Comparison of an ultrasonic cleaner and a washer disinfector in the cleaning of endodontic files

Enhancement of microbicidal efficacy of chemical disinfectants when combined with ultrasound technology

AIMS

This study investigated the antimicrobial efficacy of ultrasound technology (US) in combination with two different disinfectants (Disinfectant A and Disinfectant B), containing peracetic acid (PAA) and quaternary ammonium compounds (QACs), respectively, against two sporigenic pathogens, Aspergillus brasiliensis and Bacillus subtilis.

METHODS AND RESULTS

The microbicidal activity of the coupled treatment was compared with the use of the disinfectants alone, and the efficacy of the disinfection strategies was evaluated by the log reduction of the population of the microorganism inoculated onto stainless-steel surface. The combination treatment resulted in a log reduction of 5.40 and 3.88 (Disinfectant A + US) against A. brasiliensis and B. subtilis, at 850 and 500 ppm PAA, compared to 265 and 122 (Disinfectant A only). For Disinfectant B, in combination with US, showed a logarithmic reduction of 5.04 and 4.79 against A. brasiliensis and B. subtilis at 078% v v-1 and 392% v v-1 QACs, respectively, vs. 1.58 and 1.64 (Disinfectant B only). Moreover, no colonies or not statistically significant growth was observed within the US bath containing the disinfectant.

CONCLUSIONS

The antimicrobial efficacy of the two disinfectants was greatly enhanced when used in combination with US, and this also makes it possible to avoid the overuse of chemicals for disinfection.

Management of Instrument Sterilization Workflow in Endodontics: A Systematic Review and Meta-Analysis

Endodontic treatment consists of different working procedures, such as the isolation of the operating field, pulp chamber access, and cleaning and shaping phases with at last the need of a three-dimensional filling of the canals. Each step requires a series of single-use or sterilizable instruments. We have performed a systematic review of different sterilization and disinfection procedures aiming at drawing up a disinfection and sterilization procedure to be used on endodontic instruments. A search on PubMed and Scopus was carried out using the following keywords: “endodontic sterilization,” “endodontic autoclave,” “decontamination dental bur,” “sterilization dental burs,” and “gutta-percha points sterilization.” Eligible articles were included in the qualitative and quantitative analysis. Results of the meta-analysis showed that the most effective method in sterilization is autoclaving. The qualitative analysis showed that the use of single-use or first-use instruments requires presterilization or sterilization procedures, and for reusable tools, attention must be paid to the removal of debris deposited on the blades, not easy to remove manually.

Electrochemical ‘bubble swarm’ enhancement of ultrasonic surface cleaning

Control and excitation of electrochemical bubble swarms enhances surface cleaning within an ultrasonically activated stream.

Comparison of different cleaning procedures of implant drills using TC99

PURPOSE

This study was carried out to evaluate implant drills' cleaning protocols efficiency as tested by the use of nuclear medicine.

METHODS

Eighty-one new drills of 2 different implant systems (Nobel Biocare and BioMet 3i) were selected as study samples. Six of these drills were used as positive control group, and the rest were contaminated with TC-labeled blood. The instruments were divided randomly into 5 groups (negative control group; group 1: immersion and brushing; group 2: immersion and brushing and then evaluation under magnifier; group 3: immersion and brushing and then ultrasonic cleaning for 15 minutes; and group 4: immersion and brushing and then ultrasonic cleaning for 30 minutes) so that every group contained equal number of each implant drills brand. Then the emitted γ rays were counted by means of a gamma counter.

RESULTS

Statistically significant differences were observed between the full cleaning protocol and ultrasonication group (P < 0.009). Immersion and brushing, and ultrasonic cleaning for 30 minutes before sterilization, were the most effective methods to remove contamination.

CONCLUSIONS

Complete removal of biologic debris was not attained with any of the cleaning techniques used. It is recommended to use ultrasonic cleaner for 30 minutes after immersion and brushing to achieve the best results.

Archwire cleaning after intraoral ageing: the effects on debris, roughness, and friction

Dental material science has paid more attention to mechanical properties of as-received materials than to changes produced after intraoral exposure. Orthodontic archwires when exposed to the intraoral environment have shown a significant increase in the degree of debris, surface roughness (Ra), and frictional force. The purpose of this split-mouth study was to evaluate the effects of two methods of archwire cleaning on these variables after clinical use for 8 weeks. For eight individuals, four sets of three brackets each (n = 32) were bonded from the first molar to the first premolar. A passive segment of 0.019 × 0.025 inch stainless steel (SS) archwire was inserted into the brackets and tied by elastomeric ligature. Debris level [via scanning electron microscopy (SEM)], Ra, and frictional force were evaluated in a paired comparison after 8 weeks of intraoral exposure and after cleaning with a steel wool sponge (SWS) for 1 minute or ultrasound (US) cleaning for 15 minutes. Kruskal-Wallis, Friedman's, and Spearman and Pearson correlation tests were used for statistical analysis. The debris and Ra of SS rectangular wires increased significantly (P < 0.05) during clinical use, causing a significant increase in the frictional force level. These changes can be effectively eliminated by either of the investigated cleaning methods, although a SWS seems to be clinically more practical.

Debris, roughness and friction of stainless steel archwires following clinical use

OBJECTIVE

To investigate the degree of debris, roughness, and friction of stainless steel orthodontic archwires before and after clinical use.

MATERIALS AND METHODS

For eight individuals, two sets of three brackets (n = 16) each were bonded from the first molar to the first premolar. A passive segment of 0.019- x 0.025-inch stainless steel archwire was inserted into the brackets and tied by elastomeric ligature. Debris level (via scanning electron microscopy), roughness, and frictional force were evaluated as-received and after 8 weeks of intraoral exposure. Mann-Whitney, Wilcoxon signed-rank, and Spearman correlation tests were used for statistical analysis at the .05 level of significance.

RESULTS

There were significant increases in the level of debris (P = .0004), roughness of orthodontic wires (P = .002), and friction (P = .0001) after intraoral exposure. Significant positive correlations (P < .05) were observed between these three variables.

CONCLUSION

Stainless steel rectangular wires, when exposed to the intraoral environment for 8 weeks, showed a significant increase in the degree of debris and surface roughness, causing an increase in friction between the wire and bracket during the mechanics of sliding.

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.

Influence of Usage History, Instrument Complexity, and Different Cleaning Procedures on the Cleanliness of Blood-Contaminated Dental Surgical Instruments

Our study assessed the factors that influence the resistance of blood residues on dental surgical instruments to washer-disinfector-based cleaning procedures in a clinical setting. The use of 2 additional cleaning methods—presoaking and scrubbing by hand—and the use of newer and/or less structurally complex instruments significantly increased the efficacy of washer-disinfector cleaning.

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.