Survey of Dental Health Care Workers Regarding Their Knowledge of Viral Liver Disease and Prevention of Its Transmission, Using an Online Questionnaire skin-mucosal

Background: Over three million people in Japan are estimated to be infected with hepatitis viruses. Dentists need to be aware of measures to prevent transmission and have knowledge of extrahepatic manifestations. However, in Japan, there has been little evaluation of dentists’ knowledge of viral hepatitis. We investigated dental care workers for their knowledge of, and countermeasures against, viral hepatitis. Materials and methods: An anonymous online questionnaire surveying 1,210 members of the Japanese Society of Dental Practice Administration. Interviews were carried out with those who consented. Survey items are attributes, self-management of viral hepatitis, knowledge of liver disease, control of transmission, contacting patients with viral hepatitis, and gathering information on liver diseases. Results: 153 individuals responded to the questionnaire; 41 had not been immunized against hepatitis B and 61 knew of extrahepatic manifestations. Risk and knowledge deficit scores were significantly higher for workers in dental clinics than those in university settings (p<0.001, p=0.014). Conclusion: The respondents had insufficient knowledge of viral hepatitis, a low rate of immunization against hepatitis B and may not follow safe medical practice. It is critical that dentists understand the latest information on hepatitis viruses and acquire knowledge and skills related to medical safety and prevention of infection.

Meanwhile, because dental care workers often have contact with bodily fluids, such as the blood and saliva of patients, infection control in dental medical institutions is critical. Measures and knowledge of patients infected with HBV or HCV, the most common infections in our country, are essential for dental health workers. However, dental health workers do not necessarily have sufficient knowledge of hepatitis viruses [7,8].
Patients with viral hepatitis may be subject to discrimination and prejudice from healthcare workers, and it is also a concern that they may not declare their own hepatitis virus infection at a dental clinic [9,10].
To date, there have been few reports in Japan where dentists have been investigated in detail regarding their recognition of viral liver disease. Therefore, in this study, we conducted a survey using the Internet to evaluate the recognition of problems of hepatitis by dentists. If we can clarify the problem using this survey, we can contribute to the dissemination of knowledge of liver diseases to dental health workers.

Subjects
The subjects are the 1,210 members of the Japanese Society of Dental Practice Administration.

Methods
After all members of the Japanese Society of Dental Practice Administration had been notified, we made the anonymous, questionnaire available online from April 27 to June 30, 2017. We explained the purpose of this study on the first page of the online questionnaire and considered those who responded to have provided consent. After answering the anonymous questionnaire survey, those who agreed to a telephone interview provided their name, address and contact telephone number and submitted a written consent form. Table 1: Items in the anonymous online questionnaire.

Items
No. Question Choice Attributes 1 Residential area "Hokkaido" "Tohoku" "Kanto" "Chubu" "Kinki" Chugoku" "Shikoku" "Kyush & Okinawa" 2 Sex "Male" "Female" 3 Age "30s" "40s" "50s" "60s" "70s" "over 80s" 4 Institution "University / research institution" "General hospital" "Clinic" "Local public entity" "Company" "Other" 5 Occupation "Dentist" "Doctor" "Dental hygienist" "Dental assistant" "Dental technician" "Nurse" "Medical clerk" "Pharmacist" "Clinical laboratory technician" "Radiologist" "Managed dietician" "Public health nurse" "Administrative staff" "Corporate employee" "Student" "Other" 6 Affiliated society "Japanese Society for Oral Health" "Others" 7 Years of service "Less than 5 years" "5 to 10 years" "10 to 20 years" "20 years or more" Self-management for viral hepatitis 8 Examination of HBV infection "I have received" "I have not received" "I do not know" 9 Examination of HCV infection "I have received" "I have not received" "I do not know" 10 Presence or absence of immunization against hepatitis B "I have received" "I have not received" "I do not know" 11 Presence or absence of HBV-related liver disease "I was involved in clinical practice within a year" "I have not been involved in clinical practice within one year" 17 Interview and diagnosis of liver disease in view of extrahepatic manifestations "Well" "Little" "Hardly" "Not at all" "Do not know" "Not applicable because I am not engaged in medical treatment"

