Mechanisms of Atomization from Rotary Dental Instruments and Its Mitigation.

Since the onset of coronavirus disease 2019, the potential risk of dental procedural generated spray emissions (including aerosols and splatters), for severe acute respiratory syndrome coronavirus 2 transmission, has challenged care providers and policy makers alike. New studies have described the production and dissemination of sprays during simulated dental procedures, but findings lack generalizability beyond their measurements setting. This study aims to describe the fundamental mechanisms associated with spray production from rotary dental instrumentation with particular focus on what are currently considered high-risk components-namely, the production of small droplets that may remain suspended in the room environment for extended periods and the dispersal of high-velocity droplets resulting in formites at distant surfaces. Procedural sprays were parametrically studied with variables including rotation speed, burr-to-tooth contact, and coolant premisting modified and visualized using high-speed imaging and broadband or monochromatic laser light-sheet illumination. Droplet velocities were estimated and probability density maps for all laser illuminated sprays generated. The impact of varying the coolant parameters on heating during instrumentation was considered. Complex structured sprays were produced by water-cooled rotary instruments, which, in the worst case of an air turbine, included droplet projection speeds in excess of 12 m/s and the formation of millions of small droplets that may remain suspended. Elimination of premisting (mixing of coolant water and air prior to burr contact) resulted in a significant reduction in small droplets, but radial atomization may still occur and is modified by burr-to-tooth contact. Spatial probability distribution mapping identified a threshold for rotation speeds for radial atomization between 80,000 and 100,000 rpm. In this operatory mode, cutting efficiency is reduced but sufficient coolant effectiveness appears to be maintained. Multiple mechanisms for atomization of fluids from rotatory instrumentation exist, but parameters can be controlled to modify key spray characteristics during the current crisis.

Hemispherical differences in the shape and topography of asteroid (101955) Bennu.

We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling the northern and southern hemispheres separately, we find that longitudinal ridges previously identified in the north extend into the south but are obscured there by surface material. In the south, more numerous large boulders effectively retain surface materials and imply a higher average strength at depth to support them. The north has fewer large boulders and more evidence of boulder dynamics (toppling and downslope movement) and surface flow. These factors result in Bennu's southern hemisphere being rounder and smoother, whereas its northern hemisphere has higher slopes and a less regular shape. We infer an originally asymmetric distribution of large boulders followed by a partial disruption, leading to wedge formation in Bennu's history.

The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization.

The cosmic microwave background (CMB) B-mode signal is potentially weaker than the diffuse Galactic foregrounds over most of the sky at any frequency. A common method of separating the CMB from these foregrounds is via pixel-based parametric-model fitting. There are not currently enough all-sky maps to fit anything more than the most simple models of the sky. By simulating the emission in seven representative pixels, we demonstrate that the inclusion of a 5 GHz data point allows for more complex models of low-frequency foregrounds to be fitted than at present. It is shown that the inclusion of the C-BASS data will significantly reduce the uncertainties in a number of key parameters in the modelling of both the galactic foregrounds and the CMB. The extra data allow estimates of the synchrotron spectral index to be constrained much more strongly than is presently possible, with corresponding improvements in the accuracy of the recovery of the CMB amplitude. However, we show that to place good limits on models of the synchrotron spectral curvature will require additional low-frequency data.

Transition Metal-Substituted Krebs-Type Polyoxometalate-Doped PEDOT Films.

The transition metal-substituted Krebs-type polyoxometalates (POMs) [Sb2W20M2O70(H2O)6]n-, M = Fe(III), Co(II), or Cu(II), were surface immobilized within the conducting polymer 3,4-ethylenedioxythiophene (PEDOT) on glassy carbon electrode surfaces. The immobilized films of different thicknesses were characterized by electrochemical and surface-based techniques. The inherent redox activity for the Krebs-type POMs, [Sb2W20M2O70(H2O)6]n-, M = Fe(III), Co(II), or Cu(II), that were observed in the solution phase were maintained in the polymeric PEDOT matrix. The resulting films were found to be extremely stable toward redox switching between the various POM-based redox states. The films exhibited pH-dependent redox activity and thin layer behavior up to 100 mV s-1. The films were found to be highly conductive through the employment of electrochemical impedance spectroscopy. Surface characterization of the films was carried out by X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy graph.

