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NHSScotland: Sterile Services Provision Review Group: Survey of Decontamination in General Dental Practice

SECTION 3: RESULTS

3.1 Accuracy of general dental practitioner database

An initial review of the list of general dental practitioners provided by NHS National Services Scotland, Practitioner Services (previously known as the Dental Practice Division of the Common Services Agency) revealed many inaccuracies. For example, of the initial 50 dental practitioners approached to participate, the replies from 17% claimed that the dentist had retired or no longer worked at that practice. For just under 40% of 373 dentists selected from the original list, that dentist was no longer at the practice or the practice was no longer at the given address.

3.2 Response rate

In order to recruit the 184 dentists who agreed to participate, 373 dentists' names (from the 837 dental practices in Scotland) were selected from the original list and endeavours made to contact these dentists. Where the named dentist had moved or been replaced their named replacement was invited to participate. Seventy five of those who participated were alternatives selected in this manner.

One hundred and eighty nine practitioners either declined to participate or could not be contacted at the address supplied. Of those who declined, 102 gave reasons for non-participation. Twenty seven percent gave the reason as being a single-handed practitioner, 25% were too busy and 7% did not believe that the financial compensation for the surgery downtime was sufficient.

From the 184 surgery visits, data were available for analysis from 179 sites. Data from 5 sites were rejected because of illegibility (3) and incomplete data (2).

A summary of numbers of practices approached, participation rates and geographical coverage is provided in Table 2.

Table 2 Summary of response rates

* All health board areas in Scotland were included.

3.3 Practice facilities and patient throughput

3.3.1 Practice premises

One of the challenges facing many dental practices is the use of premises that have not been purpose built as a health care facility. This requires the provision of appropriate facilities for the surgery, waiting area, staff rooms and decontamination areas. The types of premises in which the practices were located are shown in Figure 2.

Figure 2. Type of dental practice premises

Of these practices 9% shared facilities with other healthcare providers. This included medical practitioners, podiatrists and an osteopath.

Further details relating to the practices visited are shown in Table 3.

Table 3 Practice facilities

3.3.2 Staff levels

In 25% of the sites surveyed there was only one general dental practitioner (GDP) in the practice (i.e. a single-handed practice). The staffing at each of the premises surveyed was analysed at the practice level and at the surgery level (Tables 4 & 5).

Table 4 Staffing levels at practices surveyed

Table 5 Staffing levels in the individual surgeries surveyed

3.3.3 Number of patients

The number of patients seen in the surgery and practice were estimated by requesting figures for the number of patients attending on the same day in the previous week (Table 6).

Table 6 Number of patients treated at the sites surveyed

3.4 Treatment performed

The range of treatments undertaken in these surgeries is summarised in Table 7 and reflects the broad range of procedures undertaken in general dental practice.

Table 7 Treatment procedures undertaken in the surgeries surveyed

*Based on a modified Spaulding (1968) classification. Critical = instruments that have contact with the blood stream (or likely to produce bleeding). Semi-critical = devices that come in contact with (intact) mucous membranes. Non-critical = devices that come into contact with the patient's intact skin.

3.5 Surgery Design

Within surgeries 58% had a dedicated area for decontamination of re-usable devices, of which 80% were within the surgery itself. However, in 69% of surgeries the clean and dirty areas were not clearly defined. In 38% of surgeries, the area for decontamination was physically separated from other work areas and in 30% the decontamination area was accessed via a separate entrance. Fifty two percent of surgeries did not have a dedicated sink for the cleaning of contaminated instruments.

For the 42% of surgeries that did not have a dedicated area for decontamination, a wide variety of activities were undertaken in the same area as decontamination (Table 8).

Table 8 Examples of shared equipment and activities in decontamination areas

3.6 Management of decontamination

3.6.1 Roles and responsibilities

The management of decontamination processes in many of the surgeries visited was based largely on 'word of mouth' communication between the various members of the dental team. Fifty percent of practices had no documented procedures. Whilst the ultimate legal responsibility for decontamination rests with the Practice Principal, it was unusual for these individuals or their staff to have a written job description with regard to control of infection (Figure 3).

