Properties Of Alginate Impression Materials Research Articles

Antimicrobial Efficiency of Hypochlorous Acid and Its Effect on Some Properties of Alginate Impression Material.

Dental clinicians and professionals need an affordable, nontoxic, and effective disinfectant against infectious microorganisms when dealing with the contaminated dental impressions. This study evaluated the efficiency of hypochlorous acid (HOCl) as an antimicrobial disinfectant by spraying technique for the alginate impression materials, compared with sodium hypochlorite, and its effect on dimensional stability and reproduction of details. HOCl with a concentration of 200 ppm for 5 and 10 min was compared with the control group (no treatment) as a negative control and with sodium hypochlorite (% 0.5) as a positive control. Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa were selected to assess the antimicrobial activity with the colony forming unit test in addition to the dimensional stability and reproduction of details tests. The results revealed that HOCl had significant antimicrobial activity against all tested microorganisms and experimental time. Interestingly, HOCl showed no impact on the dimensional stability of alginate impression material. HOCl could be an effective antimicrobial agent for alginate impression material without interfering with their surface details and dimensional stability.

The influence of the negative ion powder on the properties of alginate impression materials.

This paper investigated the effects of different contents of negative ion powder on the antibacterial activity and mechanical properties of the alginate impression materials. The cytotoxicity of the negative ion powder was evaluated. The antibacterial rate was evaluated by the plate count method, and the mechanical properties, including the gelation time, elastic recovery, compressive strain and compressive strength were characterized by standards method. MTT assay was used to evaluate the cytotoxicity of the negative ion powder. When the content of negative ion powder was 1-2%, the antibacterial rate could be up to 90-100%. It had no significant effect on the mechanical properties of the alginate impression materials when the added content of negative ion powder was less than 2% (p>0.05). The results of the MTT assay indicated that the material is noncytotoxic. The optimal adding ratio of negative ion powder is 1-2%.

Antimicrobial and physical properties of alginate impression material incorporated with silver nanoparticles

Self-disinfecting impression materials would reduce time and energy needed for impression disinfecting process in clinic. The aim of this study was to evaluate the antimicrobial effect of alginate mixed with nanosilver solution at a concentration of 500 ppm and 1000 ppm on common oral microorganisms and assess changes in working time, setting time, and surface detail reproduction. In this in vitro study, three groups were assigned. The first group was alginate, the second group was alginate mixed with 500 ppm nanosilver, and the third group was alginate mixed with 1000 ppm nanosilver. Antimicrobial effect on Escherichia coli, Staphylococcus aureus, and Candida albicans was studied using direct contact test in each group (n = 10). Working time (n = 10), setting time (n = 10), and surface detail reproduction (n = 10) were evaluated separately using the ISO 21563 protocol. Descriptive tables were used to describe the data. Kruskal-Wallis test used to determine significant differences in the number of colonies was counted in antimicrobial test (α = 0.05). No adverse effects observed in working time, setting time, and surface detail reproduction of alginate impressions. Alginate mixed with silver nanoparticles showed no inhibitory effect on S. aureus and C. albicans, but the number of E. coli colonies were counted in the group 1000 ppm was significantly lower than 500 ppm (P = 0.001). Antimicrobial effect of alginate mixed with silver nanoparticles is not clinically indicated. Nevertheless, its physical features did not change significantly.

Empirical study of alginate impression materials by customized proportioning system.

PURPOSEAlginate mixers available in the market do not have the automatic proportioning unit. In this study, an automatic proportioning unit for the alginate mixer and controller software were designed and produced for a new automatic proportioning unit. With this device, it was ensured that proportioning operation could arrange weight-based alginate impression materials.MATERIALS AND METHODSThe variation of coefficient in the tested groups was compared with the manual proportioning. Compression tension and tear tests were conducted to determine the mechanical properties of alginate impression materials. The experimental data were statistically analyzed using one way ANOVA and Tukey test at the 0.05 level of significance.RESULTSNo statistically significant differences in modulus of elastisity (P>0.3), tensional/compresional strength (P>0.3), resilience (P>0.2), strain in failure (P>0.4), and tear energy (P>0.7) of alginate impression materials were seen. However, a decrease in the standard deviation of tested groups was observed when the customized machine was used. To verify the efficiency of the system, powder and powder/water mixing were weighed and significant decrease was observed.CONCLUSIONIt was possible to obtain more mechanically stable alginate impression materials by using the custom-made proportioning unit.

