scholarly journals The Spread of Droplets and Aerosols of Surgical Motor Handpiece Irrigation Using Different Suction Systems

2021 ◽  
Vol 2 ◽  
Author(s):  
James K. H. Tsoi ◽  
Hao Ding ◽  
Ki Hon ◽  
Yiu Yan Leung
Keyword(s):  
High Speed ◽  
Learning Algorithm ◽  
Irrigation System ◽  
Mouth Opening ◽  
High Volume ◽  
Dental Clinic ◽  
Single Operator ◽  
Droplet Sizes ◽  
Low Volume ◽  
Phantom Head

Objective: This study aimed to compare the effectiveness of various combinations of dental suction devices in reducing the amount and distance of spread of aerosols and droplets using an electrical surgical motor model with a self-irrigation system.Materials and Methods: In a standard single-chaired air-conditioned ventilated dental clinic, an electrical dental surgical motor with a high-speed handpiece (Implantmed) cooled with 0.2% fluorescein containing normal saline was used to drill a gypsum block mounted on a phantom head in a supine position. A single operator performed thrice each of the following suction settings: (a) no suction, (b) low-volume suction, (c) low-volume + high-volume suctions, and (d) low-volume + external oral suctions. Aerosols (0.1–5 μm) were measured with a particle counter at the mouth opening of the phantom head, and droplet sizes and distances were analyzed via a machine learning algorithm by identifying fluorescence droplets on pre-loaded pieces of paper on the floor for each group.Results: The different suction systems have different performances in terms of droplet distance (p = 0.007), whereas using (c) high volume suctions (41.1 ± 22.9 cm) and (d) external oral suction unit (39 ± 18.2 cm) had significantly reduced the spread of droplets when compared with (a) without suction (58.9 ± 17.1 cm). Using (d) external oral suction or (c) high volume suction could reduce the number for all droplet sizes. The use of (c) high volume suction was most effective in reducing aerosol count of 0.3–1 μm, while (d) external oral suction was most effective in reducing aerosol count of 3–5 μm.Conclusions: Both external oral suction and high-volume suction were effective in reducing aerosols and droplets generated by the irrigation of a surgical high-speed motor handpiece. External oral suction could be an effective alternative to high volume suction in dental surgical procedures to reduce the spread of aerosols and droplets.Clinical Relevance: External oral suction or high-volume suction should be used in conjunction with low-volume suction in surgical procedure to reduce the spread of aerosols and droplets in a dental clinic environment.

scholarly journals Factors affecting aerosol size distribution during various dental procedures

2021 ◽  
Author(s):  
Shruti Choudhary ◽  
Michael J Durkin ◽  
Daniel C Stoeckel ◽  
Heidi M Steinkamp ◽  
Martin H Thornhill ◽  
...  
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
High Volume ◽  
Routine Care ◽  
Mitigation Strategies ◽  
Aerosol Size Distribution ◽  
Dental Clinic ◽  
Factors Affecting ◽  
Dental Procedures ◽  
The Impact

Objectives: To determine the impact of various aerosol mitigation interventions and establish duration of aerosol persistence in a variety of dental clinic configurations. Methods: We performed aerosol measurement studies in endodontic, orthodontic, periodontic, pediatric, and general dentistry clinics. We used an optical aerosol spectrometer and wearable particulate matter sensors to measure real-time aerosol concentration from the vantage point of the dentist during routine care in a variety of clinic configurations (e.g, open bay, single room, partitioned operatories). We compared the impact of aerosol mitigation strategies [ventilation and high-volume evacuation (HVE)] and prevalence of particulate matter in the dental clinic environment before, during and after high-speed drilling, slow speed drilling and ultrasonic scaling procedures. Results: Conical and ISOVAC HVE were superior to standard tip evacuation for aerosol-generating procedures. When aerosols were detected in the environment, they were rapidly dispersed within minutes of completing the aerosol-generating procedure. Few aerosols were detected in dental clinics, regardless of configuration, when conical and ISOVAC HVE were used. Conclusions: Dentists should consider using conical or ISOVAC HVE rather than standard tip evacuators to reduce aerosols generated during routine clinical practice. Furthermore, when such effective aerosol mitigation strategies are employed, dentists need not leave dental chairs fallow between patients as aerosols are rapidly dispersed. Clinical Significance: ISOVAC HVE is highly effective in reducing aerosol emissions. With adequate ventilation and HVE use, dental fallow time can be reduced to 5 minutes.