Wheelchair users: a guide for the GDP.

The number of wheelchair users in the UK is increasing, and it may be more convenient and appropriate for many of these individuals to receive their dental care in a general dental practice rather than in a community or tertiary facility. This article is intended to provide the average general dental practitioner (GDP) with the basic tools and increased confidence to effectively triage this cohort of the population, and accept them for treatment or refer appropriately.

Compliance with occupational exposure risk management procedures in a dental school setting.

Background The Dental Institute at King's College London has recently implemented changes focusing on infection control, including safety needle provision, personal protective equipment campaigns, mandatory lectures and formal assessment for students. We explored the effect of these changes over a five-year period.Methods We observed 49 clinical consultations in 2010 and 50 in 2014, examining clinician attire, personal protective equipment, dental operatory management, sharps hazards and aseptic technique.Results One hundred percent of operators wore gloves, apron and masks, 94% wore eye protection, 98% had uncovered wrists and 88% had tidy hair. Ninety-four percent wore safe shoes, 86% were of appropriate material, and 70-82% demonstrated correct zoning technique. Safe sharps bin placement improved from 78% to 100%, 92% were not overfilled, and 96% were free from protruding items. Sixty-eight percent of bays were appropriately barrier wrapped, 78-88% were kept tidy and 96% were free of items that could have been disposed of immediately following use. Ninety to ninety-eight percent of ultrasonic tips and 64% of burs were removed from handpieces when not in use.Conclusion Dental healthcare workers are at risk of significant occupational exposures, which can be minimised by technological advances, implementation of best practice guidelines, optimisation of the clinical working environment and reinforcement of infection control policy.

Planning for future provision of dental services in prison: an international proposal of two systems.

This article describes a proposal for the future organisation of the delivery of dental and oral health services for prisoners. This vision is based on an analysis of the existing prison dental programmes in England and the United States (Federal Bureau of Prisons, [FBOP]), together with discussions from two key individuals from both countries who championed changes to prison dental services and have published in the field of prison dental services. Both countries have similar visions. Some of the suggested work has already been addressed in the past (for example, introduction of state of the art dental facilities in the UK prison setting), some are in process (for example, electronic patients' records) and some may be addressed in the near future (for example, prisoners' involvement with the services provided for them). Some of the expressed visions for the future in this article are driven by evidence-based literature and dental workforce policy.

Multidisciplinary team working in an adult male prison establishment in the UK.

The first two articles in this series exploring the oral and dental health of male prisoners in the UK demonstrated how the general and oral health of prisoners is compromised compared to those of a similar age who are not prisoners. In caring for the oral health needs of this group the high demand for emergency dental services often precludes the delivery of preventive and routine care. Comprehensive oral care for this population requires a level of training to gain the skills and knowledge to manage prisoners' complex medical, dental and social needs and the heightened dental anxiety that prisoners exhibit. The type of training that might be required for prison dentistry will be discussed in the final article. This article will describe a number of cases selected to demonstrate the complex problems presented by male prisoners in Her Majesty's Prison (HMP), Brixton. This article will also discuss the establishment of a primary care inter-professional relationship network (IRN) developed within a prison setting involving a dentist and other healthcare professionals. After informal discussions between the dentist and other prison healthcare professionals, it became apparent that vulnerable patients were not accessing dental services. These patients also cancel/fail to attend their dental appointments more frequently. In order to improve access and provision of dental care for this group of prisoners, an IRN was developed between the dentist, diabetic nurse, forensic psychology team, communicable disease lead, general medical practitioner (GMP), prison officers and healthcare manager within HMP Brixton. The nature of the IRN is presented along with reviews with relevant patient cases. The IRN allowed information sharing between professionals and an open care culture. The network was valued by prisoners. Prison populations show higher rates of general and oral disease, therefore an IRN can help to identify vulnerable groups and allow healthcare providers to give appropriate, targeted and focused care in a timely fashion.

