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Indian Journal of Dental Research :... 2022Flow characteristics of vinyl polysiloxane (VPS) impression materials are important determinants in the selection of impression materials for the fabrication of accurate...
BACKGROUND
Flow characteristics of vinyl polysiloxane (VPS) impression materials are important determinants in the selection of impression materials for the fabrication of accurate indirect restorations.
AIMS
: The purpose of this study was to determine the flow of three commercially available VPS impression materials at different time intervals using a shark fin device (3M ESPE, Seefeld, Germany).
STUDY SETTING AND DESIGN
This in-vitro study was carried out at the prosthodontics department of a dental institution.
METHODS AND MATERIAL
The height of the shark fin produced by each impression material determined the rate of flow.
STATISTICAL ANALYSIS
The data were analysed using one-way analysis of variance (ANOVA) and post-hoc Tukey's test (p-0.05).
RESULTS
: Shark fin height of group A VPS impression material was significantly higher at 30 and 120 seconds compared to group B and group C VPS impression materials. Shark fin height produced by group B VPS impression materials at 60 and 90 seconds was significantly higher than the group C VPS impression material but non-significant compared to group A. At 120 seconds, there was no significant difference in the shark fin heights of all the tested materials.
CONCLUSION
All the materials exhibited adequate flow characteristics within clinically acceptable limits.
Topics: Materials Testing; Siloxanes; Polyvinyls; Dental Impression Materials; Dental Impression Technique
PubMed: 37006010
DOI: 10.4103/ijdr.ijdr_1137_21 -
Journal of Oral Rehabilitation Feb 1996The aim of this study was to develop a wax suitable to serve as a functional impression material. Several binary mixtures of paraffin, beeswax and rosin were prepared....
The aim of this study was to develop a wax suitable to serve as a functional impression material. Several binary mixtures of paraffin, beeswax and rosin were prepared. They were characterized by differential thermal analysis (DTA), and tested for plastic deformation, thermal expansion, detail reproduction and mechanical properties. It was found that the combinations of paraffin with rosin can function well as impression materials, as they combine a high value of plastic deformation at 37 degrees C with relatively low values at room temperature. Concentrations of rosin as small as 1% or 2% are adequate to produce this result. The flow of paraffin was significantly reduced by the addition of beeswax. A linear relationship was found between the 37 degrees C flow values of paraffin-beeswax mixtures and the proportions of the ingredients.
Topics: Dental Impression Materials; Differential Thermal Analysis; Elasticity; Hot Temperature; Inlay Casting Wax; Paraffin; Plastics; Pliability; Resins, Plant; Rheology; Stress, Mechanical; Surface Properties; Waxes
PubMed: 8850062
DOI: 10.1111/j.1365-2842.1996.tb01219.x -
The Journal of Nihon University School... Dec 1971
Studies on rubber base impression materials. XXVII. Discussions on the setting mechanism of polysulfide rubber as the dental impression material, chiefly viewed from the variations of viscosity and molecular weight. 7. Polysulfide impression material by potassium permanganate.
Topics: Air; Alcohols; Benzene; Dental Impression Materials; Elasticity; Hardness; Molecular Weight; Potassium Permanganate; Rubber; Sulfides; Temperature; Viscosity; Water
PubMed: 5292166
DOI: 10.2334/josnusd1959.13.210 -
The Journal of Prosthetic Dentistry Jan 1978A laboratory experiment has been described that utilized materials found in most dental offices and that was designed to evaluate a distinctly different polysulfide... (Comparative Study)
Comparative Study
A laboratory experiment has been described that utilized materials found in most dental offices and that was designed to evaluate a distinctly different polysulfide impression material. In this experiment the largest duplicating errors were produced with use of the stock tray and single-mix technique recommended by the manufacturer. This study therefore supports the use of the custom tray and double-mix technique for dental duplication procedures utilizing Neo-Plex impression material. Further investigation is necessary before stock trays and single-mix techniques can be recommended for routine use in fixed prosthodontics.
