Evaluation of efficacy of Aloe Vera as a Disinfectant by Immersion and Spray methods on Irreversible Hydrocolloid Impression Material and its Effect on the Dimensional Stability of Resultant Gypsum Cast - An in Vitro Study.

The need to use a natural alternative for disinfecting dental impression materials, which should be biocompatible and effective, led us to evaluate the efficacy of Aloe vera as a disinfectant by immersion and spray method on alginate impression material and its effect on the dimensional stability of the resultant gypsum cast. The efficacy of the disinfection procedures against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans was evaluated by determining the number of colony-forming units (CFU) recovered after disinfection of alginate discs inoculated with 1x106 CFU for defined intervals with aloe vera solution (99.96%). Dimensional stability was determined from the mean percentage deviation of three measurements that were taken between the fixed points on the casts using a traveling microscope and compared with corresponding measurements from the master model and controls. Statistical analysis of data was determined by analysis of variance. We found out that there is a mean percentage reduction in colony count of S. aureus, P. aeruginosa, and C. albicans after 3 minutes of immersion in aloe vera and after 3 minutes spray disinfection. Complete elimination of all the microorganism cells after 7 min immersion and spray disinfection. There was a statistically significant difference in the increase of the mean anteroposterior (AP) and cross arch (CA) dimension after 3 and 7 minutes immersion in aloe vera. Spraying with aloe vera for 7 minutes was proved to be the most effective disinfection procedure without altering dimensional stability.

Does the size matter? Evaluation of effect of incorporation of silver nanoparticles of varying particle size on the antimicrobial activity and properties of irreversible hydrocolloid impression material.

OBJECTIVES: The main objective of the present in vitro study is to evaluate the antimicrobial activity and properties of irreversible hydrocolloid impression material incorporated with silver nanoparticles of varying size at different concentrations. METHODS: Silver nanoparticles of 80-100, 50-80, 30-50 and 10-20nm size were added to irreversible hydrocolloid impression material at 0.5, 1.0, 2.0 and 5.0wt%. Antimicrobial activity of the silver nanoparticle incorporated irreversible hydrocolloid was measured using disk diffusion method. The gel strength, flow, gelation time and permanent deformation were measured according to American Dental Association specification #18. Data were analyzed using analysis of variation at a confidence interval of 95% (α=0.05). RESULTS: Silver nanoparticles of 80-100nm size have imparted superior antimicrobial activity to the irreversible hydrocolloid in a dose-dependent manner whereas finer nanoparticle size did not exhibit any antimicrobial activity. The addition of silver nanoparticles did not alter the properties of irreversible hydrocolloid at 0.5 and 1.0wt% whereas at higher concentrations significant differences in flow, gelation time and strength were observed. SIGNIFICANCE: The results of the present study indicate that silver nanoparticles of size range 80-100nm are superior in imparting antimicrobial activity to irreversible hydrocolloid compared to finer particle size range.

Disinfectant Efficacy of 0.525% Sodium Hypochlorite and Epimax on Alginate Impression Material.

AIM: Species of Streptococcus, Escherichia coli, Staphylococcus, Actinomyces, Pseudomonas, Klebsiella, and Candida are commonly seen in the oral cavity. Impression materials are commonly contaminated with microorganisms. The present study was conducted to assess the disinfection efficacy of Epimax and 0.525% sodium hypochlorite on alginate impression over a period of 10 minutes. MATERIALS AND METHODS: This study was conducted in the Department of Prosthodontics in the year 2015. An alginate impression material was prepared. For each bacteria species, 15 samples were used. Out of 15 samples, 3 were used by 0.525% sodium hypochlorite for disinfection for 5 minutes and 3 others for 10 minutes. Similarly, 3 samples were used by Epimax for 5 minutes and other 3 for 10 minutes. Three samples were used as controls. Each sample was polluted with Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus strains. RESULTS: There was no statistical difference in P. aeruginosa and C. albicans after 5 minutes, whereas S. aureus showed significant difference (p < 0.05). Epimax was found to be more effective in removing S. aureus as compared with other disinfectants. Both Epimax and 0.525% sodium hypochlorite did not show significant difference against P. aeruginosa and C. albicans, whereas significant difference was found between both agents against S. aureus (p < 0.05). It was seen that Epimax eliminated S. aureus after 5 minutes and P. aeruginosa after 10 minutes and 99.8% C. albicans after 10 minutes. About 0.525% sodium hypochlorite eliminated 99.1% of C. albicans after 10 minutes, whereas 98.5 and 99% of S. aureus and P. aeruginosa were eliminated after 10 minutes respectively. CONCLUSION: Both Epimax and 0.525% sodium hypochlorite can disinfect the alginate impression material against C. albicans, P. aeruginosa, and S. aureus strains. However, Epimax was found to be more effective against S. aureus as compared with 0.525% sodium hypochlorite. CLINICAL SIGNIFICANCE: Efficacy of disinfection of sodium hypo-chlorite and Epimax on alginate impression.

Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.

STATEMENT OF PROBLEM: Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes. PURPOSE: The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles. MATERIALS AND METHODS: The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05). RESULTS: Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles. CONCLUSIONS: Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties.

Novel method of fabricating individual trays for maxillectomy patients by computer-aided design and rapid prototyping.

PURPOSE: Making impressions for maxillectomy patients is an essential but difficult task. This study developed a novel method to fabricate individual trays by computer-aided design (CAD) and rapid prototyping (RP) to simplify the process and enhance patient safety. MATERIALS AND METHODS: Five unilateral maxillectomy patients were recruited for this study. For each patient, a computed tomography (CT) scan was taken. Based on the 3D surface reconstruction of the target area, an individual tray was manufactured by CAD/RP. With a conventional custom tray as control, two final impressions were made using the different types of tray for each patient. The trays were sectioned, and in each section the thickness of the material was measured at six evenly distributed points. Descriptive statistics and paired t-test were used to examine the difference of the impression thickness. SAS 9.3 was applied in the statistical analysis. Afterwards, all casts were then optically 3D scanned and compared digitally to evaluate the feasibility of this method. RESULTS: Impressions of all five maxillectomy patients were successfully made with individual trays fabricated by CAD/RP and traditional trays. The descriptive statistics of impression thickness measurement showed slightly more uneven results in the traditional trays, but no statistical significance was shown. A 3D digital comparison showed acceptable discrepancies within 1 mm in the majority of cast areas. The largest difference of 3 mm was observed in the buccal wall of the defective areas. Moderate deviations of 1 to 2 mm were detected in the buccal and labial vestibular groove areas. CONCLUSIONS: This study confirmed the feasibility of a novel method of fabricating individual trays by CAD/RP. Impressions made by individual trays manufactured using CAD/RP had a uniform thickness, with an acceptable level of accuracy compared to those made through conventional processes.

Comparison of antimicrobial activities and compressive strength of alginate impression materials following disinfection procedure.

AIM: This study investigated the effectiveness of disinfecting solution when incorporated into alginate powder instead of water against some microorganisms and on compressive strength of alginate. MATERIALS AND METHODS: For measuring antimicrobial activity of alginate, 60 alginate specimens were prepared and divided into two groups: One with water incorporated in the mix (control) and the other with 0.2% chlorhexidine digluconate incorporated in the mix instead of water. The tested microorganisms were: gram +ve cocci, gram -ve bacilli and yeast (each group 10 samples). For measuring compressive strength, 20 specimens of alginate were divided into two groups: One with water incorporated in the mix (control) and the other with chlorhexidine incorporated in the mix. RESULTS: The statistical analysis of antimicrobial efficacy of alginate was performed with Mann-Whitney U-test, which revealed very high significant difference when comparing among groups (p < 0.000). Student t-test analyzed the compressive strength data which revealed nonsignificant difference between groups (p > 0.05). CONCLUSION: The incorporation of disinfecting agents into impression materials could serve an important role in dental laboratory infection control and it had no adverse effect on compressive strength of the hydrocolloid alginate. CLINICAL SIGNIFICANCE: The risk of transmitting pathogenic microorganisms to dental laboratories via impression has been considered a topic of importance for a number of years.

Do dental impression materials play a role in cross contamination?