Nosocomial infection control
18 Presence or absence of medical interview sheet "There is a medical interview sheet and I am using it" "There is a medical interview sheet, but I am not using it" "There is no medical interview sheet" "I do not know the existence of a medical interview sheet" "This does not apply because I am not engaged in medical consultation"

19
For those who answered "There is a medical interview sheet and I am using it" at Q18, do you have items of liver disease in your questionnaire?
"Presence" "Absence" "I do not know" 20 Recognition of standard precautions "I know the content" "I know mostly" "I've heard the words, but I do not know the details" "I have never heard the words"

21
Presence or absence of a nosocomial infection control manual, including hepatitis "There is a manual described about hepatitis" "There is no description of hepatitis although there are manuals" "There is a manual, but the description of hepatitis is unknown" "There is no manual" "This does not apply because I am not engaged in medical consultation"

22
Use of disposable gloves "Use new gloves for each patient" "Replace gloves for every 2 or 3 patients" "Replace gloves if they tear" "Replace gloves around twice a day" "Use only for invasive procedures " " Use only when seeing patients with infectious diseases " " None at all " " Do not use gloves fundamentally " " Not applicable because they are not engaged in medical treatment "

23
Reuse of anesthetic cartridges "I have never reused them" "I reused them a long time ago" "I am still reusing them sometimes" "I do not know" "This does not apply because I have no experience in medical consultation"

24
Presence of a high-pressure steam sterilizer "Presence" "Absence" "I do not know " "This does not apply because I am not engaged in medical treatment"

25
To those who answered "Presence" to Q24. Do you sterilize used surgical instruments with a high-pressure steam sterilizer?
"I always use anautoclave" "I do not always use an autoclave" "I do not know" "I do not know because I leave it to the staff"

26
To those who answered "Presence" to Q24. How do you remove the equipment after sterilization? (Multiple answers) "Remove using a sterile instrument grasping forceps or tweezers" "Save as a sterile pack" "Remove it with a bare hands or nonsterilized rubber gloves" "Do not know" "I do not know because I leave it to the staff"

27
To those who answered "Absence" to Q 24. The reason (multiple answers) "To avoid the expense of purchasing an autoclave" "Even if there is no autoclave, I am not in trouble" "Because I am sterilizing by boiling without an autoclave" "Because there is no room for an autoclave" "I am not familiar with autoclaves" " Others " 28 Sterilization method for high-speed rotating cutting tools, such as bars "Autoclave" "It is cleaned in an ultrasonic washing machine but not autoclaved" "Just immersed in a chemical solution and not autoclaved" "Wiped with ethanol for disinfection but not autoclaved" "Just washed with detergent and not autoclaved" "None" "I do not do anything in particular" "I do not know" "I do not know because I leave it to the staff" "This does not apply because I am not engaged in medical consultation" 29 Sterilization method for low-speed rotating cutting tools, such as bars "Autoclave" "It is cleaned in an ultrasonic washing machine but not autoclaved" "Just immersed in chemical solution and not autoclaved" "Wiped with ethanol for disinfectio but not autoclaved" "Just washed with detergent and not autoclaved" "None" "I do not do anything in particular" "I do not know" "I do not know because I leave it to the staff" "This does not apply because I am not engaged in medical consultation"

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30 Management of used high-speed air turbine handpieces "Autoclave sterilization""Wipe with ethanol for disinfection but do not autoclave""I do not do anything in particular" "I do not know" "I do not know because I leave it to the staff" "This does not apply because I am not engaged in medical treatment"

31
To those who answered "autoclave sterilization" to Q30. Regarding the rate of exchange "Always replace after each patient" "Exchange sometimes" "Exchange after infectious patients" "I do not know" "I do not know because I leave it to the staff" 32 Management of used low-speed contraangle handpieces "Autoclave sterilization" "Wipe with ethanol for disinfection but do not autoclave""I do not do anything in particular" "I do not know" "I do not know because I leave it to the staff" "This does not apply because I ams not engaged in medical treatment"