Smart Machine Health and Maintenance: Tool Assembly Prognostics

2008 ◽  
Author(s):  
Edzel R. Lapira ◽  
Amit Deshpande ◽  
Jay Lee ◽  
John Snyder
Keyword(s):  
High Speed ◽  
Manufacturing Industry ◽  
Learning Algorithm ◽  
High Volume ◽  
Third Party ◽  
Manufacturing Operations ◽  
Prognostic Application ◽  
Machine Health ◽  
Smart Machine ◽  
Tool Assembly

It is well-established that unbalance in tool assembly causes excessive loads on spindle bearings and tool wear and increased vibration levels. However, in the days where high-speed machining (HSM) has become a common practice in the manufacturing industry, methodologies to measure tool assembly unbalance are not developed. In HSM the effects are worse, as the unbalance force is directly proportional to square of the spindle speed. Common practice in industry is to balance the tool assembly either with in-house balancing machines or use third-party balancing services after every batch cycle. This paper describes a data-driven methodology that detects the presence of unbalance in a tool assembly relative to the tools with known balance levels. The unbalance detection prognostic application developed as part of the Smart Machine Platform Initiative (SMPI) checks for the threshold unbalance level in the tool assembly for the given machining requirements before the start of any run. This approach uses statistical tools and a supervised learning algorithm based on the Watchdog Agent® toolbox developed by the Center for Intelligent Maintenance Systems. The proposed research finds high applicability in high-precision manufacturing operations involving high-volume production.

scholarly journals Droplet Sizes Emitted from Demonstration Electric Toothbrushes

2021 ◽  
Vol 18 (5) ◽  
pp. 2320
Author(s):  
Erwin P. Mark ◽  
Michael A. O. Lewis ◽  
Filippo Graziani ◽  
Boris Atlas ◽  
Joern Utsch
Keyword(s):  
Particle Size ◽  
Oral Cavity ◽  
High Speed ◽  
Tap Water ◽  
Transmission Risk ◽  
Measurement Device ◽  
Droplet Production ◽  
Droplet Sizes ◽  
Phantom Head

The COVID-19 pandemic has drawn attention to microbial transmission risk via aerosols in dental practice. Demonstration electric toothbrushes are used intra-orally for education. The aim of this investigation was to measure the size of droplets emitted by the brush head of two demonstration oscillating-rotating electric toothbrushes. Measurement of droplet production and size was recorded in vitro using three methods: (1) Malvern Spraytec (LASER particle size measurement device with detectable particle size of 0.1–2500 µm) and brushes mounted on a 3D-printed, two-shell form-fit fixture with a supply of tap water; (2) a DustTrak aerosol measurement device and toothpaste slurry, with brushing simulated in the oral cavity of a phantom head; (3) high-speed visualization in a simulated-use situation in the oral cavity of a phantom head, with individual evaluation of tap water, water with detergent, 70% ethanol, glycerin and toothpaste slurry. Both brushes showed the size of emitted droplets was consistently between 200 and 1200 µm, categorized as splatter (dental aerosols are <50 µm diameter). No significant incremental aerosol-sized matter was detected during toothbrush operation. The high-speed video visualization confirmed only splatter-sized droplets during operation. These findings indicate that oscillating-rotating toothbrushes do not produce aerosol-sized particles during simulated use.

scholarly journals Spray mist reduction by means of a high-volume evacuation system—Results of an experimental study

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257137
Author(s):  
Martin Koch ◽  
Christian Graetz
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
High Speed ◽  
Statistical Tests ◽  
Mouth Opening ◽  
High Volume ◽  
Worst Case ◽  
Significant Difference ◽  
Tooth Preparation ◽  
Evacuation System