OBJECTIVE: Dentists are required to institute infectious control procedures. Dental impression materials possessing antimicrobial properties may aid in reducing the risk of cross contamination since impression materials might play a role as carriers. The purpose of this study was to evaluate the antimicrobial properties of four impression materials. METHOD AND MATERIALS: Four impression materials--Orthoprint, Impregum Penta, Aquasil Ultra Monophase, and Permlastic--were evaluated by the direct contact test. The materials were tested in contact with Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. The materials were mixed; allowed to set; and examined immediately and after aging for 24, 48, and 72 hours and 1 week. Two-way ANOVA, one-way ANOVA, and Tukey multiple comparison procedures were applied to the results. RESULTS: Impregum Penta presented the broadest antibacterial spectrum of all the materials tested. There was a complete growth inhibition of S aureus and S epidermidis, and it sustained this ability for at least 7 days. It also showed an antifungal effect by partially inhibiting the growth of C albicans, a quality that was seen only immediately after setting. Aquasil Ultra showed an antifungal effect only immediately after setting. Permlastic showed a complete growth inhibition when in contact with C albicans and sustained this ability for at least 7 days. No significant antimicrobial properties were recorded for Orthoprint. When in contact with E faecalis, no significant antibacterial properties were recorded for any of the materials. CONCLUSION: None of the tested materials exhibited a long-lasting or complete antibacterial and antifungal property. Therefore, disinfection of impressions is essential.

Flexibility of Bayesian generalized linear mixed models for oral health research.

Many outcome variables in oral research are characterized by positive values and heavy skewness in the right tail. Examples are provided by many distributions of dental variables such as DMF (decayed, missing, filled teeth) scores, oral health impact profile score, gingival index scores, and microbiologic counts. Moreover, heterogeneity in data arises when more than one tooth is studied for each patient, due to the clusterization.Over the past decade, linear mixed models (LMEs) have become a common statistical tool to account for within-subject correlation in data with repeated measures. When a normal error is reasonably assumed, estimates of LMEs are supported by many statistical packages. Such is not the case for skewed data, where generalized linear mixed models (GLMMs) are required. However, the current software available supports only special cases of GLMMs or relies on crude Laplace-type approximation of integrals. In this study, a Bayesian approach is taken to estimate GLMMs for clustered skewed dental data. A Gamma GLMM and a log-normal model are employed to allow for heterogeneity across clusters, deriving from the patient-operator-tooth susceptibility typical of this clinical context. A comparison to the frequentist framework is also provided. In our case, Gamma GLMM fits data better than the log-normal distribution, while providing more precise estimates compared with the likelihood approach. A key advantage of the Bayesian framework is its ability to readily provide a flexible approach for implementation while simultaneously providing a formal procedure for solving inference problems.

In vitro antimicrobial activity of irreversible hydrocolloid impressions against 12 oral microorganisms.

This study evaluated in vitro the antimicrobial activity of irreversible hydrocolloids (one containing an antimicrobial agent) prepared with water or with a 0.2% chlorhexidine digluconate solution against 12 strains of the oral microbiota. Twenty specimens (0.5x1.0 cm) for each group (1. Jeltrate mixed with water; 2. Jeltrate mixed with 0.2% chlorhexidine digluconate solution; 3. Greengel mixed with water; 4. Greengel mixed with 0.2% chlorhexidine digluconate solution) were prepared under sterile conditions and placed in culture media inoculated with the indicator strains. After incubation in aerobiosis or microaerophilia, inhibition of the microbial growth was measured and the results were interpreted. The normal adherence curve revealed a non-normal distribution of the data, so the non-parametric Friedman Test was performed (p<0.05). The antimicrobial activity of the groups was classified in the following order: 1, 3, 4, and 2. The results suggest that the method of preparing irreversible hydrocolloids with a 0.2% digluconate chlorhexidine solution is more effective than the incorporation of an antimicrobial agent in the powder to reduce cross-contamination caused by impressions.

A self-disinfecting irreversible hydrocolloid impression material mixed with chlorhexidine solution.

OBJECTIVE: To examine the antibacterial effect and several physical properties of an irreversible hydrocolloid impression material mixed with chlorhexidine solution. MATERIALS AND METHODS: The experimental irreversible hydrocolloid specimens were prepared and allocated into four groups (Group0.1 g/L, Group0.2 g/L, Group0.5 g/L, Group1.0 g/L) according to the concentrations of chlorhexidine solution used as the mixing liquid. Specimens mixed with distilled water served as a control. The antibacterial effect, three-dimensional accuracy, flowability, and setting time were tested. Statistical analysis was performed using a one-way analysis of variance and a Tukey test, which was used for multiple comparisons (alpha=.05). RESULTS: Zones of growth inhibition were observed around the test specimens, but not around the control specimens, and there were significant intergroup differences in the diameters of the inhibition zones. In the accuracy test, no significant differences (P>.05) were detected among all the measurements for all groups, and the accuracy was clinically acceptable. Also, no significant differences in the flowability (P=.987) and setting time (P=.103) were detected. CONCLUSION: Chlorhexidine self-disinfecting irreversible hydrocolloid impression material can exhibit varying degrees of antibacterial activity without influencing the three-dimensional accuracy, flowability, and setting time.

