Development of an effective cleaning technique and ancillary analytical method for estimation of residues of selected kinase inhibitors from stainless steel and glass surfaces by swab sampling.

Importance of cleaning validation in the pharmaceutical industry cannot be overstated. It is essential for preventing cross-contamination, ensuring product quality & safety, and upholding regulatory standards. The present study involved development of an effective cleaning method for five selected kinase inhibitors binimetinib (BMT), selumetinib (SMT), brigatinib (BGT), capmatinib (CPT), and baricitinib (BRT). For checking the effectiveness of the developed cleaning technique, a sensitive and specific RP-HPLC based analytical method employing a diode array detector has been established to quantitate drug residue on glass and stainless steel surfaces. A reproducible swab sampling protocol utilizing TX714A Alpha swabs wetted with an extracting solvent has been developed to collect representative samples from both surfaces. Chromatographic separation of selected kinase inhibitors was achieved in gradient mode using an Agilent Zorbax eclipsed C18 column with acetonitrile and 10 mM ammonium formate as the mobile phase. The analytes were chromatographically separated in a 12 min run time. The mean swab recovery for each drug from glass and stainless steel surfaces exceeded 90%. Cleaning with IPA (70%) and acetone (70%) effectively removed residues for all five drugs. A solution comprising 10 mM SDS with 20% IPA demonstrated good efficacy in cleaning residues of BGT, BRT, and CPT, but exhibited lower efficacy for SMT and BMT.

[Two Cases at Community Pharmacies of Mercaptopurine Removal from a Disk-type Powder-packaging Machine by Wiping It with Water].

"Leukerin® powder 10%" containing mercaptopurine (6-MP) is an oral anticancer drug that requires careful handling. As a powder formulation, there are risks of exposure due to scattering during dispensing and possible 6-MP contamination to other drugs due to adhesion to the packaging machine. We previously reported that wiping with an alcohol-containing towel is useful for removing scattered powder after dispensing. However, it is recommended to wipe disk-type powder-packaging machines with water instead of cleaning with the alcohol-containing towel. Hence, we scattered 6-MP powder 100 mg (total amount of 6-MP: 10 mg), and then wiped with water three times using different types of cloth each time. We confirmed that third time wiping cloth did not have any 6-MP. Furthermore, we confirmed that the adhering 6-MP could be removed by wipe-cleaning (water-wiping twice and dry-wiping once) after dispensing 6-MP powder at two pharmacies that routinely dispensed 6-MP powder using a disk-type powder-packaging machine. In addition, we confirmed the adhesion of 6-MP in parts of the machine not cleaned by wipe-cleaning and also in parts that were washed only with water, in both the pharmacies. Based on the above observations, we recommend the following steps for cleaning disk-type powder-packaging machines after dispensing 6-MP powder: (1) wipe-cleaning that includes water-wiping twice and then dry-wiping once, (2) cleaning all areas of the packaging machine, and (3) wipe-cleaning with water before washing with water.

Influence of cleaning methods after 3D printing on two-body wear and fracture load of resin-based temporary crown and bridge material.

