Hepatitis B virus infection in the dental profession

Orthodontic instrument sterilization with microwave irradiation

Objective:

This study was designed to evaluate the efficiency of microwave sterilization of orthodontic instruments and molar bands immersed in plain distilled water with and without oral rinse, and to ascertain the minimum time of exposure required to sterilize.

Materials and Methods:

The orthodontic instruments (hinged and nonhinged), molar bands and mouth mirrorsused in the patient 's mouth were selected for the study. The instruments were divided into two groups – Group I with oral rinse-set A (0.01% chlorhexidine gluconate) and set B (0.025% betadine) and Group II (included sets C and D without oral rinse). The instruments of set A, B and C were microwaved at 2,450 MHz, 800 W for 5 min, whereas, set D was microwaved for 10 min at the same above mentioned specifications. The efficacy of sterilization was assessed by stab inoculation of the instruments onto trypticase soya agar plates. The plates were checked for bacterial growth following incubation at 37 °C for 24 h. For sterility control,Geobacillus stearothermophilus (MTCC 1518) was included.

Results:

No growth was observed in the plates that were inoculated with the microwaved orthodontic instruments of sets A, B and D, whereas scanty bacterial growth was observed in the plates inoculatedwith the microwaved set C instruments.

Conclusion:

Effective sterilization was achieved when the orthodontic instruments and molar bands were immersed in distilled water without oral rinse and microwaved for 10 min as also for those that were immersed in distilled water with oral rinse and microwaved for 5 min.

The need for post-vaccination serology and the timing of booster vaccinations against hepatitis B in dental health care workers

Viral hepatitis caused by the hepatitis B virus is a disease which has no oral manifestations but is of direct concern to dental health care workers due to its transmissibility by transfer of minute quantities of infected body fluids from patients with the condition. Many chronic carriers of HBV do not have signs and symptoms of hepatitis and are frequently unaware of the virus they harbour. In recent years immunization against HBV has become possible and a high success rate has been achieved in inducing immunity against HBV in dental health care workers who have completed an immunization programme. When the HBV vaccines were introduced to widespread clinical use in the 1980s it was optimistically predicted that immunity conferred by the vaccines would be for ten years. Recent research has cast severe doubts on this optimism and clinical trials have indicated that the immunity may be short-lived and varies between individuals. Longevity of immunity is dependent upon antibody levels attained by the immunization programme. Post-immunization antibody levels can be utilized as a guide to the longevity of the immunity and hence should serve as a prognostic indicator for timing of booster inoculations.

Sterilization of dental instruments and devices: an update

Dental sterilization techniques have become a focus of attention as a result of disclosure of occupational HIV transmission from an infected dentist to a cluster of patients. Although there has never been a confirmed report of a patient acquiring an infectious blood-borne disease from a dental instrument or device, recommendations for universal sterilization of dental handpieces and other devices have recently been implemented. Because of the higher rate of hepatitis B virus transmissability in the dental health care environment, an upgrade in sterilization protocols may be warranted. Stringent sterilization standards are especially necessary in higher-risk institutional dental care settings. However, a high rate of dental sterilization errors has been reported and traced to operator error. Recent institutional dental sterilization policy changes have been developed to reduce the chance of sterilization error, further diminishing the risk of cross contamination.

Prevalence of hepatitis B surface antigen and antibody among health care employees in Negri Sembilan, Malaysia, 1989

This study was based on a hepatitis B screening program conducted in one of the states in Malaysia in 1989. The majority (84.6%) of the 2986 health employees were screened. One quarter (25%) was found to have serological markers for the Hepatitis B Virus (HBV); 2.1% had Hepatitis B surface Antigen (HBsAg) and 22.8% had antibody to the Hepatitis B surface Antigen (anti-HBs). The occurrence of HBsAg was higher in ethnic Chinese (6.3%) compared to Malays (1.8%) and Indians (0.9%), even when analyzed by sex, but not with age, type of institution and geographical locality. The distribution of anti-HBs was higher with ethnic Chinese (41.6%), male sex (27.2%) and age. There was a wide variation of the prevalence of serological markers among occupations and increased relative risks of HBsAg were found among medical assistants (RR3.7; 95% CI 1.4-9.1) and laboratory staff (RR 3.2; 95% CI 1-8.8), and that of anti-HBs among medical assistants (RR 2.8; 95% CI 1.8-3.7). The variations of HBsAg among occupations by type of institutions was marginal while that of anti-HBs was higher among attendants and midwives in hospitals, medical assistants in health departments, and assistant nurses and dentists in dental centers. The patterns of distribution of serological markers of HBV among health staff reflect the situation in the community with high endemicity and resemble specific occupational factors noted in previous studies in the West.

