Properties Of Impression Materials Research Articles

Evaluation of the Efficacy of Novel Self Disinfectant Solution in Irreversible Hydrocolloid Impression Material - An Experimental Study.

Irreversible hydrocolloid materials are widely used for both diagnostic and definitive impression procedures. Impressions can be disinfected by immersion or spraying in any compatible disinfectant. Disinfectants should not adversely affect the dimensional stability of the impression and physical properties of impression material and subsequent dental cast. The study aims to evaluate the efficacy of a hypochlorous disinfectant solution mixed with irreversible hydrocolloid on setting time, antibacterial efficacy, and dimensional stability. Three groups were made with one control group and three alginate impression was made for each participants in the maxillary arch with 24-hours intervals between one another using the same brand of commercially available chromatic alginate. The working and setting time were noted. Bacterial swabs were collected using a dry sterile cotton swab in the mid palatal region. Dental casts were made using type III gypsum. The working and setting time had significant differences whereas the dimension among the cast has no significant difference. Microbial growth analysis had distinct differences among the groups. The self disinfection method using a pioneer solution of hypochlorous HOCl (100 ppm) to mix the alginate impression material rather than the water with the same powder-liquid ratio prescribed by the manufacturer had the same dimensional stability with improved antimicrobial action.

Disinfection of polyvinyl siloxane impression material using ozone gas, 0.1% riboflavin, glutaraldehyde, and microwave irradiation and their effect on physical properties.

To assess the antimicrobial effect of ozone gas (OG) 0.1% riboflavin (RF), glutaraldehyde (GaH), and microwave irradiation (MI) on Polyvinyl siloxane impression material formerly colonized with E. coli, P. Aeruginosa, E. faecalis, and S.aureus and their effect on the physical properties MATERIAL AND METHODS: One hundred disk-shaped specimens (diameter 10mm and thickness 3mm) were developed by using polyvinylsiloxane impression material and inoculated by the American Type Culture Collection (ATCC) of E. coli, P. aeruginosa, E. faecalis, and S.aureus in an in-vitro setup. The samples were arbitrarily isolated into five groups and subjected for 3min to the designated disinfection modality. Group 1 Control, group 2: GaH, group 3: 0.1% RF, group 4: MI, and group 5 OG. Following decontamination, the physical properties (contact angle, strain-in-compression, and tear strength) of impression materials were evaluated. Statistical analysis for CFU/mL (log10) for exposed E. coli, P. aeruginosa, E. faecalis, and S.aureus was performed by using analysis of variance (ANOVA) and Tukey's multiple comparison tests at a p-value of less than 0.05. The most effective antimicrobial efficacy for impression disinfection against all scrutinized microbial colonies were displayed by group 5 OG and the lowest disinfection effectiveness was unveiled by the control group with no treatment. The intragroup comparison revealed that impression disinfection with GaH, MI, and ozone corroborated analogous antimicrobial efficacy(p>0.05). The disinfecting capacity of the impression material with 0.1% RF was significantly less than MI, GaH, and OG (p<0.05). Disinfection of polyvinyl siloxane impression material with ozone gas, microwave irradiation, and glutaraldehyde demonstrated reasonable antimicrobial efficiencies against E. coli, P. aeruginosa, E. faecalis, and S.aureus with no detrimental effects on the physical properties of impression material. More studies are advocated to extrapolate the findings of the present study.

Decontamination of a siloxane impression material by using 5-aminolevulinic acid activated by photodynamic therapy, microwave irradiation, and hydrogen peroxide

AimThe present study was intended to evaluate the antimicrobial effect of PDT, H2O2, and MI on the contact angle, strain-in-compression, and tear strength of siloxane impression material formerly colonized with E. coli, S.aureus and S.mutans. Material and methodsOne hundred and twenty disk-shaped specimens (diameter 10 mm and thickness 2 mm) were prepared by polyvinylsiloxane impression material and inoculated by the American Type Culture Collection (ATCC) of E.coli, S.mutans, and S.aureus in an in-vitro situation. The specimens were broadly divided into six groups then exposed to the various disinfection approaches for 3 min per each group: group 1: Control (no treatment), group 2:PDT 5-ALA, group 3: H2O2, group 4: MI, group 5: H2O2 + MI, group 6: PDT + MI. After disinfection, assessment of mechanical properties (contact angle, strain-in-compression, and tear strength) of impression materials were instigated. Statistical analysis was executed for CFU/mL (log10) for exposed E. coli, S.aureus, and S.mutans, by two-way ANOVA and Tukey's honestly significant test (p>0.05). ResultsThe highest anti-microbial values against all inspected microbial colonies were unveiled when disinfection was performed in combination i.e., H2O2 + MI and PDT + MI and the least cleansing of impression material was seen by the control group as no treatment was provided. Solo application of MI was more effective than control, H2O2 and 5-ALA activated by PDT but less active when used in combination method H2O2 with MI and PDT with MI. PDT and control group showed the least antimicrobial effectiveness against E. coli (p<0.05) ConclusionDisinfection of impression materials with combination therapies including photodynamic therapy with microwave irradiation and hydrogen peroxide with microwave irradiation displayed highest antimicrobial efficacies against E. coli, S. aureus, and S. mutans with no adverse effects on mechanical properties of impression material.

