Serum, saliva, and GCF concentration of RANKL and osteoprotegerin in smokers versus nonsmokers with chronic periodontitis

Background: The role of host response in periodontitis pathogenesis is confirmed, and it is well established that immune response plays a major role in the alveolar bone destruction. In the investigation of these responses, the role of receptor activator of the nuclear factor-kB ligand (RANKL)-osteoprotegerin (OPG) system is the most promising. Smoking can affect the RANKL-OPG system in a manner that will further enhance bone loss in periodontitis. The aim of this study is to assess the serum, saliva, and gingival crevicular fluid (GCF) concentration of RANKL and OPG in smoker versus nonsmoker untreated chronic periodontitis (CP) patients. Materials and Methods: Thirty-nine subjects were included in the present cross-sectional study: 29 systemically healthy CP male patients (15 smokers, 14 nonsmokers) and 10 systemically and periodontally healthy nonsmoker male subjects. Serum, GCF, and whole saliva samples were obtained from the subjects. The enzyme-linked immunosorbent assay (ELISA) kits were used for assaying the concentrations of RANKL and OPG in the samples. The one-way analysis of variance (ANOVA) test and the least significant difference (LSD) post hoc test were utilized to compare differences between the groups. Results: RANKL and OPG concentrations in saliva, serum, and GCF did not show any significant difference among all groups (P > 0.05). Salivary RANKL/OPG ratios were significantly higher in the nonsmoker CP group than in the healthy control group (P > 0.05) but they were not statistically significant among smoker periodontitis patients. Conclusions: The salivary RANKL/OPG ratio was higher in nonsmokers with periodontitis in comparison with smoker periodontitis patients

The influence of ultrasound on removal of prefabricated metal post cemented with different resin cements

Background: Ultrasonic vibrations are used to remove a cemented post from a root canal requiring endodontic retreatment. Various results have been reported from the studies that evaluated the effect of ultrasonic instruments in removing the posts cemented with resin cements. The aim of this study was to evaluate the effect of ultrasonic energy on the retention of prefabricated metal post cemented with Panavia or Maxcem Elite cements. Materials and Methods: In this in vitro study, forty eight extracted single root premolars were decoronated with a diamond disc leaving a 13 mm long root and endodontically treated. The root canals were obturated by gutta-percha up to 5 mm with vertical condensation method and the 8 mm post-space was prepared to receive a no. 2 long Dentorama post. The roots were placed in an incubator for 48 h in 37΀C and 100% humidity. After mounting the teeth in acrylic blocks, posts were cemented in the root canals using Panavia F2.0 in 24 specimens and Maxcem Elite in 24 others. For half of the specimens in each subgroup, an ultrasonic device was applied for 4 min. Universal testing machine was used to measure the force needed to remove the posts with a crosshead speed of 1 mm/min until the post came out of the canal. Kruskal-Wallis test was used for statistical analysis at 5% level of significance. Results: The removal force was not significantly different among the groups (P > 0.05). Conclusion: Ultrasonic energy did not decrease the retention of posts cemented with Panavia or Maxcem Elite cements. Furthermore, it seems that there is no significant difference between removal force of self-etch (Panavia) and the self-etch self-adhesive (Maxcem Elite) resin cements

Synthesis of mesoporous functional hematite nanofibrous photoanodes by electrospinning

Iron(III) oxide (hematite, Fe2O3) nanofibers, as visible light-induced photoanode for water oxidation reaction of a water splitting process, were fabricated through electrospinning method followed by calcination treatment. The prepared samples were characterized with scanning electron microscopy, and three-electrode galvanostat/potentiostat for evaluating their photoelectrochemical (PEC) properties. The diameter of the as-spun fibers is about 300nm, and calcinated fibers have diameter less than 110nm with mesoporous structure. Optimized multilayered electrospun -Fe2O3 nanostructure mats showed photocurrent density of 0.53mA/cm(2) under dark and visible illumination conditions at voltage 1.23V and constant intensity (900mW/cm(2)). This photovoltaic performance of nanostructure mats makes it suitable choice for using in the PEC water splitting application as an efficient photoanode. This method, if combined with appropriate flexible conductive substrate, has the potential for producing flexible hematite solar fuel generators. Copyright (c) 2015 John Wiley & Sons, Ltd