Infection Control Practices Across Canada: Do Dentists Follow the Recommendations?

• Gillian M. McCarthy, BDS, M.Sc. •
• John J. Koval, PhD •
• Michael A. John, M.Sc., M.B.Ch.B., FRCP(C) •
• John K. MacDonald, MA •

Abstract

This study investigated provincial and territorial differences in dentists’ compliance with recommended infection control practices in Canada (1995). Questionnaires were mailed to a stratified random sample of 6,444 dentists, of whom 66.4% responded. Weighted analyses included Pearson’s chi-square test and multiple logistic regression. Significant provincial and territorial differences included testing for immune response after hepatitis B virus (HBV) vaccination, HBV vaccination for all clinical staff, use of infection control manuals and post-exposure protocols, biological monitoring of heat sterilizers, handwashing before treating patients, using gloves and changing them after each patient, heat-sterilizing handpieces between patients, and using masks and uniforms to protect against splatter of blood and saliva. Excellent compliance (compliance with a combination of 18 recommended infection control procedures) ranged from 0% to 10%; the best predictors were more hours of continuing education on infection control in the last two years, practice location in larger cities (> 500,000) and sex (female). Clearly, improvements in infection control are desirable for dentists in all provinces and territories. Extending mandatory continuing education initiatives to include infection control may promote better compliance with current recommendations.

MeSH Key Words: Canada; dental offices; guideline adherence; infection control, dental.


© J Can Dent Assoc 1999; 65:506-11

[Survey of Canadian Dentists |Discussion|Conclusion |References]

Infection control forms an important part of practice for all health care professions and remains one of the most cost-beneficial medical interventions available.1 In dentistry, both patients and health care workers may be exposed to a number of bloodborne and upper respiratory pathogens through exposure to blood and saliva. Professional dental associations, including provincial licensing authorities in Canada, have advocated that universal precautions be applied to all patients, as their potential infectivity may not be known.2-5

Most studies of dentists’ infection control practices have investigated compliance with specific procedures, such as the use of gloves and masks, eye protection, hepatitis B virus (HBV) vaccination and heat sterilization of dental handpieces. There are few comprehensive studies of dentists’ compliance with recommended infection control procedures, and there are no national data for dentists in Canada. In 1995, we conducted a national survey of dentists in Canada to investigate compliance with recommended infection control practices6 and access to care for patients with bloodborne pathogens.7 This paper reports the results of a comparison of infection control practices of dentists in different provinces or territories.

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Survey of Canadian Dentists
Questionnaires were mailed to a random sample of all dentists licensed to practice in Canada (n = 6,537), stratified by province or territory. Lists of dentists were obtained from each provincial or territorial authority. There were 15,232 dentists listed by Canadian licensing bodies in Canada in 1995. All listed dentists from the smaller or less densely populated provinces and territories were included. Dentists from the remaining provinces and territories were randomly sampled such that the size of the subsamples for each region were approximately equal and would yield reasonably small confidence intervals for the estimates of interest. When adjusted for non-delivery of questionnaires, the sample size was 6,444: Newfoundland, n = 149; Prince Edward Island, n = 48; Nova Scotia, n = 418; New Brunswick, n = 246; Saskatchewan, n = 332, Yukon Territory, n = 13; Northwest Territories, n = 34; British Columbia, n = 1,011; Alberta, n = 805; Manitoba, n = 477; Ontario, n = 1,655; Quebec, n = 1,256.

Ethics approval was gained from the Review Board for Health Sciences Research involving Human Subjects at the University of Western Ontario. To ensure anonymity, the study was designed such that no individual could link names and responses. Administration of the survey included an initial mailing of questionnaires with ID numbers, a reminder postcard and two additional mailings of questionnaires to non-respondents.

The survey instrument, tests for reliability, survey administration, weighting of the data and investigation of non-response bias have been described elsewhere.6-8

Statistical analyses were conducted using SPSS/PC+ (SPSS Inc., Chicago, Ill.). All statistical analyses were weighted to allow for different probability of selection and non-response among the provinces and territories.9 Pearson’s test of association and multiple logistic regression analyses were used to investigate provincial and territorial differences in compliance.

The response rate, adjusted for non-delivery, was 66.4%. Of the respondents, 174 were deemed ineligible because they did not actively treat patients, leaving 4,107 responses for data analysis. There was minimal evidence of non-response bias.8

We found significant provincial differences in occupational health measures (see Table 1). For example, for post-HBV immunization serology, compliance ranged from 49 to 78%, with 68 to 100% of dentists in a province or territory reporting HBV immunization for all hygienists and 46 to 100% for all other clinical staff. Only 0 to 70% of a province’s or territory’s dentists had a post-exposure protocol; however, 44 to 92% reported safe recapping of needles.

