• The Journal of Advanced Prosthodontics
• /
• v.5 no.1
• /
• pp.2-8
• /
• 2013

PURPOSE. Autoclaves and UV sterilizers have been commonly used to prevent cross-infections between dental patients and dental instruments or materials contaminated by saliva and blood. To develop a dental sterilizer which can sterilize most materials, such as metals, rubbers, and plastics, the sterilization effect of an atmospheric pressure non-thermal air plasma device was evaluated. MATERIALS AND METHODS. After inoculating E. coli and B. subtilis the diamond burs and polyvinyl siloxane materials were sterilized by exposing them to the plasma for different lengths of time (30, 60, 90, 120, 180 and, 240 seconds). The diamond burs and polyvinyl siloxane materials were immersed in PBS solutions, cultured on agar plates and quantified by counting the colony forming units. The data were analyzed using one-way ANOVA and significance was assessed by the LSD post hoc test (${\alpha}$=0.05). RESULTS. The device was effective in killing E. coli contained in the plasma device compared with the UV sterilizer. The atmospheric pressure non-thermal air plasma device contributed greatly to the sterilization of diamond burs and polyvinyl siloxane materials inoculated with E. coli and B. subtilis. Diamond burs and polyvinyl siloxane materials inoculated with E. coli was effective after 60 and 90 seconds. The diamond burs and polyvinyl siloxane materials inoculated with B. subtilis was effective after 120 and 180 seconds. CONCLUSION. The atmospheric pressure non-thermal air plasma device was effective in killing both E. coli and B. subtilis, and was more effective in killing E. coli than the UV sterilizer.

• The Journal of Korean Academy of Prosthodontics
• /
• v.31 no.2
• /
• pp.207-218
• /
• 1993

The purpose of this study was to evaluate the reproducing accuracy of stone casts made from complete arch impressions using different impression materials. The impression materials studied were 1) polyether, 2) polysulfide, 3) polyvinyl siloxane, and 4) irreversible hydrocolloid. Impressions were made from a partially edentulous acrylic resin model with metal inserts in canine, first molar region bilaterally and mid palatal vault region. Each distance between 2 out of 5 meauring points was measured by using 3dimensional measuring machine. Impressions were poured at once with a type IV dental stone. Data were analyzed using t-test with a sample size of six. The results were as follow : 1. Polysulfide and polyether were significantly superior to polyvinyl siloxane and irreversible hydrocolloid in reproducing full arch model(p<0.05), but there were no statistical differences in amount of dimensional reproducing accuracy for full arch impression between polysulfide and polyether(p>0.05). 2. There were statistical differences in amount of dimensional reproducing accuracy between edentulous area and tooth bound area for polysulfide and polyether(p<0.05). but no statistical differences were observed for polyvinyl siloxane and irreversible hydrocolloid(p>0.05).

• Journal of Korean society of Dental Hygiene
• /
• v.1 no.2
• /
• pp.171-180
• /
• 2001

The purpose of this study was to compared with the properties of commercial polyvinyl siloxane impression materials on the Korean product and the other country one. The materials used in this study were 5 hydrophilic polvinyly siloxane impression materials of light body automixing type (Perfect-F, Handae Chemical, Korea; Examix, GC, Japan; Contrast, VOCO, Germany; Express, 3M, U.S.A; Extrude, Kerr, U.S.A.). Specimens of each impression material were fabricated from a mold with dimensions identical to that specified in ASTM D624-91 and were subjected to tensile lode at 500 mm/min until failure for tear strength. Properties of consistency, strain in compression, recovery from deformation, detail reproduction and linear dimensional change were tested according to the testing methods of the ISO specification no.4823(1992). From this study, the follow ing results were obtained 1. The tear strength values were high ET(3.4kN/m), EP(3.4kN/m), PF(3.0kN/m), CT(3.0kN/m), but the lowest was EM(2.2kN/m)(p<0.05). 2. In the consistency, CT(47 mm) had the highest value, followed by PF(42.1 mm), ET(41.2 mm), and EM(39.6 mm), EP(39.2 mm)(p<0.05). It means more flow that the consistency value is high. 3. The strain in compression values were high followed by EM(5.8%), PF(52%), CT(4.6%), ET(4.1%), EP(2.9%)(p<0.05). 4. In the recovery from deformation, ET(99.95%) and PF(99.90%) had the highest value, followed by EP(99.75%), EM(99.74%) without statistical signification, CT(99.64%) had the lowest value(p<0.05). 5. Detail reproduction reappeared to line $20{\mu}m$ all products. 6. The linear dimensional change was a little shrinked all products. and there were not statistical signification (p>0.05). All products were satisfied the ISO specification.