Figure 3. Categories of staff in each practice with a written job description with regard to control of infection

Only 7% of practices employed an individual whose sole or principal duties were instrument re-processing. The re-processing of instruments and devices in 93% of the practices was not undertaken by a dedicated member of staff; typically this was performed by the dental nurse(s) responsible for an individual surgery.

3.6.2 Infection control polices and procedures

Twenty one percent of practices had no written infection control policy. For those practices which had a written policy, this was generally accessible (92%) to all the staff and was incorporated into their training (86%). An audit of infection control procedures had been undertaken in 11% of practices.

3.7 Awareness of guidelines and sources of assistance

The BDA Advice Sheet A12, which deals with infection control in dental practice, was available in 79% of practices. Ninety seven percent of the practices received Safety Action Notices from the Scottish Executive Health Department. However, 98% of practices had no knowledge of, or access to, Scottish Health Technical Memoranda 2010, 2030 or 2031. Similarly, the majority of practices (80%) were unaware of the Medical Device Bulletins relevant to the purchase of benchtop steam sterilizers and the re-use of single use items.

A reflection of the low level of familiarity with guidance was the fact that 74% of dental nurses and 54% of dentists did not understand the symbol for 'single use' (Figure 4), whilst 75% of the dental nurses and 57% of the dentists did not understand the symbol for 'use by date'.

Figure 4. Symbol for identifying single use instruments

The majority of surgeries did not have access to the use of appropriate technical advice from an Authorised Person (Sterilizers) (95%) and/or a Microbiologist (Sterilizers) (99%).

3.8 Procurement of re-usable devices

Procurement of re-usable devices is an activity that highlights the requirement for proper management of decontamination procedures. In 93% of the practices, the Principal or Partners were identified as having responsibility for the purchase of instruments and other medical devices. In a minority of cases associates (5%), dental nurses (13%) and practice managers (<1%) were identified as having, or sharing, this responsibility.

Eighty six percent of the practices did not generate a written specification prior to purchasing equipment. Similarly, 86% of practices did not review their current decontamination procedures in relation to devices purchased for the first time. The majority of practices (89%) purchased their instruments by placing a verbal order with a dental supply house.

Seventy seven percent of practices did not have a documented policy on when to choose single use as opposed to re-usable instruments, if both were available. Re-use of relevant specified items is illustrated in Figure 5.

Figure 5. Percentage of surgeries re-using specified devices

Forty seven percent of practices had a policy on the use of devices labelled as 'single use', of which 35% permitted their re-use, i.e. at least 15% of practices overall re-used single use devices.

3.9 Instrument cleaning

3.9.1 Methods of instrument cleaning

Table 9 summarises the methods used by the surgeries to clean their re-usable instruments.

Most surgeries used a combination of manual washing and ultrasonic cleaning, although not all instruments within a surgery were re-processed this way. Some devices, such as handpieces, are not recommended by the manufacturer to be cleaned in an ultrasonic bath.

Table 9 Methods of cleaning instruments

*Many surgeries used different combinations of cleaning methods for different instruments.

3.9.2 Manual washing

Virtually all (96%) of the surgeries used manual washing as either the sole method or as part of the cleaning process. Forty three percent of the surgeries had a designated sink which was used only for instrument cleaning, but the remainder also used the sink for hand washing (84%), beverage preparation (16%) or environmental cleaning (34%). The manual washing process was generally poorly controlled with 41% of practices not using any cleaning agent other than water. A range of cleaning agents was used (Figure 6) but there was no standardisation of concentration of cleaning agents, nor of the temperature of water used for cleaning. Only 2% of surgeries used a detergent formulated for manual washing of surgical instruments, with 37% using surgical handwash. Miscellaneous agents used for cleaning included bars of soap, disinfectants and kitchen cleaning agents.

