Dental Aerosols Research Articles

Are aerosol control devices effective in preventing the spread of dental aerosol?

BackgroundIn dental clinics, aerosols produced from dental instruments have become a matter of concern following breakout of coronavirus disease 19 (COVID-19) evolving into a pandemic. This study compared aerosol reduction systems and in terms of their ability to reduce Enterococcus faecalis (E. faecalis) contaminated aerosol in a simulated dental office set-up.MethodsClosed clinic model with manikin and mandibular molar typodont was simulated. For 10 min, the air and water dispersed by the rotating bur mounted on an aerator was contaminated by pouring the suspension containing 1–3 × 108 CFU/mL E. faecalis directly on the bur. During and after the procedures, the air within the cabin was also sampled. CFU count was recorded and scored. The mean CFU scores obtained from agar plate count and air sampling device was compared using Kruskal–Wallis H test among groups with 5% significance threshold.ResultsThe use of WS Aerosol Defender device led to greater CFU scores on the agars levelled to patient’s chest compared to other directions (p = 0.001). Combined use of VacStation and WS Aerosol Defender resulted in significantly decreased CFU score in the air samples compared to experimental and positive control groups (p = 0 < 0.05).ConclusionsAlthough the devices prevented the spread of aerosol around the patient to some extent, they could not completely eliminate the contaminated aerosol load in the cabin environment.

Efficacy of Combining an Extraoral High-Volume Evacuator with Preprocedural Mouth Rinsing in Reducing Aerosol Contamination Produced by Ultrasonic Scaling.

The coronavirus disease pandemic has afforded dental professionals an opportunity to reconsider infection control during treatment. We investigated the efficacy of combining extraoral high-volume evacuators (eHVEs) with preprocedural mouth rinsing in reducing aerosol contamination by ultrasonic scalers. A double-masked, two-group, crossover randomized clinical trial was conducted over eight weeks. A total of 10 healthy subjects were divided into two groups; they received 0.5% povidone-iodine (PI), essential oil (EO), or water as preprocedural rinse. Aerosols produced during ultrasonic scaling were collected from the chest area (PC), dentist’s mask, dentist’s chest area (DC), bracket table, and assistant’s area. Bacterial contamination was assessed using colony counting and adenosine triphosphate assays. With the eHVE 10 cm away from the mouth, bacterial contamination by aerosols was negligible. With the eHVE 20 cm away, more dental aerosols containing bacteria were detected at the DC and PC. Mouth rinsing decreased viable bacterial count by 31–38% (PI) and 22–33% (EO), compared with no rinsing. The eHVE prevents bacterial contamination when close to the patient’s mouth. Preprocedural mouth rinsing can reduce bacterial contamination where the eHVE is positioned away from the mouth, depending on the procedure. Combining an eHVE with preprocedural mouth rinsing can reduce bacterial contamination in dental offices.

DENTAL AEROSOLS SHOULD NOT BE IGNORED DURING THE COVID-19 PANDEMIC UNTIL PROVEN OTHERWISE.

Article Title and Bibliographic InformationMeethil AP, Saraswat S, Chaudhary PP, Dabdoub SM, Kumar PS. Sources of SARS-CoV-2 and other microorganisms in dental aerosols. J Dent Res 2021;100(8);817–23. doi: 10.1177/00,220,345,211,015,948.Source of FundingThe authors reported that no external funding sources directly supported this study.Type of Study/DesignExperimental research.