• Journal of dental hygiene science
• /
• v.10 no.6
• /
• pp.459-464
• /
• 2010

The purpose of this study was to evaluate the physical properties of hydrophilic polyvinyl siloxane impression materials as change of material's storage temperatures. Working time, strain-in-compression, elastic recovery and consistency were tested according to ISO Standard NO. 1563. The results are as followed. 1. Working time decreased in cold storage. 2. Strain-in-compression was different in storage temperatures. Material's strain-in compression in cold temperatures were higher than in room temperature and in incubator. 3. A coefficient of elastic recovery varied by storage temperatures. The rate in cold temperature was the lowest and in incubator was the highest. 4. Consistency of impression substance different in storage temperatures. The extent in cold temperature is the highest and in incubator was the lowest. Statistical analysis(SPSS 14.0k, p>0.05) showed that storage temperature affect to material's physical properties. We recognized that the physical properties of polyvinyl siloxane impression materials were changed according to storage temperature.

• The Journal of the Korean dental association
• /
• v.38 no.8 s.375
• /
• pp.757-764
• /
• 2000

• Imaging Science in Dentistry
• /
• v.49 no.4
• /
• pp.257-263
• /
• 2019

Purpose: This study was performed to evaluate the dimensional accuracy of digital dental models constructed from cone-beam computed tomographic (CBCT) scans of polyvinyl siloxane (PVS) impressions and cast scan models. Materials and Methods: A pair of PVS impressions was obtained from 20 subjects and scanned using CBCT (resolution, 0.1 mm). A cast scan model was constructed by scanning the gypsum model using a model scanner. After reconstruction of the digital models, the mesio-distal width of each tooth, inter-canine width, and inter-molar width were measured, and the Bolton ratios were calculated and compared. The 2 models were superimposed and the difference between the models was measured using 3-dimensional analysis. Results: The range of mean error between the cast scan model and the CBCT scan model was -0.15 mm to 0.13 mm in the mesio-distal width of the teeth and 0.03 mm to 0.42 mm in the width analysis. The differences in the Bolton ratios between the cast scan models and CBCT scan models were 0.87 (anterior ratio) and 0.72 (overall ratio), with no significant difference (P>0.05). The mean maxillary and mandibular difference when the cast scan model and the CBCT scan model were superimposed was 53 ㎛. Conclusion: There was no statistically significant difference in most of the measurements. The maximum tooth size difference was 0.15mm, and the average difference in model overlap was 53 ㎛. Digital models produced by scanning impressions at a high resolution using CBCT can be used in clinical practice.

• The Journal of Korean Academy of Prosthodontics
• /
• v.37 no.4
• /
• pp.506-515
• /
• 1999