Table 1   Provincial differences in percentages of participants reporting occupational health measures (n = 4,107)

Variable

Province/Territory
  NWT YT BC AB SK MB ON QC NB NS PEI NF
Hepatitis B immunization 96 90 90 93 88 89 91 90 92 90 90 79
HBV natural immunity 0 10 4 2 4 2 3 3 1 2 0 2
Post-HBV immunization serologya 78 56 74 71 63 49 76 58 72 58 58 51
HBV immunization for all hygienistsa 92 100 89 91 85 72 85 88 88 88 95 68
HBV immunization for all other clinical staffa 100 86 75 79 75 57 78 70 76 80 86 46
Post-exposure protocola 70 0 36 54 37 48 36 48 39 43 55 38
Always recap needles with device or scoop techniquea 78 44 50 52 59 55 50 92 48 56 44 50
Always use puncture-proof container for sharps disposal 100 100 93 95 92 95 94 95 90 96 100 94

a p < 0,0001

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Provincial or territorial differences in other infection control practices included use of an office infection control manual (30 to 78%); biological monitoring of heat sterilizers (50 to 91%); handwashing before treating patients (40 to 84%); using gloves when treating patients (93 to 100%) and changing gloves after each patient (94 to 100%); heat-sterilizing handpieces between patients (60 to 96%); and using masks (50 to 100%), eye protection (70 to 100%) and uniforms (17 to 65%) to protect against blood and saliva splatter (see Table 2).

Table 2:Percentage of respondents from each province/territory who reported infection control practices (n = 4,107)

Variable

Province/Territory
  NWT YT BC AB SK MB ON QC NB NS PEI NF
Office infection control manuala 78 30 44 78 55 61 48 49 46 59 58 48
Biologically monitor heat sterilizersa 80 50 71 91 68 75 67 70 66 74 84 57
When treating patients:
• handwashing  before patientsa		 83 40 71 71 74 77 74 82 77 80 84 73
• handwashing after degloving 74 30 63 63 67 61 62 65 59 69 74 62
• always wear glovesb 100 100 93 99 96 98 94 94 93 97 95 95
• always change gloves after each patientb 100 100 94 98 95 99 96 98 98 100 100 97
• always heat sterilize  handpieces after
each patienta		 96 80 60 94 82 89 80 71 81 79 86 76
• always give antimicrobial  mouthwash prior to   intraoral proceduresa 4 0 2 5 4 2 4 3 2 2 0 0
• always flush waterlines  after each patient 64 20 53 58 56 55 54 57 55 57 68 52
• always use rubber dam for restorative
proceduresa		 9 20 60 52 53 62 21 18 44 58 51 24
To protect against splatter of blood/saliva:
• always wear a maska		 100 80 84 90 81 85 79 86 82 75 50 75
• always wear protective eyewear/ faceshieldc 70 100 85 84 80 82 84 79 71 76 71 73
• always wear a protective uniforma 65 50 38 49 45 53 49 55 48 43 17 51
• always use high-volume suctionb 96 90 95 96 94 95 90 90 91 93 95 93

a p < 0,0001
b p < 0,01
c p < 0,05

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Reports of the routine use of gloves when treating patients, plus mask and eye protection to protect against blood and saliva splatter, ranged from 36 to 100%. Such routine use was significantly associated with younger age, marital status (single or married), fewer patients per day, female dentist, population centre where primary practice was located (population of 100,000 to 500,000) and attending continuing education on infection control.

Compliance with a combination of 18 recommended infection control practices (“excellent compliance”)6 ranged from 0 to 10%. Statistically significant predictors of excellent compliance with recommended infection control procedures were attending more than six hours of continuing education on infection control in the past two years (10+ hours, odds ratio [OR] = 9.0; 6 to 10 hours, OR = 3.8; reference group = none), population of town or city where practice was located (> 500,000, OR = 2.5; reference group = < 10,000) and female dentist (OR = 2.1). There were no significant differences by province or territory.

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Discussion

The Canadian Dental Association (CDA) and the provincial licensing authorities have published recommendations and guidelines for infection control in the dental office. Our study provides information that may be useful to focus continuing education at the provincial level.