Topics: Dental Impression Materials; Dental Impression Technique; Elasticity; Evaluation Studies as Topic; Polymers; Rubber; Sulfides
PubMed: 340664
DOI: 10.1016/s0022-3913(78)80054-7 -
The Journal of Nihon University School... Jun 1994To examine the disinfectant effects on oral microbes of an alginate impression material supplemented with 1% chlorhexidine as the aseptic ingredient (Coe Hydrophilic...
To examine the disinfectant effects on oral microbes of an alginate impression material supplemented with 1% chlorhexidine as the aseptic ingredient (Coe Hydrophilic Gel, CHG), several cell suspensions of oral microbes (3 Gram-positives, 2 Gram-negatives and 1 yeast) were exposed to the surface of cast CHG or that of a control impression material for 5 or 30 min. They were then transferred to the surfaces of agar plates. Colony formation was estimated after culture for several incubation periods. No growth of bacteria on the plates was observed when the suspensions had been exposed to CHG even for 5 min, whereas for the control material, all the bacteria formed colonies. The yeast showed colony formation irrespective of the kind of impression material and the duration of exposure. Thus, it appears that use of an impression material supplemented with 1% chlorhexidine such as CHG may protect clinical staff and dental technicians from possible bacterial infections associated with the impression procedures.
Topics: Alginates; Bacteria, Anaerobic; Candida albicans; Chlorhexidine; Colony Count, Microbial; Dental Impression Materials; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Time Factors
PubMed: 8083771
DOI: 10.2334/josnusd1959.36.135 -
Scanning Electron Microscopy 1979New materials and new techniques have enabled the fabrication of more reliable and more accurate replicas. Not only is the reproduction of detail of importance, but the...
New materials and new techniques have enabled the fabrication of more reliable and more accurate replicas. Not only is the reproduction of detail of importance, but the expertise required from the operator and the time involved to produce a replica are considered key factors. For various reasons a reliable and reproducible replication technique for scanning electron microscopy offers many advantages. Recently a new dental precision impression material has been introduced, which in combination with low viscosity resins has produced superior results over other techniques. This combination processed by means of a centrifugal casting machine has produced replicas which could easily be compared to a standard test die at magnifications up to 3000 X. More in depth testing will have to be performed to establish whether these materials can be universally applied to a broad spectrum of replication problems. The combination Reprosil/Spurr low viscosity imbedding medium yielded replicas of high quality which can be made with simple equipment and without possessing special skills. Centrifugation of the positive replication material into the negative impression virtually eliminated the entrapment of airbubbles.
Topics: Dental Impression Materials; Histological Techniques; Microscopy, Electron, Scanning
PubMed: 392716
DOI: No ID Found -
Journal of Prosthodontic Research Oct 2013This in vitro study compared the dimensional accuracy of stone index (I) and three impression techniques: tapered impression copings (T), squared impression copings (S)... (Comparative Study)
Comparative Study
OBJECTIVES
This in vitro study compared the dimensional accuracy of stone index (I) and three impression techniques: tapered impression copings (T), squared impression copings (S) and modified squared impression copings (MS) for implant-supported prostheses.
METHODS
A master cast, with four parallel implant abutment analogs and a passive framework, were fabricated. Vinyl polysiloxane impression material was used for all impressions with two metal stock trays (open and closed tray). Four groups (I, T, S and MS) were tested (n=5). A metallic framework was seated on each of the casts, one abutment screw was tightened, and the gap between the analog of implant and the framework was measured with a stereomicroscope. The groups' measurements (80 gap values) were analyzed using software (LeicaQWin - Leica Imaging Systems Ltd.) that received the images of a video camera coupled to a Leica stereomicroscope at 100× magnification. The results were statistically analyzed with Kruskal-Wallis One Way ANOVA on Ranks test followed by Dunn's Method, 0.05.
