scholarly journals Evaluating aerosol and splatter during orthodontic debonding: implications for the COVID-19 pandemic

2020 ◽  
Author(s):  
Hayley Llandro ◽  
James R Allison ◽  
Charlotte Currie ◽  
David Edwards ◽  
Charlotte Bowes ◽  
...  
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Positive Control ◽  
Aerosol Generation ◽  
Dental Procedures ◽  
Air Turbine ◽  
Fluorescein Dye ◽  
Filter Papers ◽  
Crown Preparation ◽  
Experimental Rig

Introduction: Dental procedures often produce splatter and aerosol which have potential to spread pathogens such as SARS-CoV-2. Mixed guidance exists on the aerosol generating potential of orthodontic procedures. The aim of this study was to evaluate aerosol and/or splatter contamination during an orthodontic debonding procedure.Material and Methods: Fluorescein dye was introduced into the oral cavity of a mannequin. Orthodontic debonding was carried out in triplicate with filter papers placed in the immediate environment. Composite bonding cement was removed using a slow-speed handpiece with dental suction. A positive control condition included a high-speed air-turbine crown preparation. Samples were analysed using digital image analysis and spectrofluorometric analysis.Results: Contamination across the 8-metre experimental rig was 3% of the positive control on spectrofluorometric analysis and 0% on image analysis. There was contamination of the operator, assistant, and mannequin, representing 8%, 25%, and 28% of the positive control spectrofluorometric measurements, respectively.Discussion: Orthodontic debonding produces splatter within the immediate locality of the patient. Widespread aerosol generation was not observed.Conclusions: Orthodontic debonding procedures are low risk for aerosol generation, but localised splatter is likely. This highlights the importance of personal protective equipment for the operator, assistant, and patient.

scholarly journals Evaluating splatter and settled aerosol during orthodontic debonding: implications for the COVID-19 pandemic

2020 ◽  
Author(s):  
Hayley Llandro ◽  
James R Allison ◽  
Charlotte C Currie ◽  
David C Edwards ◽  
Charlotte Bowes ◽  
...  
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Digital Image Analysis ◽  
Positive Control ◽  
List Type ◽  
Dental Procedures ◽  
Air Turbine ◽  
Fluorescein Dye ◽  
Crown Preparation ◽  
Experimental Rig

AbstractIntroductionDental procedures produce splatter and aerosol which have potential to spread pathogens such as SARS-CoV-2. Mixed evidence exists on the aerosol generating potential of orthodontic procedures. The aim of this study was to evaluate splatter and/or settled aerosol contamination during orthodontic debonding.Material and MethodsFluorescein dye was introduced into the oral cavity of a mannequin. Orthodontic debonding was undertaken with surrounding samples collected. Composite bonding cement was removed using a speed-increasing handpiece with dental suction. A positive control condition included a water-cooled, high-speed air-turbine crown preparation. Samples were analysed using digital image analysis and spectrofluorometric analysis.ResultsContamination across the 8-metre experimental rig was 3% of the positive control on spectrofluorometric analysis and 0% on image analysis. Contamination of the operator, assistant, and mannequin, was 8%, 25%, and 28% of the positive control, respectively.DiscussionSplatter and settled aerosol from orthodontic debonding is distributed mainly within the immediate locality of the mannequin. Widespread contamination was not observed.ConclusionsOrthodontic debonding is unlikely to produce widespread contamination via splatter and settled aerosol, but localised contamination is likely. This highlights the importance of personal protective equipment for the operator, assistant, and patient. Further work is required to examine suspended aerosol.Three ‘In brief’ pointsOrthodontic debonding, including removal of composite using a slow speed handpiece with dental suction, appears to pose little risk of widespread distribution of settled contamination.Splatter and settled aerosol was produced during the debonding procedure, however this was mainly localised to the patient, operator and assistant.Further work is required to examine aerosol which remains suspended in the air.

scholarly journals Splatters and Aerosols Contamination in Dental Aerosol Generating Procedures

2021 ◽  
Vol 11 (4) ◽  
pp. 1914
Author(s):  
Pingping Han ◽  
Honghui Li ◽  
Laurence J. Walsh ◽  
Sašo Ivanovski
Keyword(s):  
Particle Size ◽  
Disease Transmission ◽  
High Speed ◽  
Low Speed ◽  
Dental Procedures ◽  
Dental Equipment ◽  
Produce Contamination ◽  
Fluorescein Dye ◽  
Filter Papers ◽  
Airborne Disease

