• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.569-583
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• 1995

Disinfection of dental impressions are necessary due to contamination with patient’s saliva and blood, which is a potential for cross-infection. The purpose of this study was to evaluate the effects of disinfection of four hydrophilic rubber impression materials with three disinfecting solutions, on the dimensional stability and surface hardness of improved stone casts. Three hydrophilic vinyl polysiloxane impression materials(Express, Reprosil, Exafine) and one polyether impression material(Impregum-F) were mixed according to the manufacturer’s directions and impressions were made on a ADA specification No. 19 stainless-steeldie. On removal of the impressions, each impression was immersed in one of the disinfectants(Banicide, Potadine, Clorox) for 10 minutes. After disinfection, type IV improved stone. casts were poured. On this cast, the linear dimension and surface hardness were measuredusing a Measurescope(Nikon, Japan) and a Barcol hardness tester(Barber, Colman Co U. S. A). The results were as follows : 1. The improved stone casts from disinfected Reprosil and Impregum-F impression material did not show dimensional changes(P>0.01). Those from disinfected Express and Exafine impression material showed dimensional changes(P<0.01). The amount of shrinkage was not clinically significant. 2. The improved stone casts from disinfected Express impression material did not exhibit changes in surface hardness(P>0.01), but those from disinfected Reprosil, Exafine, Imp regnum-F impression material showed changes in surface hardness(P<0.01). 3. The dimensinal stability and surface hardness of the improved stone casts were satisfactory using Banicide on Express, all disinfectants used in this study on Reprosil, Potadin and Clorox on Exafine, Banicide and Clorox on Impregum-F. According to these results, immersion disinfection of hydrophilic rubber impression mate rials did not adversely affect the resultant casts. Nevertheless compatibility tests of impression materials and disinfectants should be done when disinfecting impressions.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.3
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• pp.496-505
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• 1998

The purpose of this study was to evalute the effect of immersion disinfection on the dimensional stability of rubber impression materials. The metallic master model was made in order to simulate the intraoral arch form. Impressions were made from four impression materials (Exaflex, Extrude, Reprosil, Impregum-F) and immersed in three disinfectant solutions (Wydex, Vi-Pon, Potadine). Casts from the impressions were measured according to the interpreparation distance. The A-B and The B-D abutment distance were compared with the control group and disinfected groups. The results were as follows; 1. The measurements of the stone cast increased relative to the master model and there was a significant difference (P<0.05). 2. The relative dimensional change of the stone cast as compared with master model ranged from 0.10% to 0.56% in the A-B distance and ranged from 0.04% to 0.27% in the B-D distance. 3. The dimensional change of the disinfected groups as compared with the control group was significantly different in the three impression materials except for Impregum-F (P<0.05). 4. The relative dimensional change of the disinfected groups compared with the control group ranged from 0% to 0.20% in the A-B distance and ranged from -0.09% to 0.11% in the B-D distance. These results suggest that immersion disinfection of rubber impression materials by chemical disinfectants causes very small dimensional change and the change is clinically acceptable for prothesis fabrication

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.290-295
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• 2016

PURPOSE. The aim of this study was to evaluate the effect of paracetic acid (PAA) and ozone disinfection on the tensile bond strength (TBS) of silicone-based resilient liners to acrylic resins. MATERIALS AND METHODS. One hundred and twenty dumbbell shaped heat-polymerized acrylic resins were prepared. From the mid segment of the specimens, 3 mm of acrylic were grinded off and separated parts were reattached by resilient liners. The specimens were divided into 2 control (control1, control7) and 4 test groups of PAA and ozone disinfection (PAA1, PAA7, ozone1 and ozone7; n=10). While control groups were immersed in distilled water for 10 min (control1) and 7 days (control7), test groups were subjected to PAA (16 g/L) or ozone rich water (4 mg/L) for 1 cycle (10 min for PAA and 60 min for ozone) per day for 7 days prior to tensile tests. Measurements of the TBS were analyzed using 3-way ANOVA and Tukey's HSD test. RESULTS. Adhesive strength of Mollosil decreased significantly by application of ozone disinfection. PAA disinfection had no negative effect on the TBS values of Mollosil and Molloplast B to acrylic resin. Single application of ozone disinfection did not have any negative effect on TBS values of Molloplast B, but prolonged exposure to ozone decreased its adhesive strength. CONCLUSION. The adhesion of resilient liners to acrylic was not adversely affected by PAA disinfection. Immersion in ozonated water significantly decreased TBS of Mollosil. Prolonged exposure to ozone negatively affects adhesion of Molloplast B to denture base materials.

