Efficacy of a chairside extraoral suction system in the reduction of aerosol contamination.

The dental setting is regarded as a high-risk environment for aerosol concentrations and transmission of respiratory infectious agents, especially in relation to the COVID-19 pandemic. Although a number of approaches and practices have evolved to reduce the spread of pathogens in the dental setting, the risk of airborne infection remains a concern. Several new extraoral suction (EOS) devices have been marketed recently; further investigation is warranted to determine their clinical effectiveness. The aim of this study was to evaluate the efficacy of a chairside EOS device (PAX 2000 Extraoral Dental Suction System) in reducing aerosol contamination from patients receiving ultrasonic scaling by a registered hygienist as a part of initial or supportive periodontal therapy. The number of colony-forming units (CFUs) was measured with agar plates before, during, and after ultrasonic scaling at 3 different locations in the dental operatory (instrument table, patient chest area, and patient foot area). Forty subjects were randomly allocated into 2 test groups (n = 20) in which ultrasonic scaling was performed with or without the use of the EOS device. The CFUs retrieved after incubation were quantified and identified by their bacterial or fungal taxon. The use of the EOS device reduced the number of CFUs during scaling at all 3 locations, but the difference was only statistically significant (P = 0.018; Mann-Whitney U test) at the patient's chest area, where the highest number of CFUs was present. The aerosols consisted of 74 different taxa of human origin. The results suggest that the tested EOS system may reduce aerosol contamination in the clinical dental setting, especially in proximity to the patient's head, where most aerosols are generated.

A Cluster Randomized Controlled Trial of the Dental Sealants Quality in Rural Schoolchildren Using Innovative Suction without Dental Assistance.

This study examined whether the moisture control innovation (tongue and cheek retractors and saliva contamination (SS-suction)) used without dental assistance could improve the quality of dental sealant in rural Thai school children compared to a standard treatment, i.e., high power suction with dental assistance. A single blind, cluster randomized controlled trial was conducted. Participants were 15 dental nurses working in sub-district health promoting hospitals and 482 children. All dental nurses attended workshops of SS-suction and revised dental sealant procedures. Children with sound lower first permanent molar teeth were simple-randomly assigned to either an intervention or control group. The children in the intervention group were sealed with SS-suction, and the children in the control group were sealed with high power suction and dental assistance. There were 244 children in the intervention group and 238 children in the control group. Dental nurses' satisfaction on SS-suction was record by visual analogue scale (VAS) for each tooth during treatment. After 15-18 months, caries on sealed surfaces were examined. The results showed that the median satisfaction score of SS-suction was 9 out of 10, and 17-18% children experienced uncomfortable sensation during insertion or removal. The uncomfortable feeling disappeared once the suction was in place. Caries on sealed surfaces did not differ significantly between the intervention and control groups. Caries on the occlusal surface was present in 26.7% and 27.5%, and caries on the buccal surface was present in 35.2% and 36.4% of cases in the intervention and control groups, respectively. In conclusion, dental nurses were satisfied with SS-suction in terms of both function and safety. The effectiveness of SS-suction was compatible with the standard procedure after 15-18 months.

Safety and immunogenicity of the bi-cistronic GLS-5310 COVID-19 DNA vaccine delivered with the GeneDerm suction device.

OBJECTIVES: The CoV2-001 phase I randomized trial evaluated the safety and immunogenicity of the GLS-5310 bi-cistronic DNA vaccine through 48 weeks of follow-up. DESIGN: A total of 45 vaccine-naïve participants were recruited between December 31, 2020, and March 30, 2021. GLS-5310, encoding for the SARS-CoV-2 spike and open reading frame 3a (ORF3a) proteins, was administered intradermally at 0.6 mg or 1.2 mg per dose, followed by application of the GeneDerm suction device as part of a two-dose regimen spaced either 8 or 12 weeks between vaccinations. RESULTS: GLS-5310 was well tolerated with no serious adverse events reported. Antibody and T cell responses were dose-independent. Anti-spike antibodies were induced in 95.5% of participants with an average geometric mean titer of ∼480 four weeks after vaccination and declined minimally through 48 weeks. Neutralizing antibodies were induced in 55.5% of participants with post-vaccination geometric mean titer of 28.4. T cell responses were induced in 97.8% of participants, averaging 716 site forming units/106 cells four weeks after vaccination, increasing to 1248 at week 24, and remaining greater than 1000 through 48 weeks. CONCLUSION: GLS-5310 administered with the GeneDerm suction device was well tolerated and induced high levels of binding antibodies and T-cell responses. Antibody responses were similar to other DNA vaccines, whereas T cell responses were many-fold greater than DNA and non-DNA vaccines.

