Circular Economy in Conjunction with Treatment Methodologies in the Biomedical and Dental Waste Sectors

Curriculum content for Environmental Sustainability in Dentistry

OBJECTIVES

(i) To identify suitable strategies and opportunities to embed Environmental Sustainability (ES) within an existing Oral Health Professional (OHP) curriculum through a series of focus groups with students and academic staff and (ii) To create high-level evidence-based and subject-specific ES content through an approach grounded in evidence and collaboration with key stakeholders in OHP education.

METHODS

Focus groups were used to explore academic staff and student views on appropriate teaching and assessment methods for ES. Content statements were developed from an extensive literature search, mapped to curriculum subjects, and validated through consultation with students, discipline-experts and education-experts.

RESULTS

Five themes were identified from the focus groups: ES transcends all disciplines of dentistry and oral healthcare; baseline knowledge transmission with relevant practical application; viewing and modifying existing teaching and assessment events through a different lens; normalising the topic of ES to support attitude and behaviour change and safeguarding against misinformation and disinformation. Forty-four content statements were developed and mapped to nineteen curriculum subjects.

CONCLUSIONS

This study identifies for the first time a comprehensive strategy for the inclusion and delivery of ES (method and content) in the curriculum. A novel method to define and map curriculum content has been explored and validated using a range of complementary methodologies. A comprehensive and robust list of evidence-based and subject-specific educational content statements have been defined in the field of Environmental Sustainability in dentistry and oral healthcare.

CLINICAL SIGNIFICANCE

Oral healthcare has a significant environmental impact, the key to all mitigation strategies is educating the profession at all levels.

Optical properties of recycled zirconia for dental applications

STATEMENT OF PROBLEM

While waste zirconia can be recycled, whether the optical properties of recycled zirconia match those of commercially available zirconia is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the optical properties of recycled zirconia by assessing its color, translucency, and opalescence across different thicknesses and shades.

MATERIAL AND METHODS

Sixty specimens were prepared from 3 mol% yttria-stabilized tetragonal zirconia polycrystal blocks (Lava Plus; 3M ESPE) (group C); 60 other specimens were prepared from waste blocks of the same zirconia (group R). The specimens were further categorized into 4 subgroups (n=15) based on their thicknesses (1.0 mm or 1.5 mm) and shades (A1 or A3). Specimen color was measured with a spectrophotometer (Easyshade Advance 4.0; Vita ZahnFabrik). The parameters of color difference (ΔE00), translucency (TP), contrast ratio (CR), and opalescence (OP) were calculated. Grain size analysis was performed using scanning electron microscopy. Data were analyzed with analysis of variance (ANOVA) (α=.05).

RESULTS

Significant differences in translucency and opalescence were observed between groups C and R in all specimens (P<.001). Group R exhibited a range of TP (4.89 to 11.27), CR (0.74 to 0.91), and OP (3.36 to 8.65) values. The ΔE00 values between groups C and R ranged from 13.99 to 21.31. Both thickness and shade significantly affected the ΔE00 values (P<.001). The grain size in group C was not significantly different from that in group R (F=0.364, df=1, P=.555). The TP and OP values of group R decreased with increasing thickness (P<.001).

CONCLUSIONS

Recycled zirconia was less translucent and opalescent than commercially available zirconia. The color difference between commercially available and recycled zirconia exceeded the acceptable threshold, even when using the same staining procedure. Recycled zirconia exhibited reduced translucency and opalescence with increasing thickness.

Hepatitis B in Healthcare Personnel: An Update on the Global Landscape

Despite the outstanding progress that has been made in the prevention, detection, and management of hepatitis B during the past decades, hepatitis B remains a problem among healthcare personnel (HCP) in many countries. We reviewed studies on all aspects of hepatitis B in HCP published from 2017 through April 2023. They revealed wide variations on the prevalence of infection among HCP, ranging from 0.6% in Europe to >8.7% in Africa, almost always in association with very low vaccination rates. Many studies found a significant association between HCP's knowledge about hepatitis B and hepatitis B vaccines, their vaccination status, and practices. This research also discloses global inequities regarding vaccination policies against hepatitis B, free-of-charge vaccinations, and access to post-exposure prophylaxis (PEP). Strategies to prevent and manage accidental exposures are needed in order to reduce the burden of hepatitis B on HCP, while written policies for all aspects of infection prevention, protective equipment, and PEP should be available. Lastly, HCP should be accordingly educated. These are all imperative given the decline of routine vaccinations in the COVID-19 era, particularly in countries with fragile vaccination programs, and the disruptions of interventions for hepatitis B that are expected to provide a pool of virus transmission to future generations.

