Current Overview for Chemical Disinfection of Dental Impressions and Models based on its Criteria of Usage: A Microbiological Study

Objectives: The aims of this study were to compare the efficacy of two proven chemical disinfectants, glutaraldehyde and povidone iodine on dental impression and models by determining the reduction in the microbial load, and to compare changes in the physical properties of the models after adding the disinfectants. Materials and Methods: Irreversible hydrocolloid upper impressions of 90 patients were made and divided into 3 groups of 30 samples each; Group A––Control group; Impressions were run under clean tap water before pouring the model. Group B––2% Glutaraldehyde sprayed on the impression and left in situ for 10 min before pouring the model. Group C –10 ml of (5%) povidone iodine incorporated into the gypsum before pouring the model. Models from all three groups were subjected to microbiological assessment at three different time intervals, T0––24 h, T1––1 month and T2––3 months of storage by comparing the colony forming units (CFUs) of bacteria and fungi. The compressive strength of 5 models from each group was also analyzed in Newton’s/mm2. Results: 2% Glutaraldehyde proved more effective than povidone iodine after 24 h of storage (T1), however at the end of 1 month (T1) and 3 months (T2) the Povidone group showed the maximum disinfection. Both the disinfectants caused a reduction in the compressive strength of the model with the povidone iodine group showing the maximum reduction. Conclusion: Although povidone iodine was the most effective disinfectant after 3 months, it showed a significant reduction in the compressive strength and caused discoloration of the model. 2% Glutaraldehyde proved to be the choice of disinfectant with minimal adverse effects

The effect of sterilization and disinfection on the physical-mechanical properties of preformed crowns

Introduction: Different sizes of crowns may be tried on children since there is no universal crown size because of distinctions in tooth morphology from one child to other. During the process of trial and error, the crown gets contaminated which needs to be sterilized for reuse of crown. This study was carried out to evaluate the physical–mechanical outcome after the sterilization and disinfection of pediatric preformed crowns. Materials and Methods: In total, sixty crowns consisted of 20 each, stainless steel crowns (SSCs) (3M ESPE), preveneered stainless steel (Kinder Krowns), and Zirconia crowns (Kinder Krowns) which were divided into four groups. G1 in which crowns did not undergo any sterilization, G2 consisted of fast sterilization, similarly G3 was slow sterilization, and G4 underwent chemical disinfection using Korsolex Plus for 15 min. Following sterilization, all the crown samples were observed under a stereomicroscope at ×200 magnification and assessed for color change, crazing, dimensional stability, and fracturing. Post hoc Tukey test and two-way ANOVA were performed for comparison between types of crowns and sterilization methods, with a significance level was set at P < 0.05. Results: There was no color change or fracturing following sterilization among crowns in any of the groups. Highest crazing was noted in stainless steel and the least in Zirconia crowns. Preveneered stainless steel was the most dimensionally stable and SSCs was the least. Conclusion: No color changes and fracture were noted in any type of crowns. Preveneered stainless steel was most dimensionally stable followed by Zirconia and SSCs. Maximum crazing was seen in SSCs and nil in Zirconia.

Comparative Study on Color Stability of Denture Reline Polymers when Using Microwave and Chemical Disinfection

This study investigated the color stability of reline resin after two methods of disinfection i.e microwave disinfection and chemical disinfection. A stainless steel moldwith a breakaway compartment (10 mm in diameter by 0.7 mm thickness) was made to fabricate specimens of various resins. Each material was mixed according to manufacturer’s instructions and applied into the mold. Prior to color stability testing, specimenswere cleaned in distilled water for 20 minutes to kill any microorganisms that may had contaminated the discs during fabrication. And then specimens were immersed in Sodium Perborate Monohydrate 200 ml of solution for 15 days and microwaved for 15 days sothat it is comparable to chemical disinfection soaking. The color stability of each specimen was measured again using spectrophotometer and values were obtained. The data of ∆E, ∆L, ∆b, ∆a were analysed by 2 way repeated measures ANOVAs test. Significant statistic changes in color parameters ∆L, ∆a, ∆b of the reline resin DPI, Ufi Gel Hard And Kooliner were observed when dentures were disinfected by Sodium Perborate Monohydrate 2% solutions. The color stability of the reline resin was influenced by time, regardless of disinfection or non disinfection. This can be attributed to bleaching (whitening) effect of reline material. Discoloration Original Research Article of resin based materials may be caused by intrinsic or extrinsic factors. Intrinsic factors are related to internal alterations in material resulting from physicochemical reactions or residual monomer oxidation with time. Thus the initiator, quantity and type of monomer and the polymerisation efficiency can affect the color stability of resin based materials. The color stability deviation value ∆E significantly increased to maximum for chemical disinfectant, least for Control group and intermediate for microwaved group. Ufi Gel showed the highest deviation ∆E and Control Group showed the lowest deviation according to results

