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The Sustainable Development Goals were introduced at the United Nations in 2015.1 Recently, in Riyadh, Kingdom of Saudi Arabia, three initiatives were launched to contribute to environmental protection, energy transformation, and sustainability programs. 2 A recent systematic review examining green dental practices and their impact found that only five studies have been conducted on this topic globally. 3
The World Health Organization categorizes healthcare waste as materials discarded from healthcare activities that could potentially transmit infectious agents. Dental facilities generate a variety of waste types, such as hazardous, non-hazardous, biohazardous, pharmaceutical, and sharp wastes.4 OHSAS 18001 standard demonstrates that an organization adheres to high standards with regard to health and safety, thus enabling it to enhance its reputation. There are color codes for biomedical waste: Red for plastic waste, yellow for infectious waste, light blue for sharp waste, grey for cytotoxic waste, and light green for infectious waste/injurious sharp waste.4
It stated that estimated carbon dioxide emissions through dental practices were 675 kilotons, as it is a very resource and labor-intensive, and energy-consuming field. 2 Many health and dental care providers prioritize efficiency over sustainability, resulting in significant waste production and carbon dioxide emissions.
The Eco-dentistry Association (EDA) defines Green Dentistry as a forward-thinking approach aimed at reducing the environmental impact of dental practices. It encompasses ecologically responsible measures that promote pollution prevention and support the health and well-being of both current and future generations.3
Farahani and Suchak were pioneers in eco-friendly dentistry back in 2007.3 Their innovative model introduced eco-friendly alternatives to conventional dental practices, aiming to replace harmful methods with sustainable ones. The six green dentistry model themes are amalgam management, radiography management, infection control management, procurement management, energy, and water conservation. 1However, despite their efforts, the majority of dentists continued to employ non-eco-friendly practices, such as using disposable patient drapes, lab coats, water cups at spittoons, and suction tips in their clinics or hospitals.1,2
In dental practice, the most common waste products include amalgams from restorative materials, radiographic chemicals, plastic/paper barriers, and disinfectant solutions. These materials can have adverse effects on both the environment and human health.2 Amalgam-filling material, composed primarily of 50% mercury, can alter pH, oxygen availability, and temperature if released into the environment, contributing to the overall waste. Proper disposal methods are crucial, including the collection and recycling of unused amalgam particles and the use of pre-capsulated amalgam, because the mercury from dry waste that arrives in landfills always ends up reaching the water table. If household waste is incinerated, the mercury in the form of vapor causes air pollution and mixed with rainwater will again lead to water contamination. In addition, the wet waste found at the outlet of the spittoons and suctions passes directly into the wastewater circuit and contaminates the treatment plants. As a result, dental offices must manage the risk of mercury pollution to the environment and public health. 8Additionally, the installation of amalgam separators in suction and vacuum lines is recommended.1
Although the toxicity of mercury is continually raised and discussed, a clear conclusion about the effects on human health at the exposure level has not yet been established, especially in situations of chronic exposure to low concentrations such as in patients with dental amalgam8. However, Mutter examined the toxicological impact of mercury dental amalgam and autopsy studies, which revealed that 60-95% of mercury found in human tissues originated from dental amalgam. Individuals with 12 or more fillings were found to have mercury levels ten times higher in various tissues, including the brain. Furthermore, Mutter suggested that methylmercury resulting from dental amalgam may pose significantly greater toxicity compared to exposure from fish consumption.6
Genotype plays a crucial role in determining the impact of mercury on neurobehavioral functions in children, with boys exhibiting greater susceptibility to genetic modifications of mercury neurotoxicity compared to girls. Additionally, Mortazavi et al. explored the correlation between maternal mercury dental amalgams and heightened mercury release, proposing a potential link to increased rates of autism in children.