Oral health of adult prisoners and factors that impact on oral health.

The first article in this series identified the medical and mental health issues among male patients in comparison to the general population. This article will discuss the oral health of male prisoners and those factors that impact upon their oral health including barriers to care. In general, the oral health of prisoners is poorer than that of age matched controls. A variety of factors including health related behaviours and pre-confinement access to dental services can influence this.

An overview of the prison population and the general health status of prisoners.

This article is the first in a series of four, which explore the oral and dental health of male prisoners in the United Kingdom. The series comprises: an overview of the general and oral health status of male prisoners, a discussion on how multi-disciplinary team working can be used to benefit the care of patients in prison environments and a description of the future planning of dental services for male prisoners. The oral health of prisoners is linked to their general health status, due in part to the presence of common risk factors such as smoking, drinking alcohol and in some cases use of recreational drugs, poor dietary and poor oral hygiene habits. Barriers to healthcare services can all have an effect on oral disease in this group. This paper highlights some of the common medical problems that oral healthcare providers face when treating prisoners in male UK prison establishments.

Rapid-acquisition myocardial perfusion scintigraphy (MPS) on a novel gamma camera using multipinhole collimation and miniaturized cadmium-zinc-telluride (CZT) detectors: prognostic value and diagnostic accuracy in a 'real-world' nuclear cardiology service.

AIMS: To study the prognostic value of rapid-acquisition adenosine stress-rest myocardial perfusion scintigraphy (MPS) on a gamma camera using multipinhole collimation and cadmium-zinc-telluride (CZT) detectors. The secondary aim was to assess the diagnostic accuracy of the technique compared with invasive coronary angiography. METHODS AND RESULTS: Retrospective analysis of 1109 consecutive patients undergoing MPS in a routine clinical setting on a high-efficiency multipinhole gamma camera. MPS acquisition, performed with a standard injection of 550 MBq of (99m)Tc-tetrofosmin, required a mean (±SD) scanning time of 322 ± 51 s. The hard cardiac event rate at a median (inter-quartile range) follow-up of 624 (552-699) days was 0.4% (95% CI 0.1-1.1) in patients with no significant perfusion abnormality versus 6.8% (95% CI 4.3-10.7%, P < 0.001) in those with an abnormal scan. In a sub-group of 165 patients, comparison with obstructive coronary artery disease on X-ray angiography gave a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for rapid-acquisition MPS of 84% (95% CI 74-91), 79% (95% CI 68-87), 82% (95% CI 72-89), 81% (95% CI 70-89), and 82% (95% CI 73-89), respectively. CONCLUSIONS: MPS performed on a CZT solid-state detector camera with multipinhole collimation is an evolutionary development that provides reliable prognostic and diagnostic information, while significantly reducing image acquisition time.

Communicating new policy on antibiotic prophylaxis with patients: a randomised controlled trial.

OBJECTIVES: This trial aimed to assess the effectiveness of two different communication tools on the levels of anxiety and concern when a change in patients' treatment was introduced. METHOD: Patients previously advised to have antibiotic prophylaxis before their dental treatments were randomised to receive information about the new policy either through a video accompanied by a written leaflet or just the leaflet. All patients completed a questionnaire to assess anxiety and concern as well as intentions regarding accepting dental treatment without antibiotic prophylaxis at enrolment point, after intervention and after meeting the cardiologist. RESULTS: Ninety questionnaires were analysed (45 in each group). The mean level of anxiety and concern scores were significantly reduced after the intervention point (p <0.05). The ANOVA model revealed a significant reduction in the levels of anxiety and concern during the trial (p <0.001). However, the main effect of group (intervention versus control) and the interaction term were not significant. At the end of trial there was no difference in the number of patients accepting dental treatment without cover in the two groups. CONCLUSION: Patients appear more likely to accept a change if it is communicated directly to them by their practitioners via face to face consultation compared with video or leaflet. When there is a lack of time for in-depth consultation, video could be a more effective method than leaflet alone.