• The Journal of Advanced Prosthodontics
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• v.11 no.3
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• pp.155-161
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• 2019

PURPOSE. Although dental impression disinfection is determinant to reduce the cross-infection risk, some studies have shown that, in real practice, the disinfection procedures vary considerably. Thus, the aim of this study was to evaluate the antimicrobial effectiveness and the impact on the dimensional stability of addition silicone' impressions of water wash and the most clinically used disinfection solutions: 3% hydrogen peroxide, commercial disinfectant MD520 (Durr) and 1% and 5.25% sodium hypochlorite. MATERIALS AND METHODS. For this investigation, dental impressions were taken on 16 volunteer dental students. The antimicrobial effectiveness of each procedure was evaluated by pour plate method. The dimensional stability was evaluated using a standardized stainless-steel model, according to ANSI/ADA nº19 specification. RESULTS. The study results showed that water wash does not alter the dimensional stability of addition silicone impressions but doesn't reduce the microbial load of the material (P>.05). On the other hand, addition silicone disinfection by immersion with 3% hydrogen peroxide, MD520 (Durr), or sodium hypochlorite at 1% and 5.25% does not alter the dimensional stability significantly but reduces > 99.9% of the microbial load of the impressions (P<.001). CONCLUSION. Addition silicone impressions should always be disinfected after water wash in order to reduce effectively the cross-infection risk. All disinfectants tested showed high antimicrobial efficiency without significant changes in three-dimensional shape of impressions. Hydrogen peroxide and sodium hypochlorite are of particular importance because are easily accessible in dental setting. The less explored hydrogen peroxide could be a valuable alternative for silicone impressions disinfection.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.249-259
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• 1989

Dental impression materials often become contaminated with patients' saliva and blood which creates the potential for cross-infection. It was the purpose of this study to investigate the effects of disinfection of three different rubber impression materials with four different disinfecting solutions. Polysulfide, vinyl polysiloxane and polyether impression materials were mixed according to the manufacturer's directions and samples were formed on a stainless steel model. On removal from the standard model, impressions were immersed in a disinfectant (acid-potentiated glutaraldehyde, phenollic compound, chlorine compound, iodophor) at room tempera tures for ten minutes. After disinfection, the distance between reference points(linear dimension) was measured using the non-contact automatic cordinate measuring projector(MZ-1, Nikon). Through statistical analyses on the data from this study,. the following conclusions were obtained. 1. Polysulfide, vinyl polysiloxane impressions were disinfected without dimensional change.(p>0.05) 2. Polyether impressions which were immersed in acid-potentiated glutaraldehyde were statistically different from control group.(p<0.05) But the amount of shrinkage(0.04%) would not be clinically significant. 3. By immersion of polysulfide, vinyl polysiloxane, polyether impressions in Banicide, Biocide, Multicide plus, sodium hypochlorite for ten minutes, clinically accurate impressions were obtained without dimensional change.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.1
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• pp.21-29
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• 2004

Statement of problem : Because dental impression can be a cross-infection source, disinfection, such as immersion disinfection is nessecary. However, the disinfection process may change the volume of the impression cast. Purpose : The purpose of this study is to find out the effects on dimensional change of different storage times and methods, of agar-alginate impression when immersed in a 5% idophor disinfectant. Material and Methods : An agar-alginate impression was made from a mandible model and then was disinfected and stored according the experimental conditions and a stone model was produced. Measurements were taken between reference points on the original mandible model and they were compared to measurements taken between reference points on the stone model. The study was divided into 4 groups. In group 1, the impression was stored in a 100% humidor for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 12 hours and 24 hours and stone models were made at each time. In group 2, the impression was immersed in 5% idophor disinfectant and then stored in a 100% humidor for the same length of times as group 1, and stone models were made at each time. In group 3, the impression was stored in extend-A-pourR, a special storage solution for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 12 hours, 24 hours 3 days, and 7 days and stone models were made at each time. In group 4, the impression was immersed in 5% idophor disinfectant and then stored in stored in extend-A-pourR, a special storage solution for the same length of times as group 3, and stone models were made at each time. 5 impressions and stone models were made at each time to make a total of 180. The Student-t test (P < .05) was used to do a statistical analysis of the measurements of the mandible model and stone models. The repeated-measure 2-way analysis of variance (P < .05) was used to do a statistical analysis of the difference in the 4 groups. Results : The percent liner dimensional change was from $0.25{\pm}0.03%$ (group 1, 30 minutes) to $0.34{\pm}0.06%$ (group 4, 7 days). No significant change was noticed between the 4 groups. Conclusion : According to the above study, in both methods, least dimensional change was recorded when the storage times were short and in both methods, immersion in 5% idophor disinfectant did not effect dimensional change in the agar-alginate impression.

