm the potential of light driven photosynthetic electron transport in generation of Au-nanoparticles, thylakoids/chloroplasts were tested for their efficacy to generate Au-nanoparticles in presence of light of PFD ranging from 60 to 600 µmol m⁻² s⁻¹. The capacity of thylakoids/chloroplasts to generate Au-nanoparticles increased remarkably with increase in PFD, which further clearly demonstrated potential of light driven photosynthetic electron transport in reduction of Au³⁺ to Au⁰ to form nanoparticles. The light driven donation of electrons to metal ions by thylakoids/chloroplasts can be exploited for large scale production of nanoparticles

Potential of isolated thylakoids/chloroplasts of <i>Spinacia oleracea</i> to generate Au-nanoparticles.

<p>(A) Impact of light of varying photon flux density on generation of Au-nanoparticles in 30 min by isolated thylakoids/chloroplasts sincubated in 2 mM Au³⁺; (B) Time dependent variation in generation of Au-nanoparticles by isolated thylakoids/chloroplasts incubated in 2 mM Au³⁺ exposed to light of varying photon flux density (µmol m⁻² s⁻¹). Values represent mean of data collected from six independent experiments. Values designated by different small letters are significantly different at P≤0.05 (Duncan's multiple range test).</p

Mechanism for generation of Au-nanoparticles by isolated chloroplasts in presence of light.

<p>Photosynthetic machinery driven by light energy splits water into protons, electrons and oxygen. While electrons are transported to NADP⁺, proton gradient is used for generation of ATP. Present investigations support that electrons can also be donated by light energy driven photosynthetic electron transport system to Au³⁺ to form Au⁰, which nucleate to generate Au nanoparticles.</p

Potential of isolated thylakoids/chloroplasts of <i>Spinacia oleracea</i> to generate Au-nanoparticles in presence of light and dark when suspended in Au³⁺ solutions (0, 0.5, 1 and 2 mM).

<p>(A) Color of Au³⁺ solutions in dark (D) and light (L); (B) and (C) absorption spectra; (D) absorbance at 545 nm of Au³⁺ solutions incubated in dark and light, respectively. Values represent mean of data collected from six independent experiments. Values designated by different small letters are significantly different at P≤0.05 (Duncan's multiple range test).</p