S McHugh

The effectiveness of various disinfectants used as endodontic intracanal medications: an in vitro study.

The purpose of this study was to compare in vitro the suitability of four disinfectants as intracanal medications: calcium hydroxide, chlorhexidine gel, chlorhexidine in the form of a controlled-release delivery system (PerioChip), and the combination of chlorhexidine gel with calcium hydroxide. Saline was used as the control. The disinfectants were tested at three different time periods (3, 8, and 14 days) by using human tooth specimens that had been previously contaminated with Enterococcus faecalis. Calcium hydroxide worked very efficiently in killing E. faecalis in the 3-day group and 8-day group. It was not as effective in the 14-day group. The different chlorhexidine formulations were also found to be effective for all time periods. More specifically, the combination of chlorhexidine gel with calcium hydroxide and the chlorhexidine gel worked slightly better than the PerioChip, but there was no significant difference among the medications.

A study of blood contamination of Siqveland matrix bands

Aims To use a sensitive forensic test to measure blood contamination of used Siqveland matrix bands following routine cleaning and sterilisation procedures in general dental practice.Materials and methods Sixteen general dental practices in the West of Scotland participated. Details of instrument cleaning procedures were recorded for each practice. A total of 133 Siqveland matrix bands were recovered following cleaning and sterilisation and were examined for residual blood contamination by the Kastle-Meyer test, a well-recognised forensic technique.Results Ultrasonic baths were used for the cleaning of 62 (47%) bands and retainers and the remainder (53%) were hand scrubbed prior to autoclaving. Overall, 21% of the matrix bands and 19% of the retainers gave a positive Kastle-Meyer test, indicative of residual blood contamination, following cleaning and sterilisation. In relation to cleaning method, 34% of hand-scrubbed bands and 32% of hand-scrubbed retainers were positive for residual blood by the Kastle-Meyer test compared with 6% and 3% respectively of ultrasonically cleaned bands and retainers (P < 0.001).Conclusions If Siqveland matrix bands are re-processed in the assembled state, then adequate pre-sterilisation cleaning cannot be achieved reliably. Ultrasonic baths are significantly more effective than hand cleaning for these items of equipment.

Pre-sterilisation cleaning of re-usable instruments in general dental practice

Objective This study examined the policies, procedures, environment and equipment used for the cleaning of dental instruments in general dental practice.Materials and methods A total of 179 surgeries were surveyed. This was an observational based study in which the cleaning processes were viewed directly by a trained surveyor. Information relating to surgery policies and equipment was also collected by interview and viewing of records. Data were recorded onto a standardised data collection form prepared for automated reading.Results The BDA advice sheet A12 was available in 79% of surgeries visited. The most common method for cleaning dental instruments was manual washing, with or without the use of an ultrasonic bath. Automated washer disinfectors were not used by any surgery visited. The manual wash process was poorly controlled, with 41% of practices using no cleaning agent other than water. Only 2% of surgeries used a detergent formulated for manual washing of instruments. When using ultrasonic baths, the interval that elapsed between changes of the ultrasonic bath cleaning solution ranged from two to 504 hours (median nine hours). Fifty-eight percent of surgeries claimed to have a dedicated area for instrument cleaning, of which 80% were within the patient treatment area. However, in 69% of surgeries the clean and dirty areas were not clearly defined. Virtually all cleaning of dental instruments was undertaken by dental nurses. Training for this was provided mainly by demonstration and observed practice of a colleague. There was little documentation associated with training. Whilst most staff wore gloves when undertaking manual cleaning, 51% of staff did not use eye protection, 57% did not use a mask and 7% used waterproof overalls.Conclusions In many dental practices, the cleaning of re-usable dental instruments is undertaken using poorly controlled processes and procedures, which increase the risk of cross infection. Clear and unambiguous advice must be provided to the dental team, especially dental nurses, on appropriate equipment, chemicals and environment for cleaning dental instruments. This should be facilitated by appropriate training programmes and the implementation of quality assurance procedures at each stage of the cleaning process.

