Tray systems in dental practices: Efficient instrument reprocessing with wash trays
A well-organised set of instruments saves time, reduces the risk of errors and makes it easier to adhere to standardised hygiene procedures. This is precisely where a tray system comes into its own in a dental practice: instruments are no longer moved around the practice on a day-to-day basis individually and in varying combinations, but are prepared, used, reprocessed and made available again as clearly defined sets.
Wash-trays can support the entire instrument cycle – from treatment through mechanical cleaning and disinfection to packaging, sterilisation and storage. However, it is crucial that the trays, instruments, cleaning and disinfection equipment, sterilisation containers and autoclave are coordinated with one another and integrated into the practice’s validated processes.
What is an instrument wash-tray system?
A wash tray is a reusable instrument holder in which the instruments required for a specific treatment are systematically arranged and secured. Depending on the design, flexible silicone ridges or other retainers hold the instruments in a defined position.
The wash tray accompanies the instrument set through several stages of reprocessing. It can – provided the manufacturer has designed it for this purpose – be used to hold the instruments during mechanical cleaning and disinfection and subsequently within a suitable sterilisation container.
However, a wash tray is not automatically a sterile packaging system. Only a sterile barrier system designed and validated for this purpose – for example, a compatible sterilisation container with a suitable filter – enables packaged sterilisation and the protection of sterile items during transport and storage. The requirements for sterile barrier systems and packaging systems are set out in DIN EN ISO 11607-1.
Dental tray, wash tray and sterilisation container: what is the difference?
These terms are sometimes used interchangeably in everyday practice, but they refer to different functions.
A dental tray is, first and foremost, an instrument holder designed to organise the layout of instruments during treatment. Not every dental tray is automatically suitable for machine cleaning, thermal disinfection or steam sterilisation.
A wash tray is designed for reprocessing in a cleaning and disinfection machine. Its design is intended to ensure that water, process chemicals and the rinsing mechanism can adequately reach the instruments and that liquids can subsequently drain away.
A sterilisation container, together with its closure and filter system, forms the packaging for sterilisation. When used as intended, the appropriate sterile barrier system protects the sterilised instruments from recontamination until they are used.
This creates a coordinated system: the instrument set remains organised in the wash tray, whilst the container acts as the sterile packaging.
Why is a tray system worthwhile in a dental practice?
Instrument reprocessing involves many repetitive steps. If instruments are sorted, transported, loaded into the washer-disinfector, checked and packed individually, each batch requires a considerable amount of manual effort.
A standardised tray system can simplify and standardise these processes
1. Less time required
A fully assembled instrument set is immediately available before treatment. The practice team does not have to search for the required instruments individually from different drawers or containers each time.
Even after treatment, the instruments remain organised as a set. This reduces the time spent on sorting, loading and packaging. Coordinated systems comprising wash trays and sterilisation containers are designed to guide instrument sets as seamlessly as possible through the entire process, from use through reprocessing to storage.
2. Standardised treatment sets
Fixed sets can be defined for common procedures, for example for:
prophylaxis,
conservative treatment,
periodontology,
endodontics,
extractions,
implantology,
oral surgery procedures.
The standardised composition simplifies preparation and makes it immediately clear if an instrument is missing. New staff members also find it easier to follow the established set structures.
3. Improved workplace safety
Pointed and sharp instruments pose a risk of injury during transport, sorting and reprocessing. If they are secured in suitable holders, they need to be picked up and moved individually less often.
However, the tray system is no substitute for safe working practices. Contaminated instruments must still be collected and transported in such a way that staff are not put at risk of puncture or cut injuries or exposure to biological agents. A suitable, closed transport container must therefore be provided for the journey from the treatment room to the reprocessing room. TRBA 250 sets out the specific occupational health and safety requirements for handling biological agents in the healthcare sector.
4. Protection of instruments
Instruments lying loose in baskets or containers may knock against one another, become entangled or be damaged. A defined method of securing them can better protect delicate tips, cutting edges and surfaces.
It is essential that the holders are suitable for the instruments. Silicone bars that are too tight or incorrectly positioned can cause pressure marks, obscure instruments or hinder cleaning.
5. Clear documentation
Coloured silicone dividers, labels, set numbers or barcodes enable unambiguous allocation. For example, a tray can be assigned to a specific type of treatment, a reprocessing batch or a defined loading pattern.
This supports batch documentation and traceability. However, authorisation remains a professional decision to be made by authorised staff and cannot be replaced by colour coding or a barcode alone.
The instrument cycle with a wash tray
The greatest benefit is achieved when the tray system is planned not as a standalone accessory, but as an integral part of a seamless workflow.
