Photopolymerization of composite resin using the argon laser. (1/99)

Because of the dental profession's increased utilization of light-cured restorative materials, there has been a corresponding increase in research into the light sources used to initiate polymerization. The argon laser is one promising source, as the wavelength of light emitted by this laser is optimal for the initiation of polymerization of composite resins. The literature reflects a strong divergence of opinion about many aspects of the effectiveness of laser curing compared to conventional light curing. Research indicates that the argon laser offers a greater depth and degree of polymerization, less time required and an enhancement of the physical properties of composite resins polymerized. These advantages are offset by reports that the increased polymerization caused by the laser results in increased shrinkage, brittleness and marginal leakage. Dentists interested in the new technology need to monitor ongoing studies.  (+info)

An evaluation of sampling and laboratory procedures for determination of heterotrophic plate counts in dental unit waterlines. (2/99)

BACKGROUND: The high numbers of heterotrophic microorganisms that have been cultured from dental unit waterlines (DUWs) have raised concern that this water may exceed suggested limits for heterotrophic plate counts (HPCs). The main purpose of this investigation was to examine HPC variability in DUWs and to examine in detail the effect of laboratory processing of water samples on HPC values. METHODS: Water samples were collected from dental offices either at the beginning of or during the clinic day and were transported to the laboratory, where they were analyzed. RESULTS: Measuring HPC levels within an office would involve testing all units, because significant differences were found between units connected to the same municipal water supply. Within a unit, the average microbial count from high-speed lines was approximately twice the average count from air/water lines. The laboratory processing of water samples significantly affected the numbers of heterotrophic microorganisms that were recovered. Incubation temperature, time and media, as well as neutralization of residual chlorine, all had significant effects on the HPC values. However, no significant differences in microbial counts were found between samples plated with the spread plate method on R2A agar and those plated with the pour plate method with Plate Count Agar. CONCLUSIONS: Dental organizations have suggested target limits in terms of numbers of heterotrophic microorganisms recovered in water from dental units, but standards for laboratory handling must be established as well. A protocol for sample collection and laboratory handling is proposed.  (+info)

Evaluation of environmental bacterial contamination and procedures to control cross infection in a sample of Italian dental surgeries. (3/99)

OBJECTIVES: To perform a pilot study on bacterial contamination in some dental surgeries (n=51) in a local health unit in Brescia (Lombardy Region, Italy) and to evaluate the procedures to control cross infection used by the personnel to reduce the risk of infection in dental practice. METHODS: A survey was carried out by interviewing 133 dental personnel with a questionnaire on the procedures used to control infection. The autoclaves, chemical baths (chemiclaves), and ovens present in the surgeries were tested for sterilisation efficiency with a spore test, and already packed and sterilised instruments were randomly sampled and tested for sterility. Microbial contamination of air, surface, and dental unit water samples were also studied. RESULTS: The dental personnel did not generally follow the principal procedures for infection control: 30% of personnel were not vaccinated against hepatitis B virus, infected instruments were often not decontaminated, periodic checks of autoclave efficiency were lacking, and the knowledge of disinfection mechanisms and procedures was incomplete. High bacteriological contamination of water at dental surgeries was often found and total bacteriological counts in air samples were high. Surface studies showed widespread bacterial contamination. CONCLUSIONS: On the basis of these results, an educational programme for the prevention of infective hazards has been prepared and carried out. The results of this pilot study will be used for planning a national survey.  (+info)

A survey of perceived problems in orthodontic education in 23 European countries. (4/99)

This paper reports on a survey of perceived problems in the provision of orthodontic education at the stages of undergraduate, postgraduate, and continuing professional education (CPE) in 23 European countries in 1997. A questionnaire, together with an explanatory letter, was mailed to all members of the EUROQUAL II BIOMED project. Answers were validated during a meeting of project participants and by further correspondence, when necessary. The topics covered in the questionnaire were adequacy of funding, numbers of orthodontic teachers, availability of equipment, regulations, training centres, numbers of orthodontists, availability of books, journals, and information technology. Completed questionnaires were returned by orthodontists from all 23 countries. Respondents from seven countries did not answer all questions. Respondents reported a perceived almost universal lack of adequate funding for postgraduate orthodontic training (from 18 out of 20 countries) and, to a lesser extent, at undergraduate (13 out of 20 countries) and CPE levels (17 out of 21 countries). Respondents from 12 of the 20 countries reported adequate numbers of qualified teachers at undergraduate level, but only seven out of 18 at postgraduate level and eight out of 19 for CPE. Lack of suitable equipment was reported as a more frequent problem by central and eastern European countries (six out of 20 countries at undergraduate level, eight out of 20 countries at postgraduate level, and 12 out of 19 at CPE level). Too few or too many regulations were only perceived to be a problem by the respondent from one country out of 19 at undergraduate level, by seven out of 19 at postgraduate level, and by eight out of 16 at CPE level). Lack of training centres was more frequently reported as a problem by respondents from central and eastern European countries, but was generally not perceived as a problem by respondents from west European countries. Respondents from seven countries reported a lack of training centres for CPE. Respondents from six countries reported that they perceived there to be too many orthodontists at postgraduate level, from seven countries that there were an appropriate number, and from seven that there were too few. A lack of books, journals, and information technology was reported to be a problem by respondents from four out of 19 countries at undergraduate level, eight out of 20 at postgraduate level, and 10 out of 20 at CPE level. At both undergraduate and postgraduate level, the majority of respondents from central and eastern European countries reported problems with books, journals, and information technology. The results of the survey confirmed many anecdotal impressions and provided an extremely useful background against which to formulate quality guidelines for orthodontic education in Europe.  (+info)