Dental aerosol-generating procedures produce a large amount of splatters and aerosols that create a major concern for airborne disease transmission, such as COVID-19. This study established a method to visualise splatter and aerosol contamination by common dental instrumentation, namely ultrasonic scaling, air-water spray, high-speed and low-speed handpieces. Mock dental procedures were performed on a mannequin model, containing teeth in a typodont and a phantom head, using irrigation water containing fluorescein dye as a tracer. Filter papers were placed in 10 different locations to collect splatters and aerosols, at distances ranging from 20 to 120 cm from the source. All four types of dental equipment produced contamination from splatters and aerosols. At 120 cm away from the source, the high-speed handpiece generated the greatest amount and size (656 ± 551 μm) of splatter particles, while the triplex syringe generated the largest amount of aerosols (particle size: 1.73 ± 2.23 μm). Of note, the low-speed handpiece produced the least amount and size (260 ± 142 μm) of splatter particles and the least amount of aerosols (particle size: 4.47 ± 5.92 μm) at 120 cm. All four dental AGPs produce contamination from droplets and aerosols, with different patterns of distribution. This simple model provides a method to test various preventive strategies to reduce risks from splatter and aerosols.

scholarly journals Evaluating aerosol and splatter following dental procedures: addressing new challenges for oral healthcare and rehabilitation

2020 ◽  
Author(s):  
James R Allison ◽  
Charlotte C Currie ◽  
David C Edwards ◽  
Charlotte Bowes ◽  
Jamie Coulter ◽  
...  
Keyword(s):  
High Speed ◽  
Descriptive Statistics ◽  
Analytic Methods ◽  
Clinical Procedures ◽  
Post Procedure ◽  
Dental Procedures ◽  
Air Turbine ◽  
Low Levels ◽  
Filter Papers ◽  
The Impact

AbstractBackgroundDental procedures often produce aerosol and splatter which are potentially high risk for spreading pathogens such as SARS-CoV-2. The existing literature is limited.Objective(s)To develop a robust, reliable and valid methodology to evaluate distribution and persistence of dental aerosol and splatter, including the evaluation of clinical procedures.MethodsFluorescein was introduced into the irrigation reservoirs of a high-speed air-turbine, ultrasonic scaler and 3-in-1 spray and procedures performed on a mannequin in triplicate. Filter papers were placed in the immediate environment. The impact of dental suction and assistant presence were also evaluated. Samples were analysed using photographic image analysis, and spectrofluorometric analysis. Descriptive statistics were calculated and Pearson’s correlation for comparison of analytic methods.ResultsAll procedures were aerosol and splatter generating. Contamination was highest closest to the source, remaining high to 1-1.5 m. Contamination was detectable at the maximum distance measured (4 m) for high-speed air-turbine with maximum relative fluorescence units (RFU) being: 46,091 at 0.5 m, 3,541 at 1.0 m, and 1,695 at 4 m. There was uneven spatial distribution with highest levels of contamination opposite the operator. Very low levels of contamination (≤0.1% of original) were detected at 30 and 60 minutes post procedure. Suction reduced contamination by 67-75% at 0.5-1.5 m. Mannequin and operator were heavily contaminated. The two analytic methods showed good correlation (r=0.930, n=244, p<0.001).ConclusionDental procedures have potential to deposit aerosol and splatter at some distance from the source, being effectively cleared by 30 minutes in our setting.

scholarly journals Evaluating dental aerosol and splatter in an open plan clinic environment: implications for the COVID-19 pandemic

2020 ◽  
Author(s):  
Richard Holliday ◽  
James R Allison ◽  
Charlotte Currie ◽  
David Edwards ◽  
Charlotte Bowes ◽  
...  
Keyword(s):  
High Speed ◽  
Time Course ◽  
Irrigation System ◽  
Dilution Effect ◽  
Realistic Model ◽  
Experimental Conditions ◽  
Environmental Cleaning ◽  
Open Plan ◽  
Fluorescein Dye ◽  
Filter Papers

Aim: To identify splatter and aerosol distribution resulting from dental aerosol generating procedures (AGPs) in the open plan clinic environment. A secondary aim is to explore the detailed time course of aerosol settling after an AGP. Methodology: Dental procedures were undertaken on a dental mannequin. Fluorescein dye was placed into the irrigation system of the high-speed air turbine handpiece for the first experimental design, and in the second, fluorescein dye was entered into the mannequin's mouth via artificial salivary ducts. Filter papers were placed at set distances around the open plan clinic environment to collect aerosol and splatter under various mitigating conditions including ventilation and aspiration flow rate. An 8-metre diameter rig was set up to investigate the effect of fallow time. Filter papers were analysed using imaging software and spectrofluorometric analysis. Results: The distribution of fluorescein contamination varied widely across the open plan clinic depending on the experimental conditions. Unmitigated (i.e. no suction) procedures have the potential to deposit contamination at large distances. Medium volume dental suction (159 L/min air) reduced contamination in the AGP bay by 53%, and in adjacent and distant bays/walkways by 81-83%. Low volume suction (40 L/min air) gave similar reductions. Cross-ventilation reduced contamination in adjacent and distant bays/walkways by 80-89%. In the most realistic model (dye in mouth with medium volume suction) the samples in distant bays (≥5 m head-to-head chair distance) either gave zero readings or very low readings (&lt; 0.0016% of the fluorescein introduced into the system during the procedure). Almost all (99.99%) of the splatter detected was retained within the AGP bay/walkway. Time course experiments showed that after 10 minutes, very little additional contaminated aerosol settled. Conclusions: The cross-infection risk from conducting AGPs in an open plan clinic environment appears small, particularly when bays are ≥ 5 m apart. There is a major dilution effect from the instrument water spray and a substantial protective effect from using dental suction. The majority of aerosol settles in the first 10 minutes indicating that environmental cleaning may be appropriate after this time.