1. Compiling the instrument set
First, it is determined which instruments are actually required for the respective procedure. Unnecessary instruments should not be included in the set simply out of habit, as each instrument must undergo the specified reprocessing procedure after use or contamination.
The instruments are arranged in the wash tray in such a way that they are clearly identifiable and securely held in place. Articulated instruments must be opened, dismantled or positioned in a manner suitable for cleaning, in accordance with the manufacturer’s instructions.
The configuration should be documented in an illustrated packing or tray list. This enables the team to quickly check that everything is present and to reproduce the set-up at any time.
2. Preparation in the treatment room
The reprocessed set, which may be sterile-packed, is only opened immediately before treatment. The instruments remain clearly arranged and can be removed in a specified order.
A well-organised tray therefore not only supports hygiene but also assists with the treatment. Missing or incorrectly sorted instruments are noticed at an early stage.
3. Safe collection and transport
After treatment, the used instruments are returned to the tray, provided this can be done without posing any additional risk and is part of the established workflow. Pointed and sharp ends should be positioned so that no unnecessary risk of injury arises during further handling.
The contaminated wash tray is then transported to the reprocessing room in a closed, sufficiently robust and clearly labelled container. Transporting contaminated instruments openly through the practice should be avoided.
4. Cleaning and disinfection in the washer-disinfector
The tray is loaded into the cleaning and disinfection machine in accordance with the validated loading pattern. To ensure effective cleaning, all instrument surfaces must be accessible to water and the process chemicals.
In particular, the following points must be observed:
Instruments must not completely cover one another.
Spray arms and rinsing dead zones must not be obstructed.
Hinges must be sufficiently open.
Liquids must be able to drain from the tray and the instruments.
The maximum load capacity must not be exceeded.
Manufacturer’s specifications for instruments, trays and the washer-disinfector must be consistent.
For Class B medical devices, machine-based cleaning and disinfection is generally the method of choice. The DIN-EN-ISO 15883 series sets out requirements for cleaning and disinfection equipment, their processes, loading carriers, validation and routine monitoring.
Special considerations for hollow-body instruments
Not every instrument can be adequately cleaned internally simply by being placed in a wash tray. Instruments with lumens, transmission instruments, suction cannulas or other internal areas may require suitable connectors, adaptors or special holding devices.
Whether an instrument must be connected to an injector system within the tray or separately is determined by the reprocessing instructions provided by the instrument and equipment manufacturer. The external arrangement within the tray must not result in necessary internal cleaning being omitted.
5. Visual inspection, maintenance and functional testing
Following the automated process, the tray is removed in the clean area. Even if an RDG programme has been successfully completed, the instruments must still be inspected.
The following are checked in particular:
Instruments that have not been adequately cleaned must not be released for sterilisation. They must undergo the specified cleaning and disinfection process again. Damaged instruments or those that can no longer be safely reprocessed are discarded.
Maintenance procedures must be carried out in accordance with the manufacturer’s instructions. Only suitable agents that do not impair the subsequent sterilisation process may be used.
6. Packing in the sterilisation container
If the instruments are to be used in a sterile condition, the inspected wash tray is placed in a suitable sterilisation container. The filter system, seal, closure and, where applicable, the tamper-evident seal must be complete and in working order.
Before each use, the following should be checked, amongst other things:
Is the container clean and undamaged?
Are the lid and base dimensionally stable?
Is the seal intact?
Is the filter correctly fitted and suitable for the intended use?
Do the fastenings and locks work properly?
Is the labelling clear?
Does the tray fit into the container without tilting or being overloaded?
Only a packaging system that has been assembled in accordance with its intended use and is suitable for the process can provide the intended sterile barrier.
7. Sterilisation in the autoclave
The closed container is loaded into the autoclave in accordance with the validated loading pattern. The specifications regarding positioning, stackability, load quantity and programme selection must be adhered to.
The sterilisation programme must be suitable for the instruments, the container and the load. The daily routine load must be covered by the validation or performance qualification of the sterilisation process.
The introduction of an additional tray system alters the loading configuration. Therefore, new tray or container configurations must not be incorporated into routine operations without prior assessment. Where necessary, the loading patterns may need to be amended or a new performance assessment carried out.
8. Release and Documentation
Following the sterilisation process, the process sequence, relevant parameters and required batch controls are evaluated. The container is then checked for dryness, integrity, correct sealing and complete labelling.
Release must be carried out by an authorised and qualified person. They should be able to clearly identify at least the following information:
steriliser and batch number,
programme used,
date of reprocessing,
tray or instrument set,
result of the process control,
Release decision,
person authorising.
A successfully completed device programme alone does not replace the documented batch and sterile goods release.