Particle Size, Mass Concentration, and Microbiota in Dental Aerosols

Many dental procedures are considered aerosol-generating procedures that may put the dental operator and patients at risk for cross-infection due to contamination from nasal secretions and saliva. This aerosol, depending on the size of the particles, may stay suspended in the air for hours. The primary objective of the study was to characterize the size and concentrations of particles emitted from 7 different dental procedures, as well as estimate the contribution of the nasal and salivary fluids of the patient to the microbiota in the emitted bioaerosol. This cross-sectional study was conducted in an open-concept dental clinic with multiple operators at the same time. Particle size characterization and mass and particle concentrations were done by using 2 direct reading instruments: Dust-Trak DRX (Model 8534) and optical particle sizer (Model 3330). Active bioaerosol sampling was done before and during procedures. Bayesian modeling (SourceTracker2) of long-reads of the 16S ribosomal DNA was used to estimate the contribution of the patients’ nasal and salivary fluids to the bioaerosol. Aerosols in most dental procedures were sub-PM1 dominant. Orthodontic debonding and denture adjustment consistently demonstrated more particles in the PM1, PM2.5, PM4, and PM10 ranges. The microbiota in bioaerosol samples were significantly different from saliva and nasal samples in both membership and abundance (P < 0.05) but not different from preoperative ambient air samples. A median of 80.15% of operator exposure was attributable to sources other than the patients’ salivary or nasal fluids. Median operator’s exposure from patients’ fluids ranged from 1.45% to 2.75%. Corridor microbiota showed more patients’ nasal bioaerosols than oral bioaerosols. High-volume saliva ejector and saliva ejector were effective in reducing bioaerosol escape. Patient nasal and salivary fluids are minor contributors to the operator’s bioaerosol exposure, which has important implications for COVID-19. Control of bioaerosolization of nasal fluids warrants further investigation.

Efficacy of Aerosol Reduction Measures for Dental Aerosol Generating Procedures.

Aerosol particles generated by dental procedures could facilitate the transmission of infectious diseases and contain carcinogen particles. Such particles can penetrate common surgical masks and reach the lungs, leading to increased risk for dental care professionals. However, the risk of inhaling contaminated aerosol and the effectiveness of aerosol reduction measures in dental offices remain unclear. The present study aimed to quantify aerosols produced by drilling and scaling procedures and to evaluate present recommendations for aerosol reduction. The concentration of aerosol particles released from the mock scaling and drilling procedures on dental mannequin were measured using a TSI Optical Particle Sizer (OPS 3330) during 15-min sessions carried out in a single-patient examination room. Using a drilling procedure as the aerosol source, the aerosol reduction performance of two types of high-volume evacuators (HVEs) and a commercial off-the-shelf air purifier was evaluated in a simulated clinical setting. Using either HVEs or the air purifier individually reduced the aerosol accumulated over the course of a 15-minutes drilling procedure at a reduction rate of 94.8 to 97.6%. Using both measures simultaneously raised the reduction rate to 99.6%. The results show that existing HVEs can effectively reduce aerosol concentration generated by a drilling procedure and can be further improved by using an air purifier. Following current regulatory guidelines can ensure a low risk of inhaling contaminated aerosol for dentists, assistants, and patients.

Redefining aerosol in dentistry during COVID-19 pandemic

The corona virus malady 2019 (COVID-19) pandemic has rekindled the well established argument regarding the role of dental aerosol in transference of severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). Aerosols and droplets are generated amid innumerable dental procedures. With the commencement of the COVID-19 pandemic droplet, a review of the infection/disease control strategies for aerosols is required. We do not know where this pandemic is directed. We do not have conclusive evidence for an optimal management strategy. Every day brings in varying information, so recognizing the hazard created by aerosols will help diminish the probability of infection transfer at the time of dental procedures. Hence, the author assessed the evidence-based medical and dental literature in relation to "aerosol' that documented the source of transmission of aerosol through various potential routes, addressed the risk potential to patients and the dental team, and assessed the additional measures that might minimize the viral transmission if regularly adopted. In this article, the author evaluated and compiled dental guidelines by various countries and various health-care associations in context to aerosol-generating procedures and has made recommendations for the restriction of dental aerosols and splatter in routine dental practice.

Comparison of Chlorhexidine and Hydrogen Peroxide as Preprocedural Mouthrinse during Ultrasonic Scaling: A Triple-Blinded Randomized Controlled Clinical Trial.