Effect of sodium fluoride addition as a disinfectant on some properties of alginate impression material

Impression materials, impression trays, and poured stone cast have been said to be the main source of cross infection between patients and dentists. However, it was observed that disinfection of the impression is not performed systematically in routine dental practice. Disinfection of alginates either by immersion or spray technique was found to cause dimensional inaccuracies, although with proper disinfection of alginates there were small dimensional changes. A variety of fluoride releasing products designed for topical use is currently available. Following their use, varied amount of fluoride is systemically absorbed depending on the fluoride concentration and the manner of its use. The objective of this study was to evaluate the effect of addition (0%, 0.25%,0.5%,1%, 2%, 3%, 4% ) of (NaF) as a self-disinfection to alginate impression material powder and its effect on setting time, tear strength, dimensional change and accuracy of alginate impression materials. Materials and methods: A total No. of (700) specimen were used in this study.These specimens were divided into (5) main groups according to the tests used. Each of the four main groups contain (70) specimen divided into 7 subgroups (ten specimens to be tested for each (7)concentrations which is composed of six percentages of NaFwith alginate powder (0.25%,0.5%,1%, 2%, 3%, 4% )and one for control (0% NaF) , while the fifth group (Microbiological test) contain 420 specimen were divided between Streptococcus mutans and Candida albicans as (120) specimen for each one that was subdivided into three subgroups (specimens taken before impression casting, specimensafter pouring of alginate with stone andspecimens of stone were taken from the casts) in which it contain the same subgroups of the other concentrationsof (NaF) to test its efficacy against (Streptococcus mutans and Candida albicans). Results: Tear strength for all experimental impression materials was greater than those of the control products. There were no statistically significant differences between the dimensional change tests and also reproduction of detail test.With regard to setting time of the impressions, statisticallyreduction were seen between the control and experimental groups of alginate impression materials that contain (NaF). Self-disinfection of alginate impression material containing NaF showed a significant reduction in the count of cell forming unit of microorganism s immediately after impressions were made. Conclusion: In cooperation of specific concentrations of (NaF) as a disinfectant in alginate dental impression produced a significant reduction of contamination, also they caused non-significant effect on dimensional stability, detail reproduction and significant increase in tear strength. Therefore it is recommended as step in preventing cross

Effect of Sodium Fluoride Addition as a Disinfectant on Some Properties of Alginate Impression Material

Effect of Sodium Fluoride Addition as a Disinfectant on Some Properties of Alginate Impression Material

Evaluation of some mechanical properties of dental alginate impression materials after fluoride addition

Objective:Fluorid-containing dental alginate impression materials can exert a considerable reduction inenamel solubility. The objective was to evaluate the effect of fluoride addition on the setting time andcompressive strength of alginate impression materials.Methodology: 60 samples were constructed from alginate impression material (30 samples for settingtime test and 30 samples for compressive strength test).Specimens of each test divided into threesubgroup. Group A: 10 specimens of alginate were mixed with distilled water [control], Group B: 10specimens of alginate were mixed with100-ppm fluoride and Group C:10 specimens of alginate weremixed with 2%Naf.Results: the result of setting time test showed that addition of 2% Naf to alginate impression materialswere delayed the setting reaction while the results of compressive strength test showed that high meanvalues were obtained from control group while group mixed with 2%Naf had lower compressivestrength.Recommendation: it can be concluded that addition of 100-ppm fluoride were affect on theproperties of alginate impression materials while addition of 2% Naf was deteriorated the properties ofalginate impression materials. So recommends the effect of fluoride addition in other concentration

The influence of mixing methods and disinfectant on the physical properties of alginate impression materials

