Emerging Trends of ICT in Airborne Disease Prevention

Information and Communication Technologies (ICT) are becoming indispensable nowadays for the healthcare industry. The utilization of ICT in healthcare services has accelerated even faster after the commencement of the COVID-19 outbreak. This study aims to perform a scientometric analysis of scholarly literature on airborne diseases in the discipline of science and technology. It explores the recent advancement of internet technologies in healthcare to control the prevalence of deadly airborne illnesses by applying analytical approaches. It presents publication trends, citation structure, influential sources, co-citation, and co-occurrence network analysis using the CiteSpace tool. It identifies the important research topics, current research hotspots, most active research areas, and leading technologies in this scientific knowledge domain. It inferred significant results from analyses that will benefit researchers and the academic fraternity across the globe to understand the evolving paths and recent scientific progress of ICT in airborne disease management. © 2022 Association for Computing Machinery.

Conceptual Design of a UVC-LED Air Purifier to Reduce Airborne Pathogen Transmission—A Feasibility Study

Existing indoor closed ultraviolet-C (UVC) air purifiers (UVC in a box) have faced technological challenges during the COVID-19 breakout, owing to demands of low energy consumption, high flow rates, and high kill rates at the same time. A new conceptual design of a novel UVC-LED (light-emitting diode) air purifier for a low-cost solution to mitigate airborne diseases is proposed. The concept focuses on performance and robustness. It contains a dust-filter assembly, an innovative UVC chamber, and a fan. The low-cost dust filter aims to suppress dust accumulation in the UVC chamber to ensure durability and is conceptually shown to be easily replaced while mitigating any possible contamination. The chamber includes novel turbulence-generating grids and a novel LED arrangement. The turbulent generator promotes air mixing, while the LEDs inactivate the pathogens at a high flow rate and sufficient kill rate. The conceptual design is portable and can fit into ventilation ducts. Computational fluid dynamics and UVC ray methods were used for analysis. The design produces a kill rate above 97% for COVID and tuberculosis and above 92% for influenza A at a flow rate of 100 L/s and power consumption of less than 300 W. An analysis of the dust-filter performance yields the irradiation and flow fields.

Social Distancing Monitoring and Alerting System using YOLO Deep Learning Algorithm

The Covid-19 disease is caused by the severe acute respiratory (SAR) syndrome coronavirus-2 and becomes the reason for the Global Pandemic since 2019. Until July 2022, the total reported cases were 572 million and reported deaths were 6.38 million around the world. In many countries the infections caused severe damages. It not only took the precious lives but also caused few other national damages like economic crisis. The only solution to stop this pandemic is to increase the vaccination and reducing the spreads. The covid 19 virus is an airborne disease and spread when people breathe virus contaminated air. The WHO and all the nations were insisting to maintain social distance to control the virus spreading. But maintaining the social distance in public places is very hard. In this project we developed a method for detecting social distance. The system uses Raspberry Pi processor to detect the distance between two people from the live video stream. The YOLOv3 technique is used to detect the object from single frame of the video. © 2022 IEEE

Model Evaluation of Secondary Chemistry due to Disinfection of Indoor Air with Germicidal Ultraviolet Lamps

Air disinfection using germicidal ultraviolet light (GUV) has received increasing attention during the COVID-19 pandemic. GUV uses UVC lamps to inactivate microorganisms, but it also initiates photochemistry in air. However, GUV's indoor-air-quality impact has not been investigated in detail. Here, we model the chemistry initiated by GUV at 254 ("GUV254”) or 222 nm ("GUV222”) in a typical indoor setting for different ventilation levels. Our analysis shows that GUV254, usually installed in the upper room, can significantly photolyze O3, generating OH radicals that oxidize indoor volatile organic compounds (VOCs) into more oxidized VOCs. Secondary organic aerosol (SOA) is also formed as a VOC-oxidation product. GUV254-induced SOA formation is of the order of 0.1-1 μg/m3 for the cases studied here. GUV222 (described by some as harmless to humans and thus applicable for the whole room) with the same effective virus-removal rate makes a smaller indoor-air-quality impact at mid-to-high ventilation rates. This is mainly because of the lower UV irradiance needed and also less efficient OH-generating O3 photolysis than GUV254. GUV222 has a higher impact than GUV254 under poor ventilation due to a small but significant photochemical production of O3 at 222 nm, which does not occur with GUV254. © 2022 American Chemical Society.