Figure 6. Agents used to manually clean instruments

Eighty six percent did not perform manual cleaning with the instruments entirely immersed to prevent aerosol generation whilst 60% carried out manual washing entirely under running water. Rinsing of washed instruments was undertaken in 84% of surgeries. Only 1% of surgeries used a separate sink for rinsing and 2% rinsed in a bowl. In most cases, water from a holding tank or from the mains supply was used for rinsing. One percent of surgeries rinsed instruments with softened water and less than 1% rinsed instruments with sterile water for irrigation. Eighty five percent of the surgeries never dried instruments after manual cleaning. Less than 1% of surgeries kept records of which instruments had been washed and by whom.

3.9.3 Personal protective equipment (PPE) used during manual washing

In relation to staff safety, the majority of those undertaking the manual washing wore gloves (99%). However, 51% of staff did not use eye protection and 93% did not use waterproof overalls.

3.9.4 Ultrasonic baths

Ultrasonic baths were present in 92% of surgeries. The age of the ultrasonic baths ranged from <1 - 14 years (median of 3 years old). The features of the ultrasonic baths are summarised in Table 10. The majority of surgeries (92%) operated the ultrasonic with the lid in the closed position.

Table 10 Ultrasonic cleaner features

The range of cleaning agents used in the ultrasonic baths is shown in Figure 7.

Figure 7. Agents used in ultrasonic cleaning baths

1. Acidic detergent;
2. Alkaline detergent;
3. Neutral detergent;
4. Enzymatic cleaner;
5. Washing up liquid;
6. Cleaner recommended by ultrasonic bath manufacturer;
7. Disinfectant / detergent.

The interval between changing the solution in the ultrasonic bath ranged from 2t o 504 hours (median of 9 hours) and 63% emptied the ultrasonic bath at the end of the working day. Eighty percent of surgeries did not change the ultrasonic cleaning fluid at 4 hourly intervals or more frequently. In 11% of surgeries the interval was 5 days or more. However, 83% of surgeries changed the ultrasonic bath solution when visibly soiled.

Ninety six percent of the surgeries did not check the efficacy of the ultrasonic generator by means of the aluminium foil ablation test. One surgery (<1%) undertook periodic tests of the cleaning efficacy of the bath.

Eighty six percent of surgeries rinsed instruments after immersion in the ultrasonic bath.

3.10 Instrument inspection

Eighty five percent of surgeries routinely inspected all instruments for cleanliness after the cleaning process. One percent of surgeries had a magnifier available for inspection of small or intricate devices and 3% had task lighting for cleanliness inspections. In 52% of surgeries cleaned instruments were checked or tested for functionality prior to use on patients.

3.11 Packaging prior to sterilization

In eighty percent of surgeries which packaged instruments prior to sterilization, the packaging area was not clearly segregated from the area where cleaning and disinfection took place. Of the surgeries with a B&I sterilizer, 28% were packaging instruments before sterilization. The type of packaging used before sterilization in a B & I sterilizer is shown in Figure 8.

Figure 8. Type of packaging used when wrapping instruments before

sterilization in a B & I Sterilizer

1= Plain top, sterilization grade paper bag; 2= Heat seal, sterilization grade paper bag; 3= Plastic/paper pouch - single; 4= Plastic/paper pouch - double.

Of the surgeries with a vacuum sterilizer 60% were packing instruments before sterilization. Of these, 17% were using a double layer of packaging, although the manufacturers of most vacuum benchtop sterilizers recommend that only a single layer of packaging should be used.

Seventy nine percent of the surgeries used packaging materials purchased against British or European standards. The pre-sterilization packaging was reused by 9% of surgeries.

3.12 Instrument sterilization

3.12.1 Types of Sterilizer

There are two types of sterilizer in common use in dental surgeries. The majority of the surgeries used benchtop bowl and instrument (B&I) sterilizers (also known as downward displacement sterilizers or unwrapped instrument & utensil sterilizers) (Table 11).

Table 11 Types of sterilizer

The B&I sterilizers were aged between 1 and 19 years (median of 5 years old), whilst the vacuum benchtop steam sterilizers were between <1 and 5 years old (median of 2 years old).

