The Effect of Er:YAG Lasers on the Reduction of Aerosol Formation for Dental Workers

A Molecular Approach for Detecting Bacteria and Fungi in Healthcare Environment Aerosols: A Systematic Review

Molecular methods have become integral to microbiological research for microbial identification. This literature review focuses on the application of molecular methods in examining airborne bacteria and fungi in healthcare facilities. In January 2024, a comprehensive electronic search was carried out in esteemed databases including PubMed, Web of Science, and Scopus, employing carefully selected keywords such as ((bacteria) OR (virus) OR (fungi)) AND (aerosol) AND ((hospital) OR (healthcare) OR (dental office)) AND ((molecular) OR (PCR) OR (NGS) OR (RNA) OR (DNA) OR (metagenomic) OR (microarray)), following the PRISMA protocol. The review specifically targets healthcare environments with elevated concentrations of pathogenic bacteria. A total of 487 articles were initially identified, but only 13 met the inclusion criteria and were included in the review. The study disclosed that the prevalent molecular methodology for appraising aerosol quality encompassed the utilization of the PCR method, incorporating either 16S rRNA (bacteria) or 18S rRNA (fungi) amplification techniques. Notably, five diverse molecular techniques, specifically PFGE, DGGE, SBT, LAMP, and DNA hybridization methods, were implemented in five distinct studies. These molecular tests exhibited superior capabilities compared to traditional bacterial and fungal cultures, providing precise strain identification. Additionally, the molecular methods allowed the detection of gene sequences associated with antibiotic resistance. In conclusion, molecular testing offers significant advantages over classical microbiological culture, providing more comprehensive information.

The Impact of Hydrogen Peroxide (H2O2) Fumigation on Bacterial Levels in Dental Office Environments: A Randomized Clinical Trial Investigation

BACKGROUND

Fumigation with hydrogen peroxide has proven to be a highly effective approach to maintaining biological safety within dental offices. The main purpose of this research was to investigate the efficacy of hydrogen peroxide (H2O2) fumigation in reducing bacterial levels in dental office environments.

METHODS

The study involved 30 participants diagnosed with moderate caries decay (ICDAS 3 and 4) in their mandibular molars. Sixty Petri dishes (two per patient) with Columbia Agar and 5% Sheep Blood were opened at the beginning of the caries treatment. After the completion of caries treatment and tooth restoration, 30 plates (G1 group) were closed. Following this, a 20 min fumigation procedure with 6% hydrogen peroxide biosanitizer using a compressed air device was conducted. After the fumigation, the remaining plates were closed (G2 group). The total number of bacteria CFUs (colony-forming units) in the dental office air was determined using the Koch sedimentation method.

RESULTS

The total bacterial colony (TBC) level, measured in cfu/m3, demonstrated a significant decrease in the number of bacteria following room environment fumigation (163.1 ± 145.7; G2 group) compared to non-fumigated samples (817.2 ± 208.2; G1 group) (p < 0.001). The predominant bacteria observed in the microbiological plates before fumigation were Micrococcus and Bacillus species, found in 80% (24/30) and 60% (18/30) of the plates, respectively. Application of H2O2 room fumigation resulted in a significant reduction in bacterial numbers: 79.2% (5/30) for Micrococcus species (p < 0.001), 83.3% (3/30) for Bacillus species (p < 0.001), and 100% (0/30) for Staphylococcus arlettae (p < 0.05).

CONCLUSION

Fumigation with 6% H2O2 is an effective method for reducing bacterial counts in a dental office environment.

Quantitative Evaluation of Aerosols Produced in the Dental Office during Caries Treatment: A Randomized Clinical Trial

BACKGROUND

Effective removal of aerosols generated during dental treatment is crucial for maintaining biosafety in dental practice. This study aimed to measure the aerosol amount and the number of aerobic bacteria in the air during caries treatment.