33
Management of used endodontic treatment instruments (reamers, files, cleansers, etc.) "Autoclave sterilization" "It is cleaned in an ultrasonic washing machine but not autoclaved" "Just immersed in chemical solution and not autoclaved" "Wiped with ethanol for disinfection but not autoclaved" "Just washed with detergent and not autoclaved" "Nothing" "I do not do anything in particular" "I do not know" "I do not know because I leave it to the staff" "This does not apply because I am not engaged in medical treatment" 34 Disinfection method for rubber or plastic equipment used for hepatitis virus infected persons "Immerse in glutaral or phthalal preparations" "Wipe with ethanol for disinfection" "Because it cannot be put in an autoclave, it is often discarded after use" "Only wash with detergent" "Nothing" "Do not know" "I do not know because I leave it to the staff" "This does not apply because I am not engaged in medical treatment"

35
Experience of having problems with hepatitis virus patients "Frequently" "Occasionally" "Very little" "Not at all" "Do not know" "Not applicable because I am not engaged in medical treatment"

36
To those who answered "Frequently" or "Occasionally" when a person infected with hepatitis virus was consulted in Q 35. The most troublesome (multiple answers) "Infection control against liver diseases" "Understanding the pathology of liver diseases" "How to treat liver diseases and nursing" "Observation treatment (tooth extraction and incision, etc.)" "Medication" "Communication with patients" "Doctor's introduction and inquiries to the doctor" "Communication with a doctor specializing in liver disease" "Others"

37
To those who answered "Frequently" or "Occasionally when a person infected with hepatitis virus was consulted in Q35, The most troublesome (single answers) Infection control against liver diseases "Understanding the pathology of liver diseases" "How to treat liver diseases and nursing" "Observation treatment (tooth extraction and incision, etc.)" "Medication" "Communication with patients" "Doctor's introduction and inquiries to the doctor" "Communication with a doctor specializing in liver disease" "Others"

38
Prejudice and discrimination against hepatitis virus infected patients "Much" "A little" "Not so much" "No at all" "Do not know"

Method of gathering information on liver diseases
39 Do you want to participate in a seminar that provides the latest information on hepatitis?
"I want to participate" "I do not want to participate too much" "Will not participate" "I do not know"

Telephone interview 40
Do you agree to a telephone interview? "I do not agree" "I agree" HBV: Hepatitis B Virus; HCV: Hepatitis C Virus Items in the anonymous, online questionnaire (Table  1) Analysis of items regarding risk behavior and onset of liver disease, and lack of knowledge (Table 2): Among the questionnaire items, risk scores were given to responses that indicated failure to self-manage hepatitis or to take safe hospital infection countermeasures. Risk was scored as 1 point and norisk as zero point. In addition, a responder with liver disease was scored as 1 point and one without liver disease as zero point. A person with no knowledge of liver disease was scored as one 005 point and one with knowledge was scored as zero point. For each subject, the scores were totaled for three items: risk behavior, presence of liver disease and lack of knowledge. A high score indicates a dangerous medical situation.

