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.

Efficacy of various decontamination methods and sterilization on contaminated and inoculated diamond-coated burs.

The objective of this study was to evaluate the efficacy of various decontamination methods and subsequent sterilization on contaminated and inoculated diamond-coated burs. One hundred forty new diamond-coated burs and 120 extracted human molars were utilized in this study. The burs were divided into 7 groups (n = 20): 1, positive control; 2, negative control; 3, new, unused burs; and 4 to 7, burs subjected to various combinations of cleaning methods (manual cleaning, use of a cleaning stone, and/or ultrasonic cleaning) after contamination. In all of the groups except group 3, the burs were sterilized and used to abrade the enamel and dentin of the sterilized extracted teeth. In groups 1 and 4 to 7, the burs were subsequently inoculated with 1 of the following microorganisms: Enterococcus faecalis (ATCC 19433), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 15442), or Geobacillus stearothermophilus (ATCC 7953). Twenty-four hours after inoculation, the burs in group 2 and groups 4 to 7 were subjected to the cleaning treatments and sterilized with steam. The burs in all 7 groups were then cultured for bacterial contamination. No growth of any bacterial type was observed in any of the groups except the positive control group. The use of a cleaning stone in combination with manual or ultrasonic cleaning resulted in the least amount of remaining tooth debris on the diamond-coated burs. The contaminated and inoculated diamond-coated burs tested in this study were successfully sterilized, and the tested bacteria were eliminated. If using a diamond-coated bur multiple times, practitioners should consider utilizing debridement with a cleaning stone followed by either manual or ultrasonic cleaning and then by a single cycle of steam sterilization.

Effectiveness of various decontamination methods on CAD/CAM camera mirror sleeves.

AIM: The purpose of this study was to evaluate the effectiveness of several methods of disinfection and sterilization of computer-aided design/computer-aided manufacturing (CAD/CAM) camera mirror sleeves (Omnicam; Dentsply Sirona). MATERIALS AND METHODS: The outer surface of seven groups of mirror sleeves were inoculated by submerging them in suspensions of Staphylococcus aureus and Pseudomonas aeruginosa. Post inoculation, the groups were decontaminated as follows: Group A: no decontamination or sterilization following inoculation (positive control); Group B: surface cleaning with a neutral soap (Dawn Dish Soap, Procter & Gamble) and water only; Group C: surface disinfection with 17% isopropanol (CaviWipes; Metrex). Groups D to F received a different high-level disinfection (HLD) solution in an HLD container (Dentsply Sirona) as follows: Group D: 0.55% ortho-phthalaldehyde (OPA) (Cidex OPA; Johnson & Johnson); Group E: 7.5% hydrogen peroxide (H2O2) (Sporox II; Sultan); Group F: 7.35% H2O2 and 0.23% peracetic acid (PAA) (Compliance; Metrex). Group G received dry-heat sterilization (Rapid Heat Sterilizer; Cox). Also, dry-heat sterilized mirror sleeves that were not exposed to bacteria and not disinfected served as a negative control. The presence of bacteria was tested on the inside and outside of the sleeves by plating samples on TSA II. A percent reduction in CFU/ml from the positive control group was determined per group. RESULTS: All methods of disinfection except Dawn Dish Soap resulted in greater than 99.99% reduction in CFU/ml compared with the positive control group. CONCLUSIONS: Both HLD or dry-heat sterilization resulted in no growth of microorganisms in cultures taken from both the outside and inside surfaces of the bacteria-contaminated mirror sleeves.

Preliminary Efficacy Testing of the Disinfectant MicrobeCare XLP for Potential Use in Military Operational Environments.

Introduction: A safe, easy-to-use, permanently bonded antiseptic that does not require post-exposure bioload reduction but maintains effectiveness over time would have far-reaching implications across multiple industries. Health care is one such arena, particularly in austere military settings where resources are at a premium. MicrobeCare XLP (MicrobeCare, Buffalo Grove, IL, USA) is a commercially available spray-on agent that is advertised to covalently bond to surfaces and provide a long-lasting antimicrobial coating inhospitable to >99.99% of surface microorganisms. A pilot study was devised to gather baseline data regarding product efficacy and laboratory parameters before consideration of extended investigations and military utilization. The product manufacturer recommends bioload reductions before product application, following product application, and after each pathogenic exposure. To investigate the product's efficacy in circumstances more closely simulating a military operational setting in which post-pathogenic exposure bioload reduction would not be possible, this step was deliberately excluded from the test sequences. Materials and Methods: Using autoclaved surgical forceps, growth of Staphylococcus aureus and Acinetobacter baumannii was evaluated in a controlled manner under multiple conditions. Test variations included duration of submersion in the MicrobeCare XLP solution and air-drying and a second autoclave sterilization. Control and treated forceps were exposed to a bacterial suspension and air-dried before being submerged in sterile saline and vortex mixed. The saline solution was serially diluted and plated on tryptic soy agar (TSA) II plates. Plates were incubated for 24 h and bacterial colony-forming units (CFU)/mL were counted. Results: Statistical significance was defined according to the American Society for Testing and Materials (ASTM) International passing criteria of 3 Log10 or 99.9% reduction of microorganisms. Additionally, p-values were calculated using two-tailed unpaired two-sample t-tests with unequal variance with a threshold of 0.05. In the S. aureus tests, none of the reduction calculations met the ASTM International passing criteria. In addition, the difference between the means of the colony counts in the MicrobeCare XLP-treated forceps and untreated control forceps was not statistically significant (p-value 0.109). Conversely, in the A. baumannii tests, each of the percent reduction calculations met the ASTM International passing criteria; the difference between the means of the colony counts in the treatment and control groups was statistically significant (p-value 0.008). Conclusion: In these independent tests, MicrobeCare XLP effectively prevented growth of A. baumannii but had unpredictable results suppressing S. aureus. These results may relate to inherent properties of the bacteria or autoclave exposure, although the manufacturer asserts that the coating withstands such degradation. Additional testing could be performed using a broader range of microorganisms and exposure to varying conditions including other sterilization methods.