Seroprevalence of hepatitis B surface antibody in South African dental personnel

Because there are no data available on the seroprevalence of hepatitis B in dental personnel in South Africa, a study was performed to assess the antibody status to hepatitis B surface antigen among 129 dental (preclinical) students and 62 dental hygienists at the Western Cape Dental School of South Africa. A total of 11 dental students and nine hygienists were positive to hepatitis B surface antibody, indicating a seroprevalence of 8.5% and 14.5%, respectively. These results, reported for the first time in dental personnel in South Africa, imply that dental students and hygienists in this part of the world are exposed to a significant risk of contracting hepatitis B.

Infection control in the Indian Health Service Dental Program: estimated costs and effects on productivity

The dental literature contains many recommendations defining standards for infection control. Little information is available, however, documenting the cost of implementing these standards. This article describes the cost incurred by the Indian Health Service Dental Program in the Oklahoma area between 1985 and 1988 for infection control. During this period, comprehensive infection control recommendations were published for oral health programs serving Native Americans and data were collected on supply utilization. While productivity data were collected for that same time period do not support the premise that infection control practices lead to decreased clinical productivity, infection control supply costs did increase over fourfold during this period.

Use of non-sterile gloves in clinical practice

This paper reviews the use of non-sterile gloves in dental practice. It is now considered to be normal practice to wear gloves for all dental procedures and although there is considerable controversy regarding patterns of glove use, there is increasing evidence to the effect that single patient use is indicated. Careful use of gloves and proper hand care are key components to effective cross-infection control in clinical practice.

Infection control in general dental practice. Results of a postal survey of 600 registered dental practitioners in New South Wales

A postal survey of 600 dental practitioners in New South Wales was conducted in 1986 to establish a data base on current infection control protocols as they apply to everyday dental practice. Three hundred and sixty-three replies (60 per cent) were returned, representing approximately 16 per cent of Australian Dental Association members in New South Wales (1987).

Barrier techniques and hepatitis B vaccine policies in dental components of local health agencies

National health organizations have issued guidelines for barrier control techniques against infectious diseases and for inoculation against hepatitis B. This study surveys the policies of local health agencies regarding the safeguards used in protecting their employees. Local health agencies (N = 201) operating independently of state health departments were mailed questionnaires seeking information regarding glove, mask, and eyewear policies, as well as hepatitis B vaccine policies for new and current employees. Of the 156 programs returning the survey, 127 (76.6%) reported having a clinical component. Many agencies did not require infection control policies to be implemented for every patient. Agencies that had dental directors who have held their positions for fewer than four years were more likely to have requirements for gloves and masks than agencies run by directors with longer tenure. Those agencies that provided dental treatment to inmates at correctional institutions were also more likely to require infection control policies. The data indicate policy inconsistencies among local dental health programs nationwide. Of considerable concern is the fact that infection control was not identified as a priority for the near future. Many local health agencies would benefit from further education in infection control.

Glass bead sterilization of orthodontic bands

The purpose of this study was threefold: to determine if bead sterilization is capable of sterilizing orthodontic bands, if so, to establish a minimal time for sterilization when bands are inoculated with bacteria and spores, and to compare bead sterilization to other methods of cleansing and disinfecting orthodontic bands used in the office setting. Ten bands per time trial inoculated with either Bacillus subtilis spores or Staphylococcus albus bacteria were used along with ten controls (inoculated but not placed in the bead sterilizer). The bands were placed one at a time into a 226 degrees C bead sterilizer for 15, 30, 45, and 60 seconds, transferred to a test tube with BHI broth, and incubated at 37 degrees C for 3 days. The results indicated that 15 seconds is required to sterilize bacteria and 45 seconds required for spores. If five bands were placed in the bead sterilizer simultaneously, twice the time was required for sterilization. Other techniques for disinfecting bands, such as a 5-second tap water rinse, 10-second soap scrub, 30-minute immersion in alcohol, and alcohol flame, were ineffective in killing bacteria or spores with one exception--the alcohol flame was capable of preventing growth on bands inoculated with Staphylococcus albus.

Upgrading sterilization in the orthodontic practice

In today's orthodontic practice, disease control must undergo major reevaluation and restructuring. The knowledge of the natural history and treatment of many highly transmissible diseases to which orthodontic personnel are at high risk is changing rapidly. Among these diseases are acquired immune deficiency syndrome (AIDS), hepatitis B virus, and the herpesvirus complex (currently five types). If barrier techniques are not in place, it is possible to cross-infect orthodontic personnel and patients alike. Clinical orthodontics, with its higher volume of patients (on a daily basis) than other dental practices, requires a custom-made sterilization schema tailored to each office. Proper organization of instruments to permit orderly processing, storing, and use is even more important than before. Turnaround time of processing instruments, corrosion control, and minimizing of dulling of cutting edges are critical. Treatment of surfaces and chair/unit facilities with improved disinfection techniques is a necessity. Protection of hands and eyes by appropriate means is discussed with practical guidelines for the use of gloves by chairside personnel. Many fomites (inanimate disease transmitters) lurk in the orthodontic office and must be eliminated. Finally, the most important ingredient to any change--the orthodontic office staff--must be enlightened, trained, and supervised by the orthodontist to effectively and efficiently switch from the old to the new.