METHODS

The study involved 50 molar teeth (n = 50) in the mandible in 50 patients divided into two groups based on the type of a high-volume evacuator (HVE); G1 (n = 25) conventional HVE (EM19 EVO, Monoart^® Euronda, Vicenza, Italy) and G2 (n = 25) a new, wider, customized HVE. The PC200 laser particle counter (Trotec GmbH, Schwerin, Germany) was used to measure aerosol particles in a range of 0.3-10.0 μm near the operator's mouth. The study used 60 microbiological plates with a microbiological medium (Columbia Agar with 5% Sheep Blood) to check the number of aerobic bacteria in the air.

RESULTS

The mean value of aerosol particles in the G1 group (conventional HVE) was 54,145 ± 7915, while in the G2 group (test, wider evacuator) was lower and amounted to 32,632 ± 1803. (p < 0.001). The median total bacteria count in the air per cubic meter in control, G1 (HVE), and G2 (NEW-HVE) groups were 50 [36-60]; 772 [643-881]; 120 [92-139], respectively. (p < 0.05). Gram-positive cocci were the predominant bacteria in the plates: Micrococcus sp. (50%), Bacillus species (36.4%), Staphylococcus epidermidis (3.8%), Staphylococcus saprophyticus (3.8%).

CONCLUSIONS

the application of the wider high-volume evacuator increases the air purity during caries treatment as well as the biological safety of a dental office.

Ultrafine particles exposure is associated with specific operative procedures in a multi-chair dental clinic

Air quality in dental clinics is critical, especially in light of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, given that dental professionals and patients are at risk of regular exposure to aerosols and bioaerosols in dental clinics. High levels of ultrafine particles (UFP) may be produced by dental procedures. This study aimed to quantify ultrafine particles (UFP) concentrations in a real multi-chair dental clinic and compare the levels of UFP produced by different dental procedures. The efficiency of a high-volume evacuator (HVE) in reducing the UFP concentrations during dental procedures was also assessed. UFP concentrations were measured both inside and outside of a dental clinic in Shanghai, China during a 12-day period from July to September 2020. Dental activities were recorded during working hours. The mean (±standard deviation) concentrations of indoor and outdoor UFP during the sampling period were 8,209 (±4,407) counts/cm³ and 15,984 (±7,977) counts/cm³, respectively. The indoor UFP concentration was much higher during working hours (10,057 ± 5,725 counts/cm³) than during non-working hours (7,163 ± 2,972 counts/cm³). The UFP concentrations increased significantly during laser periodontal treatment, root canal filling, tooth drilling, and grinding, and were slightly elevated during ultrasonic scaling or tooth extraction by piezo-surgery. The highest UFP concentration (241,136 counts/cm³) was observed during laser periodontal treatment, followed by root canal filling (75,034 counts/cm³), which showed the second highest level. The use of an HVE resulted in lower number concentration of UFP when drilling and grinding teeth with high-speed handpieces, but did not significantly reduce UFP measured during laser periodontal therapy. we found that many dental procedures can generate high concentration of UFP in dental clinics, which may have a great health impact on the dental workers. The use of an HVE may help reduce the exposure to UFP during the use of high-speed handpieces.

Aerosol and splatter generation with rotary handpieces used in restorative and orthodontic dentistry: a systematic review

Introduction

The COVID-19 pandemic has caused major disruptions in dental care globally, in part due to the potential for contaminated aerosol to be generated by dental activities. This systematic review assesses the literature for changes in aerosol-contamination levels when rotary instruments are used, (1) as distance increases from patient’s mouth; (2) as time passes after the procedure; and (3) when using different types of handpieces.

Methods

The review methods and reporting are in line with PRISMA statements. A structured search was conducted over five platforms (September 2021). Studies were assessed independently by two reviewers. To be eligible studies had to assess changes in levels of aerosol contamination over different distances, and time points, with rotary hand instruments. Studies’ methodologies and the sensitivity of the contamination-measurement approaches were evaluated. Results are presented descriptively.