Variations in classroom ventilation during the COVID-19 pandemic: Insights from monitoring 36 naturally ventilated classrooms in the UK during 2021

Seasonal changes in the measured CO2 levels at four schools are herein presented through a set of indoor air quality metrics that were gathered during the height of the COVID-19 pandemic in the UK. Data from non-intrusive environmental monitoring units were remotely collected throughout 2021 from 36 naturally ventilated classrooms at two primary schools and two secondary schools in England. Measurements were analysed to assess the indoor CO2 concentration and temperature. Relative to UK school air quality guidance, the CO2 levels within classrooms remained relatively low during periods of warmer weather, with elevated CO2 levels being evident during the colder seasons, indicating lower levels of per person ventilation during these colder periods. However, CO2 data from the cold period during the latter part of 2021, imply that the per person classroom ventilation levels were significantly lower than those achieved during a similarly cold weather period during the early part of the year. Given that the classroom architecture and usage remained unchanged, this finding suggests that changes in the ventilation behaviours within the classrooms may have altered, and raises questions as to what may have given rise to such change, in a year when, messaging and public concerns regarding COVID-19 varied within the UK. Significant variations were observed when contrasting data, both between schools, and between classrooms within the same school building;suggesting that work is required to understand and catalogue the existing ventilation provisions and architecture within UK classrooms, and that more work is required to ascertain the effects of classroom ventilation behaviours. © 2022 The Author(s)

Microscopic model on indoor propagation of respiratory droplets.

Indoor propagation of airborne diseases is yet poorly understood. Here, we theoretically study a microscopic model based on the motions of virus particles in a respiratory microdroplet, responsible for airborne transmission of diseases, to understand their indoor propagation. The virus particles are driven by a driving force that mimics force due to gushing of air by devices like indoor air conditioning along with the gravity. A viral particle within the droplet experiences viscous drag due to the droplet medium, force due to interfacial tension at the droplet boundary, the thermal forces and mutual interaction forces with the other viral particles. We use Brownian Dynamics (BD) simulations and scaling arguments to study the motion of the droplet, given by that of the center of mass of the viral assembly. The BD simulations show that in presence of the gravity force alone, the time the droplet takes to reach the ground level, defined by the gravitational potential energy being zero, from a vertical height H,tf∼γ-0.1 dependence, where γ is the interfacial tension. In presence of the driving force of magnitude F0 and duration τ0, the horizontal propagation length, Ymax from the source increase linearly with τ0, where the slope is steeper for larger F0. Our scaling analysis explains qualitatively well the simulation observations and show long-distance transmission of airborne respiratory droplets in the indoor conditions due to F0 ∼ nano-dyne.

NUMERICAL DISPERSION MODELLING OF THE DROPLETS EXPIRED BY HUMANS

Owing to the COVID-19 pandemic, in the last two years the attention of the scientific community has focused on the study of the dispersion of small droplets ejected by humans during different respiratory activities. The properties of the droplets used as input data in numerical simulations and models that forecast the dispersion of the expired particle-laden air cloud are of major importance in order to obtain reliable results. Recent numerical simulations highlighted that a lack of knowledge concerning droplet size and velocity distributions still exists. Indeed, only few works tackled this problem, since it is particularly difficult to measure droplet sizes over a wide range and to measure sizes and velocities simultaneously. Consequently, the droplet velocity is generally assumed to be either zero or equal to the air velocity. In this work, the dispersion of droplets expired by humans have been simulated numerically using as input experimental data collected during two measurement campaigns concerning speaking and coughing. The size and the 3 velocity components of the ejected droplets have been measured simultaneously for particles down to 2 μm using an extended version of the Interferometric Laser Imaging Droplet Sizing technique. © British Crown Copyright (2022)

The Role of HVAC Filters In Reducing Airborne Disease Transmission: A Review

Since 2019, the Coronavirus infection has substantially impacted the worldwide ecosystem. This disease has apparently become airborne and has spread globally. Most daily activities have been curtailed to prevent the spread of the disease. Several measures have been devised by the World Health Organization to control the transmission of disease among humans. However, interior spaces are also crucial because individuals spend most of their time inside. To improve the interior living environment, it is necessary to develop a way to prevent the spread of airborne diseases. To obtain the desired level of efficiency and the requisite level of health for people to stay indoors, it is essential to install an efficient ventilation system. To avoid the transmission of airborne infections in confined areas, the purpose of this work is to examine the impact of the filtering mechanism in a controlled environment provided by Heating, Ventilation, and Air Conditioning (HVAC) systems. According to the study, ventilation, along with MERV13 or above recirculating filters, for instance, must be used (High-Efficiency Particulate Air) This criterion can be met with HEPA or a combination of outside air, filtration, and air-cleaning technology. To reduce the transmission of airborne diseases, the outcome of the study will result in a more effective installation of the mechanism of HVAC systems in interior environments. © 2022, Penerbit Akademia Baru. All rights reserved.

