Biomedical Waste Management in Dentistry - A Blueprint Model for Successful Implementation in Dental Practice

Introduction

Dental hospitals, clinics, institutions, and laboratories constitute minor sources of biomedical waste (BMW). However, due to dynamic changes in dental practices offering a wide range of treatment options and the growing demand for dental care driven by urbanization, a substantial amount of BMW is now being generated in dentistry. The nature of biomedical waste produced in dental setups differs from that generated in medical hospitals, emphasizing the need for clear guidelines tailored to dental practice. This article proposes a blueprint model that identifies various dental materials requiring disposal in their respective color-coded bags, following cross-verification of guidelines provided to hospitals under the Biomedical Waste Management Rules established by the Government of India.

Biomedical Management Rules in India

Biomedical waste management regulations were passed by the Indian government in 1998 under Sections 6 and 25 of the Environmental Protection Act, 1986. These regulations are comparable to the Medical Tracking Act of 1988, which defines medical waste in the United States.¹ The rules were subsequently amended in 2000, 2003, 2011, 2016, 2018, and 2019.

These guidelines adopt a ‘womb-to-tomb’ approach, emphasizing segregation of waste at source, and encompassing all steps, including waste generation, collection, storage, transportation, and treatment through processes such as incineration and recycling.²

According to the Biomedical Waste Management and Handling Rules, 1998 of India, biomedical waste is defined as “any waste which is generated during the diagnosis, treatment, or immunization of human beings or animals, or in research activities pertaining thereto, or in the production or testing of biologicals.”¹

Biomedical wastes should be disposed of properly to prevent the spread of infectious diseases, fetal abnormalities, cancers, endocrine disruptions, and other health hazards. Proper disposal also helps protect environmental resources air, water, and soil, from contamination, which are vital resources both for present and future generations.

Biomedical Waste Management Rules (BMWM)

The Biomedical Waste Management Rules introduced by the Government of India in 1998, amended in 2000, 2011, and 2012, describe in detail the waste categories, along with their respective treatment and disposal methods. Biomedical waste is broadly divided into general waste, infectious waste, and non-toxic infectious waste. General waste constitutes 80-85% of the total waste generated, whereas hazardous waste accounts for about 10-15%.³

Biomedical waste produced in dental offices can be classified as:⁴

1. Dental amalgam wastes

(a) Amalgam traps

(b) Bulk mercury

(c) Contact amalgam (extracted teeth with amalgam restorations)

2. Other scrap heavy metals such as lead foils

3. X-ray processing wastes

(a) Silver-containing wastes (X-ray fixer solution)

(b) X-ray developer solution

(c) X-ray system cleaners containing chromium

4. Chemicals, disinfectants, and sterilizing agents

5. Medical waste

(a) Sharps

(b) Bio-hazardous waste

6. Non-hazardous waste

The BLUE PRINT MODEL based on the above discussed classification is as follows:

Dental Amalgam Waste

Dental amalgam consists of mercury, silver, tin, and copper. Mercury, which constitutes approximately 50% of the amalgam compound, is a known neurotoxic, nephrotoxic, and bio accumulative element. Dental mercury can enter the environment through various pathways, including air, water, and soil. It is released into the air from improperly sealed mercury containers, during the removal of old amalgam restorations, and through the finishing and polishing of new restorations. Mercury enters water when amalgam waste is disposed into the drains from dental clinics, and can contaminate soil through improper disposal in landfills. Exposure to mercury may result in kidney diseases, respiratory disorders, adverse effects on the nervous system.⁵

Dental amalgam waste generated in dental clinics remain largely unregulated. Such waste should neither be rinsed down the drain nor disposed of in municipal waste systems or biomedical waste containers designated for hazardous materials (Table 1).

Scrap Heavy Metals such as Lead

Common sources of heavy metals in dental offices include lead foils from intraoral periapical (IOPA) films, as well as lead shields and thyroid collars. Lead is a harmful metal that can contaminate soil and ground water if improperly disposed of in landfills.⁶ Exposure to lead is associated with neurotoxicity, carcinogenicity, hypertension, renal dysfunction, and various immunological effects.⁵ Lead waste, provided it is not in fine powder form, can be disposed of as solid waste (Table 2).