Results

From 422 papers identified, 23 studies were eligible. All investigated restorative procedures using rotary instruments and one study additionally looked at orthodontic bracket adhesive material removal. The results suggest contamination is significantly reduced over time and distance. However, for almost all studies that investigated these two factors, the sizes of the contaminated particles were not considered, and there were inconclusive findings regarding whether electric-driven handpieces generate lower levels of contaminated particles.

Conclusion

Aerosol contamination levels reduce as distances, and post-procedure times increase. However, there was sparce and inconsistent evidence on the clearing time and no conclusions could be drawn. High-speed handpieces produce significantly higher levels of contamination than slow-speed ones, and to a lesser extent, micro-motor handpieces. However, when micro-motor handpieces were used with water, the contamination levels rose and were similar to high-speed handpiece contamination levels.

Effect of Sodium Hypochlorite in Dental Unit Waterline on Aerosolized Bacteria-Generated from Endodontic Procedures

INTRODUCTION

Aerosol generation in a dental setting is a critical concern and approaches that aim at decreasing bacterial load in aerosols is of high priority for dental professionals. The objectives of this study were to evaluate the relative effect of various endodontic procedures on the generation and dissemination of aerosols and the effect of 0.1% sodium hypochlorite (NaOCl) in dental unit waterlines (DUWLs) on the bacterial load in the generated aerosols in a clinical setting.

METHODS

The study was completed in two phases. The classical passive sampling technique using brain heart infusion agar plates was utilized. Agar plates were strategically placed throughout the operatory at pre-defined locations.

PHASE I

To evaluate the effect of different endodontic procedures on generation and dissemination of aerosols, we collected a total of 38 samples. Following baseline collection, test samples were collected during vital pulp therapy (VPT) full pulpotomy (n=10), non-surgical root canal therapy (NSRCT; n=10), surgical root canal therapy (SRCT; n=10), and incision and drainage (I&D; n=8) procedures. Bacterial growth was expressed as colony-forming units at 48 hours post-sample collection. Data were analyzed using 1-way analysis of variance with Tukey's multiple comparisons post-hoc test.

PHASE II

To evaluate the effect of 0.1% NaOCl in DUWL on the bacterial load in the generated aerosols, a total of 30 samples were collected. All procedures including VPT (n=10), NSRCT (n=10), and SRCT (n=10) were performed with 0.1% NaOCl in DUWL. Bacterial growth was expressed as colony-forming units at 48 hours post-sample collection. Data were analyzed using 2-way analysis of variance with Tukey's multiple comparisons post-hoc test.

RESULTS

All endodontic procedures generated aerosols at all tested locations except I&D. Aerosols were disseminated as far as 3m from the patient's head with no significant difference between various locations (p>0.05). VPT procedures generated the maximum number of aerosols compared to NSRCT and SRCT. Adding 0.1% NaOCl to DUWLs significantly reduced the bacterial load in the generated aerosols in all treatment groups compared to groups treated with untreated waterlines (p<0.05). No significant difference was noted in the bacterial load between all groups with treated waterlines (p>0.05).

CONCLUSIONS

All tested endodontic procedures led to the generation and dissemination of contaminated aerosols, and the addition of 0.1% NaOCl as a biocide to the DUWL led to a statistically significant reduction in the bacterial load.