Model Evaluation of Secondary Chemistry due to Disinfection of Indoor Air with Germicidal Ultraviolet Lamps

Air disinfection using germicidal ultraviolet light (GUV) has received increasing attention during the COVID-19 pandemic. GUV uses UVC lamps to inactivate microorganisms, but it also initiates photochemistry in air. However, GUV's indoor-air-quality impact has not been investigated in detail. Here, we model the chemistry initiated by GUV at 254 ("GUV254") or 222 nm ("GUV222") in a typical indoor setting for different ventilation levels. Our analysis shows that GUV254, usually installed in the upper room, can significantly photolyze O3, generating OH radicals that oxidize indoor volatile organic compounds (VOCs) into more oxidized VOCs. Secondary organic aerosol (SOA) is also formed as a VOC-oxidation product. GUV254-induced SOA formation is of the order of 0.1-1 mu g/m3 for the cases studied here. GUV222 (described by some as harmless to humans and thus applicable for the whole room) with the same effective virus-removal rate makes a smaller indoor-air-quality impact at mid-to-high ventilation rates. This is mainly because of the lower UV irradiance needed and also less efficient OH-generating O3 photolysis than GUV254. GUV222 has a higher impact than GUV254 under poor ventilation due to a small but significant photochemical production of O3 at 222 nm, which does not occur with GUV254.

Machine Learning Techniques For Public Health System: A Scientometric Review

Technology development plays a vital role in every aspect of life, whether it is in the medical domain or any other era. In the present scenario, scientists, researchers, and healthcare experts are still looking for a new technology against Air-Borne Disease(ABD) over the world. The use of Artificial Intelligence (AI) has encouraged researchers by providing a modern approach for combating Air-Borne diseases. The current study reviews approximately 145 papers for the literature review that insights AI-based application technology to prevent ABD. For this purpose, the current study discusses ideal epidemiology study, early disease diagnosis, and its progression concerning ABD. Although the reviewed AI application-based methods for ABD control are promising, this review suggests research that integrates ML advances should be done. ML techniques may lead to success in controlling the ABD if these suggestions are implemented. Finally, this study addresses the obstacles and opportunities for future research. © 2022 IEEE.

Variations in classroom ventilation during the COVID-19 pandemic: Insights from monitoring 36 naturally ventilated classrooms in the UK during 2021

Seasonal changes in the measured CO2 levels at four schools are herein presented through a set of indoor air quality metrics that were gathered during the height of the COVID-19 pandemic in the UK. Data from non-intrusive environmental monitoring units were remotely collected throughout 2021 from 36 naturally ventilated classrooms at two primary schools and two secondary schools in England. Measurements were analysed to assess the indoor CO2 concentration and temperature . Relative to UK school air quality guidance, the CO2 levels within classrooms remained relatively low during periods of warmer weather, with elevated CO2 levels being evident during the colder seasons, indicating lower levels of per person ventilation during these colder periods. However, CO2 data from the cold period during the latter part of 2021, imply that the per person classroom ventilation levels were significantly lower than those achieved during a similarly cold weather period during the early part of the year. Given that the classroom architecture and usage remained unchanged, this finding suggests that changes in the ventilation behaviours within the classrooms may have altered, and raises questions as to what may have given rise to such change, in a year when, messaging and public concerns regarding COVID-19 varied within the UK. Significant variations were observed when contrasting data, both between schools, and between classrooms within the same school building;suggesting that work is required to understand and catalogue the existing ventilation provisions and architecture within UK classrooms, and that more work is required to ascertain the effects of classroom ventilation behaviours.

Mucin Transiently Sustains Coronavirus Infectivity through Heterogenous Changes in Phase Morphology of Evaporating Aerosol.