Background:Every year, around 2 million people suffer from hospital-acquired infections worldwide. Aerosols are produced while performing ultrasonic scaling. They are potential source of infection and cross contamination. It can result in spread of several infections including hepatitis, HIV, SARS CoV 2, etc. Preprocedural rinse before scaling is considered an effective measure to reduce the microbial load in aerosols.Materials and Methods:This study was a triple-blinded randomized controlled trial performed on 90 participants diagnosed with chronic periodontitis. Random allocation of participants into three groups, i.e., Group-1, Group-2, and Group-3, was done, wherein 0.12% chlorhexidine (CHX), 1.5% hydrogen peroxide (HP), and distilled water (DW) were used, respectively, as preprocedural mouthrinse. The participants of each group were instructed to perform mouthrinse for 60 s before the start of ultrasonic scaling sessions. Blood agar plates were kept at three locations, i.e., operator's chest area, patient's chest area, and assistant's chest area for aerosol collection after scaling. Colony-forming units (CFUs) were counted for microbiological analysis.Results:Least number of CFUs was found in the CHX group, followed by HP and DW groups. Location wise, the patient's chest area had the highest CFU count and the least was at the assistant's chest area. CFU count between the groups was statistically significant.Conclusion:Preprocedural rinse using HP can effectively be used as a method to reduce dental aerosols generated during ultrasonic scaling.

Comparison of an Air-Fed Mask System with Hospital-Issued Personal Protection Equipments for Dental Aerosol Protection During the COVID-19 Pandemic

Aim: A pilot study was conducted with the aim of developing a system to protect the eyes, nose, and mouth from the aerosol generated from a high-speed dental handpiece during the COVID-19 pandemic. Background: The SARS-CoV-2 virus is known to be present in the saliva of an infected individual during the contagious viral shedding phase of the disease. The use of rotary dental instruments places oral health practitioners at risk of contracting COVID-19 from infected individuals. In particular, it is very difficult to protect the mucous membranes of the face against the extremely fine aerosol produced from a high-speed dental handpiece. Objectives: This study aimed to develop and test a novel PPE system for use during the COVID-19 pandemic. An air-fed spray-painting mask was used under a plastic hood to protect against the aerosol from a high-speed dental handpiece. This was found to be superior compared to hospital-issued N-95 masks and eye protection in our test model. Methods: Subjects donned various forms of PPE whilst using a high-speed dental handpiece in a confined cubicle. The efficacy of each form of PPE was evaluated by adding fluorescein to the water coolant supply line of a high-speed dental handpiece before checking for facial contamination with an ophthalmology slit lamp. Results: Under our test conditions, the N-95 mask did not prevent nasal and mouth contaminations, but the combination of an air-fed mask with a sealed hood prevented these contaminations. Although goggles worn tightly did prevent contamination, the air-fed mask system was far more comfortable and did not fog up. Discussion: Under the rigorous test conditions of our model, we found hospital-issued PPE ineffective. We also found the single strategy of using positive airflow into a face mask ineffective, even with extremely high levels of airflow. Complete protection was only achieved reliably by the combination of physically sealing off the face from the surrounding airspace and using the air-fed system to provide an external source of air to breathe. We effectively made the clinical equivalent of a dive bell helmet. The air-fed mask is supplied by a standard dental air compressor and is simple to install for someone familiar with the technical aspects of compressors. The compressor does not rely on a filter and proves effective with cheap and easily accessible disposable items. Conclusion: Under rigorous testing conditions, the developed air-fed mask system with a sealed hood on low flow performed better than hospital-issued PPE against high-speed dental aerosol protection. The developed system protects the operators from the air of the room contaminated with aerosol and brings in safe air from the outside for them to breathe.

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

BackgroundThe 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. MethodsTwenty-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. ResultsThe 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. ConclusionsThe 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 ImplicationsDentists can reduce exposure to aerosols with a drape, HVE, and extraoral suction.