Antibacterial and antifungal properties of polyether impression materials.

The aim of this study was to evaluate the antibacterial and antifungal properties of polyether impression materials using the agar diffusion test. Three different types of polyether impression materials (P2, Penta Soft and Penta) were tested to determine their ability to inhibit the growth of Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The areas of inhibition zones were measured visually with a 0.1-mm incremental Boley gauge. In all groups, none of the samples of the P2 polyether impression material exhibited antibacterial or antifungal activity against any of the microorganisms. All Penta Soft and Penta samples exhibited antibacterial activity against E. faecalis and S. aureus, and only Penta samples exhibited antifungal effect against C. albicans, which decreased progressively as the setting time of the material increased.

In vitro antimicrobial activity of irreversible hydrocolloid impressions against 12 oral microorganisms

This study evaluated in vitro the antimicrobial activity of irreversible hydrocolloids (one containing an antimicrobial agent) prepared with water or with a 0.2 percent chlorhexidine digluconate solution against 12 strains of the oral microbiota. Twenty specimens (0.5 x 1.0 cm) for each group (1. Jeltrate mixed with water; 2. Jeltrate mixed with 0.2 percent chlorhexidine digluconate solution; 3. Greengel mixed with water; 4. Greengel mixed with 0.2 percent chlorhexidine digluconate solution) were prepared under sterile conditions and placed in culture media inoculated with the indicator strains. After incubation in aerobiosis or microaerophilia, inhibition of the microbial growth was measured and the results were interpreted. The normal adherence curve revealed a non-normal distribution of the data, so the non-parametric Friedman Test was performed (p < 0.05). The antimicrobial activity of the groups was classified in the following order: 1, 3, 4, and 2. The results suggest that the method of preparing irreversible hydrocolloids with a 0.2 percent digluconate chlorhexidine solution is more effective than the incorporation of an antimicrobial agent in the powder to reduce cross-contamination caused by impressions.

Este trabalho avaliou in vitro a atividade antimicrobiana de alginatos (um deles contendo agente antimicrobiano) manipulados com água ou solução de digluconato de clorexidina a 0,2 por cento contra 12 cepas da microbiota oral. Vinte espécimes (0,5 x 1,0 cm) para cada grupo (1. Jeltrate manipulado com água, 2. Jeltrate manipulado com solução de digluconato de clorexidina a 0,2 por cento; 3. Greengel manipulado com água; 4. Greengel manipulado com solução de digluconato de clorexidina a 0,2 por cento) foram confeccionados sob condições estéreis e semeados em meios de cultura inoculados com as cepas indicadoras. Após incubação em aerobiose ou microaerofilia, a inibição do crescimento microbiano foi medida e os resultados foram interpretados. A curva normal de aderência revelou uma distribuição não-normal dos dados, então o teste não paramétrico de Friedman (p < 0,05) foi realizado. A atividade antimicrobiana dos grupos foi classificada na seguinte ordem crescente: 1, 3, 4 e 2. Os resultados sugerem que a manipulação de alginatos com solução de digluconato de clorexidina a 0,2 por cento é um método efetivo para reduzir a contaminação-cruzada causada pelos moldes, mais que a incorporação do agente antimicrobiano no pó.

2000 Judson C. Hickey Scientific Writing Award. Effect of impression materials on hybridized dentin.

STATEMENT OF PROBLEM: Tooth sensitivity after crown preparation is not an uncommon complication. For dentin bonding agents to be effective in preventing postoperative sensitivity, they must remain intact throughout the fixed prosthodontic procedures. PURPOSE: This study evaluated, by analyzing the change in dentin permeability, whether a dentin bonding agent was removed from the surface of prepared teeth in the process of making an impression. MATERIAL AND METHODS: Eighty extracted human molars were cut horizontally apical to the cemento-enamel junction and horizontally through the middle of the clinical crown. The specimens were prepared to measure dentin permeability (fluid flow rate, Lp). The specimens (n = 40) were randomly assigned to either the primer-only group (PO) or the primer + adhesive group (PA). Five different impression materials were tested: vinyl polysiloxane, polyether, polysulfide, irreversible hydrocolloid, and reversible hydrocolloid. Dentinal permeability was measured after smear layer removal (control, etched Lp = ELp), after coating the dentin with either PO or PA (coated Lp = CLp), and again after making an impression (impression Lp = ILp). A 1-way ANOVA of differences, followed by a Student-Newman-Keuls test (alpha=.05), was performed to compare the ELp, CLp, and ILp values. RESULTS: A statistically significant difference was found between the CLp and ELp for all 5 impression materials in both groups (PO and PA). No difference was found between the CLp and ILp values for any of the impression materials. No significant differences were found between any of the 5 impression materials or either of the dentin surface treatments (PO or PA) when measuring the CLp and ILp. CONCLUSION: The dentin bonding agent had a significant effect in decreasing the Lp of the treated specimens. None of the impression materials significantly affected the measured CLp. There was no significant difference between the PO or PA (CLp) values.