Respiratory pathogens can be spread though the transmission of aerosolised expiratory secretions in the form of droplets or particulates. Understanding the fundamental aerosol parameters that govern how such pathogens survive whilst airborne is essential to understanding and developing methods of restricting their dissemination. Pathogen viability measurements made using Controlled Electrodynamic Levitation and Extraction of Bioaerosol onto Substrate (CELEBS) in tandem with a comparative kinetics electrodynamic balance (CKEDB) measurements allow for a direct comparison between viral viability and evaporation kinetics of the aerosol with a time resolution of seconds. Here, we report the airborne survival of mouse hepatitis virus (MHV) and determine a comparable loss of infectivity in the aerosol phase to our previous observations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Through the addition of clinically relevant concentrations of mucin to the bioaerosol, there is a transient mitigation of the loss of viral infectivity at 40% RH. Increased concentrations of mucin promoted heterogenous phase change during aerosol evaporation, characterised as the formation of inclusions within the host droplet. This research demonstrates the role of mucus in the aerosol phase and its influence on short-term airborne viral stability.

Study of ventilation and virus propagation in an urban bus induced by the HVAC and by opening of windows

The external and internal airflow and air renewal inside urban buses have taken especial relevance since the COVID-2 pandemic. Computational fluid dynamics (CFD) simulations, which focus on the estimation of indoor airflow are not conclusive about the impact of using Heat, Ventilation and Air Conditioning (HVAC) systems on diseases’ transmission risk while travelling with open windows has shown to be a good strategy to renew the indoor air. In order to estimate the COVID-2 airborne transmission by aerosols, a real urban bus was simulated by CFD. Twenty passengers (containing the driver) were included in the model with a typical inhalation–exhalation breathing cycle. The concentrations of air exhaled by ten of them were tracked during 30 min using Eulerian scalar tracer, and the concentrations inhaled by the twenty passengers were monitored. Then, the well-known Wells & Riley risk model was applied in order to estimate the cumulative inhaled viruses and the subsequent transmission risk. Four scenarios were considered: HVAC off with closed windows (Case 1), HVAC on with closed windows and 100% of air recirculation (Case 2), HVAC on with closed windows and 75% of air recirculation (Case 3), and HVAC off and the bus moving at 20 km/h with some windows opened (Case 4). Results clearly showed that the motionless condition (Case 1) caused the highest transmission risk around the emitters with negligible risk far from them. On the contrary, the HVAC on reduced the maximum risk to only 6% (Case 2) and 3% (Case 3) of the risk estimated for Case 1. Finally, travelling with some open windows promotes a large air renewal, reducing almost completely the transmission risk.

Characterization of aerosol plumes from singing and playing wind instruments associated with the risk of airborne virus transmission.

The exhalation of aerosols during musical performances or rehearsals posed a risk of airborne virus transmission in the COVID-19 pandemic. Previous research studied aerosol plumes by only focusing on one risk factor, either the source strength or convective transport capability. Furthermore, the source strength was characterized by the aerosol concentration and ignored the airflow rate needed for risk analysis in actual musical performances. This study characterizes aerosol plumes that account for both the source strength and convective transport capability by conducting experiments with 18 human subjects. The source strength was characterized by the source aerosol emission rate, defined as the source aerosol concentration multiplied by the source airflow rate (brass 383 particle/s, singing 408 particle/s, and woodwind 480 particle/s). The convective transport capability was characterized by the plume influence distance, defined as the sum of the horizontal jet length and horizontal instrument length (brass 0.6 m, singing 0.6 m and woodwind 0.8 m). Results indicate that woodwind instruments produced the highest risk with approximately 20% higher source aerosol emission rates and 30% higher plume influence distances compared with the average of the same risk indicators for singing and brass instruments. Interestingly, the clarinet performance produced moderate source aerosol concentrations at the instrument's bell, but had the highest source aerosol emission rates due to high source airflow rates. Flute performance generated plumes with the lowest source aerosol emission rates but the highest plume influence distances due to the highest source airflow rate. Notably, these comprehensive results show that the source airflow is a critical component of the risk of airborne disease transmission. The effectiveness of masking and bell covering in reducing aerosol transmission is due to the mitigation of both source aerosol concentrations and plume influence distances. This study also found a musician who generated approximately five times more source aerosol concentrations than those of the other musicians who played the same instrument. Despite voice and brass instruments producing measurably lower average risk, it is possible to have an individual musician produce aerosol plumes with high source strength, resulting in enhanced transmission risk; however, our sample size was too small to make generalizable conclusions regarding the broad musician population.

Effect of Human Mobility on the Spatial Spread of Airborne Diseases: An Epidemic Model with Indirect Transmission.