Dental practice can produce and spread some infectious diseases from patients to dentist, dental assistant, and dental labors. One possible method for preventing these cross-contamination is to immerse dental impression in chemical disinfectants. So for many investigators studied on the dimensional changes of dental impressions and on the surface qualities of stone casts made from impression following immersion in disinfectants. This study was proposed to evaluate some popular impression disinfectant combination from the point of dimensional stability. Impression was taken from dental arch-shaped metal model. Irreversible hydrocolloid and 3 elastomers(polyvinyl siloxane, polysulfide, polyether) were immersed in 3 disinfectants (2% glutaraldehyde, 1% povidone-iodine, 0.5% sodium hypochlorite) for 10 minutes and measured both cross-arch and anterior-posterior distance under stereo microscope to evaluate dimensional change. The results obtained were as follows: 1. Dimensional changes of irreversible hydrocolloid impression was statistically different in cross-arch and anterior-posterior distance when immersed in 2% glutaraldehyde solution and in anterior-posterior distance when immersed in 0.5% sodium hypochlorite solution from control group (p<0.05). 2. Dimensional changes of polyvinyl siloxane and polysulfide impression were not statistically different from control group (p>0.05). 3. Dimensional changes of polyether impression was statistically different in cross-arch distance when immersed in 0.5% sodium hypochlorite solution and in anterior-posterior distance when immersed in 1% povidone-iodine solution from control group (p<0.05). 4. In all cases, dimensional changes were less than 0.1% from the original dimension and concluded clinically acceptable.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.50 no.2
• /
• pp.116-120
• /
• 2024

External nasal splints are commonly used for immobilization following nasal fracture reduction or rhinoplasty procedures. The literature documents the use of various materials like thermoplastic materials, aluminum, Orthoplast, fiberglass, plaster of Paris, and polyvinyl siloxane. These materials are bulky, time-consuming, expensive, and cumbersome to use, and have been associated with complications including contact dermatitis and epidermolysis. Furthermore, they cannot be retained if the situation warrants prolonged stabilization and immobilization. We introduce a new technique using readily available scalp vein catheter flanges as an external nasal stent. The technique is easy to master, inexpensive, and limits edema and ecchymosis, while stabilizing the reconstructed nasal skeleton in position during the healing period.

• Imaging Science in Dentistry
• /
• v.32 no.3
• /
• pp.147-151
• /
• 2002

Purpose: To compare the standard deviation of gray levels on digital subtracted images obtained by different dental subtraction programs. Materials and Methods: Paired periapical films were taken at the lower premolar and molar areas of the phantoms involving human mandible. The bite registration group used Rinn XCP equipment and bite registration material, based on polyvinyl siloxane, for standardization. The no bite registration group used only Rinn XCP equipment. The periapical film images were digitized at 1200 dpi resolution and 256 gray levels by a flat bed scanner with transparency unit. Dental digital subtraction programs used for this study were Subtractor (Biomedisys Co., Korea) and Emago (Oral Diagnostic Systems, The Netherlands). To measure the similarities between the subtracted images, the standard deviations of the gray levels were obtained using a histogram of subtracted images, which were then analyzed statistically. Results: Subtracted images obtained by using the Emago program without manual selection of corresponding points showed the lowest standard deviation of gray levels (p<0.01). And the standard deviation of gray levels was lower in subtracted images in the group of a bite registration than in the group of no use of bite registration (p < 0.01). Conclusion: Digital radiographic subtraction without manual selection of reference points was found to be a convenient and superior method.

• The Journal of the Korean dental association
• /
• v.41 no.1 s.404
• /
• pp.35-41
• /
• 2003

Wettability of addition silicone impression material is very important property for making an accurate restoration. This study examined theimpression quality in clinical condition and the wettability of impression material. Three commercially available addition silicone impression material (Imprint; 3M, USA, Examix; GC, Japan, Perfect; Handae, Korea) were studied. A total of 90 putty/wash impressions of semi-dried premolars and wet molar teeth were examined for void production in impression body. The percentae of the sulcus reproduction ability of each material was calculated from the sulcus depths of cross-sectioned casts from the impressions with stereomicroscope. Three impression materials were used to produce die stone casts from vcid entrapment die. Voids in the stone casts were counted with the stereomicroscpe. From the experiment, the following results were obtained: 1. In direct observation, Imprint showed greatest numbers of void in impression body (P<.001).However, correlations were not found between sulcus reproduction and void production. 2. Sulcus reproduction ability of additional silicone impression material was diminished in order of Imprint, Examix, Perfect. The significant difference was found between Imprint and other material (P<.001). 3. In void entrapment laboratory test, void productions was diminished in order of Examix, Imprint, Perfect. All voids in casts were less in delayed poured cast than immediately poured cast. 4. Especially, the stone pouring time of Perfect impression material should be delayed.