Environmental sustainability related to dental materials and procedures in prosthodontics: A critical review

This article aims to review the status, challenges, and directions of environmentally sustainable oral healthcare by focusing on the dental materials and procedures used in prosthodontics. Sustainable development is a global priority and requires a systemic, integrative approach from all sectors of society. The oral healthcare sector is responsible for substantial greenhouse emissions throughout its value chain, including raw material extraction, industrial production, supply distribution, clinical practice, and management of waste. Of all dental specialties, prosthodontics has been one of the main generators of carbon emissions by fabricating a single product such as dentures or crowns in multiple steps. Dental prosthetic procedures involve chemicals and materials such as polymers, ceramics, metals, gypsum, and wax, which are often used in large quantities and for a single use. Thus, environmental risks and socioeconomic burdens can result from residuals and improper disposal, as well as waste and the embedded costs of unused materials retained by manufacturers, retail suppliers, dental laboratories, and dental clinics. To mitigate the environmental impact generated by conventional prosthodontics, we urge awareness and the adoption of sustainable good practices in the daily routine of dental clinics and laboratories. Capacity building and investment in a circular economy and digital technology can reduce the carbon footprint of prosthetic dentistry and improve the quality of life for present and future generations.

Responsible waste management: using resources efficiently (Part 1)

This chapter aims to describe the types of waste produced in dental practice, the costs associated with disposal of this waste, and the impact that the disposal method has on the environment and on human health. It discusses the waste hierarchy and explores how dental surgeries can reduce their waste generation through simple changes in practice. The chapter continues by highlighting the benefits of performing a waste audit, with examples of how correct segregation of the waste produced in practice is both cost-effective and reduces the environmental impact of its disposal. Finally, we discuss some of the barriers and enablers of changing waste disposal behaviours in the dental practice and identify how the environmentally minded practitioner can encourage pro-environmental behaviour in their dental team.

Healthcare waste in Bangladesh: Current status, the impact of Covid-19 and sustainable management with life cycle and circular economy framework

COVID-19 has accelerated the generation of healthcare (medical) waste throughout the world. Developing countries are the most affected by this hazardous and toxic medical waste due to poor management systems. In recent years, Bangladesh has experienced increasing medical waste generation with estimated growth of 3 % per year. The existing healthcare waste management in Bangladesh is far behind the sustainable waste management concept. To achieve an effective waste management structure, Bangladesh has to implement life cycle assessment (LCA) and circular economy (CE) concepts in this area. However, inadequate data and insufficient research in this field are the primary barriers to the establishment of an efficient medical waste management systen in Bangladesh. This study is introduced as a guidebook containing a comprehensive overview of the medical waste generation scenario, management techniques, Covid-19 impact from treatment to testing and vaccination, and the circular economy concept for sustainable waste management in Bangladesh. The estimated generation of medical waste in Bangladesh without considering the surge due to Covid-19 and other unusual medical emergencies would be approximately 50,000 tons (1.25 kg/bed/day) in 2025, out of which 12,435 tons were predicted to be hazardous waste. However, our calculation estimated that a total of 82,553, 168.4, and 2300 tons of medical waste was generated only from handling of Covid patients, test kits, and vaccination from March 2021 to May 2022. Applicability of existing guidelines, and legislation to handle the current situation and feasibility of LCA on medical waste management system to minimize environmental impact were scrutinized. Incineration with energy recovery and microwave sterilization were found to be the best treatment techniques with minimal environmental impact. A circular economy model with the concept of waste minimizaton, and value recovery was proposed for sustainable medical waste management. This study suggests proper training on healthcare waste management, proposing strict regulations, structured research allocation, and implementation of public-private partnerships to reduce, and control medical waste generation for creating a sustainable medical waste management system in Bangladesh.

Comparative Verification of the Accuracy of Implant Models Made of PLA, Resin, and Silicone

Polylactic acid (PLA) has gained considerable attention as an alternative to petroleum-based materials due to environmental concerns. We fabricated implant models with fused filament fabrication (FFF) 3D printers using PLA, and the accuracies of these PLA models were compared with those of plaster models made from silicone impressions and resin models made with digital light processing (DLP). A base model was obtained from an impact-training model. The scan body was mounted on the plaster, resin, and PLA models obtained from the base model, and the obtained information was converted to stereolithography (STL) data by the 3D scanner. The base model was then used as a reference, and its data were superimposed onto the STL data of each model using Geomagic control. The horizontal and vertical accuracies of PLA models, as calculated using the Tukey-Kramer method, were 97.2 ± 48.4 and 115.5 ± 15.1 μm, respectively, which suggests that the PLA model is the least accurate among the three models. In both cases, significant differences were found between PLA and gypsum and between the PLA and resin models. However, considering that the misfit of screw-retained implant frames should be ≤150 µm, PLA can be effectively used for fabricating implant models.