Preclinical safety assessment of the suction-assisted intradermal injection of the SARS-CoV-2 DNA vaccine candidate pGO-1002 in white rabbit.

pGO-1002, a non-viral DNA vaccine that expresses both spike and ORF3a antigens of SARS-CoV-2, is undergoing phase 1 and phase 2a clinical trials in Korea and the US. A preclinical repeated-dose toxicity study in New Zealand white rabbits in compliance with Good Laboratory Practice (GLP) was conducted to assess the potential toxicity, local tolerance, and immunogenicity of the vaccine and GeneDerm suction device. The dose rate was 1.2 mg/head pGO-1002, and this was administered intradermally to a group of animals (eight animals/sex/group) three times at 2-week intervals, followed by a 4-week recovery period. After each administration, suction was applied to the injection site using the GeneDerm device. Mortality, clinical signs, body weight, food consumption, skin irritation, ophthalmology, body temperature, urinalysis, and clinical pathology were also monitored. Gross observations and histopathological evaluation were performed. Overall, pGO-1002 administration-related changes were confined to minor damage or changes at the injection site, increased spleen weight and minimal increased cellularity in white pulp. All changes of injection site were considered local inflammatory changes or pharmacological actions due to the vaccine with the changes in spleen considered consistent with vaccine-induced immune activation. All findings showed reversibility during the 4-week recovery period. Animals vaccinated with pGO-1002, administered by intradermal injection and followed by application of suction with GeneDerm, developed humoral and cellular responses against the SARS-CoV-2 antigens consistent with prior studies in rats. Collectively, it was concluded that the pGO-1002 vaccine was safe and effective under these experimental conditions and these data supported future human study of the vaccine, now known as GLS-5310, for clinical trial use.

Efficiency of HEPA-filtered extra-oral suction unit on aerosols during prosthetic dental preparation: A pilot study.

OBJECTIVES: Aerosols formed during dental treatments have a huge risk for the spread of bacteria and viruses. This study is aimed at determining which part of the working area and at what size aerosol is formed and ensuring more effective use of HEPA-filtered devices. MATERIALS AND METHODS: Anterior tooth preparation was performed by one dentist with one patient. Particle measurements were made using an airborne particle counter and were taken at four different locations: the chest of the patient, the chest of the dentist, the center of the room, and near the window. Three groups were determined for this study: group 1: measurement in a 24-h ventilated room (before the tooth preparation, empty room), group 2: measurement with the use of saliva ejector (SE), and group 3: measurement with the use of saliva ejector and HEPA-filtered extra-oral suction (HEOS) unit. RESULTS: The particles generated during tooth preparation were separated according to their sizes; the concentration in different locations of the room and the efficiency of the HEOS unit were examined. CONCLUSIONS: The present study showed that as the particle size increases, the rate of spread away from the dentist's working area decreases. The HEPA-filtered extra-oral suction unit is more effective on particles smaller than 0.5 microns. Therefore, infection control methods should be arranged according to these results. CLINICAL RELEVANCE: The effective and accurate use of HEPA-filtered devices in clinics significantly reduces the spread of bacterial and viral infections and cross-infection.

Clinical Efficacy of an Extraoral Dental Evacuation Device in Aerosol Elimination During Endodontic Access Preparation.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has caused many concerns in the dental field regarding aerosol production and the transmission of the severe acute respiratory syndrome coronavirus 2 virus during dental procedures. Because of the abrupt arrival of COVID-19, there has been little to no published research on the efficacy of dental suction devices in the removal of aerosols related to COVID-19 or the impact extraoral suction devices have on patients' experiences. Therefore, the aim of this study was to measure the amount of aerosol produced during endodontic access preparation for root canal therapy with and without the use of an extraoral dental suction device and to gather information through a survey regarding patients' experiences. METHODS: Aerosol measurements were recorded in 8 closed-door resident operatories each morning before the procedures, 1 minute during the procedure, and 15 minutes after the access was complete. The CICADA DTO KN99 Extraoral Dental Suction Device (Foshan Cicada, Guangdong, China) was placed in 4 operatories, whereas no DTO extraoral suction device was used in 4 control operatories. Twenty cases with DTO and 20 cases without it were completed, and the data were analyzed. RESULTS: Aerosols 1 minute after access were higher with and without DTO. There was a significant reduction after 15 minutes when the DTO device was used compared to high-volume suction alone. Composite and zirconia produced the most aerosols at 1 minute. CONCLUSION: The results show that the reduction of aerosols is enhanced when the extraoral suction device is used in combination with traditional high-volume evacuation. However, the increased noise level when using the device can have a negative impact on patients' dental experience.