Regarding safety concerns, the FDA has conducted reviews based on the best available scientific evidence to assess the impact of low levels of mercury vapor associated with dental amalgam fillings. It's worth noting that some individuals may have allergies or sensitivities to mercury or other components of dental amalgam, such as silver, copper, or tin. For those with known allergies to any of these metals, amalgam fillings should be avoided to prevent the development of oral lesions or other contact reactions.6
The Minamata Convention on Mercury Treaty, with support from the WHO and its parties, established guidelines that led to the implementation of measures aimed at reducing the use of dental amalgam. These measures, outlined in Annex A, Part II of the treaty, included restrictions on bulk mercury use and limitations on dental amalgam for specific patient groups. Notably, dental treatment involving amalgam was prohibited for deciduous teeth, patients under 15 years old, and pregnant or breastfeeding women unless deemed medically necessary by the practitioner. In a significant development, the European Union made a pioneering move in 2023 by endorsing a proposal for the complete cessation of dental amalgam use starting January 1, 2025. This decision was motivated by the availability of viable mercury-free alternatives.6, 9
An interesting model for the environmental management of the dental practice is the “Plan-Do-Check-Act” model of Dr. Angela Rovera. This model focuses on environmental aspects: energy use, travel, product purchasing, waste production, emission to air, water use, and contamination of land. For each one of them, a plan-do-check-act is proposed. For example, for the item travel, the Plan is to reduce patients’ travel and staff travel. The Do involves multiple procedures in one visit, teledentistry, and the use of the closest dental laboratory, among others. The Check is based on measuring the frequency of appointments and type of treatment by management software and finally the act Schedules dental examinations by risk assessment approach and personalizes prevention on patients’ needs.7
In relation to the rest of the elements involved, conventional radiographs use an x-ray fixer, developer, and dental film, which contain hazardous chemicals and should not be disposed of in regular trash. Interestingly, only 20% of medical waste, is considered infectious and requires special disposal, while 3% from a dental practice requires management with protocol. It is good to have in mind that enzyme-based cleaners are biodegradable and free of harsh chemicals, making them ideal for green practices.1
For a sustainable future, it's imperative to integrate environmental sustainability into the education of Oral Health Professionals across all stages, from early undergraduate studies to postgraduate continuing professional development. Dentistry must seek alternatives to single-use plastic cups and other disposable plastic items. The suitability of these alternatives will depend on national legislation and market availability. Developing new biomaterials, potentially through regenerative dentistry, could greatly aid in transitioning towards a greener dental practice. Embracing a minimalistic and preventive approach to dentistry can benefit all stakeholders involved.5
References
1.Zia, N., Doss, J. G., John, J., & Panezai, J. (2024). Sustainability in Dentistry: Assessing knowledge, attitude, and practices of dental practitioners about green dentistry. Pakistan journal of medical sciences, 40(1Part-I), 233–241. https://doi.org/10.12669/pjms.40.1.7606
2. Alshamrani, A., & Alzahrani, F. (2024). Knowledge, Attitude and Practice of Green Dentistry among Dental Professionals in Saudi Arabia: A Cross-sectional Study. Journal of Dental Science Research Reviews & Reports. SRC/JDSR-189. DOI: doi. org/10.47363/JDSR/2024 (6), 166, 2-6.
3. Bano, V., Amin, E., Maqbool, S., Hassan, S. A., Baber, A., & Urooj, R. (2024). Awareness of the Green Dentistry Concept among Dental Professionals in Tertiary Care Dental Hospital, Rawalpindi. Life and Science, 5(2), 08-08.
4. Alawad, I. A., Albawardi, A., Alshalan, A. A., Alahedib, K. S., Daabash, M. D., & Almutairi, W. M. (2024). Dental Office Waste and Its Risks on the Environment; a Narrative Review. NATURALISTA CAMPANO, 28(1), 2601-2608.
5. Dixon, J., Field, J., Gibson, E., & Martin, N. (2024). Curriculum Content for Environmental Sustainability in Dentistry. Journal of Dentistry, 105021.
6. Fisher, J., Varenne, B., Narvaez, D., & Vickers, C. (2018). The Minamata Convention and the phase down of dental amalgam. Bulletin of the World Health Organization, 96(6), 436–438. https://doi.org/10.2471/BLT.17.203141
8. Environmental impact of mercury waste from dental practice. State of the art_Video.mp4 | FDI (fdiworlddental.org)
9. Tibau, A. V., & Grube, B. D. (2023). Dental Amalgam and the Minamata Convention on Mercury Treaty: Make Mercury History for All. J Oral Dent Health, 7(3), 227-241.
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