OBJECTIVES: To investigate the impact of different cleaning methods on the fracture load and two-body wear of additively manufactured three-unit fixed dental prostheses (FDP) for long-term temporary use, compared to the respective outcomes of milled provisional PMMA FDPs. MATERIALS AND METHODS: Shape congruent three-unit FDPs were 3D printed using three different resin-based materials [FPT, GCT, NMF] or milled [TEL] (N = 48, n = 16 per group). After printing, the FDPs were cleaned using: Isopropanol (ISO), Yellow Magic 7 (YEL), or centrifugal force (CEN). Chewing simulation was carried out with a vertical load of 50 N (480,000 × 5 °C/55 °C). Two-body wear and fracture load were measured. Data were analyzed using global univariate ANOVA with partial eta squared, Kruskal-Wallis H, Mann-Whitney U, and Spearman's rho test (p < 0.05). RESULTS: TEL showed less wear resistance than FPT (p = 0.001) for all cleaning methods tested. Concerning vertical material loss, NMF and GCT were in the same range of value (p = 0.419-0.997), except within FDPs cleaned in ISO (p = 0.021). FPT showed no impact of cleaning method on wear resistance (p = 0.219-0.692). TEL (p < 0.001) showed the highest and FPT (p < 0.001) the lowest fracture load. Regarding the cleaning methods, specimens treated with ISO showed lower fracture load than specimens cleaned with CEN (p = 0.044) or YEL (p = 0.036). CONCLUSIONS: The material selection and the cleaning method can have an impact on two-body wear and fracture load results. CLINICAL RELEVANCE: Printed restorations showed superior two-body wear resistance compared to milled FDPs but lower fracture load values. Regarding cleaning methods, ISO showed a negative effect on fracture load compared to the other methods tested.

Bioremoval of graffiti using novel commercial strains of bacteria.

Previous studies have provided evidence that bioremediation deals a novel approach to graffiti removal, thereby overcoming well-known limitations of current cleaning methods. In the present study eight bacteria aerobic, mesophilic and culturable from the American ATCC and the German DSMZ collections of microorganisms, some isolated from car paint waste, colored deposits in a pulp dryer and wastewater from dye works, were tested in the removal of silver and black graffiti spray paints using immersion strategies with glass slides. Absorbance at 600 nm and live/dead assays were performed to estimate bacterial density and activity in all samples. Also, pH and dissolved organic carbon (DOC) and inorganic carbon (DIC) measurements in the liquid media were made, as well as, thickness, colorimetric and infrared (FTIR) spectroscopy measurements in graffiti paint layers were used to evaluate the presence of the selected bacteria in the samples and the graffiti bioremoval capacity of bacteria. Data demonstrated that of the eight bacteria studied, Enterobacter aerogenes, Comamonas sp. and a mixture of Bacillus sp., Delftia lacustris, Sphingobacterium caeni, and Ochrobactrum anthropi were the most promising for bioremoval of graffiti. According to significant changes in FTIR spectra, indicating an alteration of the paint polymeric structure, coupled with the presence of a consistent quantity of live bacteria in the medium as well as a significant increase of DIC (a measure of metabolic activity) and a change in paint color.

Surface Quality Evaluation of Removable Thermoplastic Dental Appliances Related to Staining Beverages and Cleaning Agents.

(1) Background: Thermoplastic materials are not inert and subject to changes in the oral environment, which affect their surface quality. Color stability and topographic characteristics of clear thermoplastic appliances are critical considerations. The study aimed to evaluate the optical changes and surface topography of different thermoplastic materials related to staining beverages and cleaning agents. (2) Methods: Thermoplastic polyethylene terephthalate glycol (PET-G) material specimens were selected for the study: S (Duran, Scheu-Dental GmbH, Iserlohn, Germany), D (Biolon, Dreve Dentamid GmbH, Unna, Germany), and B (Crystal, Bio Art Dental Equipment, Sao Carlos, Brazil). Four different media were involved for immersion: coffee (C) and black tea (T) at 55 °C, Coca-Cola (K) at 5 °C, and distilled water (W) at 22 °C. As for cleaning, chemical options and mechanical brushing were selected (P-powder, T-tablets, and X-brushing). Color changes, and mean surface roughness were measured at 24 h, 48 h, and after 7 days. Statistical analysis was performed. After the testing period, atomic force microscopy (AFM) analyses and SEM images were registered in order to characterize the surface topography. (3) Results: Quantitative color change evaluations revealed a slight change in color after 24 h and an extremely marked change after 48 h, respective 7 days. Mean roughness values are kept below the clinically acceptable limit of 0.20 µm for all samples. Related to mean nanoroughness values Sa, and 3D evaluations of the surface quality, Biolon samples have demonstrated the most constant behavior, while Crystal samples are visibly influenced by water immersion. Related to the cleaning method, the topography of Duran samples was influenced by mechanical brushing. (4) Conclusions: Nanoscale investigations provided high accuracy and more realistic surface quality examinations of the examined samples compared to profilometry. Both SEM and AFM should be used for a more detailed description of the surface topography.