RESULTS
The mean values of abutment/framework interface gaps were: Master Cast=32 μm (SD 2); Group I=45 μm (SD 3); Group T=78 μm (SD 25); Group S=134 μm (SD 30); Group MS=143 μm (SD 27). No significant difference was detected among Index and Master Cast (P=.05).
CONCLUSION
Under the limitations of this study, it could be suggested that a more accurate working cast is possible using tapered impression copings techniques and stone index.
Topics: Dental Casting Investment; Dental Impression Materials; Dental Impression Technique
PubMed: 24075828
DOI: 10.1016/j.jpor.2013.07.001 -
Journal of the Formosan Medical... Apr 1994A light-curing polyether urethane dimethacrylate impression material was recently developed. Its polymerization reaction is activated by intensified visible light;... (Comparative Study)
Comparative Study
A light-curing polyether urethane dimethacrylate impression material was recently developed. Its polymerization reaction is activated by intensified visible light; therefore, the on-demand set allows operators to work at their own pace. Furthermore, its constant viscosity provides a constant flow rate at the critical stages of taking impressions. The purposes of this study were to evaluate the physical properties and accuracy of this light-curing impression material and to compare it with those of self-curing impression materials currently used in our dental clinic. Physical properties such as strain in compression, compression set, dimensional stability, and tear strength of the impression materials were measured according to test methods stipulated in ADA Specification No. 19 for elastomeric impression materials. The template-coping method developed by Lewinstein and Craig was used to evaluate the accuracy of the impression materials. It was found that the strain in compression of the polyether urethane dimethacrylate was higher than that of the condensation silicones, but lower than that of the addition silicones. The compression set of the condensation silicones was more than that of the polyether urethane dimethacrylate, but much less than that of the polysulfides. The dimensional stability showed that all of the impression materials, except the polyether urethane dimethacrylate, had a negative dimensional change 24 hours after mixing. The sequence is: polysulfide < condensation silicone < addition silicone. The expansion rate of the light-curing material was measured under 0.07% one day after curing. The polyether urethane dimethacrylate had extraordinary tear resistance compared to the other impression materials.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Biomechanical Phenomena; Dental Impression Materials; Humans
PubMed: 7914770
DOI: No ID Found -
Dental Materials Journal 2013The dimensional stability of a thin intra sulcular impression material reproducing the preparation finish line was evaluated. Impressions were taken of a stainless-steel...
The dimensional stability of a thin intra sulcular impression material reproducing the preparation finish line was evaluated. Impressions were taken of a stainless-steel master model of a simulated abutment with a 'gingival sulcus' using Express regular, Express fast and Aquasil. The putty-wash two-step technique was applied with spacer thicknesses of 0.5, 1 and 1.5 mm. Mid mesiodistal and bucco-lingual measurements were taken directly from the sulcular impression material after 0.5, 2, 24, 48 and 72 h via a Toolmaker's microscope. The discrepancies between the measurements of the impression material and the master model were calculated. The discrepancies changed significantly over time (p<0.001). The use of a 0.5 mm spacer resulted in a negative deviation from the model (2-46 µm), minimally after 2 h. The use of 1 and 1.5 mm spacers showed a positive deviation from the model (21-52 µm) and both are equally recommended. Investment can be postponed until 72 h.
Topics: Dental Abutments; Dental Impression Materials; Dental Impression Technique; Gingiva; Humans; Linear Models; Materials Testing; Models, Dental; Polyvinyls; Siloxanes
PubMed: 23370867
DOI: 10.4012/dmj.2012-046 -
Dentistry Today Mar 2017
Comparative Study
Topics: Dental Implantation, Endosseous; Dental Implants; Dental Impression Materials; Dental Impression Technique; Dental Prosthesis, Implant-Supported; Dental Restoration, Permanent; Esthetics, Dental; Female; Humans; Male; Polyvinyls; Resins, Synthetic; Siloxanes
PubMed: 29235338
DOI: No ID Found