3.12.2 Installation, commissioning, validation and testing of sterilizers

Fifty one percent of the sterilizers were tested on installation and 26% were commissioned, of which 38% were commissioned to SHTM 2010 standard. Sterilizers were installed by manufacturers (39%), suppliers (30%), Primary Care Trust or Health Board (3%) and by others (27%). Other agents installing sterilizers were generally the dentist or dental nurse.

In most cases it was difficult to determine, from the documentation available, whether daily, weekly, quarterly and annual testing was undertaken in accordance with SHTM 2010. Documentation available indicated that 15% of B&I sterilizers and 13% of vacuum benchtop sterilizers were tested in accordance with SHTM 2010.

Sixty five percent of surgeries did not undertake testing of the sterilizer at the beginning of each day. Integrating chemical indicators were used in 39% of sterilizers; 17% used these for every load. Biological indicators were used in 1% of sterilizers. Fifteen percent of surgeries with a vacuum benchtop sterilizer were performing a daily Bowie Dick test (used to demonstrate adequacy of air removal from a challenge load).

3.12.3 Servicing and maintenance of sterilizers

Ninety percent of sterilizers had a maintenance contract. Ninety two percent of the B&I sterilizers were serviced regularly, 88% annually and 63% quarterly.

3.12.4 Operation of Sterilizers

Written instructions for operation of the sterilizer were not available in 61% of practices. Thirty three percent of surgeries kept records of user checks undertaken of the sterilizer. Sixty percent of the vacuum benchtop steam sterilizers were fitted with a chart recorder or datalogger and 23% of the B&I sterilizers were fitted with dataloggers.

3.12.5 Paperwork associated with pressure vessel

According to paperwork made available to the survey team members, insurance cover for the pressure vessels was available in 79% of surgeries with a B&I sterilizer and 60% of surgeries with a vacuum benchtop sterilizer; a written scheme of examination approved by a Competent Person (Pressure Vessels) was available for 61% of surgeries with a B&I sterilizer and 65% of surgeries with a vacuum benchtop sterilizer; an annual visit from a Competent Person (Pressure Vessels) was made to 63% and 55% of surgeries with B&I and vacuum benchtop sterilizers respectively.

3.12.6 Sterilizer water

Figure 9 summarises the types of water that were being used to replenish the reservoirs of the sterilizers.

Figure 9. Water used in sterilizers

The frequency of draining and replenishing the sterilizer reservoir is shown in Figure 10.

Figure 10. Frequency of draining sterilizer reservoir

If the sterilizer was unavailable, for example on account of a mechanical breakdown, then the surgery took the actions shown in Figure 11.

Figure 11. Action taken by surgery when sterilizer out of service

3.13 Packaging after sterilization

Seventy percent of surgeries packaged goods for storage after sterilization. Fifty five per cent of the surgeries packaged some of their instruments after sterilization in a B&I sterilizer. Fifty percent of surgeries were packaging after sterilization in a vacuum autoclave. In 63% of surgeries post sterilization packaging did not take place in a dedicated area.

3.14 Storage after sterilization

Sterilized items were stored in cupboards (51%), drawers (86%), on shelves (32%) and on work surfaces (34%). In 91% of the surgeries this storage was in the same area as patient treatment and in 48% of surgeries it was in the same area as decontamination was undertaken. Eighty nine percent of the storage areas were visibly tidy and well organised. Nineteen percent of surgeries issued sterile packs and sterilized instruments in strict rotation (FIFO).

3.15 Traceability

None of the surgeries had any form of traceability systems for their re-usable devices. For one percent of sterilizers, records were kept of all items sterilized. Documentation for sterile product release was recorded for one sterilizer (<1%). Eleven percent of sterilizer cycles were examined before instruments were released as sterile.

3.16 Training

Staff training in decontamination was provided mainly by demonstration (97%) and observed practice (88%). There was little documentation associated with training (10%). There were no records available for staff training in 69% of surgeries.

There was no documentation of staff training in the use of sterilizers in 90% of surgeries. The training was generally provided by observed practice (88%) and demonstration (93%). Twenty seven percent of the surgeries provided training on the limitations of the type of load which may be processed and 33% on correct loading procedures.

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