Handwashing
Handwashing is one of the most important practices for preventing cross-infection in dental practice, yet there is only partial compliance among health care professionals, including dentists.10- 13 CDA guidelines recommend handwashing with a germicidal soap prior to and immediately after the use of gloves.2,3 Even if gloves are worn, hands may become contaminated as a result of punctures or when gloves are removed.14-16

Some respondents appeared to use gloves as a substitute for handwashing. It is somewhat reassuring to note that of the people who never wore gloves, 100% washed hands between patients. A number of factors associated with lower rates of compliance with handwashing have been previously identified: availability of sinks, the effect of handwashing on skin conditions, workload and low perceived risk.17-23 A major motivational factor for compliance with handwashing is an understanding of the risk of transmission of infection,18-19 suggesting that continuing education may be a useful intervention to improve compliance, although it is difficult to achieve a sustained change in behaviour without constant reinforcement.24-28

HBV Immunization
HBV immunization among dentists in Canada compares favourably with recent results from surveys in the United States (93% immunized)5 and the United Kingdom (86% immunized)29 and is higher than reported from earlier studies of dentists in Canada completed between 1987 and 1993.30-32 However, the proportion of respondents reporting testing for an immune response after HBV immunization ranged from 49% in Manitoba to 78% in the Northwest Territories, indicating some uncertainty about the efficacy of protection against HBV in Canadian dentists. This is a concern, as knowledge of HBV antibody titre is required for appropriate management of exposure to HBV. The finding indicates a need for more education focused on HBV immunization and post-exposure protocols.

Although rates of HBV immunization among dentists were generally high, lower rates of immunization of all clinical staff were reported, particularly by respondents in Newfoundland and Manitoba. Unfortunately, respondents who reported lower compliance with HBV immunization for staff were also less likely to report the use of post-exposure protocols (p < 0.0001), yet prophylaxis for HBV in non-immune persons is required within 48 hours of exposure. Since the completion of our survey, it has been found that zidovudine (AZT) reduces the risk of HIV seroconversion after an occupational injury by 79% if given within two hours of exposure.33,34 It is possible that dentists in Canada are now more aware of HIV post-exposure prophylaxis and may therefore be more likely to have a post-exposure protocol for occupational injuries. Occupational injuries were also investigated in this study; these results are presented elsewhere.35

Use of Heat Sterilizers
More than 95% of respondents from all provinces and territories other than the Northwest Territories (87%) reported using heat sterilizers.

The routine use of biological monitoring to verify heat sterilization has been recommended by CDA.2,3 The low use of biological monitoring in some provinces and territories raises concerns about the quality of sterilization in some dental practices. Although there is no evidence that pathogens, including HIV, have been transmitted via the dental handpiece, the potential for cross-infection has been demonstrated.36,37 Routine heat sterilization of handpieces between patients is therefore recommended.2,3

We found significant provincial and territorial differences in handpiece sterilization, with reports of heat sterilization after each patient ranging from 60 to 96%. Nonetheless, compliance with heat sterilization of handpieces was higher in this study than reported by previous studies of dentists in Canada,30,32 which confirms reports of improvement in compliance over time.38,39

Dental Unit Waterlines
Biofilms found in dental unit waterlines are a potential source for the transmission of pathogens,40- 43 an issue that is causing increasing concern. At the time of this study, CDA recommended that waterlines be flushed after each patient; however, provincial variation in reports of compliance ranged from 20 to 68%. CDA recommendations for dental unit waterlines have recently been updated44 but are still less stringent than those published by the American Dental Association.45

Handling of Sharps
If recommended infection control practices are used, the risk of occupationally acquired infection with bloodborne pathogens such as HBV, HCV or HIV is limited to sharps injuries. These injuries can be minimized if puncture-proof containers for sharps disposal are used and two-handed recapping of used needles is avoided.

Although there was high compliance with the use of puncture-proof containers for the disposal of used sharp items, there was considerable variation in compliance with the recommendation to recap used needles using a scoop technique or a mechanical device,3,4 indicating a need for educational interventions to reduce sharps injuries. Those dentists who did not use puncture-proof containers or post-exposure protocols also reported significantly more percutaneous injuries.35

Use of Barriers
Although there is evidence of improvement in compliance with barrier use among dentists in Canada,38,39 a minority of respondents in this study complied with recommendations for handwashing in addition to the appropriate use of barriers. Taking the influence of sociodemographic variables and continuing education into account, the results of multivariate analysis indicated that dentists in Alberta were more compliant than dentists in other provinces and territories with the use of barriers.