Antimicrobial activities of dental impression materials.

OBJECTIVE: The aim of this study was to measure the in vitro killing effects five commercial alginate impression materials had on five test microorganisms. METHODS: Two alginates with no added disinfectant, one supplemented with chlorhexidine and two others containing quaternary ammonium compounds were tested. Challenge microbes included two gram-positive cocci, two gram-negative bacilli and a yeast. Saline solutions containing standardized concentrations of test microbes were used to mix the alginates. Some set specimens were immediately homogenized and the resulting fluids diluted and spread plated. Other specimens were processed 30 or 60 min after setting. After culturing, the numbers of colonies were counted and the levels of microbial reductions determined. RESULTS: Unsupplemented alginates had no antimicrobial effects. The quaternary-ammonium-containing alginates were completely effective against all five test microorganisms. The alginate with chlorhexidine killed all the gram-negative bacilli and the majority (95-99%) of the gram-positive cocci and yeast. SIGNIFICANCE: Results indicated that disinfectant-containing alginate impression materials could reduce the number of soiling microorganisms present on and within test specimens.

TOMA DE IMPRESION, UTILIZANDO TIRAS MYLAR PARA SEPARAR LOS MUÑONES Y LA ELABORACION DE CARILLAS EN BIOLON

Constituye un tratamiento en el cual se conserva la estructura dentaria casi en su totalidad, por lo tanto disminuye el riesgo de fractura y es menos drástica la preparación del diente. Un porcentaje elevado de las piezas dentales en las cuales se confeccionaron las carillas del presente trabajo. Se debieron a decoraciones post- endodóncicas. La carilla es un tratamiento que no interfiere con la salud gingival por su buena adaptación a los márgenes de la encía y por que solo se circunscribe la mayor parte de esta cara vestibular. E las restauraciones metaloplásticas no es necesario remover la parte metálica del diente. Disminuye los costos de tratamiento

Impression materials and virus.

Results of this study indicate that impression materials vary in their ability to absorb and retain virus. Disinfection procedures specific for each material or groups of materials should be developed.

[Dimensional stability of impression materials studied with Talysurf 10]. / Studio sulla stabilità dimensionale di alcuni materiali da impronta con il Talysurf 10.

The dimensional stability of certain modeling elastomers was investigated. In order to obtain a complete picture, 2 samples of each elastomer class on the market (polysulphuric, polyether, silicone additives, condensation silicone), a total of 8 products, were tested according to the criteria outlined in ADA 19. In contrast with ADA 19 recommendations, measurements were taken using a Talysurf 10, a roughness meter that can also check for straightness, which was chosen as being equally efficient as other methods while offering highly reliable objectively verifiable data.

[The antimicrobial effect of an alginate with an antiseptic admixture]. / Untersuchungen zur antimikrobiellen Wirkung eines Alginates mit antiseptischem Zusatz.

Attempts to simplify impression disinfection lead to the production of an aseptic alginate impression material (Blueprint asept, De Trey/Dentsply, Konstanz, Germany). This study describes the aseptic properties of this new type of impression material. The in-vitro part of the experiments showed a reduction of Staphylococcus aureus by 6 and of Pseudomonas aeruginosa by 4 log steps after 60 min, and of Candida albicans by at least 3 log steps after 15 min of exposure. Under in-vivo conditions oral bacteria residing on the impression surfaces were reduced by nearly 4 log steps. Although the aseptic properties of the material were demonstrated, the biological acceptance, dimensional stability and compatibility with gypsum have to be tested in further studies.

[Profilometric research on silicone impression materials]. / Profilometricheskie issledovaniia silikonovykh slepochnykh materialov.

The data suggest that none of the materials produced in the USSR or imported, did fully reproduce the microrelief of the surface of metal standard. This is accounted for by the processes taking shape on the surfaces of elastomeric compositions upon their vulcanization.