Pilot trial of motivational interviewing in patients with peripheral artery disease.

AIM: Peripheral artery disease (PAD) is a common cause of impaired quality of life and reduced life expectancy in older adults. An important component of PAD management is improvement in health behavior, but few effective means to achieve this have been identified. The aim of the present study was to assess the efficacy of motivational interviewing (MI) to facilitate positive health behavior change in patients with PAD. METHODS: Participants (N.=23) diagnosed with PAD were randomized to MI sessions or a control group. Primary outcomes of physical activity and dietary behavior and secondary outcomes of quality of life were assessed with questionnaires at baseline and after 12 weeks. RESULTS: At 12 weeks, physical activity (330 vs. 396 met-mins/week, P=0.74) and dietary behavior (1 vs. 1, P=0.89; 2.67 vs. 2.61, P=0.62) were similar in both groups. MI participants reported significantly better quality of life compared to control participants (71 vs. 61, P=0.01). Participants' comments suggested that MI promoted a process of re-appraisal of health status. CONCLUSION: This exploratory study has indicated that MI may improve aspects of quality of life and provide a prompt to reappraise health status and health behaviors in patients with PAD. Validation of these findings and assessment of impact on health outcomes is required in a larger and long-term study.

Neurogenic hypertension and elevated vertebrobasilar arterial resistance: is there a causative link?

There is evidence of sympathetic overdrive in a significant proportion of patients with essential hypertension and an animal model of the condition, the spontaneously hypertensive rat (SHR). The reasons for this remain elusive. However, there is also evidence of narrowing of the arteries supplying the brainstem in the SHR and hypertensive humans. In this review, we discuss the possible role of brainstem hypoperfusion in driving increased sympathetic activity and hypertension.

A pilot study: are dental hygienists in Texas ready for the elderly population explosion?

PURPOSE: At the beginning of the 20th century, people 65 and older comprised 4.1% of the population. By the year 2030, it is estimated that people 65 and older, the 'Baby Boomer' generation, will comprise more than 20% of the population. This will have a profound effect on the practice of dentistry and on society as a whole. The purpose of this study was to determine whether dental hygienists in Texas felt prepared and willing to treat the elderly in alternative practice settings such as nursing homes. METHODS: After institutional review board approval, a questionnaire was mailed to 500 hygienists. A 5% systematic sample of dental hygiene graduates was taken from four dental hygiene schools in Texas, United States of America (USA). Of these, 175 were returned for a 35% response rate. Questions asked were degree held, how prepared the participants felt to treat the special needs of the elderly, if participants were willing to work in alternative practice settings such as a nursing home and if they felt additional education was needed. Frequency distributions, correlations and chi square were used to analyse the data. RESULTS: Results revealed 86.5% of the respondents felt prepared to somewhat prepared to treat the special needs of the elderly based on education; equally, 86.5% felt more education was needed to better prepare them to treat the elderly. Over half of the respondents would not be willing to work in alternative practice settings such as nursing homes. CONCLUSION: The average respondents do not feel fully prepared to treat the elderly with special needs, and they think more education is needed to better prepare them to treat this important target population.

Solid-state synthesis of embedded single-crystal metal oxide and phosphate nanoparticles and in situ crystallization.