Prevention of submicron aerosolized particle dispersion: evaluation of an aerosol box using a pediatric simulation model.

Background and Aim: The SplashGuard CG (SG) is a barrier enclosure developed to protect healthcare workers from SARS-CoV-2 transmission during aerosol-generating procedures. Our objective was to evaluate the protection provided by the SG against aerosolized particles (AP), using a pediatric simulation model of spontaneous ventilation (SV) and noninvasive ventilation (NIV). Methods: An aerosol generator was connected to the airways of a pediatric high-fidelity manikin with a breathing simulator. AP concentrations were measured both in SV and NIV in the following conditions: with and without SG, inside and outside the SG, with and without suction applied to the device. Results: In the SV simulated setting, AP peaks were lower with SG: 0.1 × 105 particles/L compared to without: 1.6 × 105, only when the ports were closed and suction applied. In the NIV simulated setting, AP peaks outside the SG were lower than without SG (20.5 × 105 particles/L), whatever the situation, without suction (14.4 × 105particles/L), with suction and ports open or closed: 10.3 and 0.7 × 105 particles/L. In SV and NIV simulated settings, the AP peaks measured within the SG were much higher than the AP peaks measured without SG, even when suction was applied to the device. Conclusions: The SG seems to decrease peak AP exposure in the 2 ventilation contexts, but only with closed port and suction in SV. However, high concentrations of AP remain inside even with suction and SG should be used cautiously.

Simulated and clinical aerosol spread in common periodontal aerosol-generating procedures.

OBJECTIVES: This study evaluated particle spread associated with various common periodontal aerosol-generating procedures (AGPs) in simulated and clinical settings. MATERIALS AND METHODS: A simulation study visualized the aerosols, droplets, and splatter spread with and without high-volume suction (HVS, 325 L/min) during common dental AGPs, namely ultrasonic scaling, air flow prophylaxis, and implant drilling after fluorescein dye was added to the water irrigant as a tracer. Each procedure was repeated 10 times. A complementary clinical study measured the spread of contaminated particles within the dental operatory and quantified airborne protein dispersion following 10 min of ultrasonic supragingival scaling of 19 participants during routine periodontal treatment. RESULTS: The simulation study data showed that air flow produced the highest amount of splatters and the ultrasonic scaler generated the most aerosol and droplet particles at 1.2 m away from the source. The use of HVS effectively reduced 37.5-96% of splatter generation for all three dental AGPs, as well as 82-93% of aerosol and droplet particles at 1.2 m for the ultrasonic scaler and air polisher. In the clinical study, higher protein levels above background levels following ultrasonic supragingival scaling were detected in fewer than 20% of patients, indicating minimal particle spread. CONCLUSIONS: While three common periodontal AGPs produce aerosols and droplet particles up to at least 1.2 m from the source, the use of HVS is of significant benefit. Routine ultrasonic supragingival scaling produced few detectable traces of salivary protein at various sites throughout the 10-min dental operatory. CLINICAL RELEVANCE: The likelihood of aerosol spread to distant sites during common periodontal AGPs is greatly reduced by high-volume suction. Clinically, limited evidence of protein contaminants was found following routine ultrasonic scaling, suggesting that the the majority of the contamination consisits of the irrigant rather than organic matter from the oral cavity.

Aerosol exposure of staff during dental treatments: a model study.