Physical Properties of Irreversible Hydrocolloid Impression Material Incorporated with Silver-Nanoparticles

Dental impression is a source of cross infection and transmission of diseases. Conventional disinfection may lead to a change in physical properties. Self-disinfectant irreversible hydrocolloid is an alternative to the disinfection and can prevent microbial cross contamination. The present study evaluates the physical properties of irreversible hydrocolloid impression material incorporated with 0.5%, 1.0% and 1.5% w/w silver nanoparticles (AgZrPO4, Sunshine Factory Co.,Ltd, China). The working time and detail reproduction were tested according to ISO 21563:2013 with some modification. The result showed that AgZrPO4 did not significantly affect the physical properties of the impression material. Based on this in vitro study, AgZrPO4 can be added to the impression material for its antimicrobial benefit without significant changes in the physical properties of the material.

The Effect of Silver-Zinc Zeolite Incorporation on Some Properties of Condensation Silicone Impression Material

Background: elastomeric impression materials are indicated when a high degree of accuracy is required, due to their excellent properties like details reproduction, dimensional stability and tear strength but with main two disadvantages those are their hydrophilicity as well as the absence of antibacterial activity. This study aimed to evaluate the effect of incorporation of 0.5% wt Ag-Zn zeolite into condensation silicone through the following tests; setting time, dimensional stability, reproduction of details, wettability, and hardness . Materials and methods: one hundred specimens were constructed of condensation silicone, divided into two groups for the first 50 specimens one0.5% by wt Ag -Zn zeolite was added, keeping the other fifty specimens without addition. Then each group further subdivided into five subgroups according to the conducted test. The tests performed were; setting time, dimensional stability, reproduction of details, hardness and wettability. Results: A statistically non-significant effect on the setting time and reproduction of details tests was observed, combined with a highly significant increase of wettability of condensation silicone after incorporation of 0.5% wt Ag-Zn zeolite with non-significant increase of dimensional change of condensation silicone following incorporation of 0.5% wt Ag-Zn zeolite. Hardness test results shoed statistically significant increase following the addition of Ag-Zn zeolite. Conclusion: Ag-Zn zeolite incorporated into condensation silicone, improved wettability which determine the extent to which an impression material replicates the structures of the oral cavity and production of bubble-free gypsum die. It also showed a statistically significant increase in the hardness of condensation silicone impression material, and had no effect on setting time, reproduction of details and dimensional stability.

Desinfeksi Hasil Cetakan

Impression taking is performed to find model of patient’s teeth and oral cavity in making restoration or orthodontic appliances. The impression enable bacteria, fungi or virus from saliva or blood in oral cavity to be transferred. Washing the impression by using running water is not enough to completely remove all of bacteria, fungi or virus has been attached on the impression. Therefore the disinfection procedure on impression is needed to avoid the cross infection between the patient and operator. Cross infection of contamination of virus, fungi or bacteria cause of B hepatitis, tuberculosis, herpes zoster and Human Immunodeficiency Virus-Acquired Immune Deficiency Syndrome (HIV-AIDS) diseases. There are many many disinfectant agents which have been recommended to be used in effort to disinfect impression such as chlorine compound, iodophore, glutaraldehide and phenol. There are several methods of disinfection can be performed such as immersion, spray or admix the disinfectant into impression material. However several disinfection methods cause side effects such as dimensional change especially on alginate impression, quality of impression surface, surface roughness and other properties of impression material. In this paper the side effects occur in impression material caused by impression disinfection will be studied and discussed. Farther the disinfection by using UV light, blue light, microwave, autoclave, gargle and the possibility of traditional flora solution using as disinfectant of impression will be explained.