• Food Science and Preservation
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• v.13 no.3
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• pp.316-321
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• 2006

Disinfection of electrolyzed water (EW) on strawberry by immersion washing and quality changes during storage at $5^{\circ}\C$ was compared with one immersed in chlorine water and not treated. Total count of strawberry washed with EW by immersion in 10 volumes of EW for 20 min was decreased to about 2 log cycle compared to the untreated And rate of microbial growth during storage was lower than ethers. Decaying ratio in strawberry treated with electrolyzed low-alkalinewater (EW-2) showed lower as of 10% level after 5 days of storage compared) to the untreated and the treated with chlorine water (CW). Hardness in the treatment of EW was not changed significantly until 3 days of storage, after then rather increased. Change in surface color of strawberries was observed; L value in the CW treated and the untreated increased whereas it decreased in the treatment of EW. And color difference(${\Delta}E$) during storage was observed the lowest in the untreated until 3 days of storage. The initial value of residual chlorine in the treatment of EW was at the level of $0.04{\sim}0.06ppm$, and $1{\sim}3$ days later showed almost the equal value to level of $0.02{\sim}0.03ppm$ in all treatments. Sensory characteristic during storage was preferable on strawberry washed with EW (EW-1 and EW-2) to the other treatments.

• Food Science and Preservation
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• v.15 no.2
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• pp.236-242
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• 2008

We investigated the optimum concentration of a $NaClO_2$ solution and the amount of gaseous $Cl_2$ for production of high yield and purity of aqueous $ClO_2$ by use of a gaseous chlorine-chlorite $ClO_2$ generator. This system produced lower concentrations of chlorine dioxide and is applicable for direct-use in food processing as a cleaner and sanitizer. The concentration of $NaClO_2$ solution and the amount of gaseous $Cl_2$ was varied from 0.01-0.1% and 100-1,000 g/hr, respectively. The concentrations of chlorite, chlorate, FAC (free available chlorine), and chlorine dioxide that were produced increased with increasing concentration of $NaClO_2$ solution and with the amount of gaseous $Cl_2$. The optimum concentration of $NaClO_2$ solution and amount of gaseous $Cl_2$ were 0.1% and 900 g/hr respectively. $ClO_2$ and FAC produced at these concentrations were 882.0 ppm and 8.0 ppm, with no detection of chlorite and chlorate. The yield and purity of $ClO_2$ were 97.0% and 96.0% respectively. Immersion-cleaning experiments showed that this protocol decreased the level of CFU/g by $10^3$- to $10^4$-fold, with a similar effect on fruit.

• Korean Journal of Agricultural Science
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• v.20 no.1
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• pp.18-24
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• 1993

This experiment was focused on determining the potential of sodium hypochlorite (NaOCl) as fungicide against seed-borne fungi. Effects of NaOCl to control seed-borne fungi were compared to the those of Benlate T in several crop seeds. 1. The effect of NaOCl on disinfection of sesame seeds without imparing germination was highest in the range of 1-2% solution for 10 min. Also, a 30 min immersion of rice seed in 1-2% solution reduced incedence of seed-borne fungi. 2. Alternaria spp. in seeds of radish and chinese cabbage and Colletoricum spp. in pepper were significantly reduced by a 10 min immersion of seeds in 1% NaOCl. 3. The effective control range of NaOCl for seed-borne fungi was much wider than that of Benlate T in sesame seeds. No clear difference between chemicals was found in rice seeds. However, germination of seeds were impaired at 1-2% NaOCl immersion for more than 1 hour.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.174-179
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• 2007

Seedlot disinfection techniques to control mung bean sprout rot caused by Colletoricum acutatum and C. gloeosporioides were evaluated for commercial production scheme. Soaking seedlots in propolis (100 X) and ethanol (20% for 30 min) appeared promising with control values of 85.5 and 80.8 respectively, but still resulted in up to 20% rot incidence. None of the C. acutatum conidia survived through hot water immersion treatment (HWT) for 10 min at temperatures of 55, 60 and $65^{\circ}C$, whereas the effective range of the dry heat treatment (DHT) was $60-65^{\circ}C$. Tolerance of mung bean seedlot, as estimated by hypocotyl elongation and root growth, was lower for HWT than for DHT. Germination and growth of sprouts were excellent over the range of $55-65^{\circ}C\;at\;5^{\circ}C$ intervals, except for HWT at $65^{\circ}C$ for 5 min. At this marginal condition, heat damage appeared so that approximately 2% of seeds failed to sprout to normal germling and retarded sprouts were less than 5% with coarse wrinkled hypocotyls. These results suggested that DHT would be more feasible to disinfect mung bean seedlots for commercial sprout production. Heat treatment at above ranges was highly effective in eliminating the epiphytic bacterial strains associated with marketed sprout rot samples. HWT of seedlot at 55 and $60^{\circ}C$ for 5 min resulted in successful control of mung bean sprout rot incidence with marketable sprout quality. DHT at 60 and $65^{\circ}C$ for 30 min also gave good results through the small-scale sprouting system. Therefore, we optimized DHT scheme at 60 and $65^{\circ}C$ for 30 min, considering the practical value of seedlot disinfection with high precision and accuracy. This was further proved to be a feasible and reliable method against anthracnose incidence and those bacterial strains associated with marketed sprout rot samples as well, through factory scale mung bean sprout production system.