BACKGROUND: Due to exposure to potentially infectious aerosols during treatments, the dental personnel is considered being at high risk for aerosol transmitted diseases like COVID-19. The aim of this study was to evaluate aerosol exposure during different dental treatments as well as the efficacy of dental suction to reduce aerosol spreading. METHODS: Dental powder-jet (PJ; Air-Flow®), a water-cooled dental handpiece with a diamond bur (HP) and water-cooled ultrasonic scaling (US) were used in a simulation head, mounted on a dental unit in various treatment settings. The influence of the use of a small saliva ejector (SE) and high-volume suction (HVS) was evaluated. As a proxy of aerosols, air-born particles (PM10) were detected using a Laser Spectrometer in 30 cm distance from the mouth. As control, background particle counts (BC) were measured before and after experiments. RESULTS: With only SE, integrated aerosol levels [median (Q25/Q75) µg/m3 s] for PJ [91,246 (58,213/118,386) µg/m3 s, p < 0.001, ANOVA] were significantly increased compared to BC [7243 (6501/8407) µg/m3 s], whilst HP [11,119 (7190/17,234) µg/m3 s, p > 0.05] and US [6558 (6002/7066) µg/m3 s; p > 0.05] did not increase aerosol levels significantly. The use of HVS significantly decreased aerosol exposure for PJ [37,170 (29,634/51,719) µg/m3 s; p < 0.01] and HP [5476 (5066/5638) µg/m3 s; p < 0.001] compared to SE only, even reaching lower particle counts than BC levels for HP usage (p < 0.001). CONCLUSIONS: To reduce the exposure to potentially infectious aerosols, HVS should be used during aerosol-forming dental treatments.

Congestion in the tube: air trapping in a ventilated patient with COVID-19 secondary to mucinous valves.

A woman in her 50s was admitted to the intensive therapy unit with acute hypoxaemic respiratory failure secondary to COVID-19 pneumonitis. The patient was intubated on admission and worsening gas exchange necessitated multiple rounds of proning . She later improved, and her ventilation was switched to spontaneous mode. However, the patient started to develop air trapping with subsequent respiratory and cardiovascular compromise. Routine investigations showed no clear cause for her sudden deterioration and a suction catheter passed easily through the endotracheal tube. Bronchoscopy revealed mucinous/phlegmatic membranes had developed across the inner diameter of the endotracheal tube. This had created a one-way valve that allowed positive pressure ventilation through the tube into her lungs but only allowed a fraction of air to passively escape in expiration. This case report highlights a less commonly regarded complication associated with long-term intubation and lack of circuit humidification in the context of productive lung pathology.

Effectiveness of barrier devices, high-volume evacuators, and extraoral suction devices on reducing dental aerosols for the dental operator: A pilot study.

BACKGROUND: The COVID-19 pandemic has increased the importance of minimizing exposure to aerosols generated during dental procedures. The authors' objective was to measure the aerosolized particles in the breathing zone of operators using several facial protection and filtration methods. METHODS: Twenty-one dentists performed maxillary anterior incisor veneer preparations using a microscope and drape and loupes with or without a face shield. In each test condition, the following 3 levels of filtration were tested: no filtration, a high-volume evacuator [HVE], and an HVE with an extraoral suction device. Measurements were made using a mass monitor attached to the operator's chest with inlet within 10 inches of the operator's face. RESULTS: The authors found that the microscope and drape provided the lowest levels of aerosolized particles compared with loupes with or without a face shield (P < .001). There was no detectable difference in the concentration of particles between operators wearing a face shield and wearing loupes alone (P = .47). The particles in each test condition were lowered when an HVE was used (P < .001) and further lowered with an extraoral suction device. CONCLUSIONS: The findings of this study suggest that the use of a surgical microscope and bag barrier drape, HVE, and extraoral suction device result in the lowest concentration of aerosolized particles. The face shield did not appear to offer any protection from aerosolized particles. HVE and extraoral suction were effective in decreasing aerosols regardless of the type of facial protection used. PRACTICAL IMPLICATIONS: Dentists can reduce exposure to aerosols with a drape, HVE, and extraoral suction.

Reduction of aerosols and splatter generated during ultrasonic scaling by adding food-grade thickeners to coolants: an in-vitro study.