Rheological properties of elastomeric impression materials for selective pressure impression technique

PurposeThe selective impression technique is recommended for removable prosthodontics. However, the viscoelastic rheological properties of impression materials, particularly the time-dependent viscoelastic changes in impression material immediately after tray seating, are unknown. The objective of this study is to clarify the viscoelastic rheological properties of impression materials by focusing on tray seating. MethodsIn this study, eight types of polyvinylsiloxane (PVS), two types of polyether, and two types of alginate impression materials were used. The storage modulus (G′; degree of stiffness) and loss tangent (tanδ; degree of hardening) were determined as functions of time from 0 to 360s, commencing immediately after the completion of mixing, using a stress control-type rheometer. Thus, G′ and tanδ at 0s and 20s were compared. ResultsStiffness was found to be widely distributed (4.49–0.26×104Pa) among PVS-types, even immediately after mixing the impression material. There was also variation among polyethers (1.55–0.5×104Pa) and among alginates (0.64–0.21×104Pa). The hardening of all impression materials progresses beyond 20s after the completion of mixing. ConclusionsThe G′ values varied with each impression material, even immediately after mixing, and the accurate impression-taking time was determined from the results of tanδ. These results provide unique insight into the selective impression technique.

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

Rheological properties of polyvinylsiloxane impression materials before mixing and during setting related to handling characteristics

The purpose of this study is to determine and compare the handling and rheological properties of polyvinylsiloxane impression pastes before mixing and during setting, and to investigate the effect of its constituents on the properties of the materials. Five polyvinylsiloxane impression materials (Examixfine, Extrude, Honigum, Imprint II, and Express) were used. A flow test and a drip test were performed to determine the handling characteristics. The rheological properties of each impression material prior to mixing (shear stress, viscosity) and during setting (storage modulus G ’ , loss modulus G ’’ , loss tangent tanδ) were measured with a stress-controlled rheometer at 25 o C and 32 o C, respectively. Inorganic filler content of each impression material was measured and observed with a SEM. The molecular weight distribution of polymer matrix was determined with a gel permeation chromatography (GPC). Express and Honigum display lower flow compared to the other materials, due to their high yield-stress values. Examixfine exhibits the greatest flow. All materials display pseudoplastic behavior, excluding the Examixfine catalyst. The viscosities at low shear rate are greatest for Express and Honigum; however, under high shear conditions, the viscosities of Extrude and Honigum are the lowest. Following mixing, each material show an increase in G ’ , finally reaching a plateau, and the tanδ rapidly decreases with time. Imprint II shows the highest final G ’ as well as the most rapid decrease in tanδ. Express and Imprint II present the highest filler content and rough filler surface, while Honigum shows the lowest filler content and small filler particles. Most products are composed of polymers over 30 kDa and oligomers less than 1 kDa. Each impression material possesses different rheological properties, which significantly affect the handling characteristics. The yield stress of the impression material minimizes unnecessary flow prior to and after seating. Viscoelastic change during setting of each impression material determines the setting time and the stiffness after setting. These rheological properties of impression materials are affected by the filler content and molecular weight distribution of polymer matrix.

COMPARISON OF EFFICACY OF GLUTARALDEHYDE AND U.V.LIGHT DISINFECTION AND THEIR EFFECT ON DIMENSIONAL STABILITY OF POLYVINYL SILOXANE IMPRESSIONS AN IN-VITRO STUDY

Dental impressions need to be washed and disinfected immediately after making, to control transfer of infectious diseases from saliva and blood of the patient to dentists and technicians. Since sterilization of impressions is not possible because of high temperature and time needed, disinfection is the method of choice. But disinfection process may sometimes affect the properties of impression material. This study has undertaken to evaluate the efficacy and effect of chemical and U.V light disinfection on poly vinyl siloxane impressions.

