Current biomedical waste management practices and cross-infection control procedures of dentists in India

Abstract

Objectives: To investigate the knowledge, attitudes and behaviour of dentists working in dental clinics and dental hospitals regarding biomedical waste management and cross-infection control. Methods: A national survey was conducted. Self-administered questionnaires were sent to 800 dentists across India. Results: A total of 494 dentists responded, giving a response rate of 61.8%. Of these, 228 of 323 (70.6%) general dentists reported using boiling water as a sterilising medium and 339 (68.6%) dentists reported disposing of hazardous waste such as syringes, blades and ampoules in dustbins and emptying these into municipal corporation bins. Conclusions: Dentists should undergo continuing education programmes on biomedical waste management and infection control guidelines. Greater cooperation between dental clinics and hospitals and pollution control boards is needed to ensure the proper handling and disposal of biomedical waste.

INTRODUCTION

Biomedical waste (waste generated during the process of diagnosis, treatment or immunisation of humans or animals, or in research activities pertaining to any of these processes, or in the production or testing of biological material) has become a serious health hazard in many countries, including India. Careless and indiscriminate disposal of this waste by dental clinics and institutions can contribute to the spread of serious diseases such as hepatitis and human immunodeficiency virus (HIV) among people who handle waste and also among the general public. Dentists may be occupationally exposed to infectious materials, including body substances and contaminated supplies, equipment, environmental surfaces, water and air. Cross-infection can be defined as the transmission of infectious agents among patients and staff within a clinical environment¹. Infection control, which is one of the most discussed topics in dentistry, has become an integral part of practice to the extent that dental health workers no longer question its necessity2., 3..

Concerns about the control of infection in dentistry were considerably increased by the report of the transmission of HIV from an American dentist to five of his patients4., 5.. Given that infection with the hepatitis B and C viruses (HBV, HCV) and HIV is not rare, cross-infection has become a major concern for dentists, dental personnel and patients⁶. Numerous surveys and studies have shown that the incidence of HBV infection after needlestick injuries caused by needles used in patients positive for HbsAg (the surface antigen for HBV) is approximately 20.0%, whereas that following similar exposure to HIV is 0.4%4., 7..

Dental care professionals are at high risk for cross-infection when treating patients. This occupational potential for disease transmission is evident given that most human microbial pathogens have been isolated from oral secretions3., 8.. In addition, the majority of carriers of infectious diseases are not easily identified9., 10.. Research has shown that infective hazards are present in dental practice because many infections can be transmitted by blood or saliva via direct or indirect contact, droplets, aerosols or contaminated instruments and equipment¹⁰. For this reason, since the late 1980s, many surveys have been carried out in several countries, especially in North America and Europe, to investigate practices to control infection and compliance with universal guidelines in dental surgeries11., 12., 13., 14., 15., 16., 17..

Previous seroepidemiological studies have confirmed these occupational hazards, showing higher concentrations of serum antigen and antibodies for HBV18., 19., HCV20., 21. and Legionella spp.²², and increased prevalences of respiratory infections²³ and symptoms²⁴, possibly related to the use of aerosols, in dentists than in the lay population.

The use of procedures to control infection and compliance with universally agreed precautions in dental surgeries are effective in preventing microbial pollution and cross-contamination, and are strongly supported by organisations such as the Centers for Disease Control and Prevention⁵, the American Dental Association, schools of dentistry, and many other health agencies and professional associations. Universal recommendations consider that all patients should be regarded as infectious and that precautions should be applied in all cases²⁵. However, infection control policies in developing countries have not been widely documented²⁶. Most hospitals have no infection control programmes because awareness of the problem and/or properly trained personnel are lacking⁶. Unfortunately, however, human behaviour does not always follow logical patterns. Some health professionals take routine precautions for granted and may forget both the rationale for and importance of certain basic procedures and practices. This can lead to complacency and a false sense of security. The reasons for this are varied and arise from contexts in which clinicians never see symptomatic patients or experience any sequelae resulting from breaches of infection control, to the extreme context in which clinicians fail to recognise that they may have patients who might transmit infectious pathogens to them or their staff. Clinicians may also fail to realise how much the development and application of appropriate infection control practices have altered and lowered the potential for direct, indirect and aerosolised cross-infection.

Although many surveys of cross-infection control procedures have been carried out in several countries, the recent literature includes no reports on how Indian dentists manage cross-infection control and biomedical waste disposal in their practices. The aim of this study was to investigate the knowledge, attitudes and behaviours of dentists working in dental clinics and dental hospitals regarding biomedical waste management and cross-infection control.