We extended a class of coupled PDE-ODE models for studying the spatial spread of airborne diseases by incorporating human mobility. Human populations are modeled with patches, and a Lagrangian perspective is used to keep track of individuals' places of residence. The movement of pathogens in the air is modeled with linear diffusion and coupled to the SIR dynamics of each human population through an integral of the density of pathogens around the population patches. In the limit of fast diffusion pathogens, the method of matched asymptotic analysis is used to reduce the coupled PDE-ODE model to a nonlinear system of ODEs for the average density of pathogens in the air. The reduced system of ODEs is used to derive the basic reproduction number and the final size relation for the model. Numerical simulations of the full PDE-ODE model and the reduced system of ODEs are used to assess the impact of human mobility, together with the diffusion of pathogens on the dynamics of the disease. Results from the two models are consistent and show that human mobility significantly affects disease dynamics. In addition, we show that an increase in the diffusion rate of pathogen leads to a lower epidemic.

Evaluation of Betacoronavirus OC43 and SARS-CoV-2 Elimination by Zefero Air Sanitizer Device in a Novel Laboratory Recirculation System.

Indoor air sanitizers contrast airborne diseases and particularly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/Coronavirus disease 2019 (COVID-19). The commercial air sanitizer Zefero (Cf7 S.r.l., San Giovanni La Punta, Italy) works alternatively using a set of integrated disinfecting technologies (namely Photocatalysis/UV mode) or by generating ozone (Ozone mode). Here we evaluated the virucidal efficacy of Zefero setup modes against human Betacoronavirus OC43 and SARS-CoV-2. For this purpose, we designed a laboratory test system in which each virus, as aerosol, was treated with Photocatalysis/UV or Ozone mode and returned into a recirculation plexiglass chamber. Aerosol samples were collected after different times of exposure, corresponding to different volumes of air treated. The viral RNA concentration was determined by qRT-PCR. In Photocatalysis/UV mode, viral RNA of OC43 or SARS-CoV-2 was not detected after 120 or 90 min treatment, respectively, whereas in Ozone mode, viruses were eliminated after 30 or 45 min, respectively. Our results indicated that the integrated technologies used in the air sanitizer Zefero are effective in eliminating both viruses. As a reliable experimental system, the recirculation chamber developed in this study represents a suitable apparatus for effectively comparing the disinfection capacity of different air sanitizers.

Numerical simulation of pulmonary airway reopening by the multiphase lattice Boltzmann method[Formula presented]

Not only coughing and sneezing, but even normal breathing can produce aerosols, because rupture of liquid plugs forms microdroplets during pulmonary airway reopening. Aerosols are important carriers of various viruses, such as influenza, SARS, MERS, and COVID-19. To control airborne disease transmission, it is important to understand aerosol formation, which is related to the pressure drop, liquid plug, and film. In addition, the detrimental pressure and shear stress at the airway wall produced in the process of airway reopening have also attracted a lot of attention. In this paper, we proposed a multiphase lattice Boltzmann method to numerically simulate pulmonary airway reopening, in which the gas-liquid transition is directly driven by the equation of state. After validating the numerical model, two rupture cases with and without aerosol formation were compared and analyzed. We found that injury of the epithelium in the case with aerosol formation was almost the same as that without aerosol formation, even though the pressure drop in the airway increased by about 50%. Further investigation showed that the aerosol size and maximum differences of the wall pressure and shear stress increased with pressure drop in the pulmonary airway. A similar trend was observed when the thickness of the liquid plug became larger, while an opposite trend occurred when the thickness of the liquid film increased. The model can be extended to study generation and transmission of bioaerosols carrying the influenza or coronavirus. © 2022 Elsevier Ltd

Sampling for SARS-CoV-2 Aerosols in Hospital Patient Rooms.

Evidence varies as to how far aerosols spread from individuals infected with SARS-CoV-2 in hospital rooms. We investigated the presence of aerosols containing SARS-CoV-2 inside of dedicated COVID-19 patient rooms. Three National Institute for Occupational Safety and Health BC 251 two-stage cyclone samplers were set up in each patient room for a six-hour sampling period. Samplers were place on tripods, which each held two samplers at various heights above the floor. Extracted samples underwent reverse transcription polymerase chain reaction for selected gene regions of the SARS-CoV-2 virus nucleocapsid. Patient medical data were compared between participants in rooms where virus-containing aerosols were detected and those where they were not. Of 576 aerosols samples collected from 19 different rooms across 32 participants, 3% (19) were positive for SARS-CoV-2, the majority from near the head and foot of the bed. Seven of the positive samples were collected inside a single patient room. No significant differences in participant clinical characteristics were found between patients in rooms with positive and negative aerosol samples. SARS-CoV-2 viral aerosols were detected from the patient rooms of nine participants (28%). These findings provide reassurance that personal protective equipment that was recommended for this virus is appropriate given its spread in hospital rooms.

