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Article
The Effect of Different Curing Techniques on the Degree of Bond Conversion for Different Types of Acrylic Resin Materials

Authors: Ahmed A Al–Ali --- Omar A Sheet --- Amer A Taqa
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2013 Volume: 13 Issue: 2 Pages: 351-357
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: To evaluate the effect of different types of curing techniques on the degree of bond conversion of methyl methycrylate to poly methyl methacrylate for different types of acrylic resin materials. Materials and methods: Three different types of acrylic resin materials are used; heat, cold and light cured resin, with four different curing techniques (auto, heat, microwave and light curing).The degree of bond conversion of these materials(taking the mean of three samples) were determined by fourier transform infrared device (FTIR). Independent t-test and ANOVA followed by Duncan Multiple Range Test were used to determine the significant difference at p<0.05 level. Results: There was a significant difference (p<0.0001) in the degree of bond conversion yielded from the three tested materials. Degree of bond conversion higher in light and heat cure acrylic than that of cold cure acrylic resin. Conclusions: Degree of bond conversion increased when curing done under high temperature as in microwave or heat curing method. However, light cure resin showed the highest degree of bond conversion.


Article
Effect of Storage Time on the Degree of Conversion of Light Cured Dental Materials

Authors: Sabah A Ismail --- Shaymaa SH Hassan --- Nayif A Jado
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2012 Volume: 12 Issue: 2 Pages: 281-288
Publisher: Mosul University جامعة الموصل

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Abstract

The aim of this study was to investigate the effect of storage time (immediately after polymerization and after one month of artificial saliva storage) on the degree of conversion (DC) of restorative type of light cured dental materials. Materials and Methods: Sixty samples of polyethylene molds were prepared. The samples were divided into three groups each of 20. The first group was filled with Composite resin, second group was filled with Compomer and the third group was filled with Resin modified glass ionomer cement (RMGIC). Each group was subdivided into two subgroups; each of ten according to storage time: The DC was tested for the first subgroup immediately after polymerization, while the DC of the second subgroup was tested after one month of storage in artificial saliva. The DC was investigated by Fourier-transform infrared spectroscopy (FTIR). Results: ANOVA test was used for statistical analysis. The results showed that there was a significant difference (p<0.05) in DC between the subgroups tested immediately after polymerization and the subgroups tested after one month of artificial saliva storage for Composite resin and Compomer. While RMGIC showed no significant difference (p>0.05) in DC between the subgroup tested immediately after polymerization and the subgroups tested after one month of artificial saliva storage. Conclusions: One month storage time has an effect on the DC of Composite and Compomer, but it has no effect on the DC of RMGIC.


Article
The effect of various pre-cured temperature of different resin materials on the degree of conversion and microhardness of cured composite resin

Author: Manal A. Sultan
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2014 Volume: 14 Issue: 2 Pages: 279-287
Publisher: Mosul University جامعة الموصل

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Abstract

Aims: The aims of this in vitro study were to evaluate the effect of different temperatures of the pre- cured composite resin materials on the degree of conversion and knoop microhardness of cured composite resin. Materials and Methods : A forty five disc-shaped specimens were prepared from ( Ceram X, shade D2, Dentsply/ Caulk, USA) after stored for 24h in different temperatures ( 5,25,and 37°C) were light cured for 40s. The FTIR test was used to measure the degree of conversion for each specimen. The knoop microhardness was measured by the use of (WOLPERT-WERKE-GMBH Baujahr Testor, GERMANY) (Vickers hardness test) for each specimen. Data obtained was analyzed using one-way analysis of variance (ANOVA) and Duncan's test at a 0.05 significance level.Results : The statistical analysis of the results (ANOVA) showed that there was statistically significant difference in the degree of conversion and in the microhardness of the prepared samples at the different temperature. As the temperature of the composite resin increase, there was an increase in the degree of conversion and increase in the micro hardness of the samples.Conclusions : The use of pre-warmed composite resin may help to improve the degree of conversion and the micro hardness of composite resin especially at the deeper areas of a restoration which could result in an increase in the expected life of a composite restoration.


Article
Evaluationof Curing Depth of Bulk-Fill Resin Composite (A comparative study)

Authors: Salam A. Al-Araji --- Mohammed A. Ibrahim --- Hala A. Ragab
Journal: Medical Journal of Babylon مجلة بابل الطبية ISSN: 1812156X 23126760 Year: 2015 Volume: 12 Issue: 1 Pages: 310-316
Publisher: Babylon University جامعة بابل

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Abstract

This study evaluated the depth of cure (DOC) of recently introduced resin composites for posterior use, bulk filled flowable composite (SureFil® SDR® flow DENTSPLY Caulk) at different depth. 30 specimens were prepared and divided into two Groups,Group 1: specimens with 2 mm depth, Group 2: specimens with 4mm depth. The composite specimens were prepared by using molds of different depth, one of them with was a hole of 4 mm depth and 4 mm internal diameter and the other was with a depth of 2 mm at the same diameter. The hole was bulk filled with SDR flowable composite resin and light cured for 20 seconds with a modern high-intensity LED curing unit (Elipar™ S10, 3M.US.), followed by 24 hours storage in complete darkness incubator at 37 C◦. The degree of conversion was measured on the top and the bottom for both depths using Fourier transform infrared (FTIR) spectroscopy. A bulk filled flowable (SDR)revealed a significant difference in degree of conversion (DOC) when the bottom surface of the specimen witha 2mm depth (DOC=76.27112163) wascompared with the bottom surface of the 4mm depth specimen (DOC=73.92160935). The 2mm depth wasshown statistically significantly higher mean values degree of conversion than 4 mm depth (P-value = 0.032). There was no statistically significant difference in the degree of conversion mean values between the top and the bottom surfaces of the specimen of the same group (P >0.05).Upon the result of thisin vitro study, it was found that the degree of conversion of the SDR bulk-fill flowable resin compositewasaffected by depths. As the depth of the resin compositewas increased the degree of conversion was decreased.

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