scholarly journals A Systematic Review of Droplet and Aerosol Generation in Dentistry

2020 ◽  
Author(s):  
Nicola Innes ◽  
Ilona Johnson ◽  
Waraf Al-Yaseen ◽  
Rebecca Harris ◽  
Rhiannon Jones ◽  
...  
Keyword(s):  
Disease Transmission ◽  
High Speed ◽  
Oral Surgery ◽  
Data Extraction ◽  
Transmission Risk ◽  
Future Research ◽  
Slow Speed ◽  
Air Polishing ◽  
Aerosol Generation ◽  
Dental Procedures

Introduction: Against the COVID-19 pandemic backdrop and potential disease transmission risk by dental procedures that can generate aerosol and droplets. Objectives: This review aimed to identify which clinical dental procedures do generate droplets and aerosols with subsequent contamination, and for these, characterise their pattern, spread and settle. Materials and Method: Six databases were searched and citation chasing undertaken (to 11/08/20). Screening stages were undertaken in duplicate, independently, by two researchers. Data extraction was performed by one reviewer and verified by another. Results: Eighty-three studies met the inclusion criteria and covered: Ultrasonic scaling (USS, n=44), high speed air-rotor (HSAR, n=31); oral surgery (n=11), slow-speed handpiece (n=4); air-water (triple) syringe (n=4), air-polishing (n=4), prophylaxis (n=2) and hand-scaling (n=2). Although no studies investigated respiratory viruses, those on bacteria, blood splatter and aerosol showed activities using powered devices produced the greatest contamination. Contamination was found for all activities, and at the furthest points studied. The operator torso operator arm, and patient body were especially affected. Heterogeneity precluded significant inter-study comparisons but intra-study comparisons allowed construction of a proposed hierarchy of procedure contamination risk: higher risk (USS, HSAR, air-water syringe [air only or air/water together], air polishing, extractions using motorised hand-pieces); moderate (slow-speed handpieces, prophylaxis with pumice, extractions) and lower (air-water syringe [water only] and hand scaling. Conclusion: Significant gaps in the evidence, low sensitivity of measures and variable quality limit firm conclusions around contamination for different procedures. However, a hierarchy of contamination from procedures can be proposed for challenge/verification by future research which should consider standardised methodologies to facilitate research synthesis. Clinical significance (49 words): This manuscript addresses uncertainty around aerosol generating procedures (AGPs) in dentistry. Findings indicate a continuum of procedure-related aerosol generation rather than the current binary AGP or non-AGP perspective. This informs discussion around AGPs and direct future research to help support knowledge and decision making around COVID-19 and dental procedures.

scholarly journals The effect of high-speed dental handpiece coolant delivery and design on aerosol and droplet production

2021 ◽  
Author(s):  
James R Allison ◽  
David Edwards ◽  
Charlotte Bowes ◽  
Kimberley Pickering ◽  
Christopher Dowson ◽  
...  
Keyword(s):  
High Speed ◽  
Positive Control ◽  
Negative Control ◽  
Compressed Air ◽  
Treatment Area ◽  
Dental Instruments ◽  
Air Turbine ◽  
Droplet Production ◽  
Open Plan ◽  
Coolant Delivery