METHODS

A national survey was conducted among dental practitioners working in either the government or private sectors in India. A self-administered questionnaire was designed to obtain information about procedures used for biomedical waste management and the prevention of cross-infection in dental practice. The questionnaire was pretested, revised and retested before use. The study population included dentists for whom postal and email addresses were held by the Indian Dental Association. Dentists in each state in India were selected randomly from the list. Surveys were sent by post and email to 800 dentists. Non-returns were followed up by two further items of correspondence. A total of 494 questionnaires were returned, giving a response rate of 61.8%. The identity of respondents was kept confidential, but written or verbal consent was obtained from each participant. This study was approved by the institutional ethics committee of Chhatrapati Shahuji Maharaj Medical University, Lucknow, and conducted in full accordance with the World Medical Association Declaration of Helsinki. The questionnaire included items on sociodemographic characteristics, biomedical waste management practices, knowledge and practice of infection control procedures, sterilisation practices, wearing of gloves and masks, methods of storing instruments, and methods of disposing of contaminated materials and sharps.

Questionnaire data were entered into a computer and analysed using spss Version 12.0 (SPSS, Inc., Chicago, IL, USA). The accuracy of input data was verified by entering the data twice and comparing the two subsequent datasets. No discrepancies were found in the data.

RESULTS

Of the 800 dentists whose participation was requested, 494 responded, giving an overall response rate of 61.8%. Of these, 192 (38.9%) participants were women and 302 (61.1%) were men. The mean age of the dentists was 38.6 ± 9.4 years and mean time in practice was 7.4 ± 3.8 years. A total of 171 (34.6%) dentists were postgraduate practitioners and 323 (65.4%) were graduate dental practitioners (Table 1).

Table 1.

Sociodemographic features of participants (n = 494)

	n	%
Gender
Male	302	61.1
Female	192	38.9
Professional status
General dental practitioners	323	65.4
Specialist dental practitioners	171	34.6

All participants (100%) expressed concern regarding the risk for cross-infection from patients to themselves and to dental assistants. As many as 93.5% of dentists agreed with the suggestion that all patients should be regarded as infectious and that precautions should be applied universally (Table 2). A total of 266 (53.8%) dentists reported using boiling water and 266 (53.8%) dentists reported using autoclaving methods of sterilisation (Table 2).

Table 2.

Questions to assess knowledge of, attitudes towards and practice of standard infection control measures. All data are given as n (%). Respondents = 494

Q1. All patients should be regarded as infectious and precautions should be applied universally
Agree	Disagree	No idea
462 (93.5%)	32 (6.5%)	0
Q2. Which methods of sterilisation do you use?
Autoclave	Dry heat	Cold chemical	Boiling water
266 (53.8%)	38 (7.7%)	95 (19.2%)	266 (53.8%)
Q3. How long is it since you last serviced your sterilisation devices?
1 week	4 weeks	6 weeks	12 weeks	> 12 weeks
114 (23.1%)	37 (7.5%)	15 (3.0%)	44 (8.9%)	284 (57.5%)
Q4. How do you pack impressions or casts for transit to and from the laboratory?
Plastic bag	Special container	No preference
342 (69.2%)	10 (2.0%)	152 (30.8%)
Q5. Do you think sharps (needles, blades, etc.) are hazardous?
Yes	No
475 (96.2%)	19 (3.8%)
Q6. How do you dispose of hazardous waste such as needles, syringes, blades and ampoules?
Puncture-resistant container	Plastic bottles	Dustbin	No preference
99 (20.0%)	0	339 (68.6%)	56 (11.3%)
Q7. How do you control infective aerosols?
High-speed aspirators	Rubber dam	Pre-procedure mouth rinse	No preference
247 (50.0%)	0	125 (25.3%)	150 (30.4%)
Q8. Which of these do you clean to provide barrier protection in the dental clinic?
Chair, table, water trunks	Head gear	Light handle	Light curing devices	Radiograph equipment	Drawer, drawer handle
364 (73.7%)	149 (30.2%)	225 (45.5%)	50 (10.1%)	83 (16.8%)	60 (12.1%)
Q9. Which of these do you consider to be an infectious agent of relevance in dentistry?
HIV	HBV, HCV	M. tuberculosis	N. gonorrhoeae	T. pallidum	P. aeruginosa	L. pneumophila
461 (93.3%)	399 (80.8%)	190 (38.5%)	0	57 (11.5%)	0	0
Q10. How do you sterilise dental handpieces?
Surface disinfectant solution	Running water for 30 s before use	Autoclave	No preference
475 (96.2%)	0	0	19 (3.8%)
Q11. Which of these items of barrier equipment do you use?
Gloves	Face mask	Protective spectacles	None
494 (100%)	342 (69.2%)	0	0
Q12. Have you attended training on the management of biomedical waste?
Yes	No
76 (15.4%)	418 (84.6%)

HIV, human immunodeficiency virus; HBV, hepatitis B virus; HCV, hepatitis C virus; M. tuberculosis, Mycobacterium tuberculosis; N. gonorrhoeae, Neisseria gonorrhoeae; T. pallidum, Treponema pallidum; P. aeruginosa, Pseudomonas aeruginosa; L. pneumophila, Legionella pneumophila.

