Effect of dentin conditioners on dentin bond strength: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Although composite resin restorations have been widely used for dental restorations, the durability of the bond affects the rate of restoration failure. However, how multiple strategies for enhancing the resin-dentin bond affect durability is unclear. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the impact of dentin conditioners on resin-dentin bond strength with different pretreatments before the application of adhesives. MATERIAL AND METHODS: The PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched from 2013 to July 2023 for in vitro studies that evaluated the impact of dentin conditioners on resin-dentin bond strength. The meta-analysis was conducted using a random-effects model with pooled effect as standardized mean differences (α=.05). RESULTS: A total of 23 studies met the inclusion criteria for qualitative analysis, of which 15 were used for quantitative analysis. The results demonstrated that, under dry bonding conditions, selective extrafibrillar demineralization dentin conditioners significantly enhanced the immediate bond strength (P<.001). The long-term bond strength was limited by the sample size of the subgroup, but a significant effect was found after using selective extrafibrillar demineralization dentin conditioners (P<.001). However, metal salt-based dentin conditioners improved the immediate bond strength only under wet bonding conditions (P=.010). Notably, acid-based dentin conditioners significantly improved the long-term bond strength under both dry and wet bonding conditions (P<.001 and P=.006). CONCLUSIONS: The application of acid-based dentin conditioners significantly improved resin-dentin bond durability under both wet and dry bonding conditions. Furthermore, selective extrafibrillar demineralization dentin conditioners demonstrated remarkable effectiveness in improving resin-dentin bond durability under dry bonding conditions; however, more data are needed to support their use.

The knowledge, training, and willingness of first year students in Xuzhou, China to perform bystander cardiopulmonary resuscitation: a cross-sectional study.

Background: Bystander Cardiopulmonary Resuscitation (CPR) can significantly improve the rate of return of spontaneous circulation in patients with cardiac arrest. Since first year students with no specific academic background are energetic and quick to learn, many Chinese schools offer first-aid training course including CPR to them before they start school. However, data on CPR knowledge, training, and willingness among first year students are lacking in most regions of China, which makes the effectiveness of CPR training unknown. Objectives: To evaluate first year students' knowledge level, training experience and rescue willingness for CPR of first year students in Xuzhou, and to analyze the influencing factors of CPR knowledge level and rescue willingness of first year students in Xuzhou. Design: A cross-sectional study. Participations: A total of 9,887 first year students from three universities in Xuzhou city were selected by multi-stage random cluster sampling method. Methods: A self-designed five-part structured questionnaire was used to investigate the knowledge, training and willingness of CPR among first year students. Independent sample t-test, χ2 -test and Logistic regression were used for data analysis. Results: The average score of CPR knowledge was 2.44 (±1.60), 99.13% of the respondents were willing to participate in CPR training, and 66.25% had received CPR training. Respondents with rural household registration, relatives who had suffered from serious diseases, relatives engaged in the medical profession, good self-rated quality of life, CPR training, and willing to CPR training had higher CPR knowledge levels. 76.77% of the respondents were willing to perform bystander CPR. Women, those who had received CPR training, and those who were willing to receive CPR training were more willing to help patients with sudden cardiac arrest. Lack of first aid knowledge and skills (82.61%) was the biggest obstacle hindering respondents from performing rescue. Conclusion: Most of the first year students of Xuzhou University in China have CPR training experience and have a strong willingness to train. Most are willing to perform bystander CPR, but have a low knowledge level. Colleges and universities can adopt diversified training methods, make plans for regular CPR retraining and other strategies to improve the quality and effect of CPR training for college students.

Electrospun Silk Fibroin-CNT Composite Fibers: Characterization and Application in Mediating Fibroblast Stimulation.

Electrospinning is a simple, low-cost, and highly efficient technique to generate desirable nano/microfibers from polymer solutions. Silk fibroin (SF), a biopolymer found in Bombyx mori cocoons, has attracted attention for various biomedical applications. In this study, functionalized CNT was incorporated in SF to generate biocomposite fibers by electrospinning. The electrospun (E-spun) fibers were well aligned with morphology mimicking the locally oriented ECM proteins in connective tissues. While as-spun fibers dissolved in water in just two minutes, ethanol vapor post-treatment promoted ß-sheet formation leading to improved fiber stability in an aqueous environment (>14 days). The addition of a minute amount of CNT effectively improved the E-spun fiber alignment and mechanical strength while retained high biocompatibility and biodegradability. The fibers' electrical conductivity increased by 13.7 folds and 21.8 folds, respectively, in the presence of 0.1 w% and 0.2 w% CNT in SF fibers. With aligned SF-CNT 0.1 % fibers as a cell culture matrix, we found electrical stimulation effectively activated fibroblasts from patients of pelvic organ prolapse (POP), a connective tissue disorder. The stimulation boosted the fibroblasts' productivity of collagen III (COLIII) and collagen I (COLI) by 74 folds and 58 folds, respectively, and reduced the COLI to COLIII ratio favorable for tissue repair. The developed material and method offer a simple, direct, and effective way to remedy the dysfunctional fibroblasts of patients for personalized cell therapeutic treatment of diseases and health conditions associated with collagen disorder.

Silk-CNT Mediated Fibroblast Stimulation toward Chronic Wound Repair.

BACKGROUND: Diabetic patients suffer from chronic wounds partly due to altered function of fibroblasts. Fibroblasts of diabetic patients synthesize collagen I (COLI) at a much higher level than collagen III (COLIII), resulting in delayed tissue granulation and, consequently, a delay in the overall wound healing process. METHODS: We aimed to revive the matrix protein productivity of diabetic fibroblasts by employing aligned, electrically conductive and biocompatible spider silk-CNT fibers as a cell culture matrix to mediate the electrical stimulation of fibroblasts to induce cell polarization and activation. RESULTS: A 5.2 and 42.7 fold increase in COLI and COLIII production was induced in diabetic fibroblasts. The stimulated cells synthesized a substantially high level of COLIII to reduce the abnormally high COLI/COLIII ratio, and the matrix metalloproteinases expression was markedly suppressed. The protein expression profile was consistent with favorable wound healing. The modulation effect was also demonstrated in normal fibroblasts of healthy individuals, suggesting that the developed method can be utilized generally for connective tissue repair. Silkworm silk-CNT fibers corroborated similar effects on restoring the function of diabetic fibroblasts. CONCLUSIONS: The approach of using an engineered biopolymer matrix to remedy dysfunctional fibroblasts of patients offers the opportunity of developing personalized cell therapy for noninvasive treatments and inspires the design of multi-functional biometrics for effective tissue regeneration.