A Review of Current Literature of Interest to the Office-Based Anesthesiologist

A Review of Current Literature of Interest to the Office-Based Anesthesiologist

Local Exhaust Ventilation to Control Dental Aerosols and Droplets

Dental procedures produce aerosols that may remain suspended and travel significant distances from the source. Dental aerosols and droplets contain oral microbes, and there is potential for infectious disease transmission and major disruption to dental services during infectious disease outbreaks. One method to control hazardous aerosols often used in industry is local exhaust ventilation (LEV). The aim of this study was to investigate the effect of LEV on aerosols and droplets produced during dental procedures. Experiments were conducted on dental mannequins in an 825.4-m3 open-plan clinic and a 49.3-m3 single surgery. Ten-minute crown preparations were performed with an air-turbine handpiece in the open-plan clinic and 10-min full-mouth ultrasonic scaling in the single surgery. Fluorescein was added to instrument irrigation reservoirs as a tracer. In both settings, optical particle counters (OPCs) were used to measure aerosol particles between 0.3 and 10.0 µm, and liquid cyclone air samplers were used to capture aerosolized fluorescein tracer. In addition, in the open-plan setting, fluorescein tracer was captured by passive settling onto filter papers in the environment. Tracer was quantified fluorometrically. An LEV device with high-efficiency particulate air filtration and a flow rate of 5,000 L/min was used. LEV reduced aerosol production from the air-turbine handpiece by 90% within 0.5 m, and this was 99% for the ultrasonic scaler. OPC particle counts were substantially reduced for both procedures and air-turbine settled droplet detection reduced by 95% within 0.5 m. The effect of LEV was substantially greater than suction alone for the air-turbine and was similar to the effect of suction for the ultrasonic scaler. LEV reduces aerosol and droplet contamination from dental procedures by at least 90% in the breathing zone of the operator, and it is therefore a valuable tool to reduce the dispersion of dental aerosols.

Self Prepared Herbal Mouthwash Used As Pre-procedural Rinse in Reducing Dental Aerosol: A Substitute to Chemical Mouthrinse: A Clinico-Microbiological Study

Aim:To evaluate and compare the efficacy of pre-procedural mouth rinses in reducing microbial content of aerosol product during ultrasonic-scaling procedures by viable bacterial count.Materials And Methods:5 patients were assigned in each group: A- Neem, B -CHX, C-Triphala, D - Control Group.In Group A, B, C -Patient were asked to rinse their mouth with 10 ml mouthwash for 30 seconds before SRP, of which A and C are self- prepared herbal mouthwashes i.e Triphala and Neem. Aerosol will be collected, cultured and incubated on blood agar plates at specified sites from operator. CFU will be counted and result will be assessed statistically. Conclusion: The study suggests that 10 ml of Neem Mouth rinse when used 10 minutes prior to ultrasonic scaling is more potent in reducing the aerosol contamination as compared to the Triphala mouth rinse and commercially available 0.2 % Chlorhexidine mouthrinse. Also the reduction in aerosol content was seen in Tray location when rinsed with CHX and aerosol reduction in Spitoon and Chest location while rinsing with Neem mouthrinse.

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.

English

BACKGROUND The objective of the study was to determine the efficacy of Triphala as a preprocedural mouth rinse &amp; comparing the efficacy with chlorhexidine and betadine in reducing the viable microbial load in dental aerosols. METHODS 32 patients with chronic periodontitis were randomly allocated into 4 groups (A, B, C &amp; D) of 8 patients each who received 0.2 % chlorhexidine (CHX), 6 % Triphala (TRP), 2 % betadine and water respectively as a pre-procedural mouth rinse. Blood agar plates were placed on the operator’s chest area and the patient’s chest area for collecting the aerosols. The agar plates were then incubated at 370C for 48 hours and colony-forming units (CFUs) were counted. RESULTS CFU was significantly reduced in groups A, B &amp; C compared to group D. Intergroup comparison showed no significant difference in the efficacy of 0.2 % CHX and 6 % TRP with P-value 0.058 in the operator’s area and with a significant difference of Pvalue 0.014 in the patient’s area. 2 % betadine was found to be least effective among the 3 test groups. The number of CFUs was greater at the patient’s chest area than that of the operator. CONCLUSIONS This study reinforces the importance of preprocedural mouth rinse. Triphala showed near equal efficacy to CHX, which is considered the gold standard in aerosol reduction and also better than 2 % betadine. Therefore, it can be considered as an alternative to CHX as a preprocedural mouth rinse. KEY WORDS Triphala, Chlorhexidine, Betadine, Aerosols, Colony Forming Units (CFUs)

