An agent-based model of the response to angioplasty and bare-metal stent deployment in an atherosclerotic blood vessel

Purpose: While animal models are widely used to investigate the development of restenosis in blood vessels following an intervention, computational models offer another means for investigating this phenomenon. A computational model of the response of a treated vessel would allow investigators to assess the effects of altering certain vessel- and stent-related variables. The authors aimed to develop a novel computational model of restenosis development following an angioplasty and bare-metal stent implantation in an atherosclerotic vessel using agent-based modeling techniques. The presented model is intended to demonstrate the body's response to the intervention and to explore how different vessel geometries or stent arrangements may affect restenosis development. Methods: The model was created on a two-dimensional grid space. It utilizes the post-procedural vessel lumen diameter and stent information as its input parameters. The simulation starting point of the model is an atherosclerotic vessel after an angioplasty and stent implantation procedure. The model subsequently generates the final lumen diameter, percent change in lumen cross-sectional area, time to lumen diameter stabilization, and local concentrations of inflammatory cytokines upon simulation completion. Simulation results were directly compared with the results from serial imaging studies and cytokine levels studies in atherosclerotic patients from the relevant literature. Results: The final lumen diameter results were all within one standard deviation of the mean lumen diameters reported in the comparison studies. The overlapping-stent simulations yielded results that matched published trends. The cytokine levels remained within the range of physiological levels throughout the simulations. Conclusion: We developed a novel computational model that successfully simulated the development of restenosis in a blood vessel following an angioplasty and bare-metal stent deployment based on the characteristics of the vessel crosssection and stent. A further development of this model could ultimately be used as a predictive tool to depict patient outcomes and inform treatment options. © 2014 Curtin, Zhou

The efficacy of baking soda dentifrice in controlling plaque and gingivitis: A systematic review

Objective: To test the efficacy of a dentifrice containing baking soda (BS), compared with dentifrice without BS for controlling plaque and gingivitis.Materials and methods: MEDLINE‐PubMed and Cochrane‐CENTRAL were searched. The inclusion criteria were randomized controlled clinical trials including healthy participants aged 18 years or older. Studies were selected that compared the effect of toothbrushing with a dentifrice with and without BS on the clinical parameters of plaque and gingivitis. Data were extracted from the selected studies, and a meta‐analysis was performed.Results: The search retrieved 21 eligible publications. Among these papers, 43 comparisons were provided, with 23 involving a single‐use design and 20 being evaluations with a follow‐up. Negative controls were found, or positive controls for which various active ingredients had been used. The included studies showed a moderate overall potential risk of bias and considerable heterogeneity. The meta‐analysis of plaque scores from the single‐brushing experiments showed that BS dentifrice (BS‐DF) was associated with significantly better outcomes than the negative control dentifrices (DiffM −0.20; P < 0.0001; 95% CI: [−0.27; −0.12]) or the positive control dentifrices (DiffM −0.18; P < 0.0001; 95% CI: [−0.24; −0.12]). This finding was only confirmed in studies that used a follow‐up design as compared to a negative control (DiffM −0.19; P = 0.01; 95% CI: [−0.34; −0.04]). The indices of gingival bleeding also improved when the comparison was a negative control (DiffM −0.08; P = 0.02; 95% CI: [−0.16; −0.01] and (DiffM −0.13; P < 0.001; 95% CI: [−0.18; −0.08]. However, for the gingival index scores, the meta‐analysis did not reveal any significant differences.Conclusion: BS‐DF showed promising results with respect to plaque removal in single‐use studies. However, the finding was partially substantiated in follow‐up studies. Studies that assessed bleeding scores indicated that a small reduction can be expected from BS, relative to a control product

Safety issues relating to the use of hydrogen peroxide in dentistry

Hydrogen peroxide is used widely in professionally and self-administered products. Hydrogen peroxide is a highly reactive substance which can damage oral soft tissues and hard tissues when present in high concentrations and with exposures of prolonged duration. This report provides an overview of health issues relating to the use of hydrogen peroxide, with an emphasis on safety with prolonged exposure to low concentrations of peroxide products. There is good evidence for the safety of hydrogen peroxide when used at low concentrations on a daily basis over extended periods of time, in seif-administered oral health care products such as dentifrices and mouthrinses. These low concentrations neither damage oral hard or soft tissues, nor do they pose a significant risk of adverse long-term effects. Caution should be exercised with the increasingly higher concentration peroxide products used for 'walking' or 'power' bleaching due to the possibility of chemical irritation of oral soft tissues with injudicious use. The volumes of material and application times should be controlled carefully. Thorough education of patients is particularly important with self-applied gels because of the lack of professional supervision with such products. Such education is part of the duty of care of the dentist who supplies bleaching gels for at-home use