Aggregate online survey
153 subjects (128 men, 25 women) completed the online questionnaires anonymously (Table 2). Individuals aged in their fifties (62, 40.5%) and sixties (51, 33.3%) accounted for about 70% of the total. There were more responses from directors of dental clinics (99 individuals, 64.7%) than university research institutes and workers in general hospitals (50 individuals, 32.7%). Almost all (91.5%) of the respondents were dentists. 77.8% (119 individuals) who had been engaged in medical treatment for more than 20 years.
Of the responders, 144 (94.1%) and 126 (82.4%) had been tested for HBV and HCV infection, respectively, but 41 (26.8%) had not been immunized against hepatitis B. Four (2.6%) and two (1.3%) had HBV-related and HCV-related liver disease, respectively. Only 72 individuals (47.1%) were aware that there are more HCV-infected people in the western part of Japan but 114 (74.5%) recognized that oral antiviral agents (direct acting antivirals, DAAs) are the standard therapeutic agents for hepatitis C. Sixty one (39.9%) knew of the extrahepatic manifestations of hepatitis virus infections and 34 (22.2%) asked questions and carried out medical examinations regarding HCV infection when examining patients with LP.
The answers to the questions regarding measures for infection control were as follows: There were 10 responders (6.5%) who used questionnaires without liver disease items, 126 (82.4%) who understood the contents of the standard precautions, 104 who had produced manuals for infection control measures, 112 (73.2%) who used disposable gloves for each patient, 129 (84.3%) who had never recycled anesthetic cartridges, 143 (93.5%) who sterilized used surgical instruments, 106 (69.3%) who sterilized used high-speed rotating cutting tools such as bars, 87 (56.9%) who sterilized used low-speed rotating cutting tools such as bars, 118 (77.1%) who sterilized used high-speed air turbine handpieces,107 (69.9%) who sterilized used lowspeed contra-angle handpieces, 97 (63.4%) who sterilized used endodontic treatment instruments (reamers, etc.), and 130 (85.0%) who disinfected in a safe way or discarded the instruments used for hepatitis virus-infected patients.
The responses regarding the treatment of patients with liver disease were as follows: Thirty-five (22.9%) had had difficult experiences with hepatitis virus-infected patients, the most serious problem was infection control against liver disease (18/35 individuals, 51.4%), and eight (5.2%) had prejudice and discrimination against hepatitis virus-infected patients. There were 108 responders (70.6%) who wished to participate in seminars providing information on liver diseases. Table 2 shows the scores for risk behavior, onset of liver disease, and lack of knowledge. Table 3 shows average values of the three sets of scores according to residential district, sex, years of service, and institution. The men had a significantly higher risk scores and knowledge deficit scores than the women (p=0.002, p=0.031). Risk scores and knowledge deficit scores were significantly higher for directors of dental clinics than for university workers (p<0.001, p=0.014). Dentists with less than 20 years of experience tended to have a higher knowledge deficit score than those with more than 20 years (p=0.053). There was no significant difference in the relationship between the responder's residential district and the scores.

Result of the telephone interviews
All but one of the 42 subjects who agreed to do so participated in a telephone interview (implementation rate 97.6%) ( Table  4). The average interview time was 14.41 minutes. Twenty-two interviewees (53.7%) reported "not performing" or "hardly performing" medical cooperation with patients with liver disease. Documents such as letters were the most frequent means of medical cooperation (16 subjects, 39.0%). Twenty-five (61.0%) responded that there were opportunities to acquire knowledge of liver diseases but reported that seminars for dentists about liver diseases were not available.

Discussion
On December 31, 2016, 104,533 dentists were registered in Japan, 80,189 men (76.7%), and 24,344 women (23.3%). (Eighty dentists per 100,000 population.) Regarding the type of facility, 89,166 dentists worked in clinics and 12,385 dentists worked in university research institutes and general hospitals: the proportion of dentists working in clinics is increasing year by year.
In this study, the directors of dental clinics had significantly higher risk scores for infection and deficiency of knowledge of hepatitis viruses and infection control than dental physicians working in university research institutes and general hospitals. This indicates a serious problem in securing medical safety in Japan, where the vast majority of dentists work in clinics. Dentists and dental health care workers are at high risk of infection with HBV and HCV during their daily occupational experiences [11].
Following a survey of 253 Japanese dental students between 2006 and 2007, we reported that their understanding of disinfection and sterilization was insufficient [7]. The introduction of a modified curriculum, with appropriate education of students in these matters, were critical issues.