X-Ray Processing Wastes

Unused developer contains the toxic substance hydroquinone and therefore must not be discharged into the drain.⁵ Used developer, in which the silver has been depleted during the developing process, may be disposed of in the drain, but not into septic tanks, as it interferes with the breakdown of waste. Used developer and fixer solutions should never be mixed at any stage.

Used fixer generated from x-ray processing is considered hazardous waste as it contains high concentrations of silver, ranging from 3,000 to 8,000 parts per million (ppm). Since concentrations above 5 ppm are deemed dangerous, it is not advisable to discharge used fixer into the drain, septic systems, or in the garbage. To minimize such waste, dental facilities are encouraged to upgrade to digital imaging systems instead of conventional IOPA film (Table 3).⁵

Chemicals, Disinfectants, and Sterilizing Agents

Sterilizing agents that are flammable or potentially reactive should never be poured down the drain, as they pose a risk of explosion. Additionally, these agents must not be discharged into septic systems, as they can disrupt the bacteria responsible for breakdown of waste (Table 4).⁵

Medical Waste

The Biomedical Waste Management Rules (2016) introduced colour-coding system for BMW segregation and disposal. These rules mandate that waste be disposed of in the respective colour-coded bags as listed below (Table 5):⁷

1. Yellow bag - Infectious non-plastic waste

2. Red bag - Infectious plastic waste

3. White puncture-resistant container - Sharps, metallic objects

4. Blue container - Glass items (including broken ones), and metal implants

The following guidelines must be observed regarding waste collection and segregation:^8-11

• The segregation of waste should be done at the source of generation into the four categories: yellow, red, blue, and white.

• Waste collection bags should be labeled with biohazard logos and should be of non-inflammable, autoclave-stable, and non-chlorinated material with a thickness of ≥50 μm.

• Containers should have well-fitting lids and should be operated using a foot pedal.

• Sharp containers should be leak-proof, puncture-proof, tamper-proof, and impermeable.

• All collection bags should be sealed once they are three-fourths full.

• Waste should not be stored for more than 48 hours.

• Personal protective equipment (PPE) should be worn while handling the containers.

• Chemical disinfection of colour-coded bins should be carried out using 1-2% sodium hypochlorite daily or at least once a week.

Non-Hazardous Waste

Non-hazardous waste should be disposed of in accordance with local governing authority regulations.

Blood Spill Clean-Up¹²

1. Wear appropriate personal protective equipment (PPE).

2. Cover the blood spill with an absorbent paper towel. Once the blood is absorbed, discard the towel in a yellow biohazard bag.

3. Collect all sharp objects using a forceps, and place them in sharps container.

4. Spray the contaminated area with household bleach and allow it to air dry for 15 minutes.

5. After the 15-minute contact period, wipe the area with absorbent paper towels and discard them in a general waste bag.

6. Remove PPE safely to avoid contamination.

7. Wash hands thoroughly with soap and water.

E-Waste Management¹³

1. Back up all important files and data before disposal.

2. De-authorize all accounts and, if possible, perform a factory reset.

3. Recycle the device at an electronics retailer or through an e-waste recycling facility.

4. Do not dispose of electronic equipment in regular garbage, as these items

contain heavy metals that can contaminate groundwater.

Conclusion

Biomedical waste management remains a significant challenge in many healthcare institutions, including dental clinics, laboratories, and teaching institutions. There is a pressing need for a blueprint model to implement effective biomedical waste management practices in dental settings, as occupational safety, infection control, and environmental protection are of paramount importance.

Although several studies across the country indicate a generally positive attitude toward BMW management, notable deficiencies persist in knowledge and practical implementation. Therefore, regulatory and authoritative bodies should take responsibility for the strict implementation of laws and systematic monitoring of waste management practices.

Source(s) of support

Nil

Conflict of Interest

None