Evaluation of pre-treated healthcare wastes during COVID-19 pandemic reveals pathogenic microbiota, antibiotics residues, and antibiotic resistance genes against beta-lactams

The disposal of healthcare waste without prior elimination of pathogens and hazardous contaminants has negative effects on the environment and public health. This study aimed to profile the complete microbial community and correlate it with the antibiotic compounds identified in microwave pre-treated healthcare wastes collected from three different waste operators in Peninsular Malaysia. The bacterial and fungal compositions were determined via amplicon sequencing by targeting the full-length 16S rRNA gene and partial 18S with full-length ITS1-ITS2 regions, respectively. The antibiotic compounds were characterized using high-throughput spectrometry. There was significant variation in bacterial and fungal composition in three groups of samples, with alpha- (p-value = 0.04) and beta-diversity (p-values <0.006 and < 0.002), respectively. FC samples were found to acquire more pathogenic microorganisms than FA and FV samples. Paenibacillus and unclassified Bacilli genera were shared among three groups of samples, meanwhile, antibiotic-resistant bacteria Proteus mirabilis, Enterococcus faecium, and Enterococcus faecalis were found in modest quantities. A total of 19 antibiotic compounds were discovered and linked with the microbial abundance detected in the healthcare waste samples. The principal component analysis demonstrated a positive antibiotic-bacteria correlation for genera Pseudomonas, Aerococcus, Comamonas, and Vagococcus, while the other bacteria were negatively linked with antibiotics. Nevertheless, deep bioinformatic analysis confirmed the presence of blaTEM-1 and penP which are associated with the production of class A beta-lactamase and beta-lactam resistance pathways. Microorganisms and contaminants, which serve as putative indicators in healthcare waste treatment evaluation revealed the ineffectiveness of microbial inactivation using the microwave sterilization method. Our findings suggested that the occurrence of clinically relevant microorganisms, antibiotic contaminants, and associated antibiotic resistance genes (ARGs) represent environmental and human health hazards when released into landfills via ARGs transmission.

Awareness of Students and Dentists on Sustainability Issues, Safety of Use and Disposal of Dental Amalgam

Among the pillars of sustainability in health care units is environmental protection. Although an EU-wide dental amalgam phase-out legislation exists, quantities of this material are still to be found in the market, dental offices or in the mouths of patients. The purpose of this study is to record the views of dentists and dental students in Greece regarding the use and safety of dental amalgam for people and the environment as well as their attitudes towards its restriction and disposal.

MATERIALS AND METHODS

Two different questionnaires, through Google forms, were filled by each group. Descriptive statistics were used to describe the variables. The chi-square test or the chi-square test with Yates correction was used to examine potential differences per group (p-value = 0.05). Overall, 564 people participated in this study; 462 (81.9%) dentists (N1) and 102 (18.1%) dental students (N2).

RESULTS

Both groups agreed that they no longer use dental amalgam often. Dentists (39.8%) and students (36.4%) consider amalgam to have a moderate burden on the environment. This answer differed significantly per year of profession and year of undergraduate studies, respectively, with dentists from 6-25 years in the profession and 4th-year students, being the least aware on the environmental footprint of dental amalgam. Further, professionals (70%) and students (60%) believe that dental amalgam has a hazardous impact on patient's health, at all or to a small extent. For staff health, dentists reported at a moderate degree dangerous impact (32.9%) while students (36.4%), respectively. The impact on patients and staff health, were found to differ significantly per region of practicing dentistry for both groups. Finally, there were suggestions made from both groups about the necessity of information sharing on amalgam and mercury safety and the impact on the environment at the level of professional organizations.

CONCLUSIONS

Students, younger dentists and those living in non-urban regions seem to be more sensitive to the environmental impact of amalgam use, disposal, and health of people. Environmental issues should be addressed thoroughly by professional organizations, enhancing relevant activities for all people involved.

A Perspective of the COVID-19 Pandemic in the Plastic Waste Management and Cooperatives of Waste Pickers in Brazil

Brazil is the fourth largest producer of plastic waste in the world. Among all the challenges the country had faced in the development of public policies for the banning of single-use plastics, the new coronavirus pandemic scenario determined the suspension of these laws indefinitely. In 2020, Brazil became the global epicenter of COVID-19. This scenario changed the habit and behavior of Brazilian consumers, who increased the consumption of plastics due to their importance in applications as protective material. The country also has social problems related to waste management that depend mainly on waste pickers. These workers need social visibility and protection not only to face the current health crisis but also to guarantee their income and survival. This work aims to discuss the increase in single-use plastics that are not intended for recycling and the respective environmental, economic, and social impacts for the country. We demonstrate the lack of data on waste management in Brazil and highlight the importance of the social inclusion of waste pickers for a circular economy. Especially after the change of scenario with the COVID-19 pandemic, the country must have adequate planning and improvements in waste management, recycling programs, and political intervention to raising awareness among the population and guaranteeing social rights for waste pickers.