Assessment of a Biosafety Device to Control Contamination by Airborne Transmission during Orthodontic/Dental Procedures

During the COVID-19 pandemic, dental professionals have faced high risk of airborne contamination between dentists, staff, and patients. The objective of this study was to evaluate the effect of an individual biosafety capsule in dentistry (IBCD) on reducing the dispersion of droplets and aerosols during orthodontic treatment and evaluate the clinician and patient’s perception of using the IBCD. For the in-vitro part of the study, aerosol quantification was performed with and without the IBCD, using a nonpathogenic bacterial strain and viral strain in the reservoir and high-speed dental handpiece. Petri dishes with MRS agar were positioned from the head of the equipment at distances of 0.5, 1, and 1.5 m. After 15 minutes of passive aerosol sampling, the dishes were closed and incubated using standard aerobic conditions at 37°C for 48 hours to count colony forming units (CFUs). For the clinical part of the study, a questionnaire was sent to clinicians and patients to understand their perception of orthodontically treat and receive treatment using the barrier. The use of IBCD showed an effective means to reduce the dispersion of bacterial and viral contamination around 99% and 96%, respectively, around the main source of aerosol ( $p<0.05$ ). Clinical results showed a 97% bacterial reduction during patient’s consultations ( $p<0.05$ ). The vast majority of clinicians and patients understand the importance of controlling the airborne dispersion to avoid contamination.

Pros and Cons of CAD/CAM Technology for Infection Prevention in Dental Settings during COVID-19 Outbreak

The purpose of this commentary is to update the evidence reported in our previous review on the advantages and limitations of computer-aided design/computer-aided manufacturing technology in the promotion of dental business, as well as to guarantee patient and occupational safety. The COVID-19 pandemic led to an unprecedented focus on infection prevention; however, waves of COVID-19 follow one another, asymptomatic cases are nearly impossible to identify by triage in a dental setting, and the effectiveness of long-lasting immune protection through vaccination remains largely unknown. Different national laws and international guidelines (mainly USA-CDC, ECDC) have often brought about dissimilar awareness and operational choices, and in general, there has been very limited attention to this technology. Here, we discuss its advantages and limitations in light of: (a) presence of SARS-CoV-2 in the oral cavity, saliva, and dental biofilm and activation of dormant microbial infections; (b) the prevention of SARS-CoV-2 transmission by aerosol and fomite contamination; (c) the detection of various oral manifestations of COVID-19; (d) specific information for the reprocessing of the scanner tip and the ward from the manufacturers.

Fibroblasts Adhesion to Laser-Modified Titanium Surfaces-A Systematic Review

OBJECTIVE

Laser treatment has been recently introduced in many fields of implant dentistry. The systematic review tried to address the question: "How does laser modification of titanium surface influence fibroblast adhesion?".

METHODS

An electronic search of the PubMed and Scopus databases was performed. The following keywords were used: (laser) AND (fibroblast) AND (titanium) AND (implant OR disc) AND (proliferation OR adhesion). Initially, 136 studies were found. Ten studies met the inclusion criteria and were included in the review. All studies chosen to be included in the review were considered to have a low risk of bias.

RESULTS

Studies included in the review varied with laser parameters or ways of observing fibroblast behavior. Studies showed that fibroblasts tend to take different shapes and create extensions on modified surfaces and that their metabolic activity is more intense. One study concentrated on laser application and showed that three-directional laser application is the most successful in terms of fibroblast adhesion. Studies which concentrated more on laser parameters showed that too low energy density (lower or equal to 0.75 J/cm2) does not influence fibroblast adhesion. Increasing the energy density over 0.75 J/cm2 causes better cell adhesion of fibroblasts to the laser-modified sample. One included study focused on increasing titanium surface wettability, which also positively influenced cell adhesion.

CONCLUSION

The studies included in the review proved a positive effect of laser-modified titanium surfaces on fibroblast adhesion. However, the application of an appropriate laser energy dose is crucial.

Erbium Laser for Skin Surgery: A Single-Center Twenty-Five Years' Experience

 (1) Introduction: The Erbium laser is a very versatile laser system used in dermatology. Its ability to be almost selectively absorbed by water makes it a perfect device for managing various cutaneous skin conditions. (2) Methods: In this paper, we report our twenty-five years' experience with the Erbium laser. More than three thousand patients were treated for common skin disorders such as flat warts, seborrheic keratosis, xanthelasmas, and scars. (3) Results: A complete response was observed in 89.6%, without significant side effects. Local anesthesia was used in only a tiny percentage of patients. (4) Conclusions: This study confirms that the Erbium laser is a valuable and flexible procedure for laser surgery with excellent safety and short healing times.