Objectives High-speed tooth preparation requires effective cooling to avoid thermal damage, which generates spray mist, which is a mixture of an aerosol, droplets and particles of different sizes. The aim of this experimental study was to analyze the efficacy of spray mist reduction with an intraoral high-volume evacuation system (HVE) during simulated high-speed tooth preparation for suboptimal versus optimal suction positions of 16 mm sized cannulas and different flow rates of the HVE. Material and methods In a manikin head, the upper first premolar was prepared with a dental turbine, and generated particles of 5–50 microns were analyzed fifty millimeters above the mouth opening with the shadow imaging technique (frame: 6.6×5.3×1.1 mm). This setup was chosen to generate a reproducible spray mist in a vertical direction towards an imaginary operator head (worst case scenario). The flow rate (FR) of the HVE was categorized into five levels (≤120 l/min up to 330 l/min). The number of particles per second (NP; p/s) was counted, and the mass volume flow of particles per second (MVF; μg/s*cm3) was calculated for 10 sec. Statistical tests were nonparametric and two-sided (p≤0.05). Results With increasing flow rate, the NP/MVF values decreased significantly (eta: 0.671/0.678; p≤0.001). Using a suboptimally positioned cannula with an FR≤160 l/min, significantly higher NP values (mean±SD) of 731.67±54.24 p/s (p≤0.019) and an MVF of 3.72±0.42 μg/s*cm3 (p≤0.010) were measured compared to those of the optimal cannula position and FR≥300 l/min (NP/MVF: 0/0). No significant difference in NP and MVF was measurable between FR≥250 l/min and FR>300 l/min (p = 0.652, p = 0.664). Conclusion Within the limitations of the current experimental study, intraoral high-flow rate suction with ≥300 l/min with an HVE effectively reduced 5–50 μm sized particles of the spray mist induced by high-speed tooth preparation with a dental turbine.

High-Volume Hospitals with High-Volume and Low-Volume Surgeons: Is There a “Field Effect” for Pancreaticoduodenectomy?

2016 ◽  
Vol 82 (5) ◽  
pp. 407-411 ◽  
Author(s):  
Thomas W. Wood ◽  
Sharona B. Ross ◽  
Ty A. Bowman ◽  
Amanda Smart ◽  
Carrie E. Ryan ◽  
...  
Keyword(s):  
Hospital Mortality ◽  
Field Effect ◽  
Hospital Volume ◽  
Patient Discharge ◽  
High Volume ◽  
Surgeon Volume ◽  
Hospital Charges ◽  
Leapfrog Group ◽  
Discharge Status ◽  
Low Volume

Since the Leapfrog Group established hospital volume criteria for pancreaticoduodenectomy (PD), the importance of surgeon volume versus hospital volume in obtaining superior outcomes has been debated. This study was undertaken to determine whether low-volume surgeons attain the same outcomes after PD as high-volume surgeons at high-volume hospitals. PDs undertaken from 2010 to 2012 were obtained from the Florida Agency for Health Care Administration. High-volume hospitals were identified. Surgeon volumes within were determined; postoperative length of stay (LOS), in-hospital mortality, discharge status, and hospital charges were examined relative to surgeon volume. Six high-volume hospitals were identified. Each hospital had at least one surgeon undertaking ≥ 12 PDs per year and at least one surgeon undertaking < 12 PDs per year. Within these six hospitals, there were 10 “high-volume” surgeons undertaking 714 PDs over the three-year period (average of 24 PDs per surgeon per year), and 33 “low-volume” surgeons undertaking 225 PDs over the three-year period (average of two PDs per surgeon per year). For all surgeons, the frequency with which surgeons undertook PD did not predict LOS, in-hospital mortality, discharge status, or hospital charges. At the six high-volume hospitals examined from 2010 to 2012, low-volume surgeons undertaking PD did not have different patient outcomes from their high-volume counterparts with respect to patient LOS, in-hospital mortality, patient discharge status, or hospital charges. Although the discussion of volume for complex operations has shifted toward surgeon volume, hospital volume must remain part of the discussion as there seems to be a hospital “field effect.”