An easy method for the clear detection of beige fat UCP1 by Western blotting.

Beige adipocytes, which consume energy mainly in an uncoupling protein 1 (UCP1)-dependent manner, are risen in white adipose tissue (WAT) depots. Since beige adipocyte development is gaining attention as a potential strategy for conquering obesity, worldwide researchers are making efforts to study its biological aspects. However, assessing UCP1 protein levels in beige adipocytes is challenging because of the high level of lipid contaminants in WAT. This study showed that an acetone precipitation method had advantages over conventional methods for eliminating lipid contaminants, achieving clear Western blot bands for WAT proteins, especially UCP1. Our results suggest that the acetone precipitation cleaning method could be useful for the clear analysis and precise evaluation of WAT proteins.

Simultaneous Determination of Four Aflatoxins in Dark Tea by Multifunctional Purification Column and Immunoaffinity Column Coupled to Liquid Chromatography Tandem Mass Spectrometry.

Dry tea matrix contains an abundance of caffeine and polyphenols which are different from the food matrix (e.g., protein, lipid, and carbohydrates), and only a few studies have tried aflatoxins determination with tea samples. Here, a specific, accurate, and sensitive method was developed and validated for the simultaneous determination of aflatoxin B1, B2, G1, and G2 in dark teas. Aflatoxins were extracted by acetonitrile/water, press-filtered, and cleaned by multifunctional purification column (MFC) and immunoaffinity column (IAC) in tandem. The cleaned extract was analyzed by liquid chromatography tandem mass spectrometry. The matrix interference was effectively reduced by MFC-IAC cleaning method. Recoveries at the spiking concentrations of 5-60 µg/kg ranged from 77.5 to 93%, with relative standard deviations <11.0%. The correlation coefficients of aflatoxins standard were >0.998. The limits of detection were 0.024-0.21 µg/kg and the limits of quantification were 0.08-0.74 µg/kg. The intra- and interday accuracy ranged from 74 to 87%, and the intra- and interday precisions ranged from 0.4 to 3.1%. After the method validation, the aflatoxins contaminations in 100 collected dark teas were detected, and the results were compared with those of other methods.

[Advances in Lymph Node Metastasis and Lymph Node Dissection 
in Early Non-small Cell Lung Cancer].

Lung cancer is the malignant tumor with the highest morbidity and mortality in China. Non-small cell lung cancer is the main pathological type. Lymph node metastasis is the most common and primary metastatic pathway in non-small cell lung cancer. Acknowledged as the major factor determining tumor staging and prognosis. Unfortunately, it's presently hard to make an accurate preoperative judgment on the lymph node metastasis of early stage non-small cell lung cancer. Consequently, there has been a long-standing controversy on lymph node sweeping for early stage non-small cell lung cancer, especially for those clinical stage I. The regularity of non-small cell lung cancer lymph node metastasis and the ways of lymph node sweeping will be reviewed in this paper.
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Preparation of thermo-responsive PNIPAAm-MWCNT membranes and evaluation of its antifouling properties in dairy wastewater.