Virus transmission by ultrasonic scaler and its prevention by antiviral agent: an in vitro study

Background

It is well recognized that dental procedures represent a potential way of infection transmission. With the COVID‐19 pandemic, the focus of dental procedure associated transmission has rapidly changed from bacteria to viruses. The aim was to develop an experimental setup for testing the spread of viruses by ultrasonic scaler (USS) generated dental spray and evaluate its mitigation by antiviral coolants.

Methods

In a virus transmission tunnel, the dental spray was generated by USS with saline coolant and suspension of Equine Arteritis Virus (EAV) delivered to the USS tip. Virus transmission by settled droplets was evaluated with adherent RK13 cell lines culture monolayer. The suspended droplets were collected by a cyclone aero‐sampler. Antiviral activity of 0.25% NaOCl and electrolyzed oxidizing water (EOW) was tested using a suspension test. Antiviral agents' transmission prevention ability was evaluated by using them as a coolant.

Results

In the suspension test with 0.25% NaOCl or EOW, the TCID50/mL was below the detection limit after 5 seconds. With saline coolant, the EAV‐induced cytopathic effect on RK13 cells was found up to the distance of 45 cm, with the number of infected cells decreasing with distance. By aero‐sampler, viral particles were detected in concentration ≤4.2 TCID50/mL. With both antiviral agents used as coolants, no EAV‐associated RK‐13 cell infection was found.

Conclusion

We managed to predictably demonstrate EAV spread by droplets because of USS action. More importantly, we managed to mitigate the spread by a simple substitution of the USS coolant with NaOCl or EOW.

SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

(1) Background: This study aimed to evaluate the microporosity of the tooth surface structure adjacent to the cemento-enamel junction (CEJ) after the removal of composite fillings with a drill in comparison with removal by an Er:YAG laser and after cleaning with a periodontal curette, chemical EDTA and NaOCl (sodium hypochlorite) conditioning. (2) Methods: The research material consisted of 30 extracted premolars with cervical composite fillings. The teeth were divided into six groups according to the method of tooth preparation: group G1 (n = 5)-a diamond drill; group G2 (n = 5)-a diamond drill + curette; group G3 (n = 5)-a diamond drill + 24% EDTA (PrefGel, Straumann, Switzerland); group G4 (n = 5)-an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) set with the following parameters: power: 1.65 W (composite removal, CR), 1.2 (tooth conditioning, TC), energy: 110 mJ (CR), 80 mJ (TC), frequency: 15 Hz, pulse duration: 50 μs, tip diameter: 1 mm, air/fluid cooling: 4, distance 1.5 mm, energy density: 14.01 J/cm2 (CR), 10.19 J/cm2 (TC); group G5 (n = 5)-an Er:YAG laser + 2% sodium hypochlorite (NaOCl); group G6 (n = 5)-an Er:YAG laser + 5.25% NaOCl. In each tooth, three cavities were made and subjected to analysis. The dentin surface was evaluated using a scanning electron microscope (SEM). (3) Results: Groups G1 and G2 exhibited mechanical damage to the tooth surface structure caused by the rotary motion of a diamond drill. The SEM image showed a smear layer that could only be removed chemically using 24% EDTA gel (group G3). The tooth surfaces prepared with the Er:YAG laser (groups G4-G6) revealed a homogeneous structure without damage along with open dentinal tubules (without smear layer) and visible denaturation of collagen fibers. The sodium hypochlorite (NaOCl) conditioning did not increase the visibility of dentinal tubules. (4) Conclusions: Dentin surfaces have open dentinal tubules after removal of the composite filling using the Er:YAG laser and therefore do not require additional NaOCl conditioning.