A new solid state organometallic route to embedded nanoparticle-containing inorganic materials is shown, through pyrolysis of metal-containing derivatives of cyclotriphosphazenes. Pyrolysis in air and at 800 °C of new molecular precursors gives individual single-crystal nanoparticles of SiP(2)O(7), TiO(2), P(4)O(7,) WP(2)O(7) and SiO(2), depending on the precursor used. High resolution transmission electron microscopy investigations reveal, in most cases, perfect single crystals of metal oxides and the first nanostructures of negative thermal expansion metal phosphates with diameters in the range 2-6 nm for all products. While all nanoparticles are new by this method, WP(2)O(7) and SiP(2)O(7) nanoparticles are reported for the first time. In situ recrystallization formation of nanocrystals of SiP(2)O(7) was also observed due to electron beam induced reactions during measurements of the nanoparticulate pyrolytic products SiO(2) and P(4)O(7). The possible mechanism for the formation of the nanoparticles at much lower temperatures than their bulk counterparts in both cases is discussed. Degrees of stabilization from the formation of P(4)O(7) affects the nanocrystalline products: nanoparticles are observed for WP(2)O(7), with coalescing crystallization occurring for the amorphous host in which SiP(2)O(7) crystals form as a solid within a solid. The approach allows the simple formation of multimetallic, monometallic, metal-oxide and metal phosphate nanocrystals embedded in an amorphous dielectric. The method and can be extended to nearly any metal capable of successful coordination as an organometallic to allow embedded nanoparticle layers and features to be deposited or written on surfaces for application as high mobility pyrophosphate lithium-ion cathode materials, catalysis and nanocrystal embedded dielectric layers.

Antibiotic prophylaxis in dentistry: part I. A qualitative study of professionals' views on the NICE guideline.

BACKGROUND: The NICE guideline for antibiotic prophylaxis before dental treatment has made a substantive change and fundamental departure from previous practice that affects long-standing beliefs and practice patterns. There is potential difficulty for healthcare professionals explaining the new guidance to patients who have long believed that they must receive antibiotics before their dental treatment. AIM: To explore clinicians' attitudes towards the NICE guidance on antibiotic prophylaxis, their use of the guideline in clinical practice, barriers to the implementation of the guideline, and how best to overcome any perceived barriers. METHODS: In-depth interviews were conducted with seven dental care professionals, two cardiologists and a cardiac care nurse. The data were analysed using the framework method to extract central themes and opinions. RESULTS: Clinicians generally perceived that initially patients would be reluctant to follow the NICE guidance. This was felt to be particularly true of the patient cohort that had previously been prescribed prophylactic antibiotics. They found it difficult to explain the new guidance to patients who have had infective endocarditis and have long believed that they must receive antibiotics before their dental treatment. Concerns were also raised about the legal position of a clinician who did not follow the guidance. Clinicians generally suggested that the provision of accurate information in the form of leaflets and valid websites would be the best way to advise patients about the new guidance. CONCLUSIONS: Clinicians anticipated difficulties in explaining to patients the change in clinical practice necessitated by adherence to the NICE guidance, most notably for patients with a history of infective endocarditis or where the patient's cardiologist did not agree with the NICE guidance. They placed particular emphasis on the provision of accurate information in order to reassure patients.

Antibiotic prophylaxis in dentistry: part II. A qualitative study of patient perspectives and understanding of the NICE guideline.

BACKGROUND: The National Institute for Health and Clinical Excellence (NICE) recommendations in 2008 for antibiotic prophylaxis before dental treatment contradict previous practice. There is a potential difficulty in explaining the new guidance to patients who have long believed that they must receive antibiotics before their dental treatment. AIM: This study investigated the patient-related barriers and facilitating factors in implementation of the NICE guidance. METHODS: In-depth interviews were conducted with nine patients concerning their views about barriers and factors that could influence the implementation of the NICE guidance on antibiotic prophylaxis before dental treatment. Data were analysed using framework analysis. RESULTS: For patients the rationale for the NICE guidance was unclear. They understood that at the population level the risk of infective endocarditis was less than the risk of adverse reaction to antibiotics. However, on an individual level they felt that the latter risk was negligible given their previous experience of antibiotics. They were aware that standards of care change over time but were concerned that this may be an example where a mistake had been made. Patients felt that the characteristics of the person advising them about the new guidance were important in whether or not they would accept them - they wished to be advised by a clinician that they knew and trusted, and who was perceived as having appropriate expertise. CONCLUSIONS: Patients generally felt that they would be most reassured by information provided by a clinician who they felt they could trust and who was qualified to comment on the issue by respecting their autonomy. The implications of the findings for the development of patient information are discussed.