scholarly journals Resilience to maintain quality of intrapartum care in war torn Yemen: a retrospective pre-post study evaluating effects of changing birth volumes in a congested frontline hospital

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Josephine Obel ◽  
Antonio Isidro Carrion Martin ◽  
Abdul Wasay Mullahzada ◽  
Ronald Kremer ◽  
Nanna Maaløe
Keyword(s):  
Quality Of Care ◽  
Birth Outcomes ◽  
Birth Outcome ◽  
High Volume ◽  
Maternal Health Service ◽  
Service Access ◽  
Intrapartum Care ◽  
Health Service Access ◽  
Low Volume

Abstract Background Fragile and conflict-affected states contribute with more than 60% of the global burden of maternal mortality. There is an alarming need for research exploring maternal health service access and quality and adaptive responses during armed conflict. Taiz Houbane Maternal and Child Health Hospital in Yemen was established during the war as such adaptive response. However, as number of births vastly exceeded the facility’s pre-dimensioned capacity, a policy was implemented to restrict admissions. We here assess the restriction’s effects on the quality of intrapartum care and birth outcomes. Methods A retrospective before and after study was conducted of all women giving birth in a high-volume month pre-restriction (August 2017; n = 1034) and a low-volume month post-restriction (November 2017; n = 436). Birth outcomes were assessed for all births (mode of birth, stillbirths, intra-facility neonatal deaths, and Apgar score < 7). Quality of intrapartum care was assessed by a criterion-based audit of all caesarean sections (n = 108 and n = 82) and of 250 randomly selected vaginal births in each month. Results Background characteristics of women were comparable between the months. Rates of labour inductions and caesarean sections increased significantly in the low-volume month (14% vs. 22% (relative risk (RR) 0.62, 95% confidence interval (CI) 0.45-0.87) and 11% vs. 19% (RR 0.55, 95% CI 0.42-0.71)). No other care or birth outcome indicators were significantly different. Structural and human resources remained constant throughout, despite differences in patient volume. Conclusions Assumptions regarding quality of care in periods of high demand may be misguiding - resilience to maintain quality of care was strong. We recommend health actors to closely monitor changes in quality of care when implementing resource changes; to enable safe care during birth for as many women as possible.

scholarly journals Center-Level Procedure Volume Does Not Predict Failure-to-Rescue After Severe Complications of Oncologic Colon and Rectal Surgery

2021 ◽  
Author(s):  
Miriam Lillo-Felipe ◽  
Rebecka Ahl Hulme ◽  
Maximilian Peter Forssten ◽  
Gary A. Bass ◽  
Yang Cao ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Postoperative Complications ◽  
High Volume ◽  
Cancer Surgery ◽  
Colon And Rectal Surgery ◽  
Surgical Volume ◽  
Failure To Rescue ◽  
Colorectal Cancer Surgery ◽  
Procedure Volume ◽  
Low Volume

Abstract Background The relationship between hospital surgical volume and outcome after colorectal cancer surgery has thoroughly been studied. However, few studies have assessed hospital surgical volume and failure-to-rescue (FTR) after colon and rectal cancer surgery. The aim of the current study is to evaluate FTR following colorectal cancer surgery between clinics based on procedure volume. Methods Patients undergoing colorectal cancer surgery in Sweden from January 2015 to January 2020 were recruited through the Swedish Colorectal Cancer Registry. The primary endpoint was FTR, defined as the proportion of patients with 30-day mortality after severe postoperative complications in colorectal cancer surgery. Severe postoperative complications were defined as Clavien–Dindo ≥ 3. FTR incidence rate ratios (IRR) were calculated comparing center volume stratified in low-volume (≤ 200 cases/year) and high-volume centers (> 200 cases/year), as well as with an alternative stratification comparing low-volume (< 50 cases/year), medium-volume (50–150 cases/year) and high-volume centers (> 150 cases/year). Results A total of 23,351 patients were included in this study, of whom 2964 suffered severe postoperative complication(s). Adjusted IRR showed no significant differences between high- and low-volume centers with an IRR of 0.97 (0.75–1.26, p = 0.844) in high-volume centers in the first stratification and an IRR of 2.06 (0.80–5.31, p = 0.134) for high-volume centers and 2.15 (0.83–5.56, p = 0.116) for medium-volume centers in the second stratification. Conclusion This nationwide retrospectively analyzed cohort study fails to demonstrate a significant association between hospital surgical volume and FTR after colorectal cancer surgery. Future studies should explore alternative characteristics and their correlation with FTR to identify possible interventions for the improvement of quality of care after colorectal cancer surgery.