In Situ Measurement of Airborne Particle Concentration in a Real Dental Office: Implications for Disease Transmission

Aerosols generated during dental procedures are one of the most significant routes for infection transmission and are particularly relevant now in the context of COVID-19 pandemic. This study aimed to assess the effectiveness of an indoor air purifier on dental aerosol dispersion in dental offices. The spread and removal of aerosol particles generated from a specific dental operation in a dental office are quantified for a single dental activity in the area near the generation and corner of the office. The effects of the air purifier, door condition, and particle sizes on the spread and removal of particles were investigated. The results show that, in the worst-case scenario, it takes 95 min for 0.5-μm particles to settle and that it takes a shorter time for the larger particles. The air purifier expedited the removal time at least 6.3 times faster than the case with no air purifier in the generation zone. Our results also indicate that particles may be transported from the source to the rest of the room even when the particle concentrations in the generation zone dropped back to the background. Therefore, it is inaccurate to conclude that indoor purifiers help reduce the transmission of COVID-19. Dental offices still need other methods to reduce the transmission of viruses.

Fallow time determination in dentistry using aerosol measurement in mechanically and non-mechanically ventilated environments.

Aim To calculate fallow time (FT) required following dental aerosol generating procedures (AGPs) in both a dental hospital (mechanically ventilated) and primary care (non-mechanically ventilated). Secondary outcomes were to identify spread and persistence of aerosol in open clinics compared to closed surgeries (mechanically ventilated environment), and identify if extraoral scavenging (EOS) reduces FT and production of aerosol.Methods In vitro simulation of fast handpiece cavity preparations using a manikin was conducted in a mechanically and non-mechanically ventilated environment using Optical Particle Sizer and NanoScan at baseline, during the procedure and fallow period.Results AGPs carried out in the non-mechanically, non-ventilated environment failed to achieve baseline particle levels after one hour. In contrast, when windows were opened after AGPs, there was an immediate reduction in all particle sizes. In mechanically ventilated environments, the baseline levels of particles were very low and particle count returned to baseline within ten minutes following the AGP. There was no detectable difference between particles in mechanically ventilated open bays and closed surgeries. The effect of the EOS on reducing the particle count was greater in the non-mechanically ventilated environment; additionally, it also reduced the spikes in particle counts in mechanically ventilated environments.Conclusion High-efficiency particulate, air-filtered mechanical ventilation, along with mitigation (high-volume suction), resulted in reduction of fallow time (ten minutes). Non-ventilated rooms failed to reach baseline level even after one hour of fallow time. There was no difference in particle counts in open bays or closed surgeries in mechanically ventilated settings with an extraoral suction device reducing particulate spikes. This study confirms that AGPs are not recommended in dental surgeries where no ventilation is possible.

Mouthwash to defeat COVID-19? –An update

Dental experts work closely with patients and present an expanded danger of individual to-individual transmission of SARS-CoV-2. Also, the utilization of ultrasonic scalers, air-water needles, and moderate and high velocity airoter handpieces, which are regular in the dental office, produce splash and aerosols. The utilization of preprocedural mouthrinses has been proposed to lessen the viral burden in saliva and oropharyngeal tissues, consequently diminishing viral burden in dental aerosols. Although some mouthrinses exhibit an antiviral impact, there is restricted proof about the clinical adequacy of any mouthrinse in the decrease of SARS-CoV-2 in the dental aerosols. Keywords: Covid­ 19, SARS CoV­2, Mouthwash, Preprocedure, Aerosol, Antimicrobial Mouthrinse, Mucormycosis.

