Three-dimensional macroscopical quantification of plaque accumulation on implant-supported fixed complete dental prostheses surfaces: A methodological pilot study.

STATEMENT OF PROBLEM: Area calculation is the primary method for quantitatively analyzing accumulated plaque on the intaglio surfaces of implant-supported fixed complete dental prostheses (IFCDPs). However, the classic calculation method for stained dental plaque is based on two-dimensional (2D) photographs, which could mislead the three-dimensional (3D) representation of an object's actual morphology, especially when a surface is not flat. PURPOSE: This pilot in vitro study, used for methodological purposes, evaluated the repeatability and precision of a 3D area calculation method to analyze simulated accumulated biofilm on the intaglio surfaces of an IFCDP. MATERIAL AND METHODS: The titanium framework of an IFCDP with a smooth intaglio surface was prepared with 8 milled sites and scanned by microcomputed tomography. Out of these, 4 sites were cubic (set sides lengths=1, 2, 3, and 4 mm), and 4 sites were hemispherical (set diameters=1, 2, 3, and 4 mm). A green-colored aerosol was sprayed onto the carved-out intaglio sites. The framework intaglio surface was 3D-scanned (n=10) and 2D-photographed (n=10) at 10 different photo angles. Two raters twice measured the 3D and 2D data from the carved-out sites' green-colored area one week apart. Intraobserver repeatability and interobserver reliability were evaluated with an independent t test. The deviation between the measurements and the microtomography values was calculated. Pearson's correlation coefficient (r) evaluated the repeatability of multiple measurements. A standard level of significance was set at α=.05. RESULTS: The differences between the 2D photographs and the microtomography values were statistically significant (P<.001), whereas the differences between the 3D scans and the microtomography values were not significant (P=.063). The overall differences between the microtomography values and the 3D measurements were smaller (2.15 ±2.30 mm2 vs. 18.91 ±22.78 mm2, P=.055) than the differences between the microtomography values and the 2D measurements. The percentage differences between the microtomography values and the 3D measurements were significantly smaller (10.41 ±8.33% vs. 65.66 ±19.22%, P<.001) than the microtomography differences values with the 2D measurements. The measurement differences between the microtomography value and the 3D measured hemispherical site data were significantly smaller than the measurement differences between the microtomography values and the 3D measured cubical site data (P=.026). The 2D method had "poor" repeatability among the 10 different shot angles (r=0.391, P<.001), whereas the 3D method had "good" repeatability among the 10 scans (r=0.999, P<.001). CONCLUSIONS: An irregular intaglio surface of an IFCDP could accurately and repeatedly be recorded and analyzed by a 3D area calculation method. This color-matching assessment of the topological environment is expected to be adopted in future studies.

[In-situ Phosphorus Removal Activity and Impact of the Organic Matter Concentration on Denitrifying Phosphorus Removal in Sludge Aggregates].

In this work, the redox potential, dissolved oxygen, and phosphate microelectrodes were used to quantitatively study the in-situ activity of dephosphorization bacteria and the impact of the organic matter concentration on denitrifying phosphorus removal in sludge aggregates in a sequencing batch reactor. The results showed that the maximum net volume release rate of phosphorus was 3.29 mg·(cm3·h)-1 in the initial anaerobic sludge aggregates, which was approximately 3 times the maximum net volume uptake rate of phosphorus at the initial anoxic stage. The release rate of phosphorus clearly decreased at the final anaerobic stage, and the maximum net volume release rate of phosphorus was only half of that at the initial anaerobic stage. At the final anoxic stage, the maximum net volume uptake rate of phosphorus decreased to 0.14 mg·(cm3·h)-1, and the phenomenon of secondary phosphorus release occurred in the deep area below 1800 µm. When the concentration of COD decreased from 350 mg·L-1 to 250 mg·L-1 and 150 mg·L-1, the maximum net volume release rate of phosphorus of dephosphorization bacteria decreased from 3.27 mg·(cm3·h)-1 to 2.44 mg·(cm3·h)-1 and 2.01 mg·(cm3·h)-1, respectively, and the rapid uptake area of phosphorus narrowed to the surface of the sludge aggregates.

Resveratrol prevents osteoporosis by upregulating FoxO1 transcriptional activity.

Resveratrol (3,5,4-trihydroxystilbene, RES), a natural antioxidant, prevents bone loss by attenuating damage caused by oxidative stress. Our previous research revealed that the forkhead box O1 (FoxO1)/ß-catenin signaling pathway affected the proliferation and differentiation of osteoblasts through its regulation of redox balance, and RES regulated the expression of FoxO1 to control white adipose tissue and then ameliorate an overweight condition. Based on previous research, we hypothesized that RES regulates FoxO1 transcriptional activity through the phosphatidylinositol-3-kinase (PI3K)/AKT signaling pathway to achieve an antioxidative effect on osteoporosis and then we confirmed this hypothesis in the present study. An ovariectomized (OVX) rat model of osteoporosis and a H2O2­induced oxidative cell injury model in RAW 264.7 cells were established to explore the underlying molecular mechanisms of how RES confers an antioxidant effect and prevents bone loss. The obtained results demonstrated that RES strongly prevented bone loss induced by oxidative stress in vivo. More specifically, RES effectively decreased the receptor activator of nuclear factor-κB ligand (RANKL) together with the tartrate-resistant acid phosphatase­5b (TRAP­5b) level, but elevated the osteoproprotegrin (OPG) level and attenuated bone microarchitecture damage. Notably, RES, due to its antioxidant effect, suppressed RANKL production and then inhibited osteoclastogenesis in the OVX rats. In vitro, RES improved the oxidative stress status of cells and thus inhibited the mRNA expression of osteoclast-specific enzymes. These data indicate that RES has a significant bone protective effect by antagonizing oxidative stress to suppress osteoclast activity, function and formation both in vivo and in vitro. Moreover, at the molecular level, we confirmed, for the first time, that RES upregulated FoxO1 transcriptional activity by inhibiting the PI3K/AKT signaling pathway, and hence promoted resistance to oxidative damage and restrained osteoclastogenesis. Inhibition of the PI3K/AKT signaling pathway may be induced by RANKL. FoxO1 is a major action target of RES to confer anti-osteoporosis function, and whose effect stems from its power to improve redox balance.