Effect of Wearing Personal Protective Equipment (PPE) on CPR Quality in Times of the COVID-19 Pandemic-A Simulation, Randomised Crossover Trial.

Cardiopulmonary resuscitation (CPR) is considered an aerosol-generating procedure. Consequently, COVID-19 resuscitation guidelines recommend the use of personal protective equipment (PPE) during resuscitation. In this simulation of randomised crossover trials, we investigated the influence of PPE on the quality of chest compressions (CCs). Thirty-four emergency medical service BLS-providers performed two 20 min CPR sequences (five 2 min cycles alternated by 2 min of rest) on manikins, once with and once without PPE, in a randomised order. The PPE was composed of a filtering facepiece 3 FFP3 mask, safety glasses, gloves and a long-sleeved gown. The primary outcome was defined as the difference between compression depth with and without PPE; secondary outcomes were defined as differences in CC rate, release and the number of effective CCs. The participants graded fatigue and performance, while generalised estimating equations (GEE) were used to analyse data. There was no significant difference in CC quality between sequences without and with PPE regarding depth (mean depth 54 ± 5 vs. 54 ± 6 mm respectively), rate (mean rate 119 ± 9 and 118 ± 6 compressions per minute), release (mean release 2 ± 2 vs. 2 ± 2 mm) and the number of effective CCs (43 ± 18 vs. 45 ± 17). The participants appraised higher fatigue when equipped with PPE in comparison to when equipped without PPE (p < 0.001), and lower performance was appraised when equipped with PPE in comparison to when equipped without PPE (p = 0.031). There is no negative effect of wearing PPE on the quality of CCs during CPR in comparison to not wearing PPE.

Evaluating the Efficacy of Chemical Disinfectants on Contaminated Dental Materials Contaminated by An Airborne Disease Tuberculosis Similar to COVID-19.

BACKGROUND: Tuberculosis (TB) is a communicable disease as well as an airborne disease. Mycobacterium tuberculosis (MTB) could survive on dental materials shipped to dental laboratories. AIMS: The aim of this study was to determine the number of bacilli held on the prosthetic material and the effect of chemical disinfection agents on various prosthetic materials that were shipped to dental laboratory of TB patient. MATERIALS AND METHODS: The study consisted of three study groups, and a control group. 10 mm x 2 mm disc-shaped (n = 18 for each group, n = 72 in total) nickel-chromium alloy (Ni-Cr), polymethylmethacrylate (PMMA), and dental ceramic (DC) samples were prepared. After exposure to MTB 24 hours in a 37°C incubator, six samples for each group (PMMA), Ni-Cr alloy and a control group DC samples) were exposed to three disinfectants; 10 minutes into 2% glutaraldehyde, 10 minutes into 5% sodium hypochlorite, and 1 minute into alcohol-based disinfectant after vortexed in distilled water. Colony forming units (CFU/ml) were calculated per milliliters. Two-way ANOVA statistical analysis method was used, and a P value less than 0.05 was considered as significant. RESULTS: The bacteria count for six Ni-Cr alloy disc-shaped specimens were recorded as 40, 10, 8, 6, 5, and 4 CFU/ml, respectively. Intensity of the colonies were found to be lower in other groups. 5 CFU/ml were detected on a single PMMA sample in the control group, and 40 CFU/ml were detected on one of the dental ceramic sample. No MTB uptake was observed on any sample in the 2% glutaraldehyde and 5% NaOCl disinfectant study groups. In alcohol-based disinfectant group, 1 CFU/ml was observed on Ni-Cr alloy sample. The effect of prosthetic materials used in this experimental study were not statistically significant on the CFU (p = 0.293). However, the disinfectants use was statistically significant on the number of colonies (p = 0.004). CONCLUSION: NaOCl and glutaraldehyde appeared to be more effective than alcohol-based disinfectant in removing MTB from Ni-Cr alloy, PMMA and dental ceramic surfaces.