A novel MWCNT-PNIPAAm nanocomposite membrane was developed with an excellent cleaning efficiency of thermo-responsive surface. The thermo-responsive N-isopropyle acryleamide (NIPAAm) monomer was polymerized on the surface of MWCNT via free radical polymerization. The prepared MWCNT-PNIPAAm nanocomposite was characterized by FTIR, SEM and TGA analyses. Various amounts of the prepared nanocomposite were incorporated into the membrane matrix by the physical blending method. The resultant membranes showed better surface wettability and pure water flux compared to pristine Polyethersulfone (PES) membrane. Furthermore, after filtration, the COD value of dairy wastewater was reduced to around 90% for all membranes. The thermo-responsive cleaning method was employed to investigate the cleaning efficiency of MWCNT-PNIPAAm membrane for dairy wastewater. The 99.9% flux recovery ratio was obtained for MWCNT-PNIPAAm-0.05% membranes. All these results confirmed that the presence of MWCNT-PNIPAAm nanocomposite in the membrane matrix improves the membrane hydrophilicity and antifouling properties.

The Effect of Temporary Cement Cleaning Methods on the Retention of Crowns.

PURPOSE: To evaluate the effect of temporary cement cleaning methods on the retention of cemented crowns using zinc phosphate cement and resin-modified glass ionomer cement. MATERIALS AND METHODS: Forty titanium specimens were fabricated to simulate prepared molars with minimally retentive taper. The Ni-Cr cast crowns were fabricated, temporarily cemented, and separated. The specimens were divided into four groups according to the temporary cement cleaning method (n = 10) as follows: control group (no temporary cementation), orange solvent group, ultrasonic cleaning group, and air-abrasion group. After the cleaning procedures, the specimens were cemented with definitive cements (zinc phosphate cement and resin-modified glass ionomer, RMGI, cement) and subjected to thermocycling (5000 cycles, 5-55°C, dwell time, 10 seconds). The tensile bond strength of each specimen was measured using a universal testing machine, and the results were analyzed using the Kruskal-Wallis and Mann-Whitney U test (α = 0.05). RESULTS: When cemented with zinc phosphate cement, the statistical analysis showed that the value of the air-abrasion group was significantly higher than those of the other groups (p < 0.01). There was no statistically significant difference among the other groups. When cemented with RMGI cement, the air-abrasion group showed the lowest value, and the control group showed the highest value (p < 0.01). The difference between the ultrasonic cleaning group and the orange solvent group was not statistically significant. CONCLUSION: The use of temporary cement did not have a significant influence on retention of permanently cemented crowns when zinc phosphate cement was used for permanent cementation. Airborne-particle abrasion after provisional cementation improved retention of crowns cemented with zinc phosphate cement; however, the use of temporary cement significantly decreased retention of permanently cemented crowns when RMGI cement was used regardless of the temporary cement cleaning method.

Advances in Lymph Node Metastasis and Lymph Node Dissection in Early Non-small Cell Lung Cancer / 中国肺癌杂志

Lung cancer is the malignant tumor with the highest morbidity and mortality in China. Non-small cell lung cancer is the main pathological type. Lymph node metastasis is the most common and primary metastatic pathway in non-small cell lung cancer. Acknowledged as the major factor determining tumor staging and prognosis. Unfortunately, it's presently hard to make an accurate preoperative judgment on the lymph node metastasis of early stage non-small cell lung cancer. Consequently, there has been a long-standing controversy on lymph node sweeping for early stage non-small cell lung cancer, especially for those clinical stage I. The regularity of non-small cell lung cancer lymph node metastasis and the ways of lymph node sweeping will be reviewed in this paper.
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Cleaning quality of different cleaning methods for reusable laparoscopic instruments / 中国感染控制杂志