Impact of COVID-19 on the sound environment in a dental office - a case study

As of February 2021, COVID-19 has not yet converged globally. Careful countermeasures are required for protecting infection of COVID-19 at dental clinics. Virus particles in saliva are likely to spread outside during dental treatment. Dental staffs must use a variety of personal protective equipment (PPE). In addition, the frequency of using dental aerosol suction devices in the dental office has increased dramatically, and the sound environment in the clinic has changed after taking the measures against COVID-19. In this study, we will report the measurement results of the changes in the sound environment during dental treatment that were perceived by dental healthcare professionals and patients.

COVID-19 and Dentistry: An Updated Overview of Dental Perspectives and a Recommended Protocol for Dental Care and Emergency Dental Treatment

This manuscript aims to provide an overview of the coronavirus disease-2019 (COVID-19) pandemic from dental perspectives, and presents standards and guidelines of dental care provision based on available research in this field as well as clinical experience and practice. The current COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading around the globe and interferes with the provision of dental care for many individuals from different communities and backgrounds. A search for the literature on PubMed, ISI Web of Science, Scopus, EMBASE, and Cochrane Library from March 1, 2020 to December 30, 2020 was conducted. Also, the bibliographies included in the indicated articles were used to identify further literature. Recommendations by health authorities in different countries were also consulted. COVID-19 is causing many fatalities and is disrupting people's daily life and the economy in many countries around the world. Due to the potential of cross-infection through dental treatments, especially dental aerosol generation procedures, the dental profession has been disrupted during this pandemic. Dental care provision has been ceased completely or partially (limited to emergency or urgent treatment) in most countries around the world. Until this pandemic is controlled by new suitable treatments and/or vaccination, there is an urgent need to adopt immediate guidelines and standards for the safe provision of dental care to meet patients' demands, especially for the dental aerosols. Guidelines and standards for dental treatment amidst the COVID-19 pandemic are required. This manuscript provides an overview of the COVID-19 pandemic from dental perspectives and presents standards and guidelines of dental care provision based on available research in this field as well as clinical experience and practice. This manuscript provides guidelines and standards for dental treatment and clinical management within dental settings amidst the COVID-19 pandemic, and resembles part of the quest to set the golden standards for dental care during the current circumstances. How to cite this article: AL-Omiri MK, Al-Shayyab MH, Al Nazeh AA, et al. COVID-19 and Dentistry: An Updated Overview of Dental Perspectives and a Recommended Protocol for Dental Care and Emergency Dental Treatment. J Contemp Dent Pract 2021;22(5):572-586.

Efficacy of Preprocedural Boric Acid Mouthrinse in Reducing Viable Bacteria in Dental Aerosols Produced during Ultrasonic Scaling.

Introduction:Aerosols and droplets contaminated with bacteria and blood are produced during ultrasonic scaling. Measures to control aerosol contamination in dental clinics are recommended by the Centers for Disease Control and Prevention. This study aimed to evaluate the efficacy of preprocedural boric acid (BA) mouthrinse in reducing bacterial contamination in dental aerosols generated during ultrasonic scaling.Materials and Methods:This was a randomised clinical trial in 90 systemically healthy subjects (25-55 yrs) diagnosed with chronic periodontitis who were allocated into three groups of 30 subjects each to receive, Group A - 0.12% chlorhexidine (CHX), Group B - 0.75% BA and Group C-water, as a preprocedural rinse for 1 min. The aerosol generated while performing ultrasonic scaling for 30 min was collected at three locations on blood agar plates. Incubation of the blood agar plates at 37°C for next 48 h for aerobic culture was performed and subsequently colony-forming units (CFUs) were counted.Results:CFUs in Group A were significantly reduced compared with Group B (P < 0.001). When we compare CFUs in all the three groups, CFUs in Groups A and B were statistically significantly reduced compared with Group C (P < 0.001). Furthermore, it was also observed that the assistant's chest area had lowest CFUs whereas patient's chest area had highest.Conclusion:This study recommends routine use of preprocedural mouthrinse as a measure to reduce bacterial aerosols generated during ultrasonic scaling and that 0.12% CHX gluconate is more effective than 0.75% BA mouthwash in reducing CFUs count.