The aims of this in vitro study were to quantify the effect of manual versus automatic mixing and of using a disinfectant on mechanical properties of three different alginate impression materials. Two of the three alginates tested were especially developed for orthodontic use: Orthotrace® and Orthofine® while the third was a conventional alginate CA37FS®. Alginates were mixed by hand or automatically using a Cavex alginate mixer II®. Mixing was performed at room temperature using tap water. The material was allowed to set in a water bath at 35°C (±1°C), simulating intra-oral setting conditions, and half of the samples were disinfected before testing. For each tested material, 10 standardized samples were used. The disinfectant used was the CavexImpreSafe® that has a bactericide, virucide, and fungicide function. The specimens were exposed for 3 minutes in a 3% solution and were then tested according to the ISO 1563: 1990 (E) standard specifications. Descriptive statistics and three-way analysis of variance were performed, and a 5% significance level was used for statistical analysis. Evaluation of tensile strength and elastic recovery of different alginate samples, hand versus automatical mixing or disinfected versus not disinfected, resulted in significant differences for all materials except for Orthofine®. Considering detail reproduction, all three alginates evaluated reproduced the 50-μm line successfully without interruption. The mixing method can significantly affect the elastic recovery and tensile strength of the alginates tested while the effect of using a disinfectant is less explicit.

Effect of Mixing Methods on Mechanical Properties of Alginate Impression Materials

A commercial mechanical mixer is available to make the mixing of alginate more convenient and more consistent for the practitioner; however, there is very little information on the mechanical properties of alginate mixed with this device as compared with hand mixing. To compare the mechanical properties of alginate impression materials mixed with a mechanical mixer (Alginator II, Cadco) and hand mixing. Three alginate impression materials (Identic, Jeltrate, and Kromopan) were tested. Strain in compression, elastic recovery, and compressive strength were measured according to ANSI/ADA specification no. 18-1992; tear energy was measured using a pants tear test. Five specimens were prepared for each group with 12 groups for the mechanical mixer and 12 groups for hand mixing, for a total of 120 specimens. A two-way analysis of variance and Fisher's PLSD test at the 0.05 level of significance were used to analyze the data. There were statistically significant differences in properties among the materials, but mixing technique had no statistically significant effect on strain in compression and tear energy. The mechanical mixer improved elastic recovery and compressive strength of the alginate impression materials tested and had no effect on strain in compression and tear energy. A mechanical mixer facilitates the mixing of alginate impression materials and improves some mechanical properties.

Effect of mixing method on rheological properties of alginate impression materials.

The apparent viscosity of alginate impression paste prepared by three mixing methods (hand-mixing technique (HM), semiautomatic instrument (SM) and automatic mixing instrument (AM)), and the gel strength and surface depression of the respective set materials were measured. The materials used were eight commercially available products mixed at a temperature of 23 +/- 0.5 degrees C and allowed to set. The AM had a high mixing speed, which reduced the working time 4.4-31.5%, compared with HM. This was the result of an increase in paste temperature during mixing. In the case of impression materials mixed with the AM, the gel strength and the surface depression at the gel fracture increased significantly, in accordance with Fisher's protected least significant difference (PLSD) analysis. This phenomenon is caused by a decrease of air bubbles in the set material.

Setting properties of alginate impression materials in dynamic viscoelasticity

summary The viscoelastic properties of three alginate impression materials were investigated. A landmark of working time was calculated using a raw phase–time curve. A landmark of setting time was calculated from an inflection point of the divided difference of the first order in the share modulus–time curve. As a result, the working time was common at the point of δ=45° in variable frequencies. The mean value was obtained with less deviation. The setting times obtained were similar for variable frequencies, The mean values showed a distinct difference for each impression material.

Setting properties of alginate impression materials in dynamic viscoelasticity.

The viscoelastic properties of three alginate impression materials were investigated. A landmark of working time was calculated using a raw phase-time curve. A landmark of setting time was calculated from an inflection point of the divided difference of the first order in the share modulus-time curve. As a result, the working time was common at the point of delta = 45 degrees in variable frequencies. The mean value was obtained with less deviation. The setting times obtained were similar for variable frequencies. The mean values showed a distinct difference for each impression material.

An in vitro study of the antiviral properties of an alginate impression material impregnated with disinfectant

The antiviral properties of a new alginate impression material impregnated with a disinfectant (didecyldimethyl ammonium chloride) were evaluated in vitro against herpes simplex virus type I and poliovirus type I. The material was exposed to the virus suspension for periods of up to 60 min. The impregnated alginate material showed no clinically acceptable effect against either virus, although log reductions of 1·0 and 1·7 plaque-forming units of herpes virus were obtained after exposure to the material containing the disinfectant for 5 and 60 min, respectively.

Elastic Properties of Alginate Impression Materials studied from Residual Strain

Elastic Properties of Alginate Impression Materials studied from Residual Strain