Objective To evaluate the cleaning quality of different cleaning methods for laparoscopic instruments, ensure the cleaning quality of instruments.Methods The used laparoscopic instruments were classified into two categories: non-lumen instruments and lumen instruments. Three cleaning methods, traditional manual cleaning (A), manual cleaning + ultrasonic cleaning (B), manual cleaning + automatic cleaning disinfector (C), were adopted respectively for treating instruments. Cleaning quality of instruments were detected with ATP bioluminescence assay.Results The qualified rates of laparoscopic non-lumen instruments cleaned by methods A, B, and C were 78.75％, 95.71％, and 96.00％ respectively, difference was significant (χ2=16.453, P＜0.001);qualified rate of methods B and C for cleaning non-lumen instruments was higher than that of method A (P＜0.016), there was no significant difference between methods B and C (P＞0.016). Qualified rates of laparoscopic lumen instruments cleaned by methods A, B, and C were 76.47％, 98.75％, and 91.55％ respectively, difference was significant (χ2=21.087, P＜0.001); qualified rates of methods B and C for cleaning lumen instruments were both higher than that of method A (P＜0.016), there was no significant difference between methods B and C (P＞0.016). Conclusion Effect of manual cleaning + ultrasonic cleaning and manual cleaning + automatic cleaning disinfector on used laparoscopic instruments are both better than that of traditional manual cleaning method, can effectively guarantee the cleaning quality of instruments and help to ensure the operation safety of patients.

Temperature Enhanced Backwash.

Decentralized drinking water treatment is limited by supply of service, consumables, spare parts and in particular, power. Therefore, gravity-driven dead-end ultrafiltration is applied to purify surface water with high suspended solid loading. To obtain high flux in the long term, an effective membrane backwash is mandatory. Also, disinfection and cleaning is required regularly. Here we propose a new process coping with these particular challenges in decentralized water production: Temperature Enhanced Backwash. Herein, the membrane is backwashed at elevated temperature and corresponding steam pressure. A mathematical description of the Temperature Enhanced Backwash reveals that membrane pores are filled predominantly with liquid phase, irrespectively of whether membranes are charged with saturated steam or boiling liquid. A steam - water mixture is discharged at the module outlet suggesting evaporation at the end of the pores. This evaporation at membrane - fluid interface supposedly creates high volume fluxes shearing off potential fouling layers. Combined with gravity-driven filtration, the overall process potentially can cope with highly intermittent electrical power supply or even its absence. The methodology shows competitive cleaning efficacy compared to mechanical backwashing as demonstrated experimentally using silica nanoparticles, humic acid and river water.

Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material.

OBJECTIVES: To evaluate the long-term effects of seven different cleaning methods on light transmittance, surface roughness, and flexural modulus of a polyurethane retainer material. MATERIALS AND METHODS: Polyurethane retainer specimens (Vivera®, Align Technology Inc) (70 specimens, n = 10 per method, 50.8 mm × 12.7 mm × 1.0 mm) were exposed to seven cleaning methods twice a week for 6 months. Before treatment and after 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified. Qualitative assessment of randomly selected specimens from each solution was performed at baseline and after 6 months using a scanning electron microscope. Statistical analyses were performed at the .05 significance level. RESULTS: Of the three test variables, light transmittance through the specimens was the only one that changed significantly from baseline to 6 months for all cleaning solutions, with all of them causing a decrease. However, except for 0.6% sodium hypochlorite showing a change in surface roughness values and 2.5% vinegar and toothbrushing showing an increase in flexural modulus, none of the other four cleaning methods resulted in significant changes in surface roughness or flexural modulus values for the polyurethane specimens between baseline and after 6 months. CONCLUSIONS: Of the seven cleaning methods, Invisalign® cleaning crystals, Polident®, and Listerine® showed the least amount of change in light transmittance values for the polyurethane specimens over 6 months, and they had no effect on surface roughness and flexural modulus values.

Cleaning verification: Exploring the effect of the cleanliness of stainless steel surface on sample recovery.

The parameters affecting the recovery of pharmaceutical residues from the surface of stainless steel coupons for quantitative cleaning verification method development have been studied, including active pharmaceutical ingredient (API) level, spiking procedure, API/excipient ratio, analyst-to-analyst variability, inter-day variability, and cleaning procedure of the coupons. The lack of a well-defined procedure that consistently cleaned coupon surface was identified as the major contributor to low and variable recoveries. Assessment of acid, base, and oxidant washes, as well as the order of treatment, showed that a base-water-acid-water-oxidizer-water wash procedure resulted in consistent, accurate spiked recovery (>90%) and reproducible results (Srel≤4%). By applying this cleaning procedure to the previously used coupons that failed the cleaning acceptance criteria, multiple analysts were able to obtain consistent recoveries from day-to-day for different APIs, and API/excipient ratios at various spike levels. We successfully applied our approach for cleaning verification of small molecules (MW<1000Da) as well as large biomolecules (MW up to 50,000Da). Method robustness was greatly influenced by the sample preparation procedure, especially for analyses using total organic carbon (TOC) determination.