9. Storage and re-issuing
Approved containers are stored under suitable conditions, protected from moisture, contamination and mechanical damage. The storage system should follow the ‘first in, first out’ principle and allow for clear stock control.
Before the next treatment, the container is checked for integrity and taken to the treatment room. Only there is it opened under aseptic conditions and the tray prepared.
If the container is damaged, damp, has been opened unintentionally or is not clearly labelled, its contents must not be used as sterile.
Which instruments are suitable for a tray system?
Tray systems are particularly suitable for regularly recurring combinations of instruments. These include, for example, basic instrument sets, prophylaxis sets and instrument sets for endodontics, periodontology, surgery or implantology.
However, suitability does not depend solely on size. Before including an instrument, the following questions must be clarified:
Is it suitable for machine cleaning and thermal disinfection?
Can it be reprocessed whilst fixed in the tray?
Do any joints need to be opened or parts dismantled?
Does it require internal cleaning via an adapter?
Is it compatible with the process chemicals used?
Is it suitable for steam sterilisation?
Is it covered by the validated process?
The manufacturer’s specifications for the medical device take precedence. A tray system can standardise reprocessing, but cannot compensate for an instrument’s lack of reprocessability.
Practices should bear the following in mind when making their selection
A suitable wash tray should not be selected solely on the basis of size or purchase price. The key factor is how well it interacts with existing equipment and processes.
Compatibility: The tray, holders and containers must be approved for or suitable for use with the existing cleaning and disinfection equipment and the autoclave. The usable capacities and loading racks must also be taken into account.
Easy-to-clean design: The tray should feature open surfaces, good water flow and reliable drainage. Inaccessible gaps and areas where residual water or dirt can accumulate are undesirable.
Flexible instrument holders: Silicone bars should be configurable so that different instrument sets can be securely held in place. At the same time, they must not unnecessarily cover the surfaces to be cleaned.
Clear labelling: Colour codes , labels or barcodes facilitate allocation to treatment, set, batch and storage location. However, colour coding should not be the sole form of identification, as colours can be confused or interpreted differently by individual staff members.
Ergonomics and health and safety: The tray should be easy to grip and transport safely. Sharp instruments must not protrude unprotected from the tray. The weight of a fully loaded tray must also be taken into account in day-to-day use.
Availability of suitable containers: If the instrument setis to be packed, sterilised and stored, a compatible sterilisation container must be available. The entire system should be able to be integrated into the practice workflow without the need for makeshift combinations.
Common mistakes when using wash trays
A tray system only improves processes if it is planned and used correctly. Typical errors include:
trays packed too densely,
incorrectly positioned or closed articulated instruments,
hollow instruments not properly secured,
holders that cover large areas of the instrument surfaces,
mixing of incomplete treatment sets,
failure to carry out visual and functional checks following the RDG process,
use of the wash tray without a suitable sterile barrier system,
damaged or incorrectly fitted container filters,
undocumented changes to tray loading,
use of new sets outside the validated load configurations.
Particularly problematic is the assumption that a properly arranged tray automatically guarantees a hygienically safe result. The demonstrable effectiveness of the entire validated reprocessing process remains crucial.
How a practice successfully introduces a tray system
The transition should take place in stages. First, the most frequently used instrument combinations are analysed and grouped into practical sets.
The following procedure is then recommended:
Record the instrument inventory and treatment procedures.
Define suitable instrument sets.
Check compatibility with the instrument washer-disinfector, autoclave and containers.
Determine tray configurations and document them photographically.
Update work instructions and loading patterns.
Assess the impact on validated processes.
Provide practical training for staff.
Test the system initially with selected sets.
Evaluate experience gained from treatment and reprocessing.
Optimise the tray configurations where necessary.
In doing so, it is not only the maximum instrument capacity that should be considered. The crucial factor is whether the number of trays is appropriate for the instrument stock, patient volume and actual reprocessing cycles.
Conclusion: A systematic approach to the entire instrument cycle
A tray system for a dental practice can do far more than simply provide a tidy place to store instruments. When properly planned, it supports the entire workflow – from treatment through cleaning, disinfection and sterilisation to storage and reissuing.
The key benefits lie in standardisation: instrument sets are clearly structured, need to be rearranged individually less often, and can be more easily monitored, documented and allocated. This saves valuable working time whilst also providing better protection for both instruments and the practice team.
However, hygienic success does not depend on the tray alone. It is based on the coordinated interaction of suitable instruments, correct tray configuration, safe transport, validated machine cleaning and disinfection, careful inspection, a suitable sterile barrier system, validated sterilisation and documented release.
A good wash tray therefore does more than just organise instruments – it structures the entire reprocessing process.