Effect of chemical disinfectants and accelerated aging on maxillofacial silicone elastomers: An In vitro Study

Maxillofacial prostheses need frequent refabrication due to degradation of color and deterioration of physical properties of the elastomer. Aims: This study attempted to evaluate the change in color stability, Shore A hardness, and surface roughness of two maxillofacial silicones, A-2186 and Cosmesil M511, when submitted to chemical disinfection and accelerated aging. Settings and Design: This was a comparative in vitro study. Subjects and Methods: The materials included two silicone elastomers – A-2186 and Cosmesil M511 (Factor II Incorporated) – functional intrinsic red pigment and three disinfectants – Fittydent tablet, chlorhexidine gluconate 4%, and neutral soap. The specimens in each group of elastomer were evaluated initially for color, hardness, and surface roughness, which were further divided into subgroups and subjected to disinfection and accelerated aging. The evaluation of color was performed with the help of an ultraviolet reflectance spectrophotometer. Shore A hardness was evaluated using a durometer and surface roughness, with a digital roughness tester followed by scanning electron microscopy analysis. Statistical Analysis Used: Analysis of variance and Tukey's multiple comparison test were used for statistical analysis. Results: Accelerated aging caused a significant decrease in color, increase in Shore A hardness, and variation in surface roughness in both silicone elastomer groups. Chemical disinfection presented significant changes in color and surface roughness whereas no significant effect on Shore hardness, irrespective of the disinfectant used. Conclusions: The maxillofacial silicone elastomers presented deterioration in color, hardening, and significant variations in surface roughness when subjected to chemical disinfection and accelerated aging, which provides a valid baseline for future research.

Control de calidad de drogas vegetales: lavado y desinfección de Artemisia annua L y Tagetes lucida Cav / Quality control of vegetable drugs: washing and disinfection of Artemisia annua L and Tagetes lucida Cav

Introducción: utilizar el lavado y desinfección química como método que permita disminuir la contaminación microbiana en el material vegetal cosechado de Artemisia annua L y Tagetes lucida Cav. Objetivos: garantizar la calidad microbiológica de las drogas vegetales obtenidas de estas 2 especies medicinales. Métodos: se utilizó material vegetal procedente de las parcelas establecidas en la Estación Experimental de Plantas Medicinales Dr Juan Tomás Roig, en suelo ferralítico rojo hidratado (ferralsols). Se emplearon 2 testigos, uno sin tratar y otro tratado con agua potable; para las pruebas a nivel de laboratorio las muestras de 300 g en A. annua y de 250 g de T lucida fueron lavadas con agua potable y después sometidas a un proceso de desinfección en una solución de hipoclorito de sodio 0,5 por ciento y 1,0 por ciento, sumergidas durante 5 y 10 min en ambos casos; para las pruebas de escalado se seleccionó el tratamiento químico que a nivel de laboratorio resultó más efectivo, se emplearon 3 réplicas de la droga cruda de 10 kg en el caso de A annua y de 6 kg en T lucida, con posterioridad las muestras se escurren sobre bastidores y después pasan a un proceso de secado en estufa de 35 a 40 ºC durante 2 d Luego de secadas se realizan los correspondientes análisis microbiológico y físico-químico. En el primer caso se determinó el conteo total de bacterias, conteo total de hongos y otras enterobacterias, además de microorganismos aislados. En el control físico- químico, los porcentajes de materia orgánica extraña; materia inorgánica extraña y hojas ennegrecidas; los índices numéricos como humedad, cenizas totales, sustancias solubles en agua, sustancias solubles en etanol 30 por ciento, sustancias solubles en etanol 70 por ciento, así como mediante tamizaje fitoquímico, la presencia de metabolitos secundarios...

