New light on the transmissibility of viral hepatitis in dental practice and its control

Evaluation of Effective Chloramine-T Concentration to Be Incorporated in Dental Stone for Antimicrobial Activity

Objective The objective of this study was to determine the antimicrobial activity of type III gypsum at three different chloramine-T concentrations and to ascertain the most effective concentration to be added for optimum inhibitory activity against Candida albicans. Method Ten discs of type III gypsum were fabricated for each group. Standard type III gypsum without any disinfectant was used for the control group. For the experimental group, an admixture of chloramine-T and standard dental stone was employed in varying w/w concentrations (0.1%, 0.25%, and 0.5%). Discs were placed in a petri dish containing Sabouraud dextrose agar lawned with Candida albicans culture and incubated for 24 hours. The zone of inhibition created around the discs was measured and evaluated. Result The mean zone of inhibition (mean ± standard deviation) in the control group was 0 mm; 0.70±1.05 mm in group 1 (0.1% w/w concentration), 2.70 ± 2.35 mm in group 2 (0.25% w/w concentration), and 20.80 ± 1.68 mm in group 3 (0.5% w/w concentration). A one-way ANOVA test showed that there was a significant difference in the inhibition zone created around all groups (p < 0.05), with the discs of group 3 yielding the most positive results. Conclusion The addition of 0.5% chloramine-T to type III gypsum showed the most promising result, out of the concentrations tested, as a self-disinfecting dental stone and could be used for further investigations.

Using a biological indicator to detect potential sources of cross-contamination in the dental operatory

The authors conducted a study using surveillance monitoring methodology to identify operatory contamination and to evaluate the effectiveness of infection control procedures. Viridans streptococci were evaluated as biological indicators of oral contamination. Viridans streptococci, abundant in human saliva, were detected on operatory surfaces after dental treatments were finished and surfaces were disinfected. The findings validate current concepts of infection control as demonstrated in barrier methods.

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.

AIDS and dental practice

Dental health care workers (DHCWs) can provide important diagnostic, treatment, and referral services for patients with AIDS and at risk for AIDS. They also have a responsibility to protect all patients in their practices, and themselves, from infectious disease transmission through the use of infection control. To determine the extent to which DHCWs are prepared to assume these responsibilities, a randomized survey of California DHCWs was conducted. Responses were obtained from 297 dentists, 128 hygienists, and 177 dental assistants. DHCWs who expressed a greater willingness to treat people with AIDS or HIV infection also practiced more thorough infection control. Respondents in all groups who perceived a greater percent of their patients to be at risk for AIDS were more likely to use infection control procedures (P less than .0001). They also were more willing to treat such patients (P less than .004) and were more likely to assess patients for AIDS by taking a thorough medical history (P less than .02) and sexual history (P less than .04). Since attitudes toward AIDS and perception of the percent of patients at risk in one's practice affect patient assessment and infection control procedures used by dental health care workers, educational programs designed to enhance DHCWs' response to the HIV epidemic should alert them to the extent of the problem and help them cope with their concerns.

Direct measurement of hepatitis B viral antibody and antigen markers in gingival crevicular fluid

Radioimmunoassay analyses of serum are widely performed to monitor the incidence of hepatitis B virus infection. As an alternative to serum analyses, the authors have explored the feasibility of using gingival crevicular fluid for the detection and quantitation of hepatitis B viral immunologic markers. The results of the study demonstrate that the hepatitis B surface antigen can be easily quantified in gingival fluid. Confirmation of the presence of the hepatitis B e antigen can also be made, but this is more difficult because of the small amounts of gingival fluid currently being assayed. Antibody to the hepatitis B surface antigen can be quantitated in high-titered persons.

Steam sterilization of air turbine dental handpieces

The efficacy of autoclaving high-speed dental handpieces was tested in two types of downward displacement steam sterilizers (instrument autoclaves), commonly used in the dentist's office. Eight series of experiments were performed with various sterilization schedules. Lubrication oils with or without antimicrobial agent were used in four of the series. Each handpiece was inoculated with 1 ml of a suspension containing equal amounts of saliva and spores of Bacillus stearothermophilus (approx. 10(6) spores/ml). Neither sterilization at 120-124 degrees C for 20 min nor at 134-136 degrees C for 10 min resulted in complete inactivation of the spores in series in which the instruments were tested without oil or with oil containing no antimicrobial agent. However, when the handpieces were lubricated with oil containing isopropanol and formaldehyde and the schedule 134-136 degrees C/10 min was used, no growth was observed. The results indicate that instrument autoclaves with built-in programs of 120-124 degrees C/20 min and 134-136 degrees C/10 min could have insufficient capacity to sterilize lubricated or unlubricated dental handpieces. The use of oils containing an antimicrobial agent can overcome this problem.