Users' demands regarding dental safety glasses. Combining a quantitative approach and grounded theory for the data analysis. (5/99)

Eye infections are common among dentists and many are concerned, but few are using proper eye protection. To understand users' demands behind the low use of safety glasses, all dental teams in Sweden were asked which factors they found most important when choosing dental safety glasses, and rate the importance of 31 statements regarding ergonomic aspects of dental safety glasses in a questionnaire. Data were analysed using the Grounded Theory and a quantitative approach. Results showed that dentists ranked the visual aspects as most important and chair assistants the protective aspects. The highly visual demanding work performed by dentists requires safety glasses that are not yet available on the market, which might explain the low use.  (+info)

Mercury vapour release from a dental aspirator. (6/99)

OBJECTIVE: To investigate the release of mercury vapour from a dental aspirator which vented its waste air through its base directly into the surgery environment. METHODOLOGY: Mercury vapour in air concentrations were measured at the breathing zone of the dentist during continuous operation of the aspirator. Further series of mercury vapour measurements taken at the aspirator exhaust vent were carried out to determine the sources of mercury vapour from this particular device. RESULTS: At the dentist's breathing zone, mercury vapour concentrations of ten times the current occupational exposure limit of 25 micrograms/m3 were recorded after 20 minutes of continuous aspirator operation. A build up of amalgam contamination within the internal corrugated tubing of the aspirator was found to be the main source of mercury vapour emissions followed by particulate amalgam trapped within the vacuum motor. As the vacuum motor heated up with run time, mercury vapour emissions increased. It was found that the bacterial air exhaust filter (designed to clean the contaminated waste air entering the surgery) offered no protection to mercury vapour. In this case the filter trapped particulate amalgam which contributed to further mercury vapour contamination as high volume air was vented through it. CONCLUSION: It is not known how many dental aspirators are in use that vent their waste air directly into the surgery or if this aspirator is representative of others in existence. The safety of dental aspirating systems with regard to mercury vapour exposure requires further investigation.  (+info)

An evaluation of the flammability of five dental gloves. (7/99)

OBJECTIVE: To assess the flammability of five brands of dental procedure glove. DESIGN: A total of ten gloves of each brand (Biogel-D, Premier Protectors, Roeko-D, Safeskin Satin Plus and Schottlander Low Allergy) underwent flammability testing. Five of these were tested as supplied (unwashed) and five following the application of the hand disinfectant Hydrex (washed). Each glove was stretched over a metal frame and the time to ignition, when exposed to a standardised butane flame, recorded. In addition, the thickness of each glove was also assessed by micrometer measurement. RESULTS: All the gloves tested ignited in less than 2.5 seconds. Two way analysis of variance revealed significant effects of glove type (P< 0.001) and treatment (P< 0.05), together with a significant interaction of these factors (P < 0.05), upon the ignition time. Washing Roeko-D gloves with Hydrex significantly (P< 0.01) retarded the ignition time compared with those in the unwashed state. Both the glove thickness and material type appeared to be related to ignition time. CONCLUSION: The work presented here demonstrates the acute and varying flammability of a range of dental procedure gloves. It should serve as a reminder to those who routinely use open flames whilst gloved of the dangers of this practice.  (+info)

Dental products devices; reclassification of endosseous dental implant accessories. Food and Drug Administration, HHS. Final rule. (8/99)

The Food and Drug Administration (FDA) is reclassifying the manually powered drill bits, screwdrivers, countertorque devices, placement and removal tools, laboratory pieces used for fabrication of dental prosthetics, trial abutments, and other manually powered endosseous dental implant accessories from class III to class I. These devices are intended to aid in the placement or removal of endosseous dental implants and abutments, prepare the site for placement of endosseous dental implants or abutments, aid in the fitting of endosseous dental implants or abutments, aid in the fabrication of dental prosthetics, and be used as an accessory with endosseous dental implants when tissue contact will last less than an hour. FDA is also exempting these devices from premarket notification. This reclassification is on the Secretary of Health and Human Services' own initiative based on new information. This action is being taken under the Federal Food, Drug, and Cosmetic Act (the act), as amended by the Medical Device Amendments of 1976 (the 1976 amendments), the Safe Medical Devices Act of 1990 (the SMDA), and the Food and Drug Administration Modernization Act of 1997 (FDAMA).  (+info)