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According to a screening study of 141 Japanese dental workers conducted in 2007, fewer than half (48.2%) of the participants had been immunized against hepatitis B [8]. Of 63 immunized individuals, 16 (25.4%) were positive for anti-HBc, indicating past exposure to the virus. The positivity rate of anti-HBc was 85.7% for respondents in their sixties and 100% for those in their seventies; this rate was extremely high for the oldest responders. In routine dental practice, dentists who did not always use disposable gloves accounted for 17% of those who tested positive. Tada et al. surveyed changes in infection control practice reported by dentists in Japan in 2008 and 2011 and factors related to these changes [12]. They reported that the rate of immunization against hepatitis B was 65.4% in 2008 and 67.1% in 2011. Infection control practices significantly associated with the proportion of dentists specializing in oral surgery, the proportion of dentists reporting a willingness to treat HIV and AIDS patients, and the proportion of dentists reporting knowledge on standard precautions. Compliance with effective infection control practices by dentists may be affected by knowledge and education.
We have also reported that 59.8% of HBV and HCV infection with liver disease patients consistently self-declared hepatitis virus infection when undergoing dental treatment [9]. The main reason for not reporting such infections at a dental clinic was because the dentist had not enquired about the possibility of an underlying disease (71.2%).
In the United States, a case of HBV infection related to tooth extraction was reported in 2007 [13]. Nosocomial infection from patient to patient was proved because the HBV nucleotide sequence matched between the patients. In 2013, in the United States, the Centers for Disease Control and Prevention (CDC) issued a report of patient-to-patient transmission of HCV in a dental office [14]. More than 7,000 patients were notified and tested for hepatitis B and hepatitis C viruses and HIV because of unsanitary conditions and improper sterilization of equipment in the office. The Oklahoma State Department of Health reported that 77 people tested positive for hepatitis C, five for hepatitis B and four for HIV.
In Japan, Ogata et al. [15] reported that the major sources of acute hepatitis C virus infection in 2013 were medical procedures and accidental needle sticks. Their study was a retrospective analysis of patients in 12 facilities nationwide who developed acute hepatitis C after 1990. Medical procedures were the most common source of infection, accounting for 32.4% of the 102 patients (33/102). These procedures were as follows: surgery (14 cases), blood transfusion (5), endoscopy (3), intravenous injection (4), invasive procedures (3), dental therapy (3) and dialysis (1).
Mahboobi et al. [16] concluded in their review that dental treatment is a risk factor for acquiring HBV and HCV and that the risk could be eliminated easily using standard precautionary measures.
Based on a revision of the medical law in Japan, general dental clinics were obliged in 2007 to establish medical safety management systems. In June 2014, the Ministry of Health, Labor and Welfare announced a requirement to sterilize the dental handpieces for each patient. In a questionnaire answered by 700 Japanese dental physicians in 2017, the rate of sterilization after replacing used handpieces for each patient was 52%, the rate of exchanging gloves for each patient was 52%, the rate of sterilization after washing used cutting bars was 64% and the ratio of sterilization after washing used root canal treatment devices was 65% [17].
Unfortunately, even in this study of members of the Japanese Society of Dental Practice Administration, the rate of sterilization of instruments was rather low. Despite being at high occupational risk of hepatitis virus infection, only around 70% of the responders had been immunized against hepatitis B The percentage of dentists who treat oral mucosal disease from the viewpoint of extrahepatic manifestations was also small.
Hepatitis C virus is known to cause extrahepatic manifestations such as oral lichen planus (OLP) [6,18]. We performed a genome-wide association study (GWAS) of Japanese HCV-related patients with or without OLP, followed by a replication analysis in an Italian population. It was found that rs884000 in neuropilin-2 (NRP2), rs538399 on insulin-like growth binding proteins factor 4 (IGFBP4), and rs9461799 (HLA-DR/DQ) were associated with HCV-positive LP [19].
If dentists encourage examination and treatment of hepatitis through dental and medical cooperation, they can identify and treat patients with undiagnosed hepatitis virus infections. We examined retrospectively oral mucosal disease and HCV infection using the medical record information of 90 patients who consulted a general dental clinic [20]. OLP was the most common oral disease. Among 51 patients who could be examined for the presence or absence of HCV infection, the incidence of that infection was 29.4% (15/51). Among the OLP patients who consulted the dental clinic, we identified a new HCV-infected patient and led an untreated HCV-infected patient to a sustained virological response (SVR).
There have been some reports that have assessed stigma and discrimination in relation to HCV infection within the healthcare setting [21]. We performed a survey of the prejudice and discrimination experienced by HCV/HBV-infected individuals from healthcare workers. Prejudice was most prevalent within the dental clinic setting [10].

Conclusion
We conclude that dentists in Japan do not have sufficient knowledge of viral hepatitis, have a low rate of immunization against hepatitis B and do not necessarily carry out safe medical practices, despite having a high risk of infection. We consider that dental care workers need to understand the latest information on hepatitis viruses and to acquire knowledge and skills related

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to medical safety and prevention of infection. It is necessary to treat the oral cavity with a view to cooperative medical treatment between medical departments and dentistry.