A study of visual and blood contamination on reprocessed endodontic files from general dental practice

Objective This study examined methods used for reprocessing endodontic instruments in general dental practice and determined the degree of residual visual contamination and blood contamination on 250 reprocessed files collected from 25 general dental practices.Materials and methods A questionnaire was administered to 25 general dental practitioners to obtain information on the re-processing of used endodontic files. Ten files which had been used and reprocessed were also collected from each practice. These were examined visually under a dissecting light microscope for residual contamination and then tested for blood deposits using the Kastle-Meyer test.Results Nineteen of the 25 practices used stainless steel hand files. No practitioners used endodontic files as single use devices. Ninety-two per cent of the practitioners discarded and replaced files when they were bent or damaged. Several decontamination methods were reported. The two combinations employed most frequently were manual cleaning and autoclaving or manual cleaning, followed by ultrasonic cleaning and autoclaving. Of the 250 files, 75% showed some degree of visual contamination and seven percent tested positive for residual blood. Blood contaminated files were significantly more heavily contaminated when examined visually. Large variations were found in residual contamination of files collected from practices using the same methods of decontamination.Conclusions While all practitioners re-used endodontic files, the variations in decontamination methods reported indicate a lack of clarity on best practice. This study demonstrates that endodontic files are not reliably decontaminated by methods currently employed in dental practice.

Sterilisation of re-usable instruments in general dental practice

Objective To examine the methods used for sterilisation of re-usable instruments in general dental practice, including the installation, commissioning and testing of benchtop steam sterilisers.Materials and methods This was an observational study in which the policies and procedures for sterilising instruments were viewed directly by trained surveyors at practice premises. Information relating to the installation, commissioning and testing of benchtop steam sterilisers was also collected by interview and observation of records. Data were recorded onto a standardised data collection form prepared for automated reading.Results Data were available from 179 surgeries surveyed. Dental practices reprocess a range of instruments from critical to non-critical. The most common type of benchtop steam steriliser is a type N, or bowl and instrument (B&I) steriliser (88%). The remainder were type B, or vacuum sterilisers, though one surgery had access to a hot air steriliser. Sterilisers were usually installed by manufacturers or suppliers (69%). Only 51% of sterilisers were tested on installation and 26% were commissioned, of which 38% were tested to SHTM 2010 standard. In most cases it was difficult to determine from the documentation available whether daily, weekly, quarterly or annual testing was undertaken in accordance with recognised standards. Written instructions for the operation of the steriliser were unavailable in 61% of practices. Insurance cover for pressure vessels was available in 79% of surgeries with a B&I steriliser. In many instances there was inadequate separation of clean and dirty areas for segregating processed from unprocessed instruments. Ninety-six percent of surgeries did not have a procedure for the identification and traceability of instruments used on patients. There was no documentation of staff training in the use of sterilisers in 90% of surgeries.Conclusion There has been significant uptake of the use of steam sterilisation to reprocess used dental instruments. However, there are significant shortcomings at various stages of the process, including installation, commissioning and periodic testing of sterilisers. These potentially compromise safety and the time, money and effort currently put into sterilising dental instruments. Complicit in these deficiencies are the manufacturers and suppliers of equipment that is inadequately installed and tested. There is a need for enhanced education and training in the use of sterilisers and the management of the process at all levels, from supplier to user. Improved access to appropriate technical advice on decontamination would also be a major benefit for the profession.