Proper monitoring of sterilization procedures used in oral surgery

The sterilization procedures used by oral surgeons in Norway have been surveyed. In 22 of the 25 oral surgical clinics controlled, instruments were sterilized by saturated steam at 121 degrees C or 134 degrees C; 3 used a dry heat oven sterilizer; dry heat and/or gas sterilization procedures supplemented steam sterilization in 17 clinics. When these sterilization procedures were monitored with biological indicators, 5 autoclaves (challenged with B. stearothermophilus spores), 2 dry heat sterilizers (B. subtilis spores), and all the Harvey Chemiclaves tested (B. subtilis spores) did not inactivate the bacterial spores. A biological monitoring system that fulfills the valid requirements for sterilization procedures given by the national health authorities and that is reliable, convenient, economical and self-contained should be used routinely in oral surgery clinics.

Avoiding cross-contamination in prosthodontics

Reduction of the potential for cross-contamination in prosthodontics may be accomplished in the following ways: 1. Use surface covers such as clear plastic wraps or bags over instruments like face-bow, articulators, and torch handles. 2. Disinfect surfaces with chemical agents such as 1% iodine surgical scrub in 70% isopropyl alcohol in a ratio of 1:2 to 1:20. 3. Use unit-doses of petroleum jelly, impression materials, waxes, indelible pencils, etc. 4. Use mechanical sterilization to sterilize prosthodontic instruments as "set ups" not commonly thought compatible with the mechanical sterilization process (wood-handled knives, spatulas, Boley gauges, bite forks, impression trays, metal rulers, and acrylic resin burs). 5. Use chemical disinfectants such as Cidex, 2% glutaraldehyde; iodophor solution, 1% stock iodine diluted to 0.5% to 0.05% in 70% isopropyl alcohol; and 5.25% sodium hypochlorite diluted to 0.5% to 0.05% with tap water to disinfect removable partial denture frameworks, acrylic resin impression trays, immediate dentures, and mold and shade guide teeth. 6. Use a mask and latex disposable examination gloves during all patient contact. Efficient application of these recommendations will reduce the potential for disease transmission during the delivery of health care.

The threat of hepatitis B from dental school patients. A one-year study

A study was conducted at the Louisiana State University School of Dentistry using the radioimmunoassay technique of serum analysis for presence of hepatitis B surface antigen (HBsAg) in all new patients accepted for treatment over a period of one year. The prevalence was 0.61 percent (22 seropositive patients from a total of 3,626 patients screened). Chronic HBsAg carriers, presence of e antigen, and high titers of antibody to hepatitis B core antigen (anti-HBc) were documented. Eighteen of the 22 seropositive patients had no past history of hepatitis, indicating the inadequacy of a history for revealing carriers of HBsAg.

Dental care and spread of hepatitis B virus infection

Sera from 576 healthy adults were tested for the hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) to evaluate the role of routine dental care as a factor in the spread of hepatitis B virus (HBV) infection. Serological evidence of prior HBV infection, manifested by acquisition of anti-HBs, was detected in 97 (16.8%) individuals, and 6 (1.0%) were identified to be asymptomatic HBsAg carriers. The anticipated correlations of HBsAg and anti-HBs with age, country of birth, and socioeconomic status were observed in the study population. However, prevalences of both HBsAg and anti-HBs were inversely related to the lifetime total of dental care visits. These findings indicated that, in a region in which the HBsAg carrier state and hepatitis B are prevalent, routine dental care is not identified as an important factor in the spread of HBV infection. While the results do not exclude the obvious possibility that cross-infections with HBV may occur during dental care in specific situations, they indicate that this mode of infection is exceptional.

Prevalence of hepatitis B surface antigen in a dental school patient population

A sample of 300 adult patients accepted for initial treatment between January 5th and 24th, 1977 at the Louisiana State University School of Dentistry had blood samples drawn and analyzed by radioimmunoassay+ for the presence of hepatitis B surface antigen (HBSAg). Two patients were positive for HBSAg (a prevalence of .67 percent. Medical questionnaire information obtained from each participant indicated that 11 patients had had hepatitis; seven were confirmed by the patients' private physicians. Both patients positive for HBSAg gave confirmed histories of having had hepatitis. The information gathered tends to indicate that dental patients who give a history of hepatitis should have a blood sample drawn and analyzed by radioimmunoassay for HBSAg to determine whether they are carriers of HBSAg. This analysis should precede any dental treatment. Further studies are planned to obtain information from another sample population.