An investigation of the decontamination of Siqveland matrix bands

Decontamination in primary care dentistry

Decontamination of reusable dental instruments has been a subject of debate within the dental profes sion since the publication in 2009 of Health Technical Memorandum 01-05: Decontamination in primary care dental practices. This paper provides a brief history of instrument reprocessing in dentistry and reviews the evidence on pre-soaking, cleaning, sterilisation and storage.

The cleaning of photographic retractors; a survey, clinical and laboratory study

OBJECTIVES

To determine the methods currently being used to decontaminate photographic retractors in specialist orthodontic practice and to investigate the effectiveness of the cleaning methods.

DESIGN

The study was carried out in two parts: I - a postal self-report questionnaire, and II - a cross-sectional clinical and laboratory investigation.

SETTING

The Orthodontic Department of the Charles Clifford Dental Hospital.

SUBJECTS AND MATERIALS

I - The questionnaire was sent to 278 specialist UK orthodontists. II - One hundred and twenty pairs of photographic retractors were collected following use. One retractor from each pair was randomly chosen to be the unwashed control and immediately placed in 20 ml of PBS-Tween for elution. The other was subjected to the one of four cleaning procedures: alcohol wipe, handwashing, ultrasonic bath or washer-disinfector, before being placed in PBS-Tween. Aliquots were taken for assay.

MAIN OUTCOME MEASURES

Antibody capture (ELISA) for amylase, to detect the presence of saliva, and for albumin, to detect the presence of serum.

RESULTS

I - The questionnaire response rate was 65% and the majority of respondents (87.2%) were routinely taking clinical photographs. A wide variety of techniques were being used to decontaminate photographic retractors. II - All unwashed controls had detectable levels of amylase and albumin. All the retractors that were cleaned using an alcohol wipe had residual detectable levels of amylase and 80% had detectable levels of albumin. Only one retractor had detectable amylase and one had detectable albumin following cleaning using the washer-disinfector. There was a highly significant statistical difference between the techniques in the proportional reduction in both amylase and albumin detected from the unwashed control and cleaned experimental retractors (p <0.001). The infective risk from inadequate cleaning of photographic retractors is discussed.

CONCLUSIONS

The washer-disinfector is the most effective method of cleaning photographic retractors, but no method was found to be 100% successful at removing amylase and albumin.

Can protein contamination be removed from hand endodontic instruments?

AIM

The aim of this study was to quantify total protein adhering to hand endodontic files and to measure and compare the efficacy of ultrasonic cleaning and washer-disinfectors, with and without presoaking, in protein removal from clinically contaminated endodontic files.

METHOD

Total protein contamination of the endodontic files was quantified using an assay reagent colorimetric method. Twelve general dental practitioners were recruited to collect clinically contaminated files. One hundred and fifty clinically contaminated files were allowed to air-dry in sterile plastic containers and a further 60 files were immersed, working end down, in enzymatic detergent immediately following clinical use. Thirty clinically contaminated files were tested for total protein contamination as a positive control. Sixty files were subjected to ultrasonic cleaning and 30 to processing in each of the washer-disinfectors. The presoaked files were divided into two groups of 30 for processing in the washer-disinfectors. A further group of brand-new, unused files were tested for protein contamination as a negative control.

RESULTS

Protein was present on 29 of the 30 new files tested. The median total mass of protein recovered from clinically contaminated hand endodontic instruments was 2.046 microg. The most effective method of presterilisation cleaning tested was a presoak in Alkazyme followed by processing in the Miele G7881 washer-disinfector.

CONCLUSION

The most effective method of presterilisation cleaning for hand endodontic files is a presoak in Alkazyme, an alkaline enzymatic detergent, followed by processing in a Miele G7881 washer-disinfector. This study provides up-to-date evidence that newer methods of presterilisation cleaning may fail to remove protein from endodontic hand instruments totally. This may have implications for all reusable dental instruments.