A cleaning method to minimize contaminant luminescence signal of empty sample carriers using off-the-shelf chemical agents.

Signals acquired during thermoluminescence or optically stimulated luminescence measurements must be completely free of any spurious and/or contamination signals to assure the credibility of the results, especially during exploratory research investigating the luminescence behavior of new materials. Experiments indicate that such unwanted signals may also stem from new (unused) and used empty sample carriers, namely cups and discs, which are widely used for such measurements, probably due to contamination from a fluorite and/or silica-related source. Fluorite and/or silicone oil appear to be the most likely sources of contamination, thus, their removal, along with any other possible source that exhibits undesirable luminescence behavior, is necessary. Conventional cleaning methods fail to eliminate such contaminants from empty cups and discs. In this work a new cleaning method is proposed incorporating off-the-shelf chemical agents. Results of thermoluminescence measurements highlight the efficiency of the new cleaning process, since it can completely remove any observed contaminants from both new and used sample carriers, of various shapes and/or materials. Consequently their signal is minimized even at relatively high beta-doses, where it is prominent, resulting in a clean and only sample-attributed signal.

Verification for Chemical Medicine Tablet Production Equipment Cleaning Method / 中国药房

OBJECTIVE:To evaluate the rationality and validity of chemical medicine tablet production equipment cleaning pro-cedure. METHODS:Among several chemical medicines prepared by similar production technology as Metoprolol succinate sus-tained-release tablets,Captopril tablets,Isosorbide mononitrate tablet and Metformin hydrochloride tablet,Metoprolol succinate sus-tained-release tablets had strongest toxicity and were included in validation test. The production equipment was cleaned and disinfect-ed according to cleaning procedure. The point which was most difficult to clean could be wiped and sampled by using the cotton swab method. The detection limit and the limit of quantitation of the residue limits were verified as well as the recovery rate of wip-ing,in order to evaluate whether the results meet the requirements. RESULTS:The cotton swab method is adopted to wipe sample and detect the point which is most difficult to clean. The visible foreign body has not been found in each sampling point. The amount of residual drug is <29.75 μg/cotton bud,and microbial limits are <50 CFU/cotton bud,indicating test items are in line with the standard. CONCLUSIONS:The cleaning method can effectively clean the production equipment,and can effectively pre-vent product contamination and cross contamination to ensure the quality,efficacy and safety of the next batch of products.

Evaluation of removal forces of implant-supported zirconia copings depending on abutment geometry, luting agent and cleaning method during re-cementation.

PURPOSE: To evaluate the effects of different abutment geometries in combination with varying luting agents and the effectiveness of different cleaning methods (prior to re-cementation) regarding the retentiveness of zirconia copings on implants. MATERIALS AND METHODS: Implants were embedded in resin blocks. Three groups of titanium abutments (pre-fabricated, height: 7.5 mm, taper: 5.7°; customized-long, height: 6.79 mm, taper: 4.8°; customized-short, height: 4.31 mm, taper: 4.8°) were used for luting of CAD/CAM-fabricated zirconia copings with a semi-permanent (Telio CS) and a provisional cement (TempBond NE). Retention forces were evaluated using a universal testing machine. Furthermore, the influence of cleaning methods (manually, manually in combination with ultrasonic bath or sandblasting) prior to re-cementation with a provisional cement (TempBond NE) was investigated with the pre-fabricated titanium abutments (height: 7.5 mm, taper: 5.7°) and SEM-analysis of inner surfaces of the copings was performed. Significant differences were determined via two-way ANOVA. RESULTS: Significant interactions between abutment geometry and luting agent were observed. TempBond NE showed the highest level of retentiveness on customized-long abutments, but was negatively affected by other abutment geometries. In contrast, luting with Telio CS demonstrated consistent results irrespective of the varying abutment geometries. Manual cleaning in combination with an ultrasonic bath was the only cleaning method tested prior to re-cementation that revealed retentiveness levels not inferior to primary cementation. CONCLUSION: No superiority for one of the two cements could be demonstrated because their influences on retentive strength are also depending on abutment geometry. Only manual cleaning in combination with an ultrasonic bath offers retentiveness levels after re-cementation comparable to those of primary luting.