Introduction: the use of washing and chemical disinfection as a method allows reducing microbial pollution in the harvested vegetal material of Artemisia annua L. and Tagetes lucida Cav Objectives: to assure the microbiological quality of vegetal drugs from these two medicinal species. Methods: there was used some vegetal material from lots on red hydrated ferralitic soils (ferrasols) located in Dr Juan Tomás Roig Experimental Center of Medicinal Plants. Two controls, one treated with drinking water and the other untreated, were used. For lab tests, the 300g A. annua and 250g T lucida samples were washed with drinking water and then were subjected to disinfection process using 0,5 and 1,0 percent sodium hypochloride in which both samples were submerged for 5 and 10 minutes. The most effective chemical treatment at lab was selected for the scaling test of three replicas of the crude drug from 10 kg of A annua and from 6 kg T lucida respectively. The samples were placed upon frames to be dried later at 35 to 40 ºC for 2 hours. After drying, the corresponding microbiological and physical-chemical analyses were performed. The microbiological analysis determined the total count of bacteria, of fungi and other enterobacteria in addition to isolated microorganisms. The physical and chemical analysis estimated the percentages of foreign organic matter, foreign inorganic matter and blackened leaves; and the indexes of humidity, total ashes, soluble substances in water, soluble substances in 30 percent etanol and soluble substances in 70 percent etanol...

Evaluación de la dureza shore a en dos técnicas de impresión con siliconas por condensación bajo la influencia del uso de desinfección química por impresión con solución de clorhexidina al 2 por ciento / Evaluation of hardness in two impression techniques with condensation silicones under influence chemical disinfection with clorhexidine 2 percent

Las siliconas de polimerización por condensación, actualmente, son muy utilizadas en el mercado odontológico. Debido a este hecho, nuestro objetivo fue estudiar la dureza Shore A de dos siliconas de condensación (Zetaplus - Zhermark y Clonage - DFL), simulando dos técnicas de impresión (densa y densa + fluida) bajo la influencia de desinfección química con solución a base de clorhexidina al 2 por ciento (aspersión por 5 minutos). Fueron confeccionados 56 muestras, a partir de matrices metálicas, divididos en 4 grupos para cada técnica de impresión, siendo la mitad de las muestras de cada técnica sometidas a desinfección química. El Test de dureza fue realizada por medio de un durómetro (modelo GSD 709) de acuerdo con las especificaciones D-2240 de la Sociedad Americana para Prueba y Materiales (ASTM), los resultados obtenidos, fueron analizados por medio del Test de análisis de varianza y al Test de Tukey (p<0,05). Se concluyó, que para cualquier condición experimental estudiada se encontró diferencia estadísticamente significativa cuando se analizaron los valores medios de desinfección química, tipo de material y técnica utilizada

Elastomerics materials currently represent a major choice in the dental market as an impression material. The aim of this study was to asses Shore A hardness of two condensation silicones (Zetaplus - Zhermack and Clonage - DFL) using two impression techniques (putty and putty/wash) under influence of chemical disinfection with clorhexidine spray to 2 percent (for five minutes). Fifty-six specimens were made in metallic matrices, subdivided in 4 groups for each impression technique; half of each technique was submitted to chemical disinfection. Hardness test was performed with a durometer (GSD 709) according ASTM specifications (D-2240), the results were submitted to analyses of variance (ANOVA) and Tukey’s test (p<0.05). It was concluded that for all experimental condition, difference statistically significant was found

Contamination of Acanthamoeba in Contact Lens Care System

Recently, the number of reports of Acanthamoeba keratitis has been increased apparently as a consequence of association with use of contact lenses, contaminated contact lens care system and high concern of ophthalmologist to Acanthamoeba keratitis. But, there were few epidemiologic studies of contamination of contact lens care system by Acanthamoeba and there was no report in Korea. We carried out a survey to demonstrate the contamination of contact lens care system by Acanthamoeba and bacteria and analysed the results according to the types of contact lenses and methods of disinfection. We examined the contact lens care system of 185 asymptomatic contact lens wearer for the contamination of Acanthamoeba and bacteria. The result showed a significant contamination of Acanthamoeba and bacteria. Twenty eight(15%) were contaminated with Acanthamoeba, eighteen(10%) were mixed with bacterial contamination and seventy four(40%) were contaminated with bacteria. There was no significant difference with sex and the result showed a lot of cocontamination with bacteria and amoeba and chemical disinfection showed a high Acanthamoeba contamination rate. Based on data from this and previous studies, the most of contact lens care system of contact lens wearer was contaminated with bacteria, amoeba and other microorganism. So, ophthalmologists should be concerned about Acanthamoeba contamination of contact lens care system.