scholarly journals Cavitation patterns in high-pressure homogenization nozzles with cylindrical orifices: Influence of mixing stream in Simultaneous Homogenization and Mixing

2021 ◽  
Author(s):  
V. Gall ◽  
E. Rütten ◽  
H. P. Karbstein
Keyword(s):  
High Pressure ◽  
Process Design ◽  
High Speed ◽  
State Of The Art ◽  
Back Pressure ◽  
High Pressure Homogenization ◽  
Unit Operation ◽  
Mixing Chamber ◽  
Cavitation Intensity ◽  
Droplet Sizes

AbstractHigh-pressure homogenization is the state of the art to produce high-quality emulsions with droplet sizes in the submicron range. In simultaneous homogenization and mixing (SHM), an additional mixing stream is inserted into a modified homogenization nozzle in order to create synergies between the unit operation homogenization and mixing. In this work, the influence of the mixing stream on cavitation patterns after a cylindrical orifice is investigated. Shadow-graphic images of the cavitation patterns were taken using a high-speed camera and an optically accessible mixing chamber. Results show that adding the mixing stream can contribute to coalescence of cavitation bubbles. Choked cavitation was observed at higher cavitation numbers σ with increasing mixing stream. The influence of the mixing stream became more significant at a higher orifice to outlet ratio, where a hydraulic flip was also observed at higher σ. The decrease of cavitation intensity with increasing back-pressure was found to be identical with conventional high-pressure homogenization. In the future, the results can be taken into account in the SHM process design to improve the efficiency of droplet break-up by preventing cavitation or at least hydraulic flip.

scholarly journals Study on the High-Speed Milling Performance of High-Volume Fraction SiCp/Al Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4143
Author(s):  
Youzheng Cui ◽  
Shenrou Gao ◽  
Fengjuan Wang ◽  
Qingming Hu ◽  
Cheng Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Volume Fraction ◽  
Simulation Analysis ◽  
Cutting Temperature ◽  
High Volume ◽  
Cutting Parameters ◽  
High Volume Fraction ◽  
High Wear Resistance ◽  
Element Analysis

Compared with other materials, high-volume fraction aluminum-based silicon carbide composites (hereinafter referred to as SiCp/Al) have many advantages, including high strength, small change in the expansion coefficient due to temperature, high wear resistance, high corrosion resistance, high fatigue resistance, low density, good dimensional stability, and thermal conductivity. SiCp/Al composites have been widely used in aerospace, ordnance, transportation service, precision instruments, and in many other fields. In this study, the ABAQUS/explicit large-scale finite element analysis platform was used to simulate the milling process of SiCp/Al composites. By changing the parameters of the tool angle, milling depth, and milling speed, the influence of these parameters on the cutting force, cutting temperature, cutting stress, and cutting chips was studied. Optimization of the parameters was based on the above change rules to obtain the best processing combination of parameters. Then, the causes of surface machining defects, such as deep pits, shallow pits, and bulges, were simulated and discussed. Finally, the best cutting parameters obtained through simulation analysis was the tool rake angle γ0 = 5°, tool clearance angle α0 = 5°, corner radius r = 0.4 mm, milling depth ap = 50 mm, and milling speed vc= 300 m/min. The optimal combination of milling parameters provides a theoretical basis for subsequent cutting.

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