Only 37 (7.5%) dentists reported servicing their sterilisation devices at 4-week intervals (Table 2). Almost all of the dentists surveyed were aware of the risk for cross-infection associated with sharps and considered sharps to be potentially hazardous to health, but the majority of respondents (n = 339, 68.6%) reported disposing of hazardous waste such as syringe needles, blades and ampoules in dustbins (Table 2).

A total of 247 (50.0%) dentists preferred to use high-speed aspirators to control infective aerosol spray, whereas 125 (25.3%) chose to use a pre-procedure mouth rinse (Table 2).

According to 461 (93.3%) dentists, risk for HIV infection was present in dentistry.

Almost all dentists (96.2%) preferred to use a surface disinfectant solution to sterilise dental handpieces (Table 2). Barrier equipment used by dentists included gloves and face masks; no respondents reported using protective spectacles (Table 2).

A total of 418 (84.6%) respondents had not attended any training programme on biomedical waste management (Table 2). The majority of dentists (65.4%) considered it important to follow set guidelines for dentists and were willing (87.9%) to enrol on biomedical waste management training courses (Table 3). In response to an item on the disposal of blood-soaked waste, 363 (73.5%) dentists stated that it should be disposed of by incineration, but 376 (76.1%) dentists reported disposing of blood-soaked waste in the same way as general waste (Table 3). A total of 333 (67.4%) dentists were unaware of any legislation on hospital and dental clinic waste management and 75.9% believed that their dental clinic or hospital clinic did not have a waste management plan (Table 3). Dentists also considered it important to follow guidelines for biomedical waste management, but regarded doing so as tedious (65.4%) (Table 3).

Table 3.

Questions to assess knowledge of, attitudes towards and practice of standard infection control measures. All data are given as n (%). Respondents = 494

Q13. Do you think it is important to follow set guidelines for dentists?
Yes, but tedious	Yes, not tedious	Not interested	Not practical
323 (65.4%)	112 (22.7%)	21 (4.3%)	38 (7.7%)
Q14. Would you like to attend a programme on hospital waste management?
Yes	No
434 (87.9%)	60 (12.1%)
Q15. How do you think bloody waste (blood-soaked cotton, extracted teeth, incised tissue) should be disposed of?
Incineration	Sterilisation	Burning	Sewage	Don’t know	Deep burial
363 (73.5%)	0	76 (15.4%)	2 (0.4%)	13 (2.6%)	40 (8.1%)
Q16. How do you dispose of bloody waste?
Incineration	Sterilisation	Burning	Sewage	Don’t know	General waste	Deep burial
43 (8.7%)	0	42 (8.5%)	5 (1.0%)	40 (8.1%)	376 (76.1%)	24 (4.9%)
Q17. Are you aware of any legislation on hospital waste management?
Yes	No
161 (32.6%)	333 (67.4%)
Q18. Does your health care or private clinic setting have a waste management plan?
Yes	No
119 (24.1%)	375 (75.9%)
Q19. Should waste be segregated into different categories?
Yes	No
463 (93.7%)	31 (6.2%)
Q20. Where do you dispose of biomedical waste?
Corporation bin	House-to-house waste collection	Authorised clinic/hospital waste collection	Any other
418 (84.6%)	25 (5.1%)	51 (10.3%)	0
Q21. The safe management of health care waste is the responsibility of government
Agree	Disagree	No comment
428 (86.6%)	45 (9.1%)	21 (4.3%)
Q22. Safe management efforts by the hospital or private clinic increase the financial burden on management
Agree	Disagree	No comment
329 (66.6%)	52 (10.5%)	113 (22.9%)
Q23. The safe management of health care waste is an extra burden on work
Agree	Disagree	No comment
344 (69.6%)	87 (17.6%)	63 (12.7%)

Surveyed dentists were knowledgeable about the need to segregate biomedical waste (93.7%) (Table 3), but disposed of biomedical waste by dumping it in civic corporation bins (84.6%) (Table 3).

DISCUSSION

Dentists have an ethical responsibility to the environment and themselves. Because of the nature of their profession, dentists and dental assistants should not forget that they are at risk for treating patients who may have infectious diseases. Dentists, dental assistants and patients may be exposed to pathogenic microorganisms localised in the oral cavity and respiratory tract, including cytomegalovirus (CMV), HBV, HCV, herpes simplex virus (HSV) type 1 and 2, HIV, Mycobacterium tuberculosis, staphylococci, streptococci and other viruses and bacteria²⁷. These microorganisms can be transmitted to dental health care professionals by direct contact with a patient’s saliva, blood, skin or oral secretions, or by indirect contact through injuries caused by contaminated sharp instruments, or by droplet infection from aerosols or spatter25., 27.. Dental health care workers should wear operating gloves for two reasons: to prevent the transmission of infection from the operator’s hands to the patient, and to prevent blood and saliva making contact with the operator’s hands²⁸.