Comparative analysis of four cleaning methods of endodontic files

Introduction: Due to the size and design of endodontic files, these instruments have been considered one of the most difficult to clean among all dental instruments. The debris maintenance within the sulcus prevents the effective sterilization and may compromise the disinfection of root canal systems in endodontic therapy. However, there is neither a method nor technique that standardized the cleaning of these instruments. Objective: To evaluate the cleaning ability of four techniques used in dentistry. Material and methods: For this purpose, 30 new size #40 Flexofile were used for the preparation of the canals of mandibular molars of pigs. After instrumentation, the contamination and the presence of debris in the sulcus was confirmed and the files were randomly divided into four groups: control group (without cleaning), group 1 (enzymatic detergent + manual brushing with nylon bristle brush), group 2 (ultrasound + enzymatic detergent), group 3 (ultrasound + water) and group 4 (gauze embedded in 70% alcohol). Next, all files were photographed and photographs were printed at high quality. The spirals containing debris were counted. Results: Manual cleaning with enzymatic detergent and nylon bristle brush, ultrasound with either water or detergent showed the best cleaning capacity in which respectively 100%, 98.9% and 96.2%, of the spirals were free of debris. Cleaning with alcohol and gauze proved to be ineffective, showing debris in more than 40% of the spirals by visual analysis. In control group, 91% of the spirals presented debris. It can be concluded that the association between manual and ultrasound cleaning may be promising in ensuring a cleaning protocol for endodontic files cleaning.

Survival of microorganisms on complete dentures following ultrasonic cleaning combined with immersion in peroxide-based cleanser solution.

OBJECTIVES: To compare ultrasonic cleaning combined with immersion in a commercially available peroxide-based cleanser solution (Polident(®) ) with other denture cleaning methods, we examined the quantity of micro-organisms that survived on dentures before and after various cleaning methods. SUBJECTS AND METHODS: One hundred complete dentures belonging to 50 nursing home residents (mean age, 84.6 years) were randomly assigned to five groups according to the cleaning method employed: (A) immersion in Polident(®) solution alone, (B) brushing with water, (C) ultrasonic cleaning with water, (D) method (A) followed by method (B) and (E) ultrasonic cleaning combined with immersion in Polident(®) solution. Before and after the dentures had been cleaned, denture biofilm was collected from the mucosal surface of each lateral half of the examined dentures. The collected micro-organisms were cultured, presumptively identified by standard methods and quantified. Comparisons between the five cleaning methods were carried out using the Kruskal-Wallis test and Dunn's multiple comparisons test. RESULTS: The denture cleaning methods involving the use of Polident(®) solution (methods A, D and E) were significantly more effective at denture disinfection than the other methods (p < 0.05); in particular, the quantity of Candida spp. was lowest after method E (median, 0.00; significantly lower than those observed after methods A, B and C; p < 0.05). CONCLUSION: It was concluded that ultrasonic cleaning combined with immersion in a peroxide-based cleanser solution effectively reduces the quantity of micro-organisms surviving on dentures and is a suitable method for elderly individuals who find brushing their dentures difficult.