Mapping healthcare waste management research: Past evolution, current challenges, and future perspectives towards a circular economy transition

Improper healthcare waste (HCW) management poses significant risks to the environment, human health, and socio-economic sustainability due to the infectious and hazardous nature of HCW. This research aims at rendering a comprehensive landscape of the body of research on HCW management by (i) mapping the scientific development of HCW research, (ii) identifying the prominent HCW research themes and trends, and (iii) providing a research agenda for HCW management towards a circular economy (CE) transition and sustainable environment. The analysis revealed four dominant HCW research themes: (1) HCW minimization, sustainable management, and policy-making; (2) HCW incineration and its associated environmental impacts; (3) hazardous HCW management practices; and (4) HCW handling and occupational safety and training. The results showed that the healthcare industry, despite its potential to contribute to the CE transition, has been overlooked in the CE discourse due to the single-use mindset of the healthcare industry in the wake of the infectious, toxic, and hazardous nature of HCW streams. The findings shed light on the HCW management domain by uncovering the current status of HCW research, highlighting the existing gaps and challenges, and providing potential avenues for further research towards a CE transition in the healthcare industry and HCW management.

Digital Entrepreneurship via Sustainable Online Communication of Dentistry Profession, Oradea, Romania: A Longitudinal Analysis

Dentistry is an entrepreneurially oriented public interest profession that must maintain a balance between professional specificity and business sustainability. Communicating with patients is vital in a competitive system, and the dentist needs to use handy resources such as websites and social media. The aim of this research is (a) to examine whether websites and social networks are a digital entrepreneurship tool used in the dentistry profession in Oradea, a city in full economic development in Romania, to promote the profession nationally and internationally, (b) to compare the changes made using digital tools in the period between 2018–2021 for all licensed dentists in the mentioned city (between 430–450 people, depending on the stage of analysis) using the content analysis method and (c) to identify how the lockdown period imposed by the emergence of the COVID-19 pandemic influenced not only the sustainability of the medical services provided to the population but also the communication practices of the dental offices. The results of examining the dentist’s online presence reveal that there is an interest among practitioners to grow their business sustainably through a digital presence that is increasingly relevant to them and their clients, but the potential remains under-exploited.

Resource Resurgence from COVID-19 Waste via Pyrolysis: a Circular Economy Approach

Since the end of 2019, COVID-19 pandemic has affected 220 countries and currently majority of the world is facing the wrath of the second wave. One of the outcomes of the ongoing pandemic is the generation of huge amount of solid polymeric "COVID-waste" comprising medical waste, personal protective equipment (PPE) waste, packaging waste, and other household waste with potential infectious components residing on it. Thermochemical route is the preferred treatment and effective way of disposal of such infectious polymeric waste. Typically, incineration is employed to ensure complete destruction of the pathogens which is not a resource-efficient method. Pyrolysis is a sustainable alternative which can handle the present COVID-waste stream in short-term and long-term yielding valuable fuel and material products. Recently published literature in this avenue have clearly shown the versatility of this technology in efficiently handling both mono and mixed stream of polymers. Based on facts, we propose a resource resurgence framework that utilizes pyrolysis as the core conversion route for effectively handling COVID-waste streams. Our framework suggests how these plants can be operational and helpful in generation of revenue in post-pandemic times as well. We expect that the conscientious adoption of pyrolysis will certainly lead us towards a circular economy paradigm.

Medical Waste Treatment Technologies for Energy, Fuels, and Materials Production: A Review

The importance of medical waste management has grown during the COVID-19 pandemic because of the increase in medical waste quantity and the significant dangers of these highly infected wastes for human health and the environment. This innovative review focuses on the possibility of materials, gas/liquid/solid fuels, thermal energy, and electric power production from medical waste fractions. Appropriate and promising treatment/disposal technologies, such as (i) acid hydrolysis, (ii) acid/enzymatic hydrolysis, (iii) anaerobic digestion, (vi) autoclaving, (v) enzymatic oxidation, (vi) hydrothermal carbonization/treatment, (vii) incineration/steam heat recovery system, (viii) pyrolysis/Rankine cycle, (ix) rotary kiln treatment, (x) microwave/steam sterilization, (xi) plasma gasification/melting, (xii) sulfonation, (xiii) batch reactor thermal cracking, and (xiv) torrefaction, were investigated. The medical waste generation data were collected according to numerous researchers from various countries, and divided into gross medical waste and hazardous medical waste. Moreover, the medical wastes were separated into categories and types according to the international literature and the medical waste fractions’ percentages were estimated. The capability of the examined medical waste treatment technologies to produce energy, fuels, and materials, and eliminate the medical waste management problem, was very promising with regard to the near future.