An assessment of the incidence of punctures in latex and non-latex dental examination gloves in routine clinical practice

Objective To investigate the puncture resistance of a recently introduced non-latex, nitrile dental glove in comparison with a latex glove worn during routine clinical dental procedures.Setting Dentists in general dental practice working within the UK during 1999.Subjects and methods 2,020 gloves worn by five general dental practitioners were examined for punctures following standard clinical use by a water inflation method. Procedures undertaken during glove usage and length of time worn were recorded.Results Following clinical use, 1.9% of the latex gloves and 5.3% of the nitrile gloves had punctures, a statistically significant difference (P < 0.0001). The puncture resistance of the nitrile gloves was superior to the puncture resistance of previously tested worn non-latex (vinyl) gloves. There was no evidence of a statistically significant difference between operators for the percentage or incidence of punctured gloves (P = 0.787) after correcting for glove type. No statistically significant difference was noted between incidence of puncture in the control, unused gloves (n = 200 for each type) and the gloves examined following clinical use (P = 0.907 for nitrile, P = 0.613 for latex).Conclusion No increase in the number of punctures was noted following clinical use for either glove type. This could be considered to indicate good puncture resistance of the gloves tested in clinical use.

A survey of the use of matrix bands and their decontamination in general dental practice

Aims The aims of this study were to determine the pattern of use and re-use of matrix bands in general practice in Scotland, to demonstrate which type of matrix band is most commonly used and to examine infection control measures of relevance to the safe use and re-use of matrix bands.Materials and methods Subjects: 621 of Scotlands 1,849 general dental practitioners were randomly selected. Data collection: A 19-item self-reported questionnaire was mailed in June 1999 with a follow-up mailing sent in August 1999. Analysis: Data analysis involved descriptive statistics and cross-tabulation. Where appropriate, differences between categories were tested for significance by a Chi-square test.Results A total of 479 questionnaires were returned, representing a response rate of 77%. Reported compliance with routine glove wearing was high (91%). Most dentists (92%) provided training on instrument cleaning and sterilisation for their dental nurses. Ultrasonic baths were used by 59% of practitioners; the remainder soaked or manually scrubbed instruments to remove debris before autoclaving. The Siqveland matrix was the matrix of choice for 96% of respondents. 7% provided a new matrix band for each patient. Most (64%) changed bands only when they were bent or damaged; 29% changed them daily or weekly. Deterrents to use of a new band for each patient were cost (39%) and time (52%). A total of 54% of respondents considered matrix band replacement unnecessary between patients.Conclusions The Siqveland matrix band is the most popular among the study group of dental practitioners. Re-use of matrix bands is common. Guidelines for the safe re-use of matrix bands are required.

A method for surveying instrument decontamination procedures in general dental practice

Objective This paper describes an objective method for assessing the decontamination procedures used for reprocessing dental instruments in primary dental care facilities.Materials and methods The study population comprised all general dental practitioners in Scotland with an NHS list number. A two-stage process was used to identify which surgeries were to be surveyed, using a proportional stratified random sampling method. First, practices were randomly selected in proportion to the distribution of practices within each of the health boards. Then, if there were more than one dentist within a selected practice, simple random sampling was used to identify a single dentist within the selected practice to be approached. The surgery that the dentist worked from and its associated decontamination facilities were the subject of the survey. A set of data collection forms provided questions designed to investigate compliance with extant guidance documents on decontamination. Specific training for the survey team members was provided during a three day course, to ensure consistency of approach. The data collection forms were piloted in 20 dental surgeries.Results A methodology was developed, which utilised both staff interviews and direct observation of decontamination processes. Data were collected on a set of 28 standard forms, which could be machine read. Three hundred and seventy-three dentists were selected at random from the dental practitioners list held by Practitioner Services, Scotland. One hundred and eighty-nine practitioners either declined to participate or could not be contacted at the address supplied. One hundred and eighty-four surgeries were surveyed, data were available for analysis from 179 sites. Data from five sites were rejected because of illegibility (three) and incomplete data (two). Each surgery survey was undertaken by a team of two surveyors, comprising one infection control/decontamination expert and one experienced dental practitioner. The survey team interviewed the dental practitioner and dental nurse, reviewed documentation relevant to the survey, directly observed decontamination practices and recorded the physical layout of the premises.Conclusion The use of machine readable data collection forms, trained survey staff and direct observation of decontamination protocols provides a workable method for accurate collection of decontamination practice in primary care facilities.

Hand hygiene undertaken by students and staff in a dental teaching hospital.

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