Determining the complex modulus of alginate irreversible hydrocolloid dental material

Objectives The aim of the study is to investigate the visco-elastic response of an alginate irreversible hydrocolloid dental impression material during setting. Methods A novel squeeze film Micro-Fourier Rheometer (MFR, GBC Scientific Equipment, Australia) was used to determine the complex modulus of an alginate irreversible hydrocolloid dental impression material (Algident, ISO 1563 Class A Type 1, Dentalfarm Australia Pty. Ltd.) during setting after mixing. Data was collected every 30 s for 10 min in one study and every 10 min for a total of 60 min in another study. A high level of repeatability was observed. Results The results indicate that the MFR is capable of recording the complex shear modulus of alginate irreversible hydrocolloid for 60 min from the start of mixing and to simultaneously report the changing visco-elastic parameters at all frequencies between 1 Hz and 100 Hz. The storage modulus shows a dramatic increase to 370% of its starting value after 6 min and then reduces to 55% after 60 min. The loss modulus increases to a maximum of 175% of its starting value after 10 min and then reduces to 94% after 60 min. Significance The MFR enables the changes in the complex modulus through the complete setting process to be followed. It is anticipated this approach may provide a better method to compare the visco-elastic properties of impression materials and assist with identification of optimum types for different clinical requirements. The high stiffness of the instrument and the use of band-limited pseudo-random noise as the input signal are the main advantages of this technique over conventional rheometers for determining the changes in alginate visco-elasticity.

Shark fin test and impression quality: A correlation analysis

To evaluate the correlation between the shark fin test and the dimensional accuracy of impressions, surface detail reproduction of impressions and rheological properties of impression materials within the manufacturer's recommended working time. Four chemically different types of impression material (Flexitime: VPS; Fusion: Polyether/VPS blend; Impregum: classical Polyether; P2: new Polyether) were subjected to the shark fin test as well as three other test regimes. Dimensional accuracy was determined as being the discrepancy in diameter between a steel master cone and stone dies poured from impressions taken from the steel master cone at defined 30s intervals after mixing within the manufacturer's recommended working time. Surface detail reproduction was calculated as being the difference in average arithmetic roughness (Ra) between a ground dentin surface and the corresponding area of the impressions, taken at the same 30s intervals. Phase angle and storage modulus were measured using a rotational rheometer. Spearman's Rho was used for correlation analysis. With respect to the majority of impression materials used, significant correlations mainly exist between shark fin test data, phase angle and storage modulus. No correlation was found between the results of the shark fin test versus dimensional accuracy, respectively, surface detail reproduction. Results obtained from the shark fin test within the manufacturer's recommended working time do not allow predictions regarding the dimensional accuracy or surface detail reproduction of impressions as clinically relevant material characteristics.

Surface characteristics of polyether and addition silicone impression materials after long-term disinfection

It has been demonstrated that short-term disinfection can affect the surface properties of impression materials. This study evaluated advancing contact angle, receding contact angle, inhibition and mass loss of a polyether impression materials, and two different viscosities of an addition silicone impression material after long-term immersion disinfection (18 hours). The brand names of the impression materials tested were Impregum F, Extrude Extra, and Extrude Wash, and all were tested by use of the Wilhelmy technique; first, for the nondisinfected state, which served as controls, and then after 1 and 18 hours of disinfection in a full-strength solution of acid glutaraldehyde. Weight changes before and after the disinfection process were also measured to detect weight loss and mass change over time. All materials exhibited some degree of inhibition. Polyether lost 0.4% mass in air, which indicated loss of a volatile component. Polyether and addition silicone were both relatively hydrophobic and could be disinfected with acid glutaraldehyde for up to 18 hours without affecting wettability.

Effect of Immersion Disinfection on Properties of Impression Materials

Dimensional change and wettability were determined for three addition silicones and a polyether impression material after disinfection by immersion for two 30-minute cycles in 2% acid-potentiated glutaraldehyde. Contact angles of water on disks were measured on a goniometer. Dimensional change was determined by change in distance between two reference lines. Contact angle (degree) and dimensional change (percent) of five samples were measured after 0-, 30-, 60-, and 1,440-minute intervals of storage in air and disinfectant. The contact angle in air increased for two addition silicones and remained constant for the remaining materials. In disinfectant, the contact angle increased for all four materials, with the contact angle of the polyether increasing the least. In air, dimensional change decreased significantly for an addition silicone and a polyether. In disinfectant, the dimensional changes of the addition silicones were not significant, but the polyether increased in dimension after 1,440 minutes. Two 30-minute cycles of disinfection in 2% acid-potentiated glutaraldehyde reduced wettability, but had little effect on the dimensional change of the addition silicones and polyethers tested.

Viscoelastic properties of setting elastomeric impression materials

An instrument was introduced to determine the relationship between induced and permanent tensile deformation of selected elastomeric dental impression materials during and after setting. The method accurately recorded viscoelastic properties of impression materials.