Objective: To compare root canal transportation and centering ability of TF Adaptive (TFA), Reciproc (R) and Pro Taper Next (PTN) . Methods: 30 single rooted premolars extracted from orthodontic treatment were randomly divided into 3 groups (n = 10) and prepare by TFA, R and PTN Respectively. The teeth were scanned by Micro-CT before and after instrumentation. The images were reconstructed and exported to Adobe Photo-shop software for analysis. Canal transportation and centering change were determined accordingly. SPSS19. 0 software was used to analyze the data. Results: There was no statistical difference in canal transportation and centering ability for coronal and middle root canal among the 3 groups (P＞ 0. 05) ; for root apical, the canal transportation in group TFA was the smallest, followed by PTN group, that of group R was the largest (between each 2 groups, P ＜ 0. 05), the centering ability of TFA group was the best, followed PTN group, that of group R was the last (between each 2 groups, P ＜ 0. 05) . Conclusion:TFA Ni-Ti instrument is superior to Reciproc and Pro Taper Next for the maintenance of the original orientation of the root canal in root canal preparation.

OBJECTIVETo compare the bactericidal efficacy of two different cold plasma (glow discharge and dielectric barrier discharge) treatments on root canal infected with Enterococcus faecalis biofilms in vitro.

METHODSOne hundred and twenty teeth infected with Enterococcus faecalis biofilm in the roots for seven days were divided into twelve groups randomly. Two served as negative control group (gas only, no discharge). Five were teeth treated by dielectric barrier discharge cold plasma and the other five were treated by glow discharge cold plasma. The treatment time in each five groups was 2, 4, 6, 8 and 10 min, respectively. The disinfection of Enterococcus faeccalis biofilm was evaluated by colony forming unit (CFU) counting. The plasma component produced by different devices was analyzed by optical emission spectroscopy (OES).

RESULTSComparing the two plasma treatments, the plasma produced by dielectric barrier discharge had better bactericidal effect than that produced by glow discharge at different treatment time (P < 0.05). The advantage was obvious with the time getting longer. The OES indicated that active components of the two type plasmas were similar. But the peak of excited Ar atom of dielectric barrier discharge was twice as that of glow discharge.

CONCLUSIONThe cold plasma produced by dielectric barrier discharge has more bactericidal efficiency in the treatment of root canal infected with Enterococcus faecalis biofilms.

Biofilms ; Dental Pulp Cavity ; Enterococcus faecalis ; Humans ; Plasma Gases ; Root Canal Therapy ; Sodium Hypochlorite

ObjectiveTo investigate the protective effect and mechanism of action of flavonoid combination of Alpiniae Officinarum Rhizoma （A. officinarum） against Helicobacter pylori （H. pylori） gastritis in mice. MethodsAfter acclimatization for one week， 56 SPF-grade healthy C57BL/6J mice were gavaged with mixed antibiotics for three consecutive days. They were randomly divided into a normal group， model group， positive drug group （triple therapy group）， and low- and high-dose groups （100， 200 mg·kg^-1） of flavonoid combination of A. officinarum. The H. pylori gastritis mice model was established by gavage with H. pylori bacterial suspension in each group except for the normal group. After successful modeling， mice were administrated with corresponding drugs once a day for two weeks. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in gastric tissue. Rapid urease test paper was used to detect the positive rate of H. pylori. Silver staining was used to observe the H. pylori adherence on the surface of gastric tissue. Immunohistochemistry was used to detect the protein expression of interleukin-8 （IL）-8 and myeloid differentiation factor （MyD88） in gastric tissue. The serum levels of IL-6， tumor necrosis factor-α （TNF-α）， IL-8， and IL-1β were detected by enzyme-linked immunosorbent assay （ELISA）. The expressions of phosphatidylinositol 3-kinase/protein kinase B （PI3K/Akt） protein were detected by Western blot. ResultsCompared with those in the normal group， mice in the model group had lower gastric weight coefficients， higher pH of gastric juice， 100% H. pylori infection rate， and significantly changed gastric histopathology. The expressions of IL-8 and MyD88 proteins in the gastric tissue of mice in the model group were significantly elevated， and the serum levels of inflammatory factors IL-6， TNF-α， IL-8， and IL-1β were significantly up-regulated in mice. Compared with that in the model group， the gastric weight coefficient of mice in each treatment group of the flavonoid combinations of A. officinarum was elevated （P<0.01）， and the pH of gastric juice was reduced （P<0.01）. The infection rate of H. pylori was reduced. The expressions of IL-8 and MyD88 proteins in the gastric tissue of mice in the treatment groups were significantly reduced （P<0.01）， and the serum levels of inflammatory factors IL-6， TNF-α， IL-8， and IL-1β were significantly reduced in a dose-dependent manner （P<0.01）. The flavonoid combinations of A. officinarum down-regulated the expression of PI3K and Akt proteins in H. pylori gastritis-infected cells （P<0.01）. ConclusionThe protective effect of flavonoid combinations of A. officinarum against H. pylori gastritis is associated with the inhibition of H. pylori infection rate and regulation of PI3K/Akt signaling pathway， resulting in inhibiting the release of inflammatory factors.