Objectives: High-speed dental instruments produce aerosol and droplets. The objective of this study was to evaluate aerosol and droplet production from a novel electric micromotor handpiece (without compressed air coolant) in real world clinical settings. Methods: 10-minute upper incisor crown preparations were performed in triplicate in an open-plan clinic with mechanical ventilation providing 3.45 air changes per hour. A 1:5 ratio electric micromotor handpiece which allows water coolant without compressed air (Ti-Max Z95L, NSK) was used at three speeds: 60,000 (60K), 120,000 (120K), and 200,000 (200K) revolutions per minute. Coolant solutions contained fluorescein sodium as a tracer (2.65 mmol L−1). High-speed air-turbine positive control, and negative control conditions were conducted. Aerosol production was evaluated at 3 locations (0.5 m, 1.5 m and 1.7 m) using: (1) an optical particle counter (OPC; 3016-IAQ, Lighthouse) to detect all aerosol; and (2) a liquid cyclone air sampler (BioSampler, SKC Ltd.) to detect aerosolised fluorescein, which was quantified by spectrofluorometric analysis. Settled droplets were detected by spectrofluorometric analysis of filter papers placed onto a rig across the open-plan clinic.Results: Local (within treatment bay) settled droplet contamination was elevated above negative control for all conditions, with no difference between conditions. Settled droplet contamination was not detected above negative controls outside the treatment bay for any condition. Aerosol detection at 1.5 m and 1.7 m, was only increased for the air-turbine positive control condition. At 0.5 m, aerosol levels were highly elevated for the air-turbine, minimally elevated for 200K and 120K, and not elevated for 60K. Conclusions: Electric micromotor handpieces which use water-jet coolant alone without compressed air, produce localised (within treatment bay) droplet contamination but are unlikely to produce aerosol contamination beyond the immediate treatment area (1.5 m), allowing them to be used safely in most open-plan clinic settings.

scholarly journals The Use of Ultrasonic Instrumentats in the Dental Practice

2020 ◽  
pp. 152-159
Author(s):  
Yuriy Andreevich Sergeev ◽  
Alexandr Anatolyevich Markov ◽  
Bayu Indra Sukmana ◽  
Herlina Uinarni ◽  
Elena Aleksandrovna Matveeva ◽  
...  
Keyword(s):  
High Speed ◽  
Soft Tissues ◽  
Frequency Noise ◽  
Cardiac Pacemakers ◽  
Noise Interference ◽  
Dental Procedures ◽  
Air Turbine ◽  
Caries Removal ◽  
Ultrasonic Devices ◽  
Research Show

The ultrasonic instrumentation in dentistry has been used since the middle of the last century. Improved visualization, ease of operation and precise cutting ability have allowed ultrasonic instruments to be widely used in dentistry. The study considers the possibilities of using ultrasound instruments in various fields of dentistry. Advantages of ultrasonic instruments include conservative preparation of the cavity, less painful caries removal procedure and minimal noise generation. All these improvements are presented in clinical cases. In addition, the gentle effect on soft tissues is a characteristic feature of ultrasonic devices when applied to operative or orthopedic dentistry during the preparation of the cavity. Although some issues, such as high-frequency noise, interference to cardiac pacemakers, and low cutting efficiency compared to conventional high-speed or low-speed air-turbine tools, still need to be considered, the results of previous research show that ultrasound tools have an extremely high potential to become a convenient and effective tool for various dental procedures deserve future development.

High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

1994 ◽  
Vol 52 ◽  
pp. 218-219
Author(s):  
Robert W. Mackin
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Three Dimensional ◽  
Image Data ◽  
Ccd Camera ◽  
Objective Lens ◽  
Array Processor ◽  
Vaginal Smears ◽  
Low Contrast ◽  
Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

scholarly journals Research on aerodynamic characteristics of two-stage axial micro air turbine spindle for small parts machining

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098437
Author(s):  
Liu Jiang ◽  
Guo Zhiping ◽  
Miao Shujing ◽  
He Xiangxin ◽  
Zhu Xinyu
Keyword(s):  
High Speed ◽  
Aerodynamic Characteristics ◽  
Maximum Efficiency ◽  
Two Stage ◽  
Output Torque ◽  
Air Turbine ◽  
Solid Foundation ◽  
Computational Fluid Dynamics Cfd ◽  
Micro Machine ◽  
Small Parts

In order to meet the requirements of output torque, efficiency and compact shape of micro-spindles for small parts machining, a two-stage axial micro air turbine spindle with an axial inlet and outlet is proposed. Based on the k-ω turbulence model of SST, the flow field and operation characteristics of the two-stage axial micro air turbine spindle were studied using computational fluid dynamics (CFD) combined with an experimental study. We obtained the air turbine spindle under different working conditions of the loss and torque characteristics. When the inlet pressure was 300 KPa, the output speed of the two-stage turbine was 100,000 rpm, 9% higher than that of a single-stage turbine output torque. The total torque reached 6.39 N·mm, and the maximum efficiency of the turbine and the spindle were 42.2% and 32.3%, respectively. Through the research on the innovative structure of the two-stage axial micro air turbine spindle, the overall performance of the principle prototype has been significantly improved and the problems of insufficient output torque and low working efficiency in high-speed micro-machining can be solved practically, which laid a solid foundation for improving the machining efficiency of small parts and reducing the size of micro machine tool.

Sign in / Sign up

Export Citation Format

Share Document