OBJECTIVE: The effectiveness of using food-grade coolant thickener solutions on the amount of aerosols generated and splatter contamination spread distance during simulated ultrasonic scaling was examined. MATERIALS AND METHODS: The study was performed using a phantom lower jaw placed on a black box. Simulated ultrasonic scaling was performed for 2 min using four coolant solutions: distilled water (control), 2% wt. polyacrylic acid (PAA), 0.4% wt. xanthan gum (XA), and 0.4% wt. carboxymethyl cellulose (CMC). The simulation was repeated 10 times for each coolant group. The generated aerosols and droplets were quantified using a handheld particle counter, and the splatter contamination spread distance was evaluated by adding tracing fluorescent dye to the coolant reservoir supplying the scaler unit. One-way multivariate analysis of variance was performed to determine the difference among coolant groups (a = .05). RESULTS: The amount of aerosols and droplets and splatter contamination distance (p < .001) pertaining to the three food-grade coolant thickener solutions were considerably lower than those for the distilled water (control). The PAA group exhibited a significantly lower splatter contamination distance (p < .001) and a number of generated droplets (p = .031) than those of the XA group. The CMC group exhibited a significantly lower splatter contamination distance (p < .001) than that of the XA group. No statistically significant difference was observed between the PAA and CMC in terms of the three dependent variables (p > .05). CONCLUSION: The food-grade coolant thickeners could reduce the amount of generated aerosols and splatter contamination distance but not completely eliminate them. PAA and CMC solutions were more effective in reducing the aerosol/splatter during scaling compared to XA. CLINICAL RELEVANCE: Many dental procedures generate aerosols and splatter, which pose a potential risk to the patients and dental personnel, especially during the current COVID-19 pandemic.

Novel suction-based in vivo cutaneous DNA transfection platform.

This work reports a suction-based cutaneous delivery method for in vivo DNA transfection. Following intradermal Mantoux injection of plasmid DNA in a rat model, a moderate negative pressure is applied to the injection site, a technique similar to Chinese báguàn and Middle Eastern hijama cupping therapies. Strong GFP expression was demonstrated with pEGFP-N1 plasmids where fluorescence was observed as early as 1 hour after dosing. Modeling indicates a strong correlation between focal strain/stress and expression patterns. The absence of visible and/or histological tissue injury contrasts with current in vivo transfection systems such as electroporation. Specific utility was demonstrated with a synthetic SARS-CoV-2 DNA vaccine, which generated host humoral immune response in rats with notable antibody production. This method enables an easy-to-use, cost-effective, and highly scalable platform for both laboratorial transfection needs and clinical applications for nucleic acid­based therapeutics and vaccines.

In Vivo Study of Aerosol, Droplets and Splatter Reduction in Dentistry.

Oral health care workers (OHCW) are exposed to pathogenic microorganisms during dental aerosol-generating procedures. Technologies aimed at the reduction of aerosol, droplets and splatter are essential. This in vivo study assessed aerosol, droplet and splatter contamination in a simulated clinical scenario. The coolant of the high-speed air turbine was colored with red concentrate. The red aerosol, droplets and splatter contamination on the wrists of the OHCW and chests of the OHCW/volunteer protective gowns, were assessed and quantified in cm2. The efficacy of various evacuation strategies was assessed: low-volume saliva ejector (LV) alone, high-volume evacuator (HV) plus LV and an extra-oral dental aerosol suction device (DASD) plus LV. The Kruskal-Wallis rank-sum test for multiple independent samples with a post-hoc test was used. No significant difference between the LV alone compared to the HV plus LV was demonstrated (p = 0.372059). The DASD combined with LV resulted in a 62% reduction of contamination of the OHCW. The HV plus LV reduced contamination by 53% compared to LV alone (p = 0.019945). The DASD demonstrated a 50% reduction in the contamination of the OHCWs wrists and a 30% reduction in chest contamination compared to HV plus LV. The DASD in conjunction with LV was more effective in reducing aerosol, droplets and splatter than HV plus LV.

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

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.

Dissemination of Aerosol and Splatter in Clinical Environment during Cavity Preparation: An In Vitro Study.

Dental health care workers around the world are in a constant state of fear and anxiety because they work in a constrained space of the dental practice. During routine dental procedures, they are exposed to aerosol and splatter. These airborne particles pose a great risk of transmitting contagious infections to health care workers and patients, especially in an era of social distancing due to COVID-19. The current study was conducted to evaluate contamination amount, duration, the distance of aerosol, and splatter produced after cavity preparation using a two-hole and four-hole handpiece. The study was performed on a dental manikin in a dental simulation laboratory at the College of Dentistry, King Faisal University Al Ahsa. The dental manikin was set to a reclined position to simulate the clinical operatory position of the patient for dental restorative procedures. Aerosol and splatter were collected on Grade 1 qualitative cotton cellulose filter paper. These were placed on adhesive tape extending from the headrest of the dental manikin in six different directions (2, 4, 6, 8, 10, and 12 o'clock) for up to 60 inches and on certain positions of the operator and assistant such as the chest, head, forearms, upper leg, and inside facemask. Class V cavity preparation was done by the principal investigator at a specific time of 3 min on tooth #11 using a two-hole high-speed handpiece, then on the next day, Class V cavity preparation was performed on tooth #21 by a four-hole handpiece. High volume suction was used throughout the cavity preparation. Immediately after cavity preparation, the first filter paper disc was replaced with new ones in all positions. The second set of filter papers was removed after 30 min. Transparent grids were used to count the contamination area on the filter paper disc. No statistically significant difference was found in the mean amount of aerosol and splatter produced by both handpieces, however, a statistically significant difference was found in an amount of aerosol and splatter produced at a 12, 24, and 36 inches distance immediately after cavity preparation and 30 min after cavity preparation, regardless of the type of handpiece used. It is advisable to refrain from removing the personal protective barriers immediately after the procedure within the vicinity of the dental practice. The use of other adjuncts such as high volume suction to reduce the spread of aerosol and splatter is also recommended.

