A Dual pH/O2 Sensing Film Based on Functionalized Electrospun Nanofibers for Real-Time Monitoring of Cellular Metabolism.

Real-time monitoring of dissolved oxygen (DO) and pH is of great significance for understanding cellular metabolism. Herein, a dual optical pH/O2 sensing membrane was prepared by the electrospinning method. Cellulose acetate (CA) and poly(ε-caprolactone) (PCL) nanofiber membrane blended with platinum (II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) was used as the DO sensing matrix, upon which electrospun nanofiber membrane of chitosan (CS) coupled with fluorescein 5-isothiocyanate (FITC) was used as the pH sensing matrix. The electrospun sensing film prepared from biocompatible biomaterials presented good response to a wide range of DO concentrations and physiological pH. We used it to monitor the exracellular acidification and oxygen consumption levels of cells and bacteria. This sensing film can provide a luminescence signal change as the DO and pH change in the growth microenvironment. Due to its advantages of good biocompatibility and high stability, we believe that the dual functional film has a high value in the field of biotechnology research.

Efficacy of four different irrigation techniques combined with 60 °C 3% sodium hypochlorite and 17% EDTA in smear layer removal.

BACKGROUND: Efforts to improve the efficacy of smear layer removal by applying irrigant activation at the final irrigation or by elevating the temperature of the irrigant have been reported. However, the combination of such activation protocols with 60 °C 3% sodium hypochlorite (NaOCl) has seldom been mentioned. The aim of this study was to compare the efficacy in smear layer removal of four different irrigation techniques combined with 60 °C 3% NaOCl and 17% EDTA. METHODS: Fifty single-rooted teeth were randomly divided into five groups (n = 10) according to the irrigant agitation protocols used during chemomechanical preparation(Dentsply Maillefer, Ballaigues, Switzerland): a side-vented needle group, a ultrasonic irrigation (UI) group, a NaviTip FX group, an EndoActivator group, and a control group (no agitation). After each instrumentation, the root canals were irrigated with 1 mL of 3% NaOCl at 60 °C for 1 minute, and after the whole instrumentation, the root canals were rinsed with 1 mL of 17% EDTA for 1 minute. Both NaOCl and EDTA were activated with one of the five irrigation protocols. The efficacy of smear layer removal was scored at the apical, middle and coronal thirds. The Data were statistically analyzed using SAS version 9.2 for Windows (rank sum test for a randomised block design and ANOVA). RESULTS: No significant differences among the NaviTip FX group, EndoActivator group and control groups, and each of these groups showed a lower score than that of UI group (P < 0.05). Within each group, all three thirds were ranked in the following order: coronal > middle > apical (P < 0.05). In the coronal third, the NaviTip FX group was better than UI group. In the middle and apical third, the differences were not significant among any of the groups. CONCLUSIONS: Even without any activation, the combination of 60 °C 3% NaOCl and 17% EDTA could remove the smear layer effectively, similar to NaviTip FX or EndoActivator, and these three protocols were more effective than UI. However, regardless of different types of irrigation technique applied, complete removal of the smear layer was not achieved, particularly in the apical third.

Association between obesity and dental caries in Chinese children.

The study sought to analyze the association between dental caries and obesity in Chinese children, and to investigate the protective and risk factors of dental caries. A total of 280 children aged 7-12 years voluntarily answered the caries examination and questionnaire. Caries was measured using the International Caries Detection and Assessment System. According to the Chinese body mass index, the participants were grouped overweight or normal-weight. The logistic regression model showed no correlation between dental caries and obesity. Drinking yogurt and chewing gum are protective factors, whereas oral breathing and genetic predisposition to caries are risk factors.

Improved Cell Viability and Biocompatibility of Bacterial Cellulose through in Situ Carboxymethylation.

Bacterial cellulose (BC) is a natural product with multiple properties, which has been utilized in tissue engineering. However, cell adhesion and proliferation are reported to be weaker on native BC, providing less support compared to other types of biomaterials, like collagen. To increase the biocompatibility and the medical performance of BC, in situ modification is used to add carboxymethyl group to BC. By partially changing the structure and physical properties of BC, carboxymethylation significantly increases cell affinity and viability, especially on the initial cell adhesion. Furthermore, in the in vivo implantation, the tissue reaction shows that carboxymethylation significantly increases the biocompatibility of BC, exhibiting better tissue condition and a lower inflammatory reaction which are proved through HE staining and immunohistochemistry. The data prove that in situ carboxymethylation is a simple and direct way of improving the performance of BC in medical applications.

Comparison of the effect of four decalcifying agents combined with 60°C 3% sodium hypochlorite on smear layer removal.

INTRODUCTION: The objective of this study was to compare the efficacy on smear layer removal of 4 decalcifying agents: 17% ethylenediaminetetraacetic acid (EDTA), 20% citric acid, BioPure MTAD, and SmearClear. METHODS: Forty-five single-rooted human teeth were used and prepared up to ProTaper F3. After each instrumentation, 1 mL of 3% NaOCl at 60°C was irrigated for 1 minute. All the samples were randomly divided into 5 groups according to the final irrigants: 17% EDTA, 20% citric acid, BioPure MTAD, SmearClear, and 3% NaOCl (control). The smear layer removal of all groups at the apical, middle, and coronal thirds was observed under the thermal field emission scanning electron microscope. RESULTS: The EDTA group was significantly more effective than the SmearClear and MTAD groups (P < .05). The efficacy of all three thirds in the EDTA, MTAD, and SmearClear groups can be arranged as coronal, middle, and apical thirds (P < .05) from excellent to poor. However, in the citric acid group, the coronal two thirds were significantly better than the apical third (P < .05), and there was no statistical significance between the coronal and middle thirds (P > .05). CONCLUSIONS: The 4 decalcifying agents could effectively, but not completely, remove the smear layer, especially in the apical third. The efficacy of 17% EDTA was better than that of MTAD and SmearClear.