Our study does provide evidence of the protective effect of barriers. Eye protection or masks significantly reduced (but did not eliminate) mucous membrane exposures. In addition, dentists who reported the routine use of gloves averaged fewer percutaneous injuries per year compared to those who reported occasional use or non-use of gloves. It is clear that better compliance with barriers reduces the risk of occupational exposures and infection.35

Combinations of Recommended Infection Control Procedures
Although dentists’ reports of compliance with many specific infection control procedures were very high in this study, compliance with combinations of recommended infection control procedures necessary to reduce the potential for cross-infection in dental practice was low. This may explain why many respondents reported that they would use extra infection control measures for patients with HIV. If universal precautions are used, all patients are treated as if they are infected with HBV, HCV or HIV; additional infection control measures are unnecessary for patients with known bloodborne infections.

Many of the dentists in this study reported concerns about HIV. These concerns included staff fears about patients with HIV (66.5%), practitioner fears about the loss of patients from the practice as a result of treating patients with HIV (67.5%), practitioner fears about personal safety (62.6%) and worry that the cost of infection control procedures necessary to treat patients with HIV would be a financial burden for the practice (45.1%). It is possible that some dentists take unnecessary infection control precautions for patients who are known to be infected with HIV to alleviate staff fears and concerns for personal safety. In Canada, such extra precautions can lead to charges of discrimination.46,47 Recent publicity about such charges may have contributed to increased compliance with recommended infection control procedures and a better understanding of the concept of universal precautions.39

This study had some limitations. Not all infection control procedures recommended by CDA were investigated because of concerns that a larger number of items would reduce the response rate. Furthermore, because the frequency of routine use of pre-procedural antimicrobial mouthwash and rubber dams for restorative procedures was low, neither practice was included in our measure of “excellent compliance”: the subset of compliers would have been too small for further analyses. It should also be noted that post-HBV immunization serology was not included as this was not a recommendation at the time of the survey, although this has now changed.48 Also, there is evidence that self-reports may overestimate compliance with recommended infection control procedures.49 Given the low frequency of compliance reported for certain procedures and combinations of procedures, this problem may not be relevant in this study.

Provincial and territorial differences in “excellent compliance” appeared to be influenced by attending continuing education on infection control, sex (female) and practice location in population centres greater than 500,000. Reports of more than six hours of continuing education on infection control in the preceding two years were the most important predictor of “excellent compliance” with recommended infection control procedures, although the dynamics of this association are not clear. Dentists who are more conscientious about the use of recommended infection control procedures may also be more conscientious about attending continuing education programs. The association with continuing education confirms a previous report that improvements in compliance with recommended infection control procedures by dentists in Ontario may be linked to the introduction of mandatory continuing dental education by the Royal College of Dental Surgeons of Ontario.39 Continuing dental education is currently required in nine of the 12 provinces and territories in order to maintain licensure. If additional weight was given to credits for courses in infection control or if these were mandatory components of continuing dental education, compliance with recommended infection control procedures might increase further.

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Conclusion

In conclusion, we found that most dentists comply with the use of gloves, masks, protective eyewear and HBV immunization for themselves; however, many dentists do not utilize the full range of recommended infection control procedures that are necessary to minimize the risk of cross-infection in dental practice. It is important to note that in international comparisons of the infection control practices of dentists, Canadian practice appears better or comparable to the practices of dentists reported in the international literature.6 Our results lend support to the concept of mandatory continuing education that includes a specific component on infection control. With today’s increasing concerns about the transmission of bloodborne pathogens, such as the hepatitis viruses and HIV, and the rise in drug-resistant micro-organisms, compliance with recommended infection control must improve.

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Dr. McCarthy is an associate professor in the school of dentistry, department of epidemiology and biostatistics, The University of Western Ontario. She is currently a career scientist of the Ontario Ministry of Health, Health Research Personnel Development Program.

Dr. Koval is an associate professor in the department of epidemiology and biostatistics, faculty of medicine and dentistry, The University of Western Ontario.

Dr. John is an assistant professor in the department of microbiology and immunology, faculty of medicine and dentistry, The University of Western Ontario.

Mr. MacDonald is a research assistant in the school of dentistry and the department of epidemiology and biostatistics, faculty of medicine and dentistry, The University of Western Ontario.

Reprint requests to: Dr. Gillian M. McCarthy, The University of Western Ontario, Faculty of Medecine and Dentistry, School of Dentistry, Dental Sciences Building, London, ON N6A 5C1
This study was supported by a grant from the National Health Research and Development Program, Health Canada (6606-5463-AIDS).

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