Aerosol Generation During Laryngology Procedures in the Operating Room.

OBJECTIVE: Severe acute respiratory syndrome coronavirus-2 spreads through respiratory fluids. We aim to quantify aerosolized particles during laryngology procedures to understand their potential for transmission of infectious aerosol-based diseases. STUDY DESIGN: Prospective quantification of aerosol generation. METHODS: Airborne particles (0.3-25 µm in diameter) were measured during live-patient laryngology surgeries using an optical particle counter positioned 60 cm from the oral cavity to the surgeon's left. Measurements taken during the procedures were compared to baseline concentrations recorded immediately before each procedure. Procedures included direct laryngoscopy with general endotracheal anesthesia (GETA), direct laryngoscopy with jet ventilation, and carbon dioxide (CO2 ) laser use with or without jet ventilation, all utilizing intermittent suction. RESULTS: Greater than 99% of measured particles were 0.3 to 1.0 µm in diameter. Compared to baseline, direct laryngoscopy was associated with a significant 6.71% increase in cumulative particles, primarily 0.3 to 1.0 µm particles (P < .0001). 1.0 to 25 µm particles significantly decreased (P < .001). Jet ventilation was not associated with a significant change in cumulative particles; when analyzing differential particle sizes, only 10 to 25 µm particles exhibited a significant increase compared to baseline (+42.40%, P = .002). Significant increases in cumulative particles were recorded during CO2 laser use (+14.70%, P < .0001), specifically in 0.3 to 2.5 µm particles. Overall, there was no difference when comparing CO2 laser use during jet ventilation versus GETA. CONCLUSIONS: CO2 laser use during laryngology surgery is associated with significant increases in airborne particles. Although direct laryngoscopy with GETA is associated with slight increases in particles, jet ventilation overall does not increase particle aerosolization. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2759-2765, 2021.

COVID-19: dental aerosol contamination in open plan dental clinics and future implications.

Study design An experimental study design was used to investigate the spread of splatter/aerosol during simulated dental procedures on a mannequin in open plan clinic and dental clinical teaching laboratory settings. All experiments were based on crown preparation of an artificial maxillary central incisor using a high-speed air turbine over a ten-minute period. Fluorescein dye was introduced into the irrigation system of the handpiece (model 1) and the mannequin's mouth was used to simulate salivary flow (model 2) under varying experimental conditions (suction flow rate, cross ventilation and exposure time). Six experiments were conducted in the open plan clinic while three experiments were undertaken in the clinical laboratory. Customised rigs with collection platforms consisting of filter papers were placed in open plan bays and adjacent walkways. Samples were also collected from a 400 cm2 area in each of the eight adjacent bays. Time course experiments repeated the same procedures on three occasions in a clinical laboratory and utilised a rig with eight four-metre rods supporting collection platforms around a dental mannequin. The distribution of fluorescein dye was analysed by fluoroscopy and spectrofluorometry.Results Contamination levels showed variations under different experimental conditions. In the absence of suction and cross ventilation, contamination was observed at large distances. Use of suction reduced contamination in the operating bay by 53% and 81.83%, while cross ventilation reduced contamination in adjacent and distant areas by 80-89%. Minimal contamination was detected at a distance of >5 m from the operating bay, with the use of medium-volume suction demonstrating that 1.5-metre-high partitions with open fronts limit 99.99% of splatter from aerosol generating procedures (AGPs) to the operating bay. Minimal additional aerosol contamination was detected ten minutes after the procedure.Conclusions Contamination from dental AGPS has the potential to contaminate distant sites in open plan clinics. Risk of cross infection is small if the bays are >5 m apart and contamination can be minimised with the use of suction and cross ventilation.