In the present study, all dental practitioners expressed concern about the risk for cross-infection from patients to themselves and their dental assistants and the majority accepted that all patients should be regarded as potentially infectious and that universal precautions should be applied in all cases (Table 2). All dentists stated that they preferred to use gloves and face masks as barrier techniques, but none reported using protective spectacles (Table 2). This finding is supported by similar observations in other published documentation29., 30.. Treasure and Treasure¹⁶ found that in New Zealand, 42.0% of dentists wore gloves, 64.8% wore masks and 66.4% wore protective spectacles. McCarthy and MacDonald³¹ reported that 91.8% of dentists in Ontario, Canada, always wore gloves, 74.8% always wore masks and 83.6% always wore protective spectacles.

In the present study, most general dental practitioners preferred to use boiling water and most specialist practitioners preferred to use autoclaving as a method of sterilising dental instruments, but neither group reported servicing their sterilising equipment more frequently than every 12 weeks. This demonstrates respondents’ attitudes towards cross-infection control practices in dental practice. Centers for Disease Control recommendations assert that sterilisation devices, such as autoclaves and boilers, must be checked at 4-week intervals. However, dentists in the present survey reported using plastic bags to send impressions and casts to and from laboratories, which is an important measure for the control of cross-infection.

Our data indicate that most of the dental practitioners surveyed expressed concern regarding HBV, HCV, HIV and Mycobacterium tuberculosis infection, but very few expressed concern about infection by other organisms, such as Neisseria gonorrhoeae, Treponema pallidum, Pseudomonas aeruginosa and Legionella pneumophila (Table 2). This suggests that the dentists who participated in this survey were inadequately informed about these organisms.

Participating dental practitioners were aware that sharps are hazardous and should be disposed of in puncture-resistant containers, but reported using dustbins to dispose of sharps such as needles, knives and ampoules. This is important because this method of disposal allows for needlestick injury, the recycling of syringes in the market and contamination of the environment. Another study performed in the city of Bangalore in India showed that 47.6% of dentists hand health care waste to street garbage collectors³².

Responses to the questionnaire showed that participants were knowledgeable about how blood-soaked waste should be disposed of. The majority of respondents indicated that it should be disposed of by incineration, but, when asked how they managed blood-soaked waste, reported that they disposed of it as general waste. This method of disposal can lead to the spreading of infection.

In this study, almost all of the dentists surveyed stated that they preferred to clean handpieces by wiping them with disinfectants and only a few stated that they had no preferred method. However, live blood cells, bacterial and viral particles are known to be able to survive inside handpieces even after thorough disinfection³³. According to Miller³⁴, the most common reason for not sterilising handpieces is fear of damaging the equipment.

In dental practice, there is evidence that high-volume suction plays an important role in minimising the contamination of the treatment room by micro-particle aerosols that contain significant microbiological load³. The present data revealed that only 50.0% of the dentists surveyed used high-volume suction to control infection spread by aerosols.

Most of the dentists surveyed had not attended a biomedical waste management training course, but did show interest in receiving training. Survey results also showed that most respondents did not segregate waste at the point of generation in the clinic or hospital. They were also unaware of any legislation on hospital and clinic waste management or of any waste management guidelines. Possible reasons for this include: that surveyed dentists consider recommendations should be followed but are tedious; that practitioners consider it the responsibility of government to impose regulations, and that the imposition of regulations increases the financial and labour-associated burden on the dental practice (Table 3).

CONCLUSIONS

The results of the present study show that Indian dentists are inadequately informed about infection control procedures and biomedical waste management. The topics of cross-infection control and biomedical waste management do not arouse interest in dentists, and continuing dental education on how to avoid cross-infection in dental practice is deficient. Improved compliance with recommended infection control measures is required for all dentists. Continuing education programmes and short courses on cross-infection, infection control procedures and biomedical waste management are suitable means of improving the knowledge of dentists. Demonstration programmes should be conducted for employees (contractual or permanent) who are in direct contact with health care-related waste in order to improve their understanding of the associated risks and the importance of applying health and safety measures during the handling and segregation of waste. Professional health care waste management representatives should be employed. Information on the risks involved in health care waste management practices should be disseminated to the general public and across the community. All waste management staff should be trained in emergency response and made aware of the correct procedures for prompt reporting. Accidents or incidents, including near misses, spillages, damage of containers, inappropriate segregation and any incidents involving sharps should be reported to the waste management officer (if waste is involved) or to another designated person.

Acknowledgements